Refactor CompiledTemplate to handle include/render internally

- render() now accepts Liquid::Context or Hash
- include/render handled internally using file_system from registers
- Only yields to block for truly external tags/filters
- Cleaner separation of concerns

.github/probots.yml

@@ -1,2 +0,0 @@
-enabled:
-  - cla

.github/workflows/cla.yml

@@ -0,0 +1,22 @@
+name: Contributor License Agreement (CLA)
+
+on:
+  pull_request_target:
+    types: [opened, synchronize]
+  issue_comment:
+    types: [created]
+
+jobs:
+  cla:
+    runs-on: ubuntu-latest
+    if: |
+      (github.event.issue.pull_request 
+        && !github.event.issue.pull_request.merged_at
+        && contains(github.event.comment.body, 'signed')
+      ) 
+      || (github.event.pull_request && !github.event.pull_request.merged)
+    steps:
+      - uses: Shopify/shopify-cla-action@v1
+        with:
+          github-token: ${{ secrets.GITHUB_TOKEN }}
+          cla-token: ${{ secrets.CLA_TOKEN }}

.github/workflows/liquid.yml

@@ -1,39 +1,52 @@
 name: Liquid
 on: [push, pull_request]
+
+env:
+  BUNDLE_JOBS: 4
+  BUNDLE_RETRY: 3
+
 jobs:
   test:
     runs-on: ubuntu-latest
     strategy:
       matrix:
         entry:
-          - { ruby: 2.5, allowed-failure: false } # minimum supported
-          - { ruby: 3.0, allowed-failure: false } # latest
-          - { ruby: ruby-head, allowed-failure: true }
-    name: test (${{ matrix.entry.ruby }})
+          - { ruby: 3.0, allowed-failure: false } # minimum supported
+          - { ruby: 3.2, allowed-failure: false }
+          - { ruby: 3.3, allowed-failure: false }
+          - { ruby: 3.3, allowed-failure: false }
+          - { ruby: 3.4, allowed-failure: false } # latest
+          - {
+              ruby: 3.4,
+              allowed-failure: false,
+              rubyopt: "--enable-frozen-string-literal",
+            }
+          - { ruby: 3.4, allowed-failure: false, rubyopt: "--yjit" }
+          - { ruby: ruby-head, allowed-failure: false }
+          - {
+              ruby: ruby-head,
+              allowed-failure: false,
+              rubyopt: "--enable-frozen-string-literal",
+            }
+          - { ruby: ruby-head, allowed-failure: false, rubyopt: "--yjit" }
+    name: Test Ruby ${{ matrix.entry.ruby }}
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - uses: ruby/setup-ruby@v1
         with:
           ruby-version: ${{ matrix.entry.ruby }}
-      - uses: actions/cache@v1
-        with:
-          path: vendor/bundle
-          key: ${{ runner.os }}-gems-${{ hashFiles('Gemfile') }}
-          restore-keys: ${{ runner.os }}-gems-
-      - run: bundle install --jobs=3 --retry=3 --path=vendor/bundle
+          bundler-cache: true
+          bundler: latest
       - run: bundle exec rake
         continue-on-error: ${{ matrix.entry.allowed-failure }}
+        env:
+          RUBYOPT: ${{ matrix.entry.rubyopt }}
+
   memory_profile:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - uses: ruby/setup-ruby@v1
         with:
-          ruby-version: 2.7
-      - uses: actions/cache@v1
-        with:
-          path: vendor/bundle
-          key: ${{ runner.os }}-gems-${{ hashFiles('Gemfile') }}
-          restore-keys: ${{ runner.os }}-gems-
-      - run: bundle install --jobs=3 --retry=3 --path=vendor/bundle
+          bundler-cache: true
       - run: bundle exec rake memory_profile:run

.gitignore

@@ -4,7 +4,6 @@
 pkg
 *.rbc
 .rvmrc
-.ruby-version
-Gemfile.lock
 .bundle
 .byebug_history
+Gemfile.lock

.rubocop.yml

@@ -10,8 +10,8 @@ Performance:
   Enabled: true
 
 AllCops:
-  TargetRubyVersion: 2.5
   NewCops: disable
+  SuggestExtensions: false
   Exclude:
     - 'vendor/bundle/**/*'
 
@@ -19,6 +19,10 @@ Naming/MethodName:
   Exclude:
     - 'example/server/liquid_servlet.rb'
 
-# Backport https://github.com/Shopify/ruby-style-guide/pull/258
-Layout/BeginEndAlignment:
-  Enabled: true
+Style/ClassMethodsDefinitions:
+  Enabled: false
+
+# liquid filter calls were being mistaken to be calls on arrays
+Style/ConcatArrayLiterals:
+  Exclude:
+    - 'test/integration/standard_filter_test.rb'

.rubocop_todo.yml

@@ -1,27 +1,74 @@
 # This configuration was generated by
 # `rubocop --auto-gen-config`
-# on 2020-12-11 18:53:41 UTC using RuboCop version 1.6.1.
+# on 2022-05-18 19:25:47 UTC using RuboCop version 1.29.1.
 # The point is for the user to remove these configuration records
 # one by one as the offenses are removed from the code base.
 # Note that changes in the inspected code, or installation of new
 # versions of RuboCop, may require this file to be generated again.
 
-# Offense count: 2
-# Cop supports --auto-correct.
-# Configuration parameters: EnforcedStyle.
-# SupportedStyles: runtime_error, standard_error
-Lint/InheritException:
+# Offense count: 1
+# This cop supports safe auto-correction (--auto-correct).
+# Configuration parameters: TreatCommentsAsGroupSeparators, ConsiderPunctuation, Include.
+# Include: **/*.gemspec
+Gemspec/OrderedDependencies:
   Exclude:
-    - 'lib/liquid/interrupts.rb'
+    - 'liquid.gemspec'
 
-# Offense count: 113
-# Cop supports --auto-correct.
-# Configuration parameters: AutoCorrect, AllowHeredoc, AllowURI, URISchemes, IgnoreCopDirectives, IgnoredPatterns.
-# URISchemes: http, https
-Layout/LineLength:
-  Max: 260
+# Offense count: 6
+# This cop supports safe auto-correction (--auto-correct).
+Layout/ClosingHeredocIndentation:
+  Exclude:
+    - 'test/integration/tags/for_tag_test.rb'
+
+# Offense count: 34
+# This cop supports safe auto-correction (--auto-correct).
+Layout/EmptyLineAfterGuardClause:
+  Exclude:
+    - 'lib/liquid/block.rb'
+    - 'lib/liquid/block_body.rb'
+    - 'lib/liquid/context.rb'
+    - 'lib/liquid/drop.rb'
+    - 'lib/liquid/lexer.rb'
+    - 'lib/liquid/parser.rb'
+    - 'lib/liquid/profiler/hooks.rb'
+    - 'lib/liquid/standardfilters.rb'
+    - 'lib/liquid/tags/for.rb'
+    - 'lib/liquid/tags/if.rb'
+    - 'lib/liquid/utils.rb'
+    - 'lib/liquid/variable.rb'
+    - 'lib/liquid/variable_lookup.rb'
+    - 'performance/shopify/money_filter.rb'
+    - 'performance/shopify/paginate.rb'
 
 # Offense count: 8
+# This cop supports safe auto-correction (--auto-correct).
+# Configuration parameters: AllowAliasSyntax, AllowedMethods.
+# AllowedMethods: alias_method, public, protected, private
+Layout/EmptyLinesAroundAttributeAccessor:
+  Exclude:
+    - 'lib/liquid/template.rb'
+    - 'test/integration/filter_test.rb'
+    - 'test/integration/tags/include_tag_test.rb'
+    - 'test/unit/strainer_template_unit_test.rb'
+
+# Offense count: 17
+# This cop supports safe auto-correction (--auto-correct).
+# Configuration parameters: EnforcedStyle, IndentationWidth.
+# SupportedStyles: aligned, indented
+Layout/LineEndStringConcatenationIndentation:
+  Exclude:
+    - 'test/integration/tags/for_tag_test.rb'
+    - 'test/integration/tags/increment_tag_test.rb'
+
+# Offense count: 1
+# This cop supports safe auto-correction (--auto-correct).
+# Configuration parameters: EnforcedStyle, IndentationWidth.
+# SupportedStyles: aligned, indented
+Layout/MultilineOperationIndentation:
+  Exclude:
+    - 'lib/liquid/expression.rb'
+
+# Offense count: 9
 Lint/MissingSuper:
   Exclude:
     - 'lib/liquid/forloop_drop.rb'
@@ -33,7 +80,7 @@ Lint/MissingSuper:
     - 'test/integration/tags/for_tag_test.rb'
     - 'test/integration/tags/table_row_test.rb'
 
-# Offense count: 43
+# Offense count: 44
 Naming/ConstantName:
   Exclude:
     - 'lib/liquid.rb'
@@ -51,7 +98,83 @@ Naming/ConstantName:
     - 'performance/shopify/paginate.rb'
     - 'test/integration/tags/include_tag_test.rb'
 
+# Offense count: 9
+# Configuration parameters: CheckIdentifiers, CheckConstants, CheckVariables, CheckStrings, CheckSymbols, CheckComments, CheckFilepaths, FlaggedTerms.
+Naming/InclusiveLanguage:
+  Exclude:
+    - 'lib/liquid/drop.rb'
+    - 'lib/liquid/parse_context.rb'
+    - 'test/integration/drop_test.rb'
+    - 'test/integration/tags/if_else_tag_test.rb'
+
 # Offense count: 2
 Style/ClassVars:
   Exclude:
     - 'lib/liquid/condition.rb'
+
+# Offense count: 3
+# This cop supports safe auto-correction (--auto-correct).
+Style/ExplicitBlockArgument:
+  Exclude:
+    - 'test/integration/context_test.rb'
+    - 'test/integration/tag/disableable_test.rb'
+    - 'test/integration/tags/for_tag_test.rb'
+
+# Offense count: 2982
+# This cop supports safe auto-correction (--auto-correct).
+# Configuration parameters: EnforcedStyle, ConsistentQuotesInMultiline.
+# SupportedStyles: single_quotes, double_quotes
+Style/StringLiterals:
+  Enabled: false
+
+# Offense count: 20
+# This cop supports safe auto-correction (--auto-correct).
+# Configuration parameters: EnforcedStyle.
+# SupportedStyles: single_quotes, double_quotes
+Style/StringLiteralsInInterpolation:
+  Exclude:
+    - 'lib/liquid/condition.rb'
+    - 'lib/liquid/strainer_template.rb'
+    - 'lib/liquid/tag/disableable.rb'
+    - 'performance/shopify/shop_filter.rb'
+    - 'performance/shopify/tag_filter.rb'
+
+# Offense count: 6
+# This cop supports safe auto-correction (--auto-correct).
+# Configuration parameters: EnforcedStyleForMultiline.
+# SupportedStylesForMultiline: comma, consistent_comma, no_comma
+Style/TrailingCommaInArrayLiteral:
+  Exclude:
+    - 'example/server/example_servlet.rb'
+    - 'lib/liquid/condition.rb'
+    - 'test/integration/context_test.rb'
+    - 'test/integration/standard_filter_test.rb'
+    - 'test/unit/parse_tree_visitor_test.rb'
+
+# Offense count: 1
+# This cop supports safe auto-correction (--auto-correct).
+# Configuration parameters: EnforcedStyleForMultiline.
+# SupportedStylesForMultiline: comma, consistent_comma, no_comma
+Style/TrailingCommaInHashLiteral:
+  Exclude:
+    - 'lib/liquid/expression.rb'
+
+# Offense count: 19
+# This cop supports safe auto-correction (--auto-correct).
+# Configuration parameters: EnforcedStyle, MinSize, WordRegex.
+# SupportedStyles: percent, brackets
+Style/WordArray:
+  Exclude:
+    - 'lib/liquid/tags/if.rb'
+    - 'liquid.gemspec'
+    - 'test/integration/assign_test.rb'
+    - 'test/integration/context_test.rb'
+    - 'test/integration/drop_test.rb'
+    - 'test/integration/standard_filter_test.rb'
+
+# Offense count: 117
+# This cop supports safe auto-correction (--auto-correct).
+# Configuration parameters: AllowHeredoc, AllowURI, URISchemes, IgnoreCopDirectives, AllowedPatterns, IgnoredPatterns.
+# URISchemes: http, https
+Layout/LineLength:
+  Max: 260

.ruby-version

@@ -0,0 +1 @@
+3.4.1

CONTRIBUTING.md

@@ -26,3 +26,11 @@
 * If it makes sense, add tests for your code and/or run a performance benchmark
 * Make sure all tests pass (`bundle exec rake`)
 * Create a pull request
+
+## Releasing
+
+* Bump the version in `lib/liquid/version.rb`
+* Update the `History.md` file
+* Open a PR like [this one](https://github.com/Shopify/liquid/pull/1894) and merge it to `main`
+* Create a new release using the [GitHub UI](https://github.com/Shopify/liquid/releases/new)
+

Gemfile

@@ -7,22 +7,25 @@ end
 
 gemspec
 
+gem "base64"
+
 group :benchmark, :test do
   gem 'benchmark-ips'
   gem 'memory_profiler'
   gem 'terminal-table'
+  gem "lru_redux"
 
   install_if -> { RUBY_PLATFORM !~ /mingw|mswin|java/ && RUBY_ENGINE != 'truffleruby' } do
     gem 'stackprof'
   end
 end
 
-group :test do
-  gem 'rubocop', '~> 1.4', require: false
-  gem 'rubocop-shopify', '~> 1.0.7', require: false
-  gem 'rubocop-performance', require: false
-
-  platform :mri, :truffleruby do
-    gem 'liquid-c', github: 'Shopify/liquid-c', ref: 'master'
-  end
+group :development do
+  gem "webrick"
+end
+
+group :test do
+  gem 'rubocop', '~> 1.61.0'
+  gem 'rubocop-shopify', '~> 2.12.0', require: false
+  gem 'rubocop-performance', require: false
 end

History.md

@@ -1,5 +1,115 @@
 # Liquid Change Log
 
+## 5.8.1 (unreleased)
+
+## 5.8.1
+
+* Fix `{% doc %}` tag to be visitable [Guilherme Carreiro]
+
+## 5.8.0
+
+* Introduce the new `{% doc %}` tag [Guilherme Carreiro]
+
+## 5.7.3
+
+* Raise Liquid::SyntaxError when parsing invalidly encoded strings [Chris AtLee]
+
+## 5.7.2 2025-01-31
+
+* Fix array filters to not support nested properties [Guilherme Carreiro]
+
+## 5.7.1 2025-01-24
+
+* Fix the `find` and `find_index`filters to return `nil` when filtering empty arrays [Guilherme Carreiro]
+* Fix the `has` filter to return `false` when filtering empty arrays [Guilherme Carreiro]
+
+## 5.7.0 2025-01-16
+
+### Features
+
+* Add `find`, `find_index`, `has`, and `reject` filters to arrays [Guilherme Carreiro]
+* Compatibility with Ruby 3.4 [Ian Ker-Seymer]
+
+## 5.6.4 2025-01-14
+
+### Fixes
+* Add a default `string_scanner` to avoid errors with `Liquid::VariableLookup.parse("foo.bar")` [Ian Ker-Seymer]
+
+## 5.6.3 2025-01-13
+* Remove `lru_redux` dependency [Michael Go]
+
+## 5.6.2 2025-01-13
+
+### Fixes
+* Preserve the old behavior of requiring floats to start with a digit [Michael Go]
+
+## 5.6.1 2025-01-13
+
+### Performance improvements
+* Faster Expression parser / Tokenizer with StringScanner [Michael Go]
+
+## 5.6.0 2024-12-19
+
+### Architectural changes
+* Added new `Environment` class to manage configuration and state that was previously stored in `Template` [Ian Ker-Seymer]
+* Moved tag registration from `Template` to `Environment` [Ian Ker-Seymer]
+* Removed `StrainerFactory` in favor of `Environment`-based strainer creation [Ian Ker-Seymer]
+* Consolidated standard tags into a new `Tags` module with `STANDARD_TAGS` constant [Ian Ker-Seymer]
+
+### Performance improvements
+* Optimized `Lexer` with a new `Lexer2` implementation using jump tables for faster tokenization, requires Ruby 3.4 [Ian Ker-Seymer]
+* Improved variable rendering with specialized handling for different types [Michael Go]
+* Reduced array allocations by using frozen empty constants [Michael Go]
+
+### API changes
+* Deprecated several `Template` class methods in favor of `Environment` methods [Ian Ker-Seymer]
+* Added deprecation warnings system [Ian Ker-Seymer]
+* Changed how filters and tags are registered to use Environment [Ian Ker-Seymer]
+
+### Fixes
+* Fixed table row handling of break interrupts [Alex Coco]
+* Improved variable output handling for arrays [Ian Ker-Seymer]
+* Fix Tokenizer to handle null source value (#1873) [Bahar Pourazar]
+
+## 5.5.0 2024-03-21
+
+Please reference the GitHub release for more information.
+
+## 5.4.0 2022-07-29
+
+### Breaking Changes
+* Drop support for end-of-life Ruby versions (2.5 and 2.6) (#1578) [Andy Waite]
+
+### Features
+* Allow `#` to be used as an inline comment tag (#1498) [CP Clermont]
+
+### Fixes
+* `PartialCache` now shares snippet cache with subcontexts by default (#1553) [Chris AtLee]
+* Hash registers no longer leak into subcontexts as static registers (#1564) [Chris AtLee]
+* Fix `ParseTreeVisitor` for `with` variable expressions in `Render` tag (#1596) [CP Clermont]
+
+### Changed
+* Liquid::Context#registers now always returns a Liquid::Registers object, though supports the most used Hash functions for compatibility (#1553)
+
+## 5.3.0 2022-03-22
+
+### Fixes
+* StandardFilter: Fix missing @context on iterations (#1525) [Thierry Joyal]
+* Fix warning about block and default value in `static_registers.rb` (#1531) [Peter Zhu]
+
+### Deprecation
+* Condition#evaluate to require mandatory context argument in Liquid 6.0.0 (#1527) [Thierry Joyal]
+
+## 5.2.0 2022-03-01
+
+### Features
+* Add `remove_last`, and `replace_last` filters (#1422) [Anders Hagbard]
+* Eagerly cache global filters (#1524) [Jean Boussier]
+
+### Fixes
+* Fix some internal errors in filters from invalid input (#1476) [Dylan Thacker-Smith]
+* Allow dash in filter kwarg name for consistency with Liquid::C (#1518) [CP Clermont]
+
 ## 5.1.0 / 2021-09-09
 
 ### Features

OPTIMIZATION.md

@@ -0,0 +1,70 @@
+# Liquid Compiled Template Optimization Log
+
+This document tracks optimizations made to the compiled Liquid template engine.
+Each entry shows before/after code and measured impact.
+
+---
+
+## Baseline Measurement
+
+**Date:** 2024-12-31
+**Commit:** (pending profiler implementation)
+
+### Current State
+
+The compiled template engine generates Ruby code from Liquid templates.
+Before optimizations, here's a sample of generated code for a simple loop:
+
+```ruby
+# Template: {% for product in products %}{{ forloop.index }}: {{ product.name }}{% endfor %}
+
+->(assigns, __context__, __external__) do
+  __output__ = +""
+  
+  __coll1__ = assigns["products"]
+  __coll1__ = __coll1__.to_a if __coll1__.is_a?(Range)
+  __len3__ = __coll1__.respond_to?(:length) ? __coll1__.length : 0
+  __idx2__ = 0
+  catch(:__loop__break__) do
+    (__coll1__.respond_to?(:each) ? __coll1__ : []).each do |__item__|
+      catch(:__loop__continue__) do
+        assigns["product"] = __item__
+        assigns['forloop'] = {
+          'name' => "product-products",
+          'length' => __len3__,
+          'index' => __idx2__ + 1,
+          'index0' => __idx2__,
+          'rindex' => __len3__ - __idx2__,
+          'rindex0' => __len3__ - __idx2__ - 1,
+          'first' => __idx2__ == 0,
+          'last' => __idx2__ == __len3__ - 1,
+        }
+        __output__ << LR.output(LR.lookup(assigns["forloop"], "index", __context__))
+        __output__ << ": "
+        __output__ << LR.output(LR.lookup(assigns["product"], "name", __context__))
+      end
+      __idx2__ += 1
+    end
+  end
+  assigns.delete("product")
+  assigns.delete('forloop')
+  
+  __output__
+end
+```
+
+### Issues Identified
+
+1. **catch/throw overhead** - Used even when no break/continue in loop
+2. **Hash allocation per iteration** - 8 key/value pairs computed every time
+3. **respond_to? checks** - Redundant after type is known
+4. **LR.lookup for forloop** - Unnecessary indirection for known hash
+5. **String literals not frozen** - Allocates on each render
+6. **Output buffer grows dynamically** - No pre-allocation
+
+---
+
+## Optimization Log
+
+<!-- Entries will be added here as optimizations are implemented -->
+

README.md

@@ -1,11 +1,11 @@
-[![Build Status](https://api.travis-ci.org/Shopify/liquid.svg?branch=master)](http://travis-ci.org/Shopify/liquid)
+[![Build status](https://github.com/Shopify/liquid/actions/workflows/liquid.yml/badge.svg)](https://github.com/Shopify/liquid/actions/workflows/liquid.yml)
 [![Inline docs](http://inch-ci.org/github/Shopify/liquid.svg?branch=master)](http://inch-ci.org/github/Shopify/liquid)
 
 # Liquid template engine
 
 * [Contributing guidelines](CONTRIBUTING.md)
 * [Version history](History.md)
-* [Liquid documentation from Shopify](http://docs.shopify.com/themes/liquid-basics)
+* [Liquid documentation from Shopify](https://shopify.dev/docs/api/liquid)
 * [Liquid Wiki at GitHub](https://github.com/Shopify/liquid/wiki)
 * [Website](http://liquidmarkup.org/)
 
@@ -52,24 +52,66 @@ For standard use you can just pass it the content of a file and call render with
 @template.render('name' => 'tobi')                # => "hi tobi"
 ```
 
+### Concept of Environments
+
+In Liquid, a "Environment" is a scoped environment that encapsulates custom tags, filters, and other configurations. This allows you to define and isolate different sets of functionality for different contexts, avoiding global overrides that can lead to conflicts and unexpected behavior.
+
+By using environments, you can:
+
+1. **Encapsulate Logic**: Keep the logic for different parts of your application separate.
+2. **Avoid Conflicts**: Prevent custom tags and filters from clashing with each other.
+3. **Improve Maintainability**: Make it easier to manage and understand the scope of customizations.
+4. **Enhance Security**: Limit the availability of certain tags and filters to specific contexts.
+
+We encourage the use of Environments over globally overriding things because it promotes better software design principles such as modularity, encapsulation, and separation of concerns.
+
+Here's an example of how you can define and use Environments in Liquid:
+
+```ruby
+user_environment = Liquid::Environment.build do |environment|
+  environment.register_tag("renderobj", RenderObjTag)
+end
+
+Liquid::Template.parse(<<~LIQUID, environment: user_environment)
+  {% renderobj src: "path/to/model.obj" %}
+LIQUID
+```
+
+In this example, `RenderObjTag` is a custom tag that is only available within the `user_environment`.
+
+Similarly, you can define another environment for a different context, such as email templates:
+
+```ruby
+email_environment = Liquid::Environment.build do |environment|
+  environment.register_tag("unsubscribe_footer", UnsubscribeFooter)
+end
+
+Liquid::Template.parse(<<~LIQUID, environment: email_environment)
+  {% unsubscribe_footer %}
+LIQUID
+```
+
+By using Environments, you ensure that custom tags and filters are only available in the contexts where they are needed, making your Liquid templates more robust and easier to manage. For smaller projects, a global environment is available via `Liquid::Environment.default`.
+
 ### Error Modes
 
 Setting the error mode of Liquid lets you specify how strictly you want your templates to be interpreted.
 Normally the parser is very lax and will accept almost anything without error. Unfortunately this can make
-it very hard to debug and can lead to unexpected behaviour. 
+it very hard to debug and can lead to unexpected behaviour.
 
 Liquid also comes with a stricter parser that can be used when editing templates to give better error messages
 when templates are invalid. You can enable this new parser like this:
 
 ```ruby
-Liquid::Template.error_mode = :strict # Raises a SyntaxError when invalid syntax is used
-Liquid::Template.error_mode = :warn # Adds errors to template.errors but continues as normal
-Liquid::Template.error_mode = :lax # The default mode, accepts almost anything.
+Liquid::Environment.default.error_mode = :strict
+Liquid::Environment.default.error_mode = :strict # Raises a SyntaxError when invalid syntax is used
+Liquid::Environment.default.error_mode = :warn # Adds strict errors to template.errors but continues as normal
+Liquid::Environment.default.error_mode = :lax # The default mode, accepts almost anything.
 ```
 
 If you want to set the error mode only on specific templates you can pass `:error_mode` as an option to `parse`:
 ```ruby
-Liquid::Template.parse(source, :error_mode => :strict)
+Liquid::Template.parse(source, error_mode: :strict)
 ```
 This is useful for doing things like enabling strict mode only in the theme editor.
 
@@ -111,4 +153,4 @@ template.render!({ 'x' => 1}, { strict_variables: true })
 
 To help track usages of a feature or code path in production, we have released opt-in usage tracking. To enable this, we provide an empty `Liquid:: Usage.increment` method which you can customize to your needs. The feature is well suited to https://github.com/Shopify/statsd-instrument. However, the choice of implementation is up to you.
 
-Once you have enabled usage tracking, we recommend reporting any events through Github Issues that your system may be logging. It is highly likely this event has been added to consider deprecating or improving code specific to this event, so please raise any concerns.
+Once you have enabled usage tracking, we recommend reporting any events through Github Issues that your system may be logging. It is highly likely this event has been added to consider deprecating or improving code specific to this event, so please raise any concerns.

Rakefile

@@ -43,8 +43,6 @@ task :test do
   Rake::Task['base_test'].invoke
 
   if RUBY_ENGINE == 'ruby' || RUBY_ENGINE == 'truffleruby'
-    ENV['LIQUID_C'] = '1'
-
     ENV['LIQUID_PARSER_MODE'] = 'lax'
     Rake::Task['integration_test'].reenable
     Rake::Task['integration_test'].invoke
@@ -73,7 +71,7 @@ end
 
 namespace :benchmark do
   desc "Run the liquid benchmark with lax parsing"
-  task :run do
+  task :lax do
     ruby "./performance/benchmark.rb lax"
   end
 
@@ -81,6 +79,33 @@ namespace :benchmark do
   task :strict do
     ruby "./performance/benchmark.rb strict"
   end
+
+  desc "Run the liquid benchmark with both lax and strict parsing"
+  task run: [:lax, :strict]
+
+  desc "Run unit benchmarks"
+  namespace :unit do
+    task :all do
+      Dir["./performance/unit/*_benchmark.rb"].each do |file|
+        puts "🧪 Running #{file}"
+        ruby file
+      end
+    end
+
+    task :lexer do
+      Dir["./performance/unit/lexer_benchmark.rb"].each do |file|
+        puts "🧪 Running #{file}"
+        ruby file
+      end
+    end
+
+    task :expression do
+      Dir["./performance/unit/expression_benchmark.rb"].each do |file|
+        puts "🧪 Running #{file}"
+        ruby file
+      end
+    end
+  end
 end
 
 namespace :profile do

example/server/example_servlet.rb

@@ -30,14 +30,18 @@ class Servlet < LiquidServlet
   private
 
   def products_list
-    [{ 'name' => 'Arbor Draft', 'price' => 39900, 'description' => 'the *arbor draft* is a excellent product' },
-     { 'name' => 'Arbor Element', 'price' => 40000, 'description' => 'the *arbor element* rocks for freestyling' },
-     { 'name' => 'Arbor Diamond', 'price' => 59900, 'description' => 'the *arbor diamond* is a made up product because im obsessed with arbor and have no creativity' }]
+    [
+      { 'name' => 'Arbor Draft', 'price' => 39900, 'description' => 'the *arbor draft* is a excellent product' },
+      { 'name' => 'Arbor Element', 'price' => 40000, 'description' => 'the *arbor element* rocks for freestyling' },
+      { 'name' => 'Arbor Diamond', 'price' => 59900, 'description' => 'the *arbor diamond* is a made up product because im obsessed with arbor and have no creativity' }
+    ]
   end
 
   def more_products_list
-    [{ 'name' => 'Arbor Catalyst', 'price' => 39900, 'description' => 'the *arbor catalyst* is an advanced drop-through for freestyle and flatground performance and versatility' },
-     { 'name' => 'Arbor Fish', 'price' => 40000, 'description' => 'the *arbor fish* is a compact pin that features an extended wheelbase and time-honored teardrop shape' }]
+    [
+      { 'name' => 'Arbor Catalyst', 'price' => 39900, 'description' => 'the *arbor catalyst* is an advanced drop-through for freestyle and flatground performance and versatility' },
+      { 'name' => 'Arbor Fish', 'price' => 40000, 'description' => 'the *arbor fish* is a compact pin that features an extended wheelbase and time-honored teardrop shape' }
+    ]
   end
 
   def description

lib/liquid.rb

@@ -21,6 +21,8 @@
 # OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
 # WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 
+require "strscan"
+
 module Liquid
   FilterSeparator             = /\|/
   ArgumentSeparator           = ','
@@ -29,6 +31,7 @@ module Liquid
   WhitespaceControl           = '-'
   TagStart                    = /\{\%/
   TagEnd                      = /\%\}/
+  TagName                     = /#|\w+/
   VariableSignature           = /\(?[\w\-\.\[\]]\)?/
   VariableSegment             = /[\w\-]/
   VariableStart               = /\{\{/
@@ -36,20 +39,28 @@ module Liquid
   VariableIncompleteEnd       = /\}\}?/
   QuotedString                = /"[^"]*"|'[^']*'/
   QuotedFragment              = /#{QuotedString}|(?:[^\s,\|'"]|#{QuotedString})+/o
-  TagAttributes               = /(\w+)\s*\:\s*(#{QuotedFragment})/o
+  TagAttributes               = /(\w[\w-]*)\s*\:\s*(#{QuotedFragment})/o
   AnyStartingTag              = /#{TagStart}|#{VariableStart}/o
   PartialTemplateParser       = /#{TagStart}.*?#{TagEnd}|#{VariableStart}.*?#{VariableIncompleteEnd}/om
   TemplateParser              = /(#{PartialTemplateParser}|#{AnyStartingTag})/om
-  VariableParser              = /\[[^\]]+\]|#{VariableSegment}+\??/o
+  VariableParser              = /\[(?>[^\[\]]+|\g<0>)*\]|#{VariableSegment}+\??/o
 
   RAISE_EXCEPTION_LAMBDA = ->(_e) { raise }
-
-  singleton_class.send(:attr_accessor, :cache_classes)
-  self.cache_classes = true
+  HAS_STRING_SCANNER_SCAN_BYTE = StringScanner.instance_methods.include?(:scan_byte)
 end
 
 require "liquid/version"
+require "liquid/deprecations"
+require "liquid/const"
+require 'liquid/standardfilters'
+require 'liquid/file_system'
+require 'liquid/parser_switching'
+require 'liquid/tag'
+require 'liquid/block'
 require 'liquid/parse_tree_visitor'
+require 'liquid/interrupts'
+require 'liquid/tags'
+require "liquid/environment"
 require 'liquid/lexer'
 require 'liquid/parser'
 require 'liquid/i18n'
@@ -59,34 +70,23 @@ require 'liquid/forloop_drop'
 require 'liquid/extensions'
 require 'liquid/errors'
 require 'liquid/interrupts'
-require 'liquid/strainer_factory'
 require 'liquid/strainer_template'
-require 'liquid/expression'
 require 'liquid/context'
-require 'liquid/parser_switching'
 require 'liquid/tag'
-require 'liquid/tag/disabler'
-require 'liquid/tag/disableable'
-require 'liquid/block'
 require 'liquid/block_body'
 require 'liquid/document'
 require 'liquid/variable'
 require 'liquid/variable_lookup'
 require 'liquid/range_lookup'
-require 'liquid/file_system'
 require 'liquid/resource_limits'
+require 'liquid/expression'
 require 'liquid/template'
-require 'liquid/standardfilters'
 require 'liquid/condition'
 require 'liquid/utils'
 require 'liquid/tokenizer'
 require 'liquid/parse_context'
 require 'liquid/partial_cache'
 require 'liquid/usage'
-require 'liquid/register'
-require 'liquid/static_registers'
+require 'liquid/registers'
 require 'liquid/template_factory'
-
-# Load all the tags of the standard library
-#
-Dir["#{__dir__}/liquid/tags/*.rb"].each { |f| require f }
+require 'liquid/box'

lib/liquid/block.rb

@@ -36,13 +36,17 @@ module Liquid
     # @api private
     def self.raise_unknown_tag(tag, block_name, block_delimiter, parse_context)
       if tag == 'else'
-        raise SyntaxError, parse_context.locale.t("errors.syntax.unexpected_else",
-          block_name: block_name)
+        raise SyntaxError, parse_context.locale.t(
+          "errors.syntax.unexpected_else",
+          block_name: block_name,
+        )
       elsif tag.start_with?('end')
-        raise SyntaxError, parse_context.locale.t("errors.syntax.invalid_delimiter",
+        raise SyntaxError, parse_context.locale.t(
+          "errors.syntax.invalid_delimiter",
           tag: tag,
           block_name: block_name,
-          block_delimiter: block_delimiter)
+          block_delimiter: block_delimiter,
+        )
       else
         raise SyntaxError, parse_context.locale.t("errors.syntax.unknown_tag", tag: tag)
       end

lib/liquid/block_body.rb

@@ -4,8 +4,9 @@ require 'English'
 
 module Liquid
   class BlockBody
-    LiquidTagToken      = /\A\s*(\w+)\s*(.*?)\z/o
-    FullToken           = /\A#{TagStart}#{WhitespaceControl}?(\s*)(\w+)(\s*)(.*?)#{WhitespaceControl}?#{TagEnd}\z/om
+    LiquidTagToken      = /\A\s*(#{TagName})\s*(.*?)\z/o
+    FullToken           = /\A#{TagStart}#{WhitespaceControl}?(\s*)(#{TagName})(\s*)(.*?)#{WhitespaceControl}?#{TagEnd}\z/om
+    FullTokenPossiblyInvalid = /\A(.*)#{TagStart}#{WhitespaceControl}?\s*(\w+)\s*(.*)?#{WhitespaceControl}?#{TagEnd}\z/om
     ContentOfVariable   = /\A#{VariableStart}#{WhitespaceControl}?(.*?)#{WhitespaceControl}?#{VariableEnd}\z/om
     WhitespaceOrNothing = /\A\s*\z/
     TAGSTART            = "{%"
@@ -37,7 +38,7 @@ module Liquid
 
     private def parse_for_liquid_tag(tokenizer, parse_context)
       while (token = tokenizer.shift)
-        unless token.empty? || token =~ WhitespaceOrNothing
+        unless token.empty? || token.match?(WhitespaceOrNothing)
           unless token =~ LiquidTagToken
             # line isn't empty but didn't match tag syntax, yield and let the
             # caller raise a syntax error
@@ -45,7 +46,13 @@ module Liquid
           end
           tag_name = Regexp.last_match(1)
           markup   = Regexp.last_match(2)
-          unless (tag = registered_tags[tag_name])
+
+          if tag_name == 'liquid'
+            parse_context.line_number -= 1
+            next parse_liquid_tag(markup, parse_context)
+          end
+
+          unless (tag = parse_context.environment.tag_for_name(tag_name))
             # end parsing if we reach an unknown tag and let the caller decide
             # determine how to proceed
             return yield tag_name, markup
@@ -109,14 +116,22 @@ module Liquid
       end
     end
 
-    private def parse_for_document(tokenizer, parse_context)
+    private def handle_invalid_tag_token(token, parse_context)
+      if token.end_with?('%}')
+        yield token, token
+      else
+        BlockBody.raise_missing_tag_terminator(token, parse_context)
+      end
+    end
+
+    private def parse_for_document(tokenizer, parse_context, &block)
       while (token = tokenizer.shift)
         next if token.empty?
         case
         when token.start_with?(TAGSTART)
           whitespace_handler(token, parse_context)
           unless token =~ FullToken
-            BlockBody.raise_missing_tag_terminator(token, parse_context)
+            return handle_invalid_tag_token(token, parse_context, &block)
           end
           tag_name = Regexp.last_match(2)
           markup   = Regexp.last_match(4)
@@ -132,7 +147,7 @@ module Liquid
             next
           end
 
-          unless (tag = registered_tags[tag_name])
+          unless (tag = parse_context.environment.tag_for_name(tag_name))
             # end parsing if we reach an unknown tag and let the caller decide
             # determine how to proceed
             return yield tag_name, markup
@@ -150,7 +165,7 @@ module Liquid
           end
           parse_context.trim_whitespace = false
           @nodelist << token
-          @blank &&= !!(token =~ WhitespaceOrNothing)
+          @blank &&= token.match?(WhitespaceOrNothing)
         end
         parse_context.line_number = tokenizer.line_number
       end
@@ -231,10 +246,17 @@ module Liquid
     end
 
     def create_variable(token, parse_context)
-      token.scan(ContentOfVariable) do |content|
-        markup = content.first
+      if token.end_with?("}}")
+        i = 2
+        i = 3 if token[i] == "-"
+        parse_end = token.length - 3
+        parse_end -= 1 if token[parse_end] == "-"
+        markup_end = parse_end - i + 1
+        markup = markup_end <= 0 ? "" : token.slice(i, markup_end)
+
         return Variable.new(markup, parse_context)
       end
+
       BlockBody.raise_missing_variable_terminator(token, parse_context)
     end
 
@@ -247,9 +269,5 @@ module Liquid
     def raise_missing_variable_terminator(token, parse_context)
       BlockBody.raise_missing_variable_terminator(token, parse_context)
     end
-
-    def registered_tags
-      Template.tags
-    end
   end
 end

lib/liquid/box.rb

@@ -0,0 +1,507 @@
+# frozen_string_literal: true
+
+# Liquid::Box - Secure sandboxed execution environment for compiled Liquid templates
+#
+# On Ruby 4.0+, this uses the native Ruby::Box for true isolation.
+# On earlier Ruby versions, this provides a polyfill that WARNS about insecurity.
+#
+# == SECURITY WARNING
+#
+# The polyfill on Ruby < 4.0 provides NO REAL SECURITY. It's a compatibility shim
+# that allows code to run, but malicious templates could potentially escape.
+# Use Ruby 4.0+ in production for actual sandboxing.
+#
+# == Usage
+#
+#   template = Liquid::Template.parse("Hello {{ name }}!")
+#   compiled = template.compile_to_ruby
+#
+#   # compiled is a Liquid::CompiledTemplate which wraps a Box
+#   result = compiled.render({ "name" => "World" })
+#   # => "Hello World!"
+#
+#   # Access the generated Ruby code:
+#   puts compiled.source
+#
+
+module Liquid
+  # Check if we have Ruby 4.0's native Box AND it's enabled
+  # Ruby::Box may be defined but disabled (requires RUBY_BOX=1 env var before Ruby starts)
+  RUBY_BOX_AVAILABLE = begin
+    if defined?(Ruby::Box)
+      # Try to create a box to see if it's actually enabled
+      test_box = Ruby::Box.new
+      true
+    else
+      false
+    end
+  rescue RuntimeError => e
+    # Ruby::Box exists but is disabled
+    false
+  end
+
+  unless RUBY_BOX_AVAILABLE
+    # Warn once on load that we're using the insecure polyfill
+    warn "[Liquid::Box] WARNING: Ruby::Box not available or disabled. " \
+         "Using INSECURE polyfill. Compiled templates are NOT sandboxed! " \
+         "(Ruby 4.0+ with RUBY_BOX=1 required for secure execution)" if $VERBOSE
+  end
+
+  # Polyfill for Ruby::Box when not available (Ruby < 4.0)
+  # This provides the same API but NO SECURITY - it just evals code in the main environment.
+  module BoxPolyfill
+    class Box
+      def initialize
+        @constants = {}
+        @binding = TOPLEVEL_BINDING.dup
+      end
+
+      def eval(code)
+        ::Kernel.eval(code, @binding)
+      end
+
+      def const_get(name)
+        ::Object.const_get(name)
+      end
+    end
+  end
+
+  # Liquid::Box wraps either Ruby::Box (secure) or BoxPolyfill::Box (insecure)
+  #
+  # This provides a secure sandboxed environment for executing compiled Liquid templates.
+  # On Ruby 4.0+, templates run in true isolation with dangerous methods removed.
+  # On Ruby < 4.0, templates run without sandboxing (development/testing only).
+  #
+  class Box
+    attr_reader :box
+
+    class << self
+      # Returns true if we have real sandboxing (Ruby 4.0+)
+      def secure?
+        RUBY_BOX_AVAILABLE
+      end
+
+      # Create a pre-configured box for Liquid template execution.
+      # This is the recommended way to get a Box instance.
+      def create_for_liquid
+        box = new
+        box.load_liquid_runtime!
+        box.lock!
+        box
+      end
+    end
+
+    def initialize
+      @box = RUBY_BOX_AVAILABLE ? Ruby::Box.new : BoxPolyfill::Box.new
+      @locked = false
+      @user_constants = []
+      @warned_insecure = false
+    end
+
+    # Load code into the sandbox before locking.
+    # Use this to define filters, helpers, and the Liquid runtime.
+    def load_runtime(code)
+      raise "Cannot load runtime after lock!" if @locked
+      before = @box.eval("Object.constants")
+      @box.eval(code)
+      after = @box.eval("Object.constants")
+      @user_constants += (after - before).map(&:to_s)
+    end
+
+    # Load the standard Liquid runtime helpers (LR module).
+    # Call this before lock! to set up the execution environment.
+    # The runtime provides all helper methods that compiled templates use.
+    def load_liquid_runtime!
+      raise "Cannot load runtime after lock!" if @locked
+
+      if RUBY_BOX_AVAILABLE
+        # Add gem paths to box's load_path so it can find base64, bigdecimal, etc.
+        # These are safe, side-effect-free libs that only provide pure functions
+        setup_gem_load_paths!
+
+        # Load dependencies INTO the box - we need the actual libraries,
+        # not reimplementations, to handle all edge cases correctly
+        @box.require('cgi')
+        @box.require('base64')
+        @box.require('bigdecimal')
+        @box.require('bigdecimal/util')  # For String#to_d etc.
+        @box.require('date')  # For date filter
+        @box.require('time')  # For Time.parse
+
+        # Now load the runtime which captures method references from these
+        @box.require(RUNTIME_PATH)
+      else
+        # Polyfill: just require it normally
+        require 'cgi'
+        require 'base64'
+        require 'bigdecimal'
+        require 'bigdecimal/util'
+        require 'date'
+        require 'time'
+        require RUNTIME_PATH
+      end
+
+      # Track constants to preserve after lock
+      @user_constants << "LR"
+      @user_constants << "LiquidRuntime"
+      @user_constants << "CGI"
+      @user_constants << "Base64"
+      @user_constants << "BigDecimal"
+      @user_constants << "Date"
+      @user_constants << "DateTime"
+      @user_constants << "Time"
+      @user_constants << "Liquid"  # For Liquid::Compile::CompiledContext
+    end
+
+    # Add gem paths to the box's load_path so require works for gems
+    def setup_gem_load_paths!
+      return unless RUBY_BOX_AVAILABLE
+
+      # Find gem paths from the main environment's $LOAD_PATH
+      # and from Gem.path if available
+      gem_lib_paths = []
+
+      # Method 1: Find from $LOAD_PATH entries containing "gems"
+      $LOAD_PATH.each do |path|
+        gem_lib_paths << path if path.include?('/gems/')
+      end
+
+      # Method 2: Use Gem.path if available
+      if defined?(Gem) && Gem.respond_to?(:path)
+        Gem.path.each do |gem_path|
+          Dir.glob("#{gem_path}/gems/*/lib").each do |lib_path|
+            gem_lib_paths << lib_path
+          end
+        end
+      end
+
+      # Add unique paths to box's load_path
+      gem_lib_paths.uniq.each do |path|
+        @box.load_path << path unless @box.load_path.include?(path)
+      end
+    end
+
+    # Lock the sandbox. After this:
+    # - No more runtime can be loaded
+    # - Dangerous methods are removed (on Ruby 4.0+)
+    # - Templates can be compiled and executed
+    def lock!
+      return if @locked
+
+      if RUBY_BOX_AVAILABLE
+        apply_sandbox!
+      else
+        warn_insecure!
+      end
+
+      @locked = true
+    end
+
+    def locked?
+      @locked
+    end
+
+    # Returns true if this box provides real security (Ruby 4.0+)
+    def secure?
+      RUBY_BOX_AVAILABLE
+    end
+
+    # Evaluate code in the sandbox.
+    # Use this to compile templates into the sandbox.
+    def eval(code)
+      raise "Must call lock! before eval" unless @locked
+      warn_insecure! unless RUBY_BOX_AVAILABLE
+      @box.eval(code)
+    end
+
+    # Get a constant from the sandbox by name.
+    def const_get(name)
+      @box.const_get(name)
+    end
+
+    def [](name)
+      const_get(name)
+    end
+
+    private
+
+    def warn_insecure!
+      return if @warned_insecure
+      @warned_insecure = true
+
+      $stderr.puts <<~WARNING
+        ╔══════════════════════════════════════════════════════════════════════════════╗
+        ║ SECURITY WARNING: Liquid::Box running WITHOUT sandboxing                     ║
+        ║                                                                              ║
+        ║ Ruby::Box requires Ruby 4.0+. On earlier versions, compiled Liquid templates ║
+        ║ execute with FULL Ruby capabilities. This is NOT SECURE for untrusted input. ║
+        ║                                                                              ║
+        ║ For production use with untrusted templates, upgrade to Ruby 4.0+.           ║
+        ╚══════════════════════════════════════════════════════════════════════════════╝
+      WARNING
+    end
+
+    # Apply sandbox restrictions (Ruby 4.0+ only)
+    def apply_sandbox!
+      neuter_file_system!
+      neuter_process_control!
+      neuter_concurrency!
+      neuter_introspection!
+      neuter_serialization!
+      neuter_time!
+      neuter_environment!
+      neuter_kernel!
+      neuter_basic_object!
+      neuter_object!
+      neuter_main_singleton!
+      neuter_module!
+      cleanup_globals!
+      remove_dangerous_constants!
+    end
+
+    def neuter_file_system!
+      @box.eval(<<~'RUBY')
+        class << File
+          instance_methods(false).each { |m| undef_method(m) rescue nil }
+        end
+        class << IO
+          instance_methods(false).each { |m| undef_method(m) rescue nil }
+        end
+        class << Dir
+          instance_methods(false).each { |m| undef_method(m) rescue nil }
+        end
+        class IO
+          [:read, :write, :gets, :puts, :print, :readline, :readlines, :getc, :getbyte,
+           :sysread, :syswrite, :close, :eof, :eof?, :rewind, :seek].each do |m|
+            undef_method(m) rescue nil
+          end
+        end
+      RUBY
+    end
+
+    def neuter_process_control!
+      @box.eval(<<~'RUBY')
+        class << Process
+          instance_methods(false).each { |m| undef_method(m) rescue nil }
+        end
+        class << Signal
+          instance_methods(false).each { |m| undef_method(m) rescue nil }
+        end
+      RUBY
+    end
+
+    def neuter_concurrency!
+      @box.eval(<<~'RUBY')
+        class << Thread
+          [:new, :start, :fork, :kill, :exit, :pass, :stop, :main, :current, :list,
+           :abort_on_exception, :abort_on_exception=].each { |m| undef_method(m) rescue nil }
+        end
+        class << Fiber
+          [:new, :yield, :current].each { |m| undef_method(m) rescue nil }
+        end
+        if defined?(Ractor)
+          class << Ractor
+            instance_methods(false).each { |m| undef_method(m) rescue nil }
+          end
+        end
+      RUBY
+    end
+
+    def neuter_introspection!
+      @box.eval(<<~'RUBY')
+        class << ObjectSpace
+          instance_methods(false).each { |m| undef_method(m) rescue nil }
+        end
+        class << GC
+          instance_methods(false).each { |m| undef_method(m) rescue nil }
+        end
+        if defined?(RubyVM)
+          class << RubyVM
+            instance_methods(false).each { |m| undef_method(m) rescue nil }
+          end
+          if defined?(RubyVM::InstructionSequence)
+            class << RubyVM::InstructionSequence
+              instance_methods(false).each { |m| undef_method(m) rescue nil }
+            end
+          end
+        end
+        class << TracePoint
+          [:new, :stat, :trace].each { |m| undef_method(m) rescue nil }
+        end
+      RUBY
+    end
+
+    def neuter_serialization!
+      @box.eval(<<~'RUBY')
+        class << Marshal
+          [:dump, :load, :restore].each { |m| undef_method(m) rescue nil }
+        end
+      RUBY
+    end
+
+    def neuter_time!
+      # Time is mostly safe for date filters - only neuter methods that could be used
+      # to manipulate system state or sleep/wait.
+      # Keep: now, at, parse, mktime - needed for date filter
+      # Remove: nothing for now - Time is pure computation
+      #
+      # Note: If you want stricter isolation, templates should receive "now" via assigns
+      # @box.eval(<<~'RUBY')
+      #   class << Time
+      #     [:now, :new, :at, :mktime, :local, :utc, :gm].each { |m| undef_method(m) rescue nil }
+      #   end
+      # RUBY
+    end
+
+    def neuter_environment!
+      @box.eval(<<~'RUBY')
+        ENV.clear rescue nil
+        class << ENV
+          instance_methods(false).each { |m| undef_method(m) rescue nil }
+        end
+      RUBY
+    end
+
+    def neuter_kernel!
+      @box.eval(<<~'RUBY')
+        module Kernel
+          [:eval, :`, :system, :exec, :spawn, :fork, :binding,
+           :open, :require, :require_relative, :load, :autoload, :autoload?,
+           :gets, :readline, :readlines, :select, :test,
+           :trap, :exit, :exit!, :abort, :at_exit, :syscall, :sleep,
+           :puts, :print, :printf, :putc, :p, :pp, :warn,
+           :caller, :caller_locations, :set_trace_func, :trace_var, :untrace_var,
+           :global_variables, :local_variables,
+           :gem, :gem_original_require, :Pathname,
+          ].each { |m| undef_method(m) rescue nil }
+        end
+
+        class << Kernel
+          [:eval, :`, :system, :exec, :spawn, :fork, :binding,
+           :open, :require, :require_relative, :load,
+           :puts, :print, :p, :pp, :warn,
+          ].each { |m| undef_method(m) rescue nil }
+        end
+      RUBY
+    end
+
+    def neuter_basic_object!
+      @box.eval(<<~'RUBY')
+        class BasicObject
+          undef_method(:instance_eval) rescue nil
+          undef_method(:instance_exec) rescue nil
+          # Don't undef __send__ - it causes warnings and is equivalent to send
+          # which we already restrict via public_send
+        end
+      RUBY
+    end
+
+    def neuter_object!
+      @box.eval(<<~'RUBY')
+        class Object
+          # Keep public_send - it's safe (only calls public methods) and useful
+          [:gem, :gem_original_require, :require, :require_relative, :load,
+           :display, :define_singleton_method,
+           :instance_variable_set, :remove_instance_variable,
+           :extend, :send,
+          ].each { |m| undef_method(m) rescue nil }
+        end
+      RUBY
+    end
+
+    def neuter_main_singleton!
+      # 'using' is defined on main's singleton class, must remove before undef_method is gone
+      @box.eval(<<~'RUBY')
+        class << self
+          undef_method(:using) rescue nil
+        end
+      RUBY
+    end
+
+    def neuter_module!
+      @box.eval(<<~'RUBY')
+        class Module
+          undef_method(:refine) rescue nil
+          undef_method(:using) rescue nil
+          undef_method(:const_set) rescue nil
+          undef_method(:remove_const) rescue nil
+          undef_method(:include) rescue nil
+          undef_method(:prepend) rescue nil
+          undef_method(:extend) rescue nil
+          undef_method(:class_eval) rescue nil
+          undef_method(:module_eval) rescue nil
+          undef_method(:class_exec) rescue nil
+          undef_method(:module_exec) rescue nil
+          undef_method(:define_method) rescue nil
+          undef_method(:alias_method) rescue nil
+          undef_method(:module_function) rescue nil
+          undef_method(:prepend_features) rescue nil
+          undef_method(:append_features) rescue nil
+          undef_method(:extend_object) rescue nil
+          undef_method(:public) rescue nil
+          undef_method(:private) rescue nil
+          undef_method(:protected) rescue nil
+          undef_method(:attr) rescue nil
+          undef_method(:attr_reader) rescue nil
+          undef_method(:attr_writer) rescue nil
+          undef_method(:attr_accessor) rescue nil
+          # Remove escape hatches LAST
+          undef_method(:remove_method) rescue nil
+          undef_method(:undef_method) rescue nil
+          undef_method(:send) rescue nil
+          undef_method(:public_send) rescue nil
+        end
+
+        class Class
+          undef_method(:send) rescue nil
+          undef_method(:public_send) rescue nil
+        end
+      RUBY
+    end
+
+    def cleanup_globals!
+      @box.eval(<<~'RUBY')
+        $stdin = nil
+        $stdout = nil
+        $stderr = nil
+        $LOAD_PATH.clear rescue nil
+        $LOAD_PATH.freeze rescue nil
+        $LOADED_FEATURES.clear rescue nil
+        $LOADED_FEATURES.freeze rescue nil
+        ARGV.clear rescue nil
+        ARGV.freeze rescue nil
+      RUBY
+    end
+
+    def remove_dangerous_constants!
+      keep = %w[
+        BasicObject Object Module Class Kernel
+        String Integer Float Numeric Rational Complex
+        Array Hash Range Set
+        Symbol Regexp MatchData
+        TrueClass FalseClass NilClass
+        Proc Method UnboundMethod
+        Struct Data
+        Comparable Enumerable Enumerator
+        StandardError RuntimeError ArgumentError TypeError NameError
+        NoMethodError KeyError IndexError StopIteration FrozenError
+        ZeroDivisionError RangeError FloatDomainError LocalJumpError
+        Math Random
+        Exception SystemStackError
+      ] + @user_constants
+
+      @box.eval(<<~RUBY)
+        _keep = #{keep.inspect}
+        (Object.constants.map(&:to_s) - _keep).each do |c|
+          Object.send(:remove_const, c.to_sym) rescue nil
+        end
+        (Kernel.constants.map(&:to_s) - _keep).each do |c|
+          Kernel.send(:remove_const, c.to_sym) rescue nil
+        end
+      RUBY
+    end
+
+    # Path to the runtime file that gets loaded into the sandbox
+    RUNTIME_PATH = File.expand_path('compile/runtime.rb', __dir__)
+  end
+end

lib/liquid/compile.rb

@@ -0,0 +1,88 @@
+# frozen_string_literal: true
+
+# Liquid Ruby Compiler
+#
+# This module provides the ability to compile Liquid templates to pure Ruby code.
+# Compiled templates execute in a secure sandbox using Liquid::Box (on Ruby 4.0+).
+#
+# ## Usage
+#
+#   template = Liquid::Template.parse("Hello, {{ name }}!")
+#   compiled = template.compile_to_ruby
+#
+#   # Render securely (sandboxed on Ruby 4.0+)
+#   result = compiled.render({ "name" => "World" })
+#   # => "Hello, World!"
+#
+#   # Access the generated Ruby source
+#   puts compiled.source
+#
+#   # Check security status
+#   compiled.secure?  # => true on Ruby 4.0+
+#
+# ## Security
+#
+# On Ruby 4.0+, compiled templates execute in a Ruby::Box sandbox that prevents:
+# - File system access (File, IO, Dir)
+# - Process control (system, exec, spawn, fork)
+# - Network access (Socket, Net::HTTP)
+# - Code loading (require, load, eval)
+# - Dangerous metaprogramming (define_method, const_set, send)
+#
+# On Ruby < 4.0, a polyfill is used that prints a security warning to STDERR.
+# The polyfill provides NO ACTUAL SECURITY - use Ruby 4.0+ in production.
+#
+# ## Performance Benefits
+#
+# Compiled templates are ~1.5x faster than interpreted Liquid because:
+#
+# 1. **No Context Object**: Variables accessed directly from assigns hash
+# 2. **No Filter Dispatch**: Filters compiled to direct Ruby calls
+# 3. **No Resource Limits**: No per-node overhead for limit tracking
+# 4. **Native Scoping**: Ruby's block scoping instead of manual stacks
+# 5. **Direct Concatenation**: Output built with << operations
+# 6. **Native Control Flow**: break/continue use Ruby's throw/catch
+# 7. **No to_liquid Calls**: Values used directly
+# 8. **No Profiling Hooks**: No profiler overhead
+#
+# ## Limitations
+#
+# - {% render %} and {% include %} resolved at compile time when possible
+# - Custom tags need explicit compiler implementations
+# - Custom filters must be available at runtime
+#
+module Liquid
+  module Compile
+    autoload :CompiledTemplate, 'liquid/compile/compiled_template'
+    autoload :CompiledContext, 'liquid/compile/compiled_context'
+    autoload :CodeGenerator, 'liquid/compile/code_generator'
+    autoload :RubyCompiler, 'liquid/compile/ruby_compiler'
+    autoload :ExpressionCompiler, 'liquid/compile/expression_compiler'
+    autoload :FilterCompiler, 'liquid/compile/filter_compiler'
+    autoload :VariableCompiler, 'liquid/compile/variable_compiler'
+    autoload :BlockBodyCompiler, 'liquid/compile/block_body_compiler'
+    autoload :ConditionCompiler, 'liquid/compile/condition_compiler'
+    autoload :SourceMapper, 'liquid/compile/source_mapper'
+
+    module Tags
+      autoload :IfCompiler, 'liquid/compile/tags/if_compiler'
+      autoload :UnlessCompiler, 'liquid/compile/tags/unless_compiler'
+      autoload :CaseCompiler, 'liquid/compile/tags/case_compiler'
+      autoload :ForCompiler, 'liquid/compile/tags/for_compiler'
+      autoload :AssignCompiler, 'liquid/compile/tags/assign_compiler'
+      autoload :CaptureCompiler, 'liquid/compile/tags/capture_compiler'
+      autoload :CycleCompiler, 'liquid/compile/tags/cycle_compiler'
+      autoload :IncrementCompiler, 'liquid/compile/tags/increment_compiler'
+      autoload :DecrementCompiler, 'liquid/compile/tags/decrement_compiler'
+      autoload :RawCompiler, 'liquid/compile/tags/raw_compiler'
+      autoload :EchoCompiler, 'liquid/compile/tags/echo_compiler'
+      autoload :BreakCompiler, 'liquid/compile/tags/break_compiler'
+      autoload :ContinueCompiler, 'liquid/compile/tags/continue_compiler'
+      autoload :CommentCompiler, 'liquid/compile/tags/comment_compiler'
+      autoload :TableRowCompiler, 'liquid/compile/tags/tablerow_compiler'
+      autoload :RenderCompiler, 'liquid/compile/tags/render_compiler'
+      autoload :IncludeCompiler, 'liquid/compile/tags/include_compiler'
+      autoload :IfchangedCompiler, 'liquid/compile/tags/ifchanged_compiler'
+    end
+  end
+end

lib/liquid/compile/block_body_compiler.rb

@@ -0,0 +1,49 @@
+# frozen_string_literal: true
+
+module Liquid
+  module Compile
+    # BlockBodyCompiler compiles a BlockBody (a list of nodes) to Ruby code.
+    #
+    # A BlockBody contains:
+    # - String literals (text to output)
+    # - Variable expressions ({{ ... }})
+    # - Tags ({% ... %})
+    class BlockBodyCompiler
+      # Compile a BlockBody to Ruby code
+      # @param body [Liquid::BlockBody] The block body
+      # @param compiler [RubyCompiler] The main compiler instance
+      # @param code [CodeGenerator] The code generator
+      def self.compile(body, compiler, code)
+        return if body.nil?
+
+        nodelist = body.nodelist
+        return if nodelist.nil? || nodelist.empty?
+
+        nodelist.each do |node|
+          compile_node(node, compiler, code)
+        end
+      end
+
+      # Compile a single node
+      def self.compile_node(node, compiler, code)
+        case node
+        when String
+          compile_string(node, code)
+        when Variable
+          VariableCompiler.compile(node, compiler, code)
+        when Tag
+          compiler.send(:compile_tag, node, code)
+        else
+          raise CompileError, "Unknown node type in BlockBody: #{node.class}"
+        end
+      end
+
+      private
+
+      def self.compile_string(str, code)
+        return if str.empty?
+        code.line "__output__ << #{str.inspect}"
+      end
+    end
+  end
+end

lib/liquid/compile/code_generator.rb

@@ -0,0 +1,82 @@
+# frozen_string_literal: true
+
+module Liquid
+  module Compile
+    # CodeGenerator provides a clean interface for building Ruby code strings
+    # with proper indentation and formatting.
+    class CodeGenerator
+      INDENT_SIZE = 2
+
+      def initialize
+        @lines = []
+        @indent_level = 0
+      end
+
+      # Add a line of code at the current indentation level
+      # @param text [String] The code to add
+      def line(text)
+        @lines << ("  " * @indent_level) + text
+      end
+
+      # Add a blank line
+      def blank_line
+        @lines << ""
+      end
+
+      # Add multiple lines (useful for multi-line strings)
+      # @param text [String] Multi-line string to add
+      def lines(text)
+        text.each_line do |l|
+          line(l.chomp)
+        end
+      end
+
+      # Increase indentation for a block
+      def indent
+        @indent_level += 1
+        yield
+        @indent_level -= 1
+      end
+
+      # Get the current indentation string
+      def current_indent
+        "  " * @indent_level
+      end
+
+      # Add raw code without indentation adjustment
+      def raw(text)
+        @lines << text
+      end
+
+      # Convert to final Ruby code string
+      def to_s
+        @lines.join("\n")
+      end
+
+      # Generate an inline expression (doesn't add to lines, returns string)
+      # @param expr [String] The expression
+      # @return [String] The expression wrapped appropriately
+      def self.inline(expr)
+        expr
+      end
+
+      # Generate a string literal
+      # @param str [String] The string to escape
+      # @return [String] Ruby string literal
+      def self.string_literal(str)
+        str.inspect
+      end
+
+      # Generate a safe variable name from a Liquid variable name
+      # @param name [String] The Liquid variable name
+      # @return [String] A safe Ruby variable name
+      def self.safe_var_name(name)
+        # Replace invalid characters with underscores
+        safe = name.to_s.gsub(/[^a-zA-Z0-9_]/, '_')
+        # Ensure it starts with a letter or underscore
+        safe = "_#{safe}" if safe =~ /\A\d/
+        safe
+      end
+    end
+  end
+end

lib/liquid/compile/compiled_context.rb

@@ -0,0 +1,81 @@
+# frozen_string_literal: true
+
+module Liquid
+  module Compile
+    # CompiledContext is a lightweight context-like object for compiled templates.
+    #
+    # It duck-types to Liquid::Context well enough for Drops to work, providing:
+    # - Variable lookup via [] and find_variable
+    # - strict_variables flag
+    # - registers hash
+    # - evaluate method for expressions
+    #
+    # This allows Drops to access other variables and use context features
+    # while still running in compiled mode.
+    class CompiledContext
+      attr_reader :assigns, :registers
+      attr_accessor :strict_variables, :strict_filters
+
+      def initialize(assigns, registers: {}, strict_variables: false, strict_filters: false)
+        @assigns = assigns
+        @registers = registers.is_a?(Liquid::Registers) ? registers : Liquid::Registers.new(registers)
+        @strict_variables = strict_variables
+        @strict_filters = strict_filters
+      end
+
+      # Variable lookup - used by Drops to access other variables
+      def [](key)
+        @assigns[key.to_s]
+      end
+
+      # Find a variable by name
+      def find_variable(key)
+        result = @assigns[key.to_s]
+        result = result.to_liquid if result.respond_to?(:to_liquid)
+        result.context = self if result.respond_to?(:context=)
+        result
+      end
+
+      # Evaluate an expression (for Drops that need to evaluate sub-expressions)
+      def evaluate(expr)
+        case expr
+        when String, Integer, Float, TrueClass, FalseClass, NilClass
+          expr
+        when Liquid::VariableLookup
+          expr.evaluate(self)
+        else
+          expr
+        end
+      end
+
+      # Lookup and evaluate - handles Procs in assigns
+      def lookup_and_evaluate(obj, key)
+        value = obj[key]
+        value = value.call(self) if value.is_a?(Proc)
+        value
+      end
+
+      # Handle errors (simplified - just return message)
+      def handle_error(error, _line_number = nil)
+        error.message
+      end
+
+      # Check if execution should be interrupted
+      def interrupt?
+        false
+      end
+
+      # Stub for resource limits (no-op in compiled mode)
+      def resource_limits
+        @resource_limits ||= ResourceLimitStub.new
+      end
+    end
+
+    # Stub for resource limits in compiled mode
+    class ResourceLimitStub
+      def increment_render_score(_score); end
+      def increment_write_score(_output); end
+      def reached?; false; end
+    end
+  end
+end

lib/liquid/compile/compiled_template.rb

@@ -0,0 +1,349 @@
+# frozen_string_literal: true
+
+module Liquid
+  module Compile
+    # CompiledTemplate represents a compiled Liquid template ready for secure execution.
+    #
+    # This class wraps generated Ruby code and provides a secure execution environment
+    # using Liquid::Box. On Ruby 4.0+, execution happens in a true sandbox. On earlier
+    # versions, a polyfill is used with a security warning.
+    #
+    # == Usage
+    #
+    #   template = Liquid::Template.parse("Hello, {{ name }}!")
+    #   compiled = template.compile_to_ruby
+    #
+    #   # Render with a Liquid::Context (preferred)
+    #   context = Liquid::Context.new({ "name" => "World" })
+    #   result = compiled.render(context)
+    #   # => "Hello, World!"
+    #
+    #   # Or render with a simple hash
+    #   result = compiled.render({ "name" => "World" })
+    #
+    class CompiledTemplate
+      attr_reader :source, :external_tags
+      attr_accessor :filter_handler
+
+      # @param source [String] The generated Ruby code
+      # @param external_tags [Hash] Map of variable names to Tag objects for runtime delegation
+      # @param has_external_filters [Boolean] Whether external filters are used
+      def initialize(source, external_tags = {}, has_external_filters = false)
+        @source = source
+        @external_tags = external_tags
+        @has_external_filters = has_external_filters
+        @filter_handler = nil
+        @proc = nil
+        @box = nil
+      end
+
+      # Returns true if this template has external tags that need runtime delegation
+      def has_external_tags?
+        !@external_tags.empty?
+      end
+
+      # Returns true if this template uses external filters
+      def has_external_filters?
+        @has_external_filters
+      end
+
+      # Returns true if execution will be sandboxed (Ruby 4.0+)
+      def secure?
+        Liquid::Box.secure?
+      end
+
+      # Render the compiled template.
+      #
+      # @param context_or_assigns [Liquid::Context, Hash] A Liquid context or hash of assigns
+      # @param registers [Hash] Registers (only used when passing a Hash)
+      # @param filter_handler [Object] Optional filter handler module
+      # @yield [call_type, *args] Called for external tags/filters only
+      # @return [String] The rendered output
+      #
+      def render(context_or_assigns = {}, registers: {}, filter_handler: nil, &block)
+        compiled_proc = to_proc
+        handler = filter_handler || @filter_handler
+
+        # Accept either a Liquid::Context or a Hash of assigns
+        if context_or_assigns.is_a?(Liquid::Context)
+          liquid_context = context_or_assigns
+          assigns = extract_assigns(liquid_context)
+          file_system = liquid_context.registers[:file_system]
+
+          # Build external handler that handles include/render internally
+          external_handler = build_external_handler(liquid_context, file_system, handler, &block)
+
+          # Use a wrapper context that delegates to the Liquid::Context
+          context = ContextWrapper.new(liquid_context)
+        else
+          assigns = context_or_assigns
+          file_system = registers[:file_system]
+
+          # Create a minimal context for Drop support
+          context = CompiledContext.new(assigns, registers: registers)
+
+          # Build external handler
+          external_handler = build_external_handler(nil, file_system, handler, &block)
+        end
+
+        compiled_proc.call(assigns, context, external_handler)
+      end
+
+      alias call render
+
+      def code
+        @source
+      end
+
+      def to_s
+        @source
+      end
+
+      def to_proc
+        @proc ||= compile_to_proc
+      end
+
+      private
+
+      def extract_assigns(liquid_context)
+        # Get the first environment (static_environments)
+        liquid_context.environments.first || {}
+      end
+
+      # Build the external call handler
+      # Handles :include and :render internally using file_system
+      # Yields to block for :tag and :filter if block given
+      def build_external_handler(liquid_context, file_system, filter_handler, &block)
+        external_tags = @external_tags
+
+        ->(call_type, *args) do
+          case call_type
+          when :include
+            handle_include(liquid_context, file_system, *args)
+
+          when :render
+            handle_render(liquid_context, file_system, *args)
+
+          when :tag
+            if block
+              block.call(call_type, *args)
+            else
+              handle_tag(liquid_context, external_tags, *args)
+            end
+
+          when :filter
+            if block
+              block.call(call_type, *args)
+            else
+              handle_filter(liquid_context, filter_handler, *args)
+            end
+
+          else
+            if block
+              block.call(call_type, *args)
+            else
+              raise ArgumentError, "Unknown external call type: #{call_type}"
+            end
+          end
+        end
+      end
+
+      def handle_include(liquid_context, file_system, template_name, variable, attrs, alias_name, assigns, context)
+        raise Liquid::FileSystemError, "Could not find asset #{template_name}" unless file_system
+
+        snippet_source = file_system.read_template_file(template_name)
+        snippet = Liquid::Template.parse(snippet_source, line_numbers: true)
+        snippet.name = template_name
+
+        # Include shares scope with parent
+        if liquid_context
+          # Set attributes in context
+          attrs&.each { |k, v| liquid_context[k] = v }
+
+          context_var_name = alias_name || template_name.to_s.split('/').last
+          if variable
+            if variable.is_a?(Array)
+              return variable.map do |item|
+                liquid_context[context_var_name] = item
+                snippet.render(liquid_context)
+              end.join
+            else
+              liquid_context[context_var_name] = variable
+            end
+          end
+
+          snippet.render(liquid_context)
+        else
+          # No liquid context - just use assigns
+          render_assigns = assigns.merge(attrs || {})
+          snippet.render(render_assigns)
+        end
+      end
+
+      def handle_render(liquid_context, file_system, template_name, variable, attrs, alias_name, is_for_loop, context)
+        raise Liquid::FileSystemError, "Could not find asset #{template_name}" unless file_system
+
+        snippet_source = file_system.read_template_file(template_name)
+        snippet = Liquid::Template.parse(snippet_source, line_numbers: true)
+        snippet.name = template_name
+
+        # Render creates isolated scope - only attrs are passed
+        render_assigns = attrs&.dup || {}
+        context_var_name = alias_name || template_name.to_s.split('/').last.sub(/\.liquid$/, '')
+
+        if variable
+          if is_for_loop && variable.is_a?(Array)
+            return variable.map do |item|
+              render_assigns[context_var_name] = item
+              if liquid_context
+                isolated_ctx = Liquid::Context.build(
+                  static_environments: render_assigns,
+                  registers: liquid_context.registers,
+                  rethrow_errors: false,
+                )
+                isolated_ctx.exception_renderer = liquid_context.exception_renderer
+                snippet.render(isolated_ctx)
+              else
+                snippet.render(render_assigns)
+              end
+            end.join
+          else
+            render_assigns[context_var_name] = variable
+          end
+        end
+
+        if liquid_context
+          isolated_ctx = Liquid::Context.build(
+            static_environments: render_assigns,
+            registers: liquid_context.registers,
+            rethrow_errors: false,
+          )
+          isolated_ctx.exception_renderer = liquid_context.exception_renderer
+          snippet.render(isolated_ctx)
+        else
+          snippet.render(render_assigns)
+        end
+      end
+
+      def handle_tag(liquid_context, external_tags, tag_var, tag_assigns)
+        tag = external_tags[tag_var]
+        return '' unless tag
+
+        if liquid_context
+          output = +''
+          tag.render_to_output_buffer(liquid_context, output)
+          output
+        else
+          # Create a minimal context
+          ctx = Liquid::Context.new([tag_assigns], {}, {}, false, nil, {}, Liquid::Environment.default)
+          output = +''
+          tag.render_to_output_buffer(ctx, output)
+          output
+        end
+      end
+
+      def handle_filter(liquid_context, filter_handler, filter_name, input, *filter_args)
+        # Try filter handler first
+        if filter_handler&.respond_to?(filter_name)
+          return filter_handler.public_send(filter_name, input, *filter_args)
+        end
+
+        # Try liquid context's strainer
+        if liquid_context
+          strainer = liquid_context.strainer
+          if strainer.class.invokable?(filter_name)
+            return strainer.invoke(filter_name, input, *filter_args)
+          end
+        end
+
+        # Return input unchanged if filter not found
+        input
+      end
+
+      def compile_to_proc
+        if Liquid::Box.secure?
+          compile_in_sandbox
+        else
+          compile_insecure
+        end
+      end
+
+      def compile_in_sandbox
+        @box ||= begin
+          box = Liquid::Box.new
+          box.load_liquid_runtime!
+          box.lock!
+          box
+        end
+
+        template_class_name = "CompiledTemplate_#{object_id}"
+        class_code = <<~RUBY
+          class #{template_class_name}
+            TEMPLATE_PROC = #{@source}
+
+            def self.render(*args, &block)
+              TEMPLATE_PROC.call(*args, &block)
+            end
+          end
+        RUBY
+
+        @box.eval(class_code)
+        template_class = @box[template_class_name]
+
+        ->(assigns, context, external_handler) do
+          template_class.render(assigns, context, external_handler)
+        end
+      end
+
+      def compile_insecure
+        warn_once_insecure unless Liquid::Box.secure?
+
+        require_relative 'runtime' unless defined?(::LR)
+
+        # rubocop:disable Security/Eval
+        eval(@source)
+        # rubocop:enable Security/Eval
+      end
+
+      def warn_once_insecure
+        return if @warned_insecure
+
+        @warned_insecure = true
+        warn "[SECURITY WARNING] Liquid compiled template running outside of Ruby::Box sandbox. " \
+             "On Ruby 4.0+, this runs in a secure sandbox. On earlier versions, be cautious " \
+             "about running untrusted templates."
+      end
+
+      # Wrapper around Liquid::Context for compiled template compatibility
+      class ContextWrapper
+        def initialize(liquid_context)
+          @liquid_context = liquid_context
+        end
+
+        def [](key)
+          @liquid_context[key]
+        end
+
+        def []=(key, value)
+          @liquid_context[key] = value
+        end
+
+        def key?(key)
+          @liquid_context.key?(key)
+        end
+
+        def registers
+          @liquid_context.registers
+        end
+
+        def strainer
+          @liquid_context.strainer
+        end
+
+        def handle_error(e, line_number = nil)
+          @liquid_context.handle_error(e, line_number)
+        end
+      end
+    end
+  end
+end

lib/liquid/compile/condition_compiler.rb

@@ -0,0 +1,145 @@
+# frozen_string_literal: true
+
+module Liquid
+  module Compile
+    # ConditionCompiler compiles Liquid conditions to Ruby boolean expressions.
+    #
+    # Handles:
+    # - Simple truthiness: {% if variable %}
+    # - Comparisons: {% if a == b %}, {% if a > b %}
+    # - Logical operators: {% if a and b %}, {% if a or b %}
+    # - Special checks: {% if a == blank %}, {% if a == empty %}
+    class ConditionCompiler
+      # Operator mappings from Liquid to Ruby
+      OPERATORS = {
+        '==' => '==',
+        '!=' => '!=',
+        '<>' => '!=',
+        '<' => '<',
+        '>' => '>',
+        '<=' => '<=',
+        '>=' => '>=',
+        'contains' => :contains,
+      }.freeze
+
+      # Compile a Condition to a Ruby boolean expression
+      # @param condition [Liquid::Condition] The condition
+      # @param compiler [RubyCompiler] The main compiler instance
+      # @return [String] Ruby code expression that evaluates to true/false
+      def self.compile(condition, compiler)
+        if condition.is_a?(ElseCondition)
+          return "true"
+        end
+
+        compile_condition_chain(condition, compiler)
+      end
+
+      private
+
+      def self.compile_condition_chain(condition, compiler)
+        # Compile the current condition
+        current = compile_single_condition(condition, compiler)
+
+        # Check for chained conditions (and/or)
+        if condition.child_condition
+          child = compile_condition_chain(condition.child_condition, compiler)
+          child_relation = condition.send(:child_relation)
+
+          case child_relation
+          when :and
+            "(#{current} && #{child})"
+          when :or
+            "(#{current} || #{child})"
+          else
+            current
+          end
+        else
+          current
+        end
+      end
+
+      def self.compile_single_condition(condition, compiler)
+        left = condition.left
+        op = condition.operator
+        right = condition.right
+
+        # If no operator, just check truthiness
+        # Inline: Liquid truthiness is "not nil and not false"
+        if op.nil?
+          left_expr = ExpressionCompiler.compile(left, compiler)
+          # For simple variable access, we can use a more compact form
+          # Complex expressions need temp variable to avoid double evaluation
+          if simple_expression?(left)
+            return "(#{left_expr} != nil && #{left_expr} != false)"
+          else
+            return "((__v__ = #{left_expr}) != nil && __v__ != false)"
+          end
+        end
+
+        # Compile left and right expressions
+        left_expr = compile_condition_value(left, compiler)
+        right_expr = compile_condition_value(right, compiler)
+
+        # Handle special operators
+        case OPERATORS[op]
+        when :contains
+          compile_contains(left_expr, right_expr, compiler)
+        when '=='
+          compile_equality(left, right, left_expr, right_expr, compiler)
+        when '!='
+          "!(#{compile_equality(left, right, left_expr, right_expr, compiler)})"
+        else
+          # Standard comparison
+          ruby_op = OPERATORS[op] || op
+          "(#{left_expr} #{ruby_op} #{right_expr} rescue false)"
+        end
+      end
+
+      def self.compile_condition_value(expr, compiler)
+        if expr.is_a?(Condition::MethodLiteral)
+          # For blank/empty checks, we return a special marker
+          # The equality handler will deal with this
+          ":__method_literal_#{expr.method_name}__"
+        else
+          ExpressionCompiler.compile(expr, compiler)
+        end
+      end
+
+      def self.compile_equality(left, right, left_expr, right_expr, compiler)
+        # Handle blank/empty method literals
+        if left.is_a?(Condition::MethodLiteral)
+          method_name = left.method_name
+          "(#{right_expr}.respond_to?(:#{method_name}) ? #{right_expr}.#{method_name} : nil)"
+        elsif right.is_a?(Condition::MethodLiteral)
+          method_name = right.method_name
+          "(#{left_expr}.respond_to?(:#{method_name}) ? #{left_expr}.#{method_name} : nil)"
+        else
+          "(#{left_expr} == #{right_expr})"
+        end
+      end
+
+      def self.compile_contains(left_expr, right_expr, compiler)
+        # The contains operator checks if left includes right
+        # For strings, right is converted to a string
+        "(lambda { |left, right| " \
+          "return false if left.nil? || right.nil? || !left.respond_to?(:include?); " \
+          "right = right.to_s if left.is_a?(String); " \
+          "left.include?(right) rescue false " \
+          "}.call(#{left_expr}, #{right_expr}))"
+      end
+
+      # Check if an expression is simple (doesn't need temp variable to avoid double evaluation)
+      def self.simple_expression?(expr)
+        case expr
+        when nil, true, false, Integer, Float, String
+          true
+        when VariableLookup
+          # Simple variable or property access is safe to evaluate twice
+          true
+        else
+          false
+        end
+      end
+    end
+  end
+end

lib/liquid/compile/expression_compiler.rb

@@ -0,0 +1,155 @@
+# frozen_string_literal: true
+
+module Liquid
+  module Compile
+    # ExpressionCompiler compiles Liquid expressions to Ruby code.
+    #
+    # Expressions include:
+    # - Literals: nil, true, false, strings, numbers
+    # - Variable lookups: foo, foo.bar, foo[0], foo["key"]
+    # - Ranges: (1..10), (start..end)
+    class ExpressionCompiler
+      # Compile an expression to a Ruby code string
+      # @param expr [Object] The parsed expression
+      # @param compiler [RubyCompiler] The main compiler instance
+      # @return [String] Ruby code that evaluates to the expression value
+      def self.compile(expr, compiler)
+        case expr
+        when nil
+          "nil"
+        when true
+          "true"
+        when false
+          "false"
+        when String
+          expr.inspect
+        when Integer, Float
+          expr.inspect
+        when Range
+          "(#{expr.begin.inspect}..#{expr.end.inspect})"
+        when VariableLookup
+          compile_variable_lookup(expr, compiler)
+        when RangeLookup
+          compile_range_lookup(expr, compiler)
+        when Condition::MethodLiteral
+          # Handle blank/empty method literals
+          compile_method_literal(expr, compiler)
+        else
+          raise CompileError, "Unknown expression type: #{expr.class} (#{expr.inspect})"
+        end
+      end
+
+      # Compile a variable lookup expression
+      # @param lookup [VariableLookup] The variable lookup
+      # @param compiler [RubyCompiler] The main compiler instance
+      # @return [String] Ruby code that evaluates to the variable value
+      def self.compile_variable_lookup(lookup, compiler)
+        # Start with the base variable
+        name = lookup.name
+
+        # Check for forloop property inlining
+        if name == 'forloop' && lookup.lookups.length == 1
+          loop_ctx = compiler.current_loop_context
+          if loop_ctx && loop_ctx[:idx_var]
+            inlined = compile_forloop_property(lookup.lookups.first, loop_ctx)
+            return inlined if inlined
+          end
+        end
+
+        # Handle dynamic name (expression in brackets)
+        base = if name.is_a?(VariableLookup) || name.is_a?(RangeLookup)
+          # Dynamic name like [expr].foo
+          "assigns[#{compile(name, compiler)}]"
+        elsif name.is_a?(String)
+          "assigns[#{name.inspect}]"
+        elsif name.is_a?(Integer)
+          "assigns[#{name.inspect}]"
+        else
+          compile(name, compiler)
+        end
+
+        # Apply each lookup in the chain
+        lookup.lookups.each_with_index do |key, index|
+          if key.is_a?(VariableLookup) || key.is_a?(RangeLookup)
+            # Dynamic key like foo[expr]
+            base = "LR.lookup(#{base}, #{compile(key, compiler)}, __context__)"
+          elsif key.is_a?(Integer)
+            # Numeric index like foo[0]
+            base = "LR.lookup(#{base}, #{key}, __context__)"
+          elsif key.is_a?(String)
+            # Always use LR.lookup which tries key access first,
+            # then falls back to method call for command methods (first, last, size)
+            base = "LR.lookup(#{base}, #{key.inspect}, __context__)"
+          else
+            base = "LR.lookup(#{base}, #{compile(key, compiler)}, __context__)"
+          end
+        end
+
+        base
+      end
+
+      # Inline forloop property access to avoid hash allocation
+      # @param prop [String] Property name (index, index0, first, last, etc.)
+      # @param loop_ctx [Hash] Loop context with idx_var, len_var, loop_name
+      # @return [String, nil] Inlined Ruby code or nil if can't inline
+      def self.compile_forloop_property(prop, loop_ctx)
+        idx = loop_ctx[:idx_var]
+        len = loop_ctx[:len_var]
+        name = loop_ctx[:loop_name]
+
+        case prop
+        when 'index'
+          "(#{idx} + 1)"
+        when 'index0'
+          idx
+        when 'rindex'
+          "(#{len} - #{idx})"
+        when 'rindex0'
+          "(#{len} - #{idx} - 1)"
+        when 'first'
+          "(#{idx} == 0)"
+        when 'last'
+          "(#{idx} == #{len} - 1)"
+        when 'length'
+          len
+        when 'name'
+          name ? name.inspect : "nil"
+        else
+          nil # Unknown property, fall back to hash lookup
+        end
+      end
+
+      # Compile a range lookup expression
+      # @param range [RangeLookup] The range lookup
+      # @param compiler [RubyCompiler] The main compiler instance
+      # @return [String] Ruby code that evaluates to the range
+      def self.compile_range_lookup(range, compiler)
+        start_expr = compile(range.start_obj, compiler)
+        end_expr = compile(range.end_obj, compiler)
+
+        # Convert to integers and create range
+        "(LR.to_integer(#{start_expr})...LR.to_integer(#{end_expr})).to_a"
+      end
+
+      # Compile a method literal (blank/empty)
+      def self.compile_method_literal(literal, compiler)
+        # These are used in conditions like `if foo == blank`
+        # They represent special method calls
+        literal.to_s.inspect
+      end
+
+      # Compile an expression for use in a condition
+      # @param expr [Object] The expression
+      # @param compiler [RubyCompiler] The main compiler
+      # @return [String] Ruby code for the condition value
+      def self.compile_for_condition(expr, compiler)
+        if expr.is_a?(Condition::MethodLiteral)
+          # Return the method name symbol for special handling
+          ":#{expr.method_name}"
+        else
+          compile(expr, compiler)
+        end
+      end
+    end
+  end
+end

lib/liquid/compile/filter_compiler.rb

@@ -0,0 +1,230 @@
+# frozen_string_literal: true
+
+module Liquid
+  module Compile
+    # FilterCompiler compiles Liquid filter chains to Ruby code.
+    #
+    # Filters are applied in sequence: {{ value | filter1: arg1 | filter2: arg2 }}
+    # becomes a chain of method calls on the value.
+    class FilterCompiler
+      # Standard filters that map directly to Ruby methods or simple expressions
+      SIMPLE_FILTERS = {
+        'size' => ->(input, _args, _kwargs, _compiler) { "(#{input}.respond_to?(:size) ? #{input}.size : 0)" },
+        'downcase' => ->(input, _args, _kwargs, _compiler) { "LR.to_s(#{input}).downcase" },
+        'upcase' => ->(input, _args, _kwargs, _compiler) { "LR.to_s(#{input}).upcase" },
+        'capitalize' => ->(input, _args, _kwargs, _compiler) { "LR.to_s(#{input}).capitalize" },
+        'strip' => ->(input, _args, _kwargs, _compiler) { "LR.to_s(#{input}).strip" },
+        'lstrip' => ->(input, _args, _kwargs, _compiler) { "LR.to_s(#{input}).lstrip" },
+        'rstrip' => ->(input, _args, _kwargs, _compiler) { "LR.to_s(#{input}).rstrip" },
+        'reverse' => ->(input, _args, _kwargs, _compiler) { "(#{input}.is_a?(Array) ? #{input}.reverse : LR.to_s(#{input}).reverse)" },
+        'first' => ->(input, _args, _kwargs, _compiler) { "(#{input}.respond_to?(:first) ? #{input}.first : nil)" },
+        'last' => ->(input, _args, _kwargs, _compiler) { "(#{input}.respond_to?(:last) ? #{input}.last : nil)" },
+        'uniq' => ->(input, _args, _kwargs, _compiler) { "(#{input}.respond_to?(:uniq) ? #{input}.uniq : #{input})" },
+        'compact' => ->(input, _args, _kwargs, _compiler) { "(#{input}.respond_to?(:compact) ? #{input}.compact : #{input})" },
+        'flatten' => ->(input, _args, _kwargs, _compiler) { "(#{input}.respond_to?(:flatten) ? #{input}.flatten : #{input})" },
+        'sort' => ->(input, _args, _kwargs, _compiler) { "(#{input}.respond_to?(:sort) ? #{input}.sort : #{input})" },
+        'abs' => ->(input, _args, _kwargs, _compiler) { "LR.to_number(#{input}).abs" },
+        'ceil' => ->(input, _args, _kwargs, _compiler) { "LR.to_number(#{input}).ceil.to_i" },
+        'floor' => ->(input, _args, _kwargs, _compiler) { "LR.to_number(#{input}).floor.to_i" },
+        'escape' => ->(input, _args, _kwargs, _compiler) { "(#{input}.nil? ? nil : LR.escape_html(#{input}))" },
+        'h' => ->(input, _args, _kwargs, _compiler) { "(#{input}.nil? ? nil : LR.escape_html(#{input}))" },
+        'url_encode' => ->(input, _args, _kwargs, _compiler) { "(#{input}.nil? ? nil : LR.url_encode(#{input}))" },
+        'url_decode' => ->(input, _args, _kwargs, _compiler) { "(#{input}.nil? ? nil : LR.url_decode(#{input}))" },
+        'base64_encode' => ->(input, _args, _kwargs, _compiler) { "LR.base64_encode(#{input})" },
+        'base64_decode' => ->(input, _args, _kwargs, _compiler) { "LR.base64_decode(#{input})" },
+        'base64_url_safe_encode' => ->(input, _args, _kwargs, _compiler) { "LR.base64_url_safe_encode(#{input})" },
+        'base64_url_safe_decode' => ->(input, _args, _kwargs, _compiler) { "LR.base64_url_safe_decode(#{input})" },
+        'strip_html' => ->(input, _args, _kwargs, _compiler) { "LR.strip_html(#{input})" },
+        'strip_newlines' => ->(input, _args, _kwargs, _compiler) { "LR.to_s(#{input}).gsub(/\\r?\\n/, '')" },
+        'newline_to_br' => ->(input, _args, _kwargs, _compiler) { "LR.to_s(#{input}).gsub(/\\r?\\n/, \"<br />\\n\")" },
+      }.freeze
+
+      # Filters with arguments that need special handling
+      # All use LR.method() calls to pre-loaded runtime
+      PARAMETERIZED_FILTERS = {
+        'append' => ->(input, args, _kwargs, compiler) {
+          arg = compile_arg(args[0], compiler)
+          "LR.to_s(#{input}) + LR.to_s(#{arg})"
+        },
+        'prepend' => ->(input, args, _kwargs, compiler) {
+          arg = compile_arg(args[0], compiler)
+          "LR.to_s(#{arg}) + LR.to_s(#{input})"
+        },
+        'plus' => ->(input, args, _kwargs, compiler) {
+          arg = compile_arg(args[0], compiler)
+          "(LR.to_number(#{input}) + LR.to_number(#{arg}))"
+        },
+        'minus' => ->(input, args, _kwargs, compiler) {
+          arg = compile_arg(args[0], compiler)
+          "(LR.to_number(#{input}) - LR.to_number(#{arg}))"
+        },
+        'times' => ->(input, args, _kwargs, compiler) {
+          arg = compile_arg(args[0], compiler)
+          "(LR.to_number(#{input}) * LR.to_number(#{arg}))"
+        },
+        'divided_by' => ->(input, args, _kwargs, compiler) {
+          arg = compile_arg(args[0], compiler)
+          "(LR.to_number(#{input}) / LR.to_number(#{arg}))"
+        },
+        'modulo' => ->(input, args, _kwargs, compiler) {
+          arg = compile_arg(args[0], compiler)
+          "(LR.to_number(#{input}) % LR.to_number(#{arg}))"
+        },
+        'round' => ->(input, args, _kwargs, compiler) {
+          if args.empty?
+            "LR.to_number(#{input}).round.to_i"
+          else
+            arg = compile_arg(args[0], compiler)
+            "LR.to_number(#{input}).round(LR.to_number(#{arg}))"
+          end
+        },
+        'at_least' => ->(input, args, _kwargs, compiler) {
+          arg = compile_arg(args[0], compiler)
+          "[LR.to_number(#{input}), LR.to_number(#{arg})].max"
+        },
+        'at_most' => ->(input, args, _kwargs, compiler) {
+          arg = compile_arg(args[0], compiler)
+          "[LR.to_number(#{input}), LR.to_number(#{arg})].min"
+        },
+        'default' => ->(input, args, kwargs, compiler) {
+          default_val = args.empty? ? "''" : compile_arg(args[0], compiler)
+          allow_false = kwargs && kwargs['allow_false'] ? "allow_false: #{compile_arg(kwargs['allow_false'], compiler)}" : ''
+          "LR.default(#{input}, #{default_val}#{allow_false.empty? ? '' : ', ' + allow_false})"
+        },
+        'split' => ->(input, args, _kwargs, compiler) {
+          pattern = args.empty? ? "' '" : compile_arg(args[0], compiler)
+          "LR.to_s(#{input}).split(LR.to_s(#{pattern}))"
+        },
+        'join' => ->(input, args, _kwargs, compiler) {
+          glue = args.empty? ? "' '" : compile_arg(args[0], compiler)
+          "(#{input}.is_a?(Array) ? #{input}.map { |i| LR.to_s(i) }.join(LR.to_s(#{glue})) : LR.to_s(#{input}))"
+        },
+        'replace' => ->(input, args, _kwargs, compiler) {
+          string = compile_arg(args[0], compiler)
+          replacement = args.length > 1 ? compile_arg(args[1], compiler) : "''"
+          "LR.to_s(#{input}).gsub(LR.to_s(#{string}), LR.to_s(#{replacement}))"
+        },
+        'replace_first' => ->(input, args, _kwargs, compiler) {
+          string = compile_arg(args[0], compiler)
+          replacement = args.length > 1 ? compile_arg(args[1], compiler) : "''"
+          "LR.to_s(#{input}).sub(LR.to_s(#{string}), LR.to_s(#{replacement}))"
+        },
+        'remove' => ->(input, args, _kwargs, compiler) {
+          string = compile_arg(args[0], compiler)
+          "LR.to_s(#{input}).gsub(LR.to_s(#{string}), '')"
+        },
+        'remove_first' => ->(input, args, _kwargs, compiler) {
+          string = compile_arg(args[0], compiler)
+          "LR.to_s(#{input}).sub(LR.to_s(#{string}), '')"
+        },
+        'truncate' => ->(input, args, _kwargs, compiler) {
+          length = args.empty? ? "50" : compile_arg(args[0], compiler)
+          ellipsis = args.length > 1 ? compile_arg(args[1], compiler) : "'...'"
+          "LR.truncate(#{input}, #{length}, #{ellipsis})"
+        },
+        'truncatewords' => ->(input, args, _kwargs, compiler) {
+          words = args.empty? ? "15" : compile_arg(args[0], compiler)
+          ellipsis = args.length > 1 ? compile_arg(args[1], compiler) : "'...'"
+          "LR.truncatewords(#{input}, #{words}, #{ellipsis})"
+        },
+        'slice' => ->(input, args, _kwargs, compiler) {
+          offset = compile_arg(args[0], compiler)
+          length = args.length > 1 ? compile_arg(args[1], compiler) : "1"
+          "LR.slice(#{input}, #{offset}, #{length})"
+        },
+        'map' => ->(input, args, _kwargs, compiler) {
+          property = compile_arg(args[0], compiler)
+          "(#{input}.is_a?(Array) ? #{input}.map { |item| item.respond_to?(:[]) ? item[#{property}] : nil } : [])"
+        },
+        'where' => ->(input, args, _kwargs, compiler) {
+          property = compile_arg(args[0], compiler)
+          if args.length > 1
+            target = compile_arg(args[1], compiler)
+            "(#{input}.is_a?(Array) ? #{input}.select { |item| item.respond_to?(:[]) && item[#{property}] == #{target} } : [])"
+          else
+            "(#{input}.is_a?(Array) ? #{input}.select { |item| item.respond_to?(:[]) && LR.truthy?(item[#{property}]) } : [])"
+          end
+        },
+        'reject' => ->(input, args, _kwargs, compiler) {
+          property = compile_arg(args[0], compiler)
+          if args.length > 1
+            target = compile_arg(args[1], compiler)
+            "(#{input}.is_a?(Array) ? #{input}.reject { |item| item.respond_to?(:[]) && item[#{property}] == #{target} } : [])"
+          else
+            "(#{input}.is_a?(Array) ? #{input}.reject { |item| item.respond_to?(:[]) && LR.truthy?(item[#{property}]) } : [])"
+          end
+        },
+        'concat' => ->(input, args, _kwargs, compiler) {
+          arr = compile_arg(args[0], compiler)
+          "(#{input}.is_a?(Array) ? #{input} + (#{arr}.respond_to?(:to_ary) ? #{arr}.to_ary : []) : [])"
+        },
+        'sort_natural' => ->(input, args, _kwargs, compiler) {
+          if args.empty?
+            "(#{input}.is_a?(Array) ? #{input}.sort_by { |a| a.to_s.downcase } : #{input})"
+          else
+            property = compile_arg(args[0], compiler)
+            "(#{input}.is_a?(Array) ? #{input}.sort_by { |a| a.respond_to?(:[]) ? a[#{property}].to_s.downcase : '' } : #{input})"
+          end
+        },
+        'date' => ->(input, args, _kwargs, compiler) {
+          format = compile_arg(args[0], compiler)
+          "LR.date(#{input}, #{format})"
+        },
+        'escape_once' => ->(input, _args, _kwargs, _compiler) {
+          "LR.escape_once(#{input})"
+        },
+      }.freeze
+
+      # Compile a filter chain
+      # @param input_expr [String] Ruby expression for the input value
+      # @param filters [Array] Array of filter definitions [name, args, kwargs]
+      # @param compiler [RubyCompiler] The main compiler instance
+      # @return [String] Ruby code that applies all filters
+      def self.compile(input_expr, filters, compiler)
+        result = input_expr
+
+        filters.each do |filter_name, filter_args, filter_kwargs|
+          result = compile_filter(result, filter_name, filter_args || [], filter_kwargs, compiler)
+        end
+
+        result
+      end
+
+      # Compile a single filter application
+      def self.compile_filter(input, name, args, kwargs, compiler)
+        if SIMPLE_FILTERS.key?(name)
+          SIMPLE_FILTERS[name].call(input, args, kwargs, compiler)
+        elsif PARAMETERIZED_FILTERS.key?(name)
+          PARAMETERIZED_FILTERS[name].call(input, args, kwargs, compiler)
+        else
+          # Fall back to a generic filter call
+          compile_generic_filter(input, name, args, kwargs, compiler)
+        end
+      end
+
+      # Compile a filter that's not built-in
+      # Yields [:filter, name, input, args] to the external handler
+      def self.compile_generic_filter(input, name, args, kwargs, compiler)
+        # Mark that we're using external filters
+        compiler.register_external_filter
+
+        compiled_args = args.map { |arg| compile_arg(arg, compiler) }
+
+        if kwargs && !kwargs.empty?
+          kwargs_hash = kwargs.map { |k, v| "#{k.inspect} => #{compile_arg(v, compiler)}" }.join(", ")
+          compiled_args << "{ #{kwargs_hash} }"
+        end
+
+        args_str = compiled_args.empty? ? "[]" : "[#{compiled_args.join(', ')}]"
+
+        # Yield to the external handler
+        "__external__.call(:filter, #{name.inspect}, #{input}, #{args_str})"
+      end
+
+      # Compile a filter argument
+      def self.compile_arg(arg, compiler)
+        ExpressionCompiler.compile(arg, compiler)
+      end
+    end
+  end
+end

lib/liquid/compile/ruby_compiler.rb

@@ -0,0 +1,418 @@
+# frozen_string_literal: true
+
+module Liquid
+  module Compile
+    # RubyCompiler transforms a parsed Liquid template into pure Ruby code.
+    #
+    # The compiled code is a string that can be eval'd to create a proc/lambda
+    # that takes an assigns hash and returns the rendered output string.
+    #
+    # ## Optimization Opportunities
+    #
+    # The compiled Ruby code has several significant advantages over interpreted Liquid:
+    #
+    # 1. **No Context Object**: Instead of using a Context for variable lookups,
+    #    variables are extracted directly from the assigns hash and stored in
+    #    local Ruby variables. This eliminates hash lookups on every access.
+    #
+    # 2. **No Filter Invocation Overhead**: Filters are compiled to direct Ruby
+    #    method calls rather than going through context.invoke().
+    #
+    # 3. **No Resource Limits Tracking**: The compiled code doesn't track render
+    #    scores, write scores, or assign scores, eliminating per-node overhead.
+    #
+    # 4. **No Stack-based Scoping**: Ruby's native block scoping is used instead
+    #    of manually managing scope stacks with push/pop operations.
+    #
+    # 5. **Direct String Concatenation**: Output is built with direct << operations
+    #    rather than through render_to_output_buffer abstractions.
+    #
+    # 6. **Native Control Flow**: break/continue become Ruby's break/next,
+    #    eliminating interrupt objects and checks.
+    #
+    # 7. **No to_liquid Calls**: Values are used directly without conversion.
+    #
+    # 8. **Potential for Constant Folding**: Expressions with only literals
+    #    could be evaluated at compile time (future enhancement).
+    #
+    # 9. **Potential for Dead Code Elimination**: Unreachable branches like
+    #    `{% if false %}` could be removed (future enhancement).
+    #
+    # 10. **No Profiling Hooks**: No profiler overhead in the generated code.
+    #
+    # 11. **No Exception Rendering**: Errors propagate naturally rather than
+    #     being caught and rendered inline.
+    #
+    # ## Usage
+    #
+    #   template = Liquid::Template.parse("Hello, {{ name }}!")
+    #   ruby_code = template.compile_to_ruby
+    #   render_proc = eval(ruby_code)
+    #   result = render_proc.call({ "name" => "World" })
+    #   # => "Hello, World!"
+    #
+    class RubyCompiler
+      attr_reader :template, :options
+
+      # @param template [Liquid::Template] The parsed template to compile
+      # @param options [Hash] Compilation options
+      # @option options [Boolean] :strict_variables Raise on undefined variables (default: false)
+      # @option options [Boolean] :include_filters Include filter helper methods (default: true)
+      # @option options [Boolean] :debug Emit source comments for debugging (default: false)
+      # @option options [Object] :file_system File system for loading partials (default: template's environment)
+      def initialize(template, options = {})
+        @template = template
+        @options = {
+          strict_variables: false,
+          include_filters: true,
+          debug: false,
+          file_system: nil,
+        }.merge(options)
+        @var_counter = 0
+        @partials = {}        # Registered partials: name => method_name
+        @partial_sources = {} # Partial sources: name => source code
+        @partial_counter = 0
+        @external_tags = {}   # External tags: var_name => tag object
+        @external_tag_counter = 0
+        @has_external_filters = false  # Whether we need the filter helper
+        @loop_context_stack = []       # Stack of loop contexts for break/continue
+      end
+
+      # Push a loop context onto the stack (for nested loops)
+      # @param break_var [String, nil] Variable name for break flag, or nil if no break
+      # @param idx_var [String, nil] Variable name for loop index
+      # @param len_var [String, nil] Variable name for collection length
+      # @param loop_name [String, nil] Name of the loop (for forloop.name)
+      def push_loop_context(break_var: nil, idx_var: nil, len_var: nil, loop_name: nil)
+        @loop_context_stack.push({
+          break_var: break_var,
+          idx_var: idx_var,
+          len_var: len_var,
+          loop_name: loop_name
+        })
+      end
+
+      # Pop the current loop context
+      def pop_loop_context
+        @loop_context_stack.pop
+      end
+
+      # Get the current loop context (for break/continue compilation)
+      # @return [Hash, nil] Current loop context or nil if not in a loop
+      def current_loop_context
+        @loop_context_stack.last
+      end
+
+      # Mark that we have external filters
+      def register_external_filter
+        @has_external_filters = true
+      end
+
+      # Check if external filters are used
+      def has_external_filters?
+        @has_external_filters
+      end
+
+      # Register an external tag that will be called at runtime
+      # @param tag [Liquid::Tag] The tag to register
+      # @return [String] The variable name for this tag
+      def register_external_tag(tag)
+        @external_tag_counter += 1
+        var_name = "__ext_tag_#{@external_tag_counter}__"
+        @external_tags[var_name] = tag
+        var_name
+      end
+
+      # Get all registered external tags
+      # @return [Hash] Map of variable names to tag objects
+      def external_tags
+        @external_tags
+      end
+
+      # Get the file system for loading partials
+      def file_system
+        @options[:file_system] || @template.instance_variable_get(:@environment)&.file_system
+      end
+
+      # Load a partial source from the file system
+      # @param name [String] The partial name
+      # @return [String, nil] The partial source or nil if not found
+      def load_partial(name)
+        return @partial_sources[name] if @partial_sources.key?(name)
+
+        fs = file_system
+        return nil unless fs && fs.respond_to?(:read_template_file)
+
+        begin
+          source = fs.read_template_file(name)
+          @partial_sources[name] = source
+          source
+        rescue Liquid::FileSystemError
+          nil
+        end
+      end
+
+      # Register a partial and return its method name
+      # @param name [String] The partial name
+      # @param source [String] The partial source
+      # @return [String] The method name for this partial
+      def register_partial(name, source)
+        return @partials[name] if @partials.key?(name)
+
+        @partial_counter += 1
+        method_name = "__partial_#{@partial_counter}__"
+        @partials[name] = method_name
+        method_name
+      end
+
+      # Get all registered partials
+      def registered_partials
+        @partials
+      end
+
+      # Check if debug mode is enabled
+      def debug?
+        @options[:debug]
+      end
+
+      # Emit a debug comment with source location info
+      # This creates a lightweight source map that allows tracing errors
+      # back to the original Liquid source
+      def emit_debug_comment(code, node, description = nil)
+        return unless debug?
+
+        line_number = node.respond_to?(:line_number) ? node.line_number : nil
+        raw_markup = extract_raw_markup(node)
+
+        comment_parts = []
+        comment_parts << "LIQUID"
+        comment_parts << "L#{line_number}" if line_number
+        comment_parts << description if description
+        comment_parts << raw_markup.inspect if raw_markup && raw_markup.length < 80
+
+        code.line "# #{comment_parts.join(' | ')}"
+      end
+
+      # Extract the raw markup from a node for debug output
+      def extract_raw_markup(node)
+        case node
+        when Variable
+          "{{ #{node.raw} }}"
+        when Tag
+          if node.respond_to?(:raw)
+            "{% #{node.tag_name} #{node.raw} %}"
+          elsif node.respond_to?(:markup)
+            "{% #{node.tag_name} #{node.markup} %}"
+          else
+            "{% #{node.class.name.split('::').last.downcase} %}"
+          end
+        else
+          nil
+        end
+      end
+
+      # Compile the template to a Ruby code string
+      # @return [String] Ruby code that can be eval'd to create a render proc
+      # @return [Hash] If external tags are used, returns { code: String, external_tags: Hash }
+      def compile
+        code = CodeGenerator.new
+
+        # Add debug header if enabled
+        if debug?
+          code.line "# Compiled from Liquid template: #{@template.name || '(unnamed)'}"
+          code.line "# Debug mode enabled - comments contain source locations"
+          code.line "# Format: # LIQUID | L<line> | <description> | <source>"
+          code.blank_line
+        end
+
+        # First pass: compile the document body to discover partials and external tags
+        main_code = CodeGenerator.new
+        compile_node(@template.root, main_code)
+
+        # Lambda signature: (assigns, context, external_handler)
+        # - assigns: Hash of template variables
+        # - context: CompiledContext for Drop support
+        # - external_handler: Proc that handles [:tag, ...] and [:filter, ...] calls
+        code.line "->(assigns, __context__, __external__) do"
+
+        code.indent do
+          # Initialize the output buffer
+          code.line '__output__ = +""'
+          code.blank_line
+
+          # Compile partial methods (before main body so they're available)
+          compile_partials(code)
+
+          # Add the main body code
+          code.raw(main_code.to_s)
+
+          code.blank_line
+          code.line "__output__"
+        end
+        code.line "end"
+
+        code.to_s
+      end
+
+      # Compile all registered partials as inner methods
+      def compile_partials(code)
+        @partials.each do |name, method_name|
+          source = @partial_sources[name]
+          next unless source
+
+          code.line "# Partial: #{name}"
+          code.line "#{method_name} = ->(partial_assigns) do"
+          code.indent do
+            code.line "__partial_output__ = +''"
+            code.line "# Merge partial assigns with parent assigns"
+            code.line "__assigns_backup__ = assigns.dup"
+            code.line "assigns.merge!(partial_assigns)"
+            code.blank_line
+
+            # Parse and compile the partial
+            # Note: We need to handle this carefully to avoid circular references
+            begin
+              compile_partial_source(source, code)
+            rescue => e
+              code.line "# Error compiling partial: #{e.message.inspect}"
+              code.line "__partial_output__ << '[PARTIAL ERROR: ' + #{name.inspect} + ']'"
+            end
+
+            code.blank_line
+            code.line "# Restore assigns"
+            code.line "assigns.replace(__assigns_backup__)"
+            code.line "__partial_output__"
+          end
+          code.line "end"
+          code.blank_line
+        end
+      end
+
+      # Compile a partial source string
+      def compile_partial_source(source, code)
+        # Parse the partial source using the same environment
+        environment = @template.instance_variable_get(:@environment) || Liquid::Environment.default
+        parse_context = Liquid::ParseContext.new(environment: environment)
+        tokenizer = parse_context.new_tokenizer(source)
+        document = Liquid::Document.parse(tokenizer, parse_context)
+
+        # Compile the partial's body, but swap output variable
+        code.line "__saved_output__ = __output__"
+        code.line "__output__ = __partial_output__"
+
+        # Compile the document
+        BlockBodyCompiler.compile(document.body, self, code)
+
+        code.line "__output__ = __saved_output__"
+      end
+
+      # Generate a unique variable name for internal use
+      def generate_var_name(prefix = "v")
+        @var_counter += 1
+        "__#{prefix}#{@var_counter}__"
+      end
+
+      # Compile a single node
+      def compile_node(node, code)
+        case node
+        when Document
+          BlockBodyCompiler.compile(node.body, self, code)
+        when BlockBody
+          BlockBodyCompiler.compile(node, self, code)
+        when String
+          compile_string(node, code)
+        when Variable
+          emit_debug_comment(code, node, "variable")
+          VariableCompiler.compile(node, self, code)
+        when Tag
+          emit_debug_comment(code, node, node.class.name.split('::').last.downcase)
+          compile_tag(node, code)
+        else
+          raise CompileError, "Unknown node type: #{node.class}"
+        end
+      end
+
+      private
+
+      def compile_string(str, code)
+        return if str.empty?
+        if debug? && str.length < 40
+          code.line "# LIQUID | text | #{str.inspect}"
+        end
+        code.line "__output__ << #{str.inspect}"
+      end
+
+      def compile_tag(tag, code)
+        # First, check if the tag implements to_ruby (custom compilation)
+        if tag.respond_to?(:to_ruby)
+          tag.to_ruby(code, self)
+        # Then check for a built-in compiler class
+        elsif (compiler_class = find_tag_compiler(tag))
+          compiler_class.compile(tag, self, code)
+        else
+          # Unknown tag - yield to caller at runtime
+          compile_external_tag(tag, code)
+        end
+      end
+
+      def compile_external_tag(tag, code)
+        tag_var = register_external_tag(tag)
+        tag_name = tag.class.name.split('::').last
+        if debug?
+          code.line "# External tag: #{tag_name} (yields to caller)"
+        end
+        # Yield [:tag, tag_var, assigns] to the external handler
+        code.line "__output__ << __external__.call(:tag, #{tag_var.inspect}, assigns)"
+      end
+
+      def find_tag_compiler(tag)
+        case tag
+        when Liquid::Unless  # Check Unless before If since Unless < If
+          Tags::UnlessCompiler
+        when Liquid::If
+          Tags::IfCompiler
+        when Liquid::Case
+          Tags::CaseCompiler
+        when Liquid::For
+          Tags::ForCompiler
+        when Liquid::Assign
+          Tags::AssignCompiler
+        when Liquid::Capture
+          Tags::CaptureCompiler
+        when Liquid::Cycle
+          Tags::CycleCompiler
+        when Liquid::Increment
+          Tags::IncrementCompiler
+        when Liquid::Decrement
+          Tags::DecrementCompiler
+        when Liquid::Raw
+          Tags::RawCompiler
+        when Liquid::Echo
+          Tags::EchoCompiler
+        when Liquid::Break
+          Tags::BreakCompiler
+        when Liquid::Continue
+          Tags::ContinueCompiler
+        when Liquid::Comment, Liquid::InlineComment, Liquid::Doc
+          Tags::CommentCompiler
+        when Liquid::TableRow
+          Tags::TableRowCompiler
+        when Liquid::Render
+          Tags::RenderCompiler
+        when Liquid::Include
+          Tags::IncludeCompiler
+        when Liquid::Ifchanged
+          Tags::IfchangedCompiler
+        else
+          nil
+        end
+      end
+
+      # NOTE: compile_helper_methods was removed - helpers are now provided by the
+      # pre-loaded LR module (compile/runtime.rb). Templates call LR.to_s(), LR.lookup(), etc.
+    end
+
+    # Custom error for compilation issues
+    class CompileError < StandardError; end
+  end
+end

lib/liquid/compile/runtime.rb

@@ -0,0 +1,252 @@
+# frozen_string_literal: true
+
+# Liquid Compiled Template Runtime
+#
+# This module provides ALL helpers for compiled Liquid templates.
+# It is loaded into the sandbox BEFORE lock!, so these methods
+# are available to all compiled templates.
+#
+# Templates reference these as LR.method_name(args)
+#
+# == Security Note
+#
+# It is SAFE to expose side-effect-free, non-IO methods that don't leak
+# objects with dangerous methods. For example:
+#
+#   - CGI.escapeHTML(str) -> returns a String (safe)
+#   - Base64.strict_encode64(str) -> returns a String (safe)
+#   - BigDecimal(str) -> returns a Numeric (safe)
+#
+# These are pure functions that take values and return values.
+# They don't provide any capability to escape the sandbox.
+#
+# We capture METHOD REFERENCES (e.g., CGI.method(:escapeHTML)) before the
+# sandbox locks. This means templates can use the functionality without
+# having direct access to the CGI, Base64, or BigDecimal constants.
+#
+# Dependencies (CGI, Base64, BigDecimal) are loaded by box.rb into the
+# sandbox BEFORE this file runs. The constants are preserved after lock.
+
+module LR
+  # === Type Conversion ===
+
+  # Convert to string like Liquid does
+  def self.to_s(obj)
+    case obj
+    when nil then ''
+    when Array then obj.join
+    else obj.to_s
+    end
+  end
+
+  # Convert to number for arithmetic
+  # Use Kernel.BigDecimal to access from root namespace
+  def self.to_number(obj)
+    case obj
+    when Numeric then obj
+    when String
+      if obj.strip =~ /\A-?\d+\.\d+\z/
+        Kernel.BigDecimal(obj)
+      else
+        obj.to_i
+      end
+    else 0
+    end
+  end
+
+  # Convert to integer
+  def self.to_integer(obj)
+    return obj if obj.is_a?(Integer)
+    Integer(obj.to_s) rescue 0
+  end
+
+  # === Truthiness ===
+
+  # Liquid truthiness: only nil and false are falsy
+  def self.truthy?(obj)
+    obj != nil && obj != false
+  end
+
+  # === Output ===
+
+  # Output a value, converting to string safely (handles arrays recursively)
+  def self.output(obj)
+    case obj
+    when nil then ''
+    when Array then obj.map { |o| output(o) }.join
+    when BigDecimal
+      # Format BigDecimal like Liquid does - avoid scientific notation
+      obj.to_s('F')
+    else obj.to_s
+    end
+  end
+
+  # === Lookup ===
+
+  # Variable lookup - handles hash/array access, method calls, to_liquid, and drop context
+  def self.lookup(obj, key, context = nil)
+    return nil if obj.nil?
+
+    # Set context on Drops BEFORE accessing their methods
+    obj = obj.to_liquid if obj.respond_to?(:to_liquid)
+    obj.context = context if context && obj.respond_to?(:context=)
+
+    # Perform the lookup
+    result = if obj.respond_to?(:[]) && (obj.respond_to?(:key?) && obj.key?(key) || obj.respond_to?(:fetch) && key.is_a?(Integer))
+      obj[key]
+    elsif obj.respond_to?(key)
+      obj.public_send(key)
+    else
+      nil
+    end
+
+    # Convert result to liquid and set context for nested Drops
+    result = result.to_liquid if result.respond_to?(:to_liquid)
+    result.context = context if context && result.respond_to?(:context=)
+    result
+  end
+
+  # === HTML/URL Encoding ===
+  # Capture method references before sandbox locks - only the specific methods we need
+  CGI_ESCAPE_HTML = CGI.method(:escapeHTML)
+  CGI_ESCAPE = CGI.method(:escape)
+  CGI_UNESCAPE = CGI.method(:unescape)
+
+  HTML_ESCAPE_MAP = { '&' => '&amp;', '<' => '&lt;', '>' => '&gt;', '"' => '&quot;', "'" => '&#39;' }.freeze
+
+  def self.escape_html(obj)
+    CGI_ESCAPE_HTML.call(to_s(obj))
+  end
+
+  def self.url_encode(obj)
+    CGI_ESCAPE.call(to_s(obj))
+  end
+
+  def self.url_decode(obj)
+    CGI_UNESCAPE.call(to_s(obj))
+  end
+
+  def self.escape_once(obj)
+    # Only escape if not already escaped
+    to_s(obj).gsub(/["><']|&(?!([a-zA-Z]+|(#\d+));)/, HTML_ESCAPE_MAP)
+  end
+
+  # === Base64 ===
+  # Capture method references before sandbox locks
+  BASE64_ENCODE = Base64.method(:strict_encode64)
+  BASE64_DECODE = Base64.method(:strict_decode64)
+  BASE64_URL_ENCODE = Base64.method(:urlsafe_encode64)
+  BASE64_URL_DECODE = Base64.method(:urlsafe_decode64)
+
+  def self.base64_encode(obj)
+    BASE64_ENCODE.call(to_s(obj))
+  end
+
+  def self.base64_decode(obj)
+    BASE64_DECODE.call(to_s(obj))
+  end
+
+  def self.base64_url_safe_encode(obj)
+    BASE64_URL_ENCODE.call(to_s(obj))
+  end
+
+  def self.base64_url_safe_decode(obj)
+    BASE64_URL_DECODE.call(to_s(obj))
+  end
+
+  # === String Manipulation ===
+
+  def self.strip_html(obj)
+    to_s(obj).gsub(%r{<script.*?</script>|<!--.*?-->|<style.*?</style>}m, '').gsub(/<.*?>/m, '')
+  end
+
+  # Truncate string to length with ellipsis
+  def self.truncate(input, length = 50, ellipsis = '...')
+    str = to_s(input)
+    ell_str = to_s(ellipsis)
+    len = length.to_i
+    l = [len - ell_str.length, 0].max
+    str.length > len ? str[0, l] + ell_str : str
+  end
+
+  # Truncate to word count
+  def self.truncatewords(input, num_words = 15, ellipsis = '...')
+    max_words = [num_words.to_i, 1].max
+    words = to_s(input).split(' ', max_words + 1)
+    if words.length > max_words
+      words[0, max_words].join(' ') + to_s(ellipsis)
+    else
+      input.to_s
+    end
+  end
+
+  # === Date Formatting ===
+
+  def self.date(input, format)
+    return input if format.to_s.empty?
+    d = case input
+    when Time, Date then input
+    when 'now', 'today' then Time.now
+    when /\A\d+\z/, Integer then Time.at(input.to_i)
+    when String then (Time.parse(input) rescue input)
+    else input
+    end
+    d.respond_to?(:strftime) ? d.strftime(format.to_s) : input
+  end
+
+  # === Collection Helpers ===
+
+  # Convert to array for iteration - returns Array or empty Array
+  # This guarantees the result supports [], .length, .empty? without respond_to? checks
+  def self.to_array(collection)
+    case collection
+    when Array then collection
+    when Range then collection.to_a
+    when nil then EMPTY_ARRAY
+    else
+      collection.respond_to?(:to_a) ? collection.to_a : EMPTY_ARRAY
+    end
+  end
+
+  # Frozen empty array to avoid allocations
+  EMPTY_ARRAY = [].freeze
+
+  # Iterate safely, handling ranges and non-iterables
+  def self.iterate(collection)
+    case collection
+    when Range then collection.to_a
+    when nil then EMPTY_ARRAY
+    else collection.respond_to?(:each) ? collection : EMPTY_ARRAY
+    end
+  end
+
+  # Get collection length safely
+  def self.size(collection)
+    collection.respond_to?(:size) ? collection.size : 0
+  end
+
+  # === Default Filter ===
+
+  def self.default(input, default_value, allow_false: false)
+    if allow_false
+      (input.nil? || (input.respond_to?(:empty?) && input.empty?)) ? default_value : input
+    else
+      (!truthy?(input) || (input.respond_to?(:empty?) && input.empty?)) ? default_value : input
+    end
+  end
+
+  # === Array/String Slice ===
+
+  def self.slice(input, offset, length = 1)
+    off = to_integer(offset)
+    len = to_integer(length)
+    if input.is_a?(Array)
+      input.slice(off, len) || []
+    else
+      to_s(input).slice(off, len) || ''
+    end
+  end
+end
+
+# Alias for backwards compatibility
+LiquidRuntime = LR

lib/liquid/compile/source_mapper.rb

@@ -0,0 +1,130 @@
+# frozen_string_literal: true
+
+module Liquid
+  module Compile
+    # SourceMapper provides utilities for mapping errors in compiled Ruby code
+    # back to the original Liquid source.
+    #
+    # When code is compiled with debug: true, comments are embedded that contain
+    # source location information. This class can parse those comments and
+    # help trace errors back to the original Liquid template.
+    #
+    # ## Usage
+    #
+    #   template = Liquid::Template.parse(source, line_numbers: true)
+    #   ruby_code = template.compile_to_ruby(debug: true)
+    #   render_proc = eval(ruby_code)
+    #
+    #   begin
+    #     result = render_proc.call(assigns)
+    #   rescue => e
+    #     location = SourceMapper.find_source_location(ruby_code, e)
+    #     puts "Error at Liquid line #{location[:liquid_line]}: #{location[:source]}"
+    #   end
+    #
+    class SourceMapper
+      # Pattern to match LIQUID debug comments
+      LIQUID_COMMENT_PATTERN = /^(\s*)# LIQUID(?: \| L(\d+))?(?: \| ([^|]+))?(?: \| (.+))?$/
+
+      # Parse compiled Ruby code and extract source mapping entries
+      # @param ruby_code [String] The compiled Ruby code with debug comments
+      # @return [Array<Hash>] Array of source mapping entries
+      def self.parse(ruby_code)
+        entries = []
+        ruby_line = 0
+
+        ruby_code.each_line do |line|
+          ruby_line += 1
+
+          if line =~ LIQUID_COMMENT_PATTERN
+            entries << {
+              ruby_line: ruby_line,
+              liquid_line: $2&.to_i,
+              type: $3&.strip,
+              source: parse_source_string($4),
+            }
+          end
+        end
+
+        entries
+      end
+
+      # Find the source location for an error based on Ruby line number
+      # @param ruby_code [String] The compiled Ruby code
+      # @param error [Exception] The exception that was raised
+      # @return [Hash, nil] Source location info or nil if not found
+      def self.find_source_location(ruby_code, error)
+        # Extract the line number from the error
+        ruby_line = extract_error_line(error)
+        return nil unless ruby_line
+
+        find_source_for_ruby_line(ruby_code, ruby_line)
+      end
+
+      # Find the source location for a specific Ruby line number
+      # @param ruby_code [String] The compiled Ruby code
+      # @param target_line [Integer] The Ruby line number
+      # @return [Hash, nil] Source location info or nil if not found
+      def self.find_source_for_ruby_line(ruby_code, target_line)
+        entries = parse(ruby_code)
+
+        # Find the closest LIQUID comment at or before the target line
+        closest = nil
+        entries.each do |entry|
+          break if entry[:ruby_line] > target_line
+          closest = entry
+        end
+
+        closest
+      end
+
+      # Format an error message with source location info
+      # @param ruby_code [String] The compiled Ruby code
+      # @param error [Exception] The exception
+      # @return [String] Formatted error message
+      def self.format_error(ruby_code, error)
+        location = find_source_location(ruby_code, error)
+
+        message = "#{error.class}: #{error.message}"
+
+        if location
+          liquid_line = location[:liquid_line] ? "line #{location[:liquid_line]}" : "unknown line"
+          source = location[:source] || location[:type] || "unknown"
+          message += "\n  in Liquid template at #{liquid_line}"
+          message += "\n  source: #{source}" if location[:source]
+        end
+
+        message
+      end
+
+      private
+
+      def self.extract_error_line(error)
+        # Look for (eval):N in backtrace
+        error.backtrace&.each do |frame|
+          if frame =~ /\(eval.*?\):(\d+)/
+            return $1.to_i
+          end
+        end
+        nil
+      end
+
+      def self.parse_source_string(str)
+        return nil unless str
+
+        # Remove surrounding quotes if present
+        str = str.strip
+        if str.start_with?('"') && str.end_with?('"')
+          # Unescape the string
+          begin
+            eval(str)
+          rescue
+            str[1..-2]
+          end
+        else
+          str
+        end
+      end
+    end
+  end
+end

lib/liquid/compile/tags/assign_compiler.rb

@@ -0,0 +1,19 @@
+# frozen_string_literal: true
+
+module Liquid
+  module Compile
+    module Tags
+      # Compiles {% assign var = expression %} tags
+      class AssignCompiler
+        def self.compile(tag, compiler, code)
+          var_name = tag.to
+          # Use VariableCompiler to get the expression with filters applied
+          value_expr = VariableCompiler.compile_to_expression(tag.from, compiler)
+
+          # Store in the assigns hash
+          code.line "assigns[#{var_name.inspect}] = #{value_expr}"
+        end
+      end
+    end
+  end
+end

lib/liquid/compile/tags/break_compiler.rb

@@ -0,0 +1,28 @@
+# frozen_string_literal: true
+
+module Liquid
+  module Compile
+    module Tags
+      # Compiles {% break %} tags
+      #
+      # Break is implemented with a flag variable that's checked in the while condition.
+      # This avoids catch/throw overhead entirely.
+      #
+      # Generated code sets the break flag and uses `next` to exit the current iteration.
+      # The while loop condition checks the flag and exits if set.
+      class BreakCompiler
+        def self.compile(_tag, compiler, code)
+          loop_ctx = compiler.current_loop_context
+          if loop_ctx && loop_ctx[:break_var]
+            # Set the break flag and exit this iteration
+            code.line "#{loop_ctx[:break_var]} = true"
+            code.line "next"
+          else
+            # Fallback: shouldn't happen if contains_tag? works correctly
+            code.line "break"
+          end
+        end
+      end
+    end
+  end
+end

lib/liquid/compile/tags/capture_compiler.rb

@@ -0,0 +1,31 @@
+# frozen_string_literal: true
+
+module Liquid
+  module Compile
+    module Tags
+      # Compiles {% capture var %}...{% endcapture %} tags
+      #
+      # Captures the output of the block into a variable
+      class CaptureCompiler
+        def self.compile(tag, compiler, code)
+          var_name = tag.instance_variable_get(:@to)
+          capture_var = compiler.generate_var_name("capture")
+
+          # Save current output, create new buffer for capture
+          code.line "#{capture_var} = __output__"
+          code.line "__output__ = +''"
+
+          # Compile the body - access the @body BlockBody directly
+          body = tag.instance_variable_get(:@body)
+          if body
+            BlockBodyCompiler.compile(body, compiler, code)
+          end
+
+          # Save captured content and restore output buffer
+          code.line "assigns[#{var_name.inspect}] = __output__"
+          code.line "__output__ = #{capture_var}"
+        end
+      end
+    end
+  end
+end

lib/liquid/compile/tags/case_compiler.rb

@@ -0,0 +1,47 @@
+# frozen_string_literal: true
+
+module Liquid
+  module Compile
+    module Tags
+      # Compiles {% case %} / {% when %} / {% else %} / {% endcase %} tags
+      class CaseCompiler
+        def self.compile(tag, compiler, code)
+          # Compile the case expression and store it in a variable
+          # to avoid evaluating it multiple times
+          case_var = compiler.generate_var_name("case")
+          case_expr = ExpressionCompiler.compile(tag.left, compiler)
+          code.line "#{case_var} = #{case_expr}"
+
+          blocks = tag.blocks
+          is_first = true
+          has_else = false
+
+          blocks.each do |block|
+            if block.else?
+              has_else = true
+              code.line "else"
+            else
+              # 'when' condition - compare case expression with the when value
+              when_expr = ExpressionCompiler.compile(block.right, compiler)
+
+              if is_first
+                code.line "if #{case_var} == #{when_expr}"
+                is_first = false
+              else
+                code.line "elsif #{case_var} == #{when_expr}"
+              end
+            end
+
+            code.indent do
+              if block.attachment
+                BlockBodyCompiler.compile(block.attachment, compiler, code)
+              end
+            end
+          end
+
+          code.line "end" unless blocks.empty?
+        end
+      end
+    end
+  end
+end

lib/liquid/compile/tags/comment_compiler.rb

@@ -0,0 +1,18 @@
+# frozen_string_literal: true
+
+module Liquid
+  module Compile
+    module Tags
+      # Compiles {% comment %}...{% endcomment %} tags
+      # Also handles inline_comment (#) and doc tags
+      #
+      # Comments produce no output
+      class CommentCompiler
+        def self.compile(_tag, _compiler, code)
+          # Comments produce no output
+          code.line "# (liquid comment)"
+        end
+      end
+    end
+  end
+end

lib/liquid/compile/tags/continue_compiler.rb

@@ -0,0 +1,24 @@
+# frozen_string_literal: true
+
+module Liquid
+  module Compile
+    module Tags
+      # Compiles {% continue %} tags
+      #
+      # Continue is implemented with Ruby's native `next` statement.
+      # Since we use a while loop (not each), `next` correctly skips
+      # to the next iteration, but we must increment the index first.
+      class ContinueCompiler
+        def self.compile(_tag, compiler, code)
+          # Get the index variable from the loop context
+          loop_ctx = compiler.current_loop_context
+          if loop_ctx && loop_ctx[:idx_var]
+            # Increment index before next, otherwise we'd infinite loop
+            code.line "#{loop_ctx[:idx_var]} += 1"
+          end
+          code.line "next"
+        end
+      end
+    end
+  end
+end

lib/liquid/compile/tags/cycle_compiler.rb

@@ -0,0 +1,45 @@
+# frozen_string_literal: true
+
+module Liquid
+  module Compile
+    module Tags
+      # Compiles {% cycle 'a', 'b', 'c' %} tags
+      #
+      # Cycles through a list of values, outputting the next one each iteration
+      class CycleCompiler
+        def self.compile(tag, compiler, code)
+          variables = tag.variables
+          name_expr = ExpressionCompiler.compile(tag.instance_variable_get(:@name), compiler)
+          is_named = tag.named?
+
+          cycle_var = compiler.generate_var_name("cycle")
+          key_var = compiler.generate_var_name("cycle_key")
+
+          # Initialize cycle storage if needed
+          code.line "assigns[:__cycle__] ||= {}"
+
+          # Get the cycle key
+          if is_named
+            code.line "#{key_var} = #{name_expr}"
+          else
+            code.line "#{key_var} = #{variables.object_id}"
+          end
+
+          # Get current index
+          code.line "#{cycle_var} = assigns[:__cycle__][#{key_var}].to_i"
+
+          # Get the value at current index
+          code.line "case #{cycle_var} % #{variables.size}"
+          variables.each_with_index do |var, idx|
+            var_expr = ExpressionCompiler.compile(var, compiler)
+            code.line "when #{idx} then __output__ << LR.to_s(#{var_expr})"
+          end
+          code.line "end"
+
+          # Increment counter
+          code.line "assigns[:__cycle__][#{key_var}] = #{cycle_var} + 1"
+        end
+      end
+    end
+  end
+end

lib/liquid/compile/tags/decrement_compiler.rb

@@ -0,0 +1,26 @@
+# frozen_string_literal: true
+
+module Liquid
+  module Compile
+    module Tags
+      # Compiles {% decrement var %} tags
+      #
+      # Decrements a counter and outputs its value.
+      # Uses a separate namespace from regular assigns (shares with increment).
+      class DecrementCompiler
+        def self.compile(tag, compiler, code)
+          var_name = tag.variable_name
+
+          # Initialize counter storage if needed
+          code.line "assigns[:__counters__] ||= {}"
+
+          # Get current value (default 0), decrement it, output, then store
+          dec_var = compiler.generate_var_name("dec")
+          code.line "#{dec_var} = (assigns[:__counters__][#{var_name.inspect}] || 0) - 1"
+          code.line "assigns[:__counters__][#{var_name.inspect}] = #{dec_var}"
+          code.line "__output__ << #{dec_var}.to_s"
+        end
+      end
+    end
+  end
+end

lib/liquid/compile/tags/echo_compiler.rb

@@ -0,0 +1,17 @@
+# frozen_string_literal: true
+
+module Liquid
+  module Compile
+    module Tags
+      # Compiles {% echo expression %} tags
+      #
+      # Same as {{ expression }} but usable in {% liquid %} blocks
+      class EchoCompiler
+        def self.compile(tag, compiler, code)
+          variable = tag.variable
+          VariableCompiler.compile(variable, compiler, code)
+        end
+      end
+    end
+  end
+end

lib/liquid/compile/tags/for_compiler.rb

@@ -0,0 +1,339 @@
+# frozen_string_literal: true
+
+require 'set'
+
+module Liquid
+  module Compile
+    module Tags
+      # Compiles {% for %} / {% else %} / {% endfor %} tags
+      #
+      # Supports:
+      # - Iteration: {% for item in collection %}
+      # - Limit/Offset: {% for item in collection limit:3 offset:2 %}
+      # - Reversed: {% for item in collection reversed %}
+      # - Forloop object: forloop.index, forloop.first, forloop.last, etc.
+      # - Else block: {% for item in collection %}...{% else %}empty{% endfor %}
+      #
+      # Optimizations:
+      # - Detects break/continue usage at compile time
+      # - Uses while loop with index for minimal overhead
+      # - Break implemented with flag variable (no catch/throw)
+      # - Continue implemented with next (native Ruby)
+      # - Avoids Hash allocation for forloop when not used
+      class ForCompiler
+        def self.compile(tag, compiler, code)
+          var_name = tag.variable_name
+          collection_expr = ExpressionCompiler.compile(tag.collection_name, compiler)
+
+          # Generate unique variable names for this loop
+          coll_var = compiler.generate_var_name("coll")
+          idx_var = compiler.generate_var_name("idx")
+          len_var = compiler.generate_var_name("len")
+
+          # Evaluate the collection and convert to array for indexed access
+          # After this, coll_var is guaranteed to be an Array (or nil)
+          code.line "#{coll_var} = #{collection_expr}"
+          code.line "#{coll_var} = LR.to_array(#{coll_var})"
+
+          # Handle limit and offset
+          if tag.from || tag.limit
+            compile_slice(tag, coll_var, compiler, code)
+          end
+
+          # Handle reversed
+          if tag.instance_variable_get(:@reversed)
+            code.line "#{coll_var} = #{coll_var}.reverse"
+          end
+
+          # Check if collection is empty for else block
+          for_block = tag.instance_variable_get(:@for_block)
+          else_block = tag.instance_variable_get(:@else_block)
+
+          if else_block
+            code.line "if #{coll_var}.nil? || #{coll_var}.empty?"
+            code.indent do
+              BlockBodyCompiler.compile(else_block, compiler, code)
+            end
+            code.line "else"
+            code.indent do
+              compile_loop(tag, var_name, coll_var, idx_var, len_var, for_block, compiler, code)
+            end
+            code.line "end"
+          else
+            code.line "if #{coll_var} && !#{coll_var}.empty?"
+            code.indent do
+              compile_loop(tag, var_name, coll_var, idx_var, len_var, for_block, compiler, code)
+            end
+            code.line "end"
+          end
+        end
+
+        private
+
+        def self.compile_slice(tag, coll_var, compiler, code)
+          from_expr = if tag.from == :continue
+            # Continue from previous offset - we'd need register tracking for this
+            # For now, default to 0
+            "0"
+          elsif tag.from
+            ExpressionCompiler.compile(tag.from, compiler)
+          else
+            "0"
+          end
+
+          if tag.limit
+            limit_expr = ExpressionCompiler.compile(tag.limit, compiler)
+            code.line "#{coll_var} = #{coll_var}[LR.to_integer(#{from_expr}), LR.to_integer(#{limit_expr})] || []"
+          else
+            code.line "#{coll_var} = #{coll_var}.drop(LR.to_integer(#{from_expr}))"
+          end
+        end
+
+        def self.compile_loop(tag, var_name, coll_var, idx_var, len_var, for_block, compiler, code)
+          # Analyze loop body for break/continue usage and forloop access
+          has_break = contains_tag?(for_block, Break)
+          forloop_props = detect_forloop_properties(for_block)
+          uses_forloop = !forloop_props.empty?
+
+          # Calculate length (needed for forloop or bounds checking)
+          code.line "#{len_var} = #{coll_var}.length"
+          code.line "#{idx_var} = 0"
+
+          # Break uses a flag variable - no catch/throw overhead
+          if has_break
+            break_var = compiler.generate_var_name("brk")
+            code.line "#{break_var} = false"
+            code.line "while #{idx_var} < #{len_var} && !#{break_var}"
+          else
+            code.line "while #{idx_var} < #{len_var}"
+          end
+
+          # Check if all forloop properties can be inlined (no hash needed)
+          inlinable_props = %w[index index0 rindex rindex0 first last length name]
+          needs_forloop_hash = uses_forloop && !forloop_props.all? { |p| inlinable_props.include?(p) }
+
+          code.indent do
+            # Set the loop variable directly from array index
+            code.line "assigns[#{var_name.inspect}] = #{coll_var}[#{idx_var}]"
+
+            # Only create forloop hash if we have properties that can't be inlined
+            if needs_forloop_hash
+              compile_forloop_hash(tag, idx_var, len_var, code)
+            end
+
+            # Compile the loop body
+            # The BreakCompiler/ContinueCompiler will emit the right code
+            # based on the context we pass through the compiler
+            compiler.push_loop_context(
+              break_var: has_break ? break_var : nil,
+              idx_var: idx_var,
+              len_var: len_var,
+              loop_name: tag.instance_variable_get(:@name)
+            )
+            BlockBodyCompiler.compile(for_block, compiler, code)
+            compiler.pop_loop_context
+
+            # Increment index
+            code.line "#{idx_var} += 1"
+          end
+          code.line "end"
+
+          # Clean up
+          code.line "assigns.delete(#{var_name.inspect})"
+          code.line "assigns.delete('forloop')" if needs_forloop_hash
+        end
+
+        def self.compile_forloop_hash(tag, idx_var, len_var, code)
+          loop_name = tag.instance_variable_get(:@name)
+          code.line "assigns['forloop'] = {"
+          code.indent do
+            code.line "'name' => #{loop_name.inspect},"
+            code.line "'length' => #{len_var},"
+            code.line "'index' => #{idx_var} + 1,"
+            code.line "'index0' => #{idx_var},"
+            code.line "'rindex' => #{len_var} - #{idx_var},"
+            code.line "'rindex0' => #{len_var} - #{idx_var} - 1,"
+            code.line "'first' => #{idx_var} == 0,"
+            code.line "'last' => #{idx_var} == #{len_var} - 1,"
+          end
+          code.line "}"
+        end
+
+        # Check if a block body contains a specific tag type (recursively)
+        def self.contains_tag?(body, tag_class)
+          return false if body.nil?
+          nodelist = body.nodelist
+          return false if nodelist.nil?
+
+          nodelist.any? do |node|
+            case node
+            when tag_class
+              true
+            when Block
+              # Check nested blocks (if, for, case, etc.)
+              contains_tag?(node.instance_variable_get(:@body), tag_class) ||
+                (node.respond_to?(:nodelist) && contains_tag_in_nodelist?(node.nodelist, tag_class))
+            when Tag
+              # Tags with blocks
+              check_tag_for_nested(node, tag_class)
+            else
+              false
+            end
+          end
+        end
+
+        def self.check_tag_for_nested(tag, tag_class)
+          # Check various block-holding tags
+          [:@for_block, :@else_block, :@body, :@consequent, :@alternative].each do |ivar|
+            if tag.instance_variable_defined?(ivar)
+              block = tag.instance_variable_get(ivar)
+              return true if contains_tag?(block, tag_class)
+            end
+          end
+
+          # Check If tag's blocks array
+          if tag.respond_to?(:blocks)
+            tag.blocks.each do |block|
+              if block.respond_to?(:attachment)
+                return true if contains_tag?(block.attachment, tag_class)
+              end
+            end
+          end
+
+          false
+        end
+
+        def self.contains_tag_in_nodelist?(nodelist, tag_class)
+          return false if nodelist.nil?
+          nodelist.any? { |n| n.is_a?(tag_class) || (n.is_a?(Tag) && check_tag_for_nested(n, tag_class)) }
+        end
+
+        # Check if the loop body accesses forloop variable
+        def self.uses_forloop_var?(body)
+          return false if body.nil?
+          nodelist = body.nodelist
+          return false if nodelist.nil?
+
+          nodelist.any? do |node|
+            case node
+            when Variable
+              # Check if variable references forloop
+              lookup = node.name
+              if lookup.is_a?(VariableLookup)
+                return true if lookup.name == 'forloop'
+              end
+              false
+            when Tag
+              # Recursively check tag bodies and conditions
+              check_tag_for_forloop(node)
+            else
+              false
+            end
+          end
+        end
+
+        def self.check_tag_for_forloop(tag)
+          # Check block bodies
+          [:@for_block, :@else_block, :@body, :@consequent, :@alternative].each do |ivar|
+            if tag.instance_variable_defined?(ivar)
+              block = tag.instance_variable_get(ivar)
+              return true if uses_forloop_var?(block)
+            end
+          end
+
+          # Check If/Unless/Case conditions
+          if tag.respond_to?(:blocks)
+            tag.blocks.each do |block|
+              # Check condition expressions
+              if block.respond_to?(:left) && variable_references_forloop?(block.left)
+                return true
+              end
+              if block.respond_to?(:right) && variable_references_forloop?(block.right)
+                return true
+              end
+              # Check block attachment (body)
+              if block.respond_to?(:attachment)
+                return true if uses_forloop_var?(block.attachment)
+              end
+            end
+          end
+
+          false
+        end
+
+        # Check if an expression references forloop variable
+        def self.variable_references_forloop?(expr)
+          case expr
+          when VariableLookup
+            expr.name == 'forloop'
+          when Variable
+            expr.name.is_a?(VariableLookup) && expr.name.name == 'forloop'
+          else
+            false
+          end
+        end
+
+        # Detect which forloop properties are used (for potential future optimization)
+        # Returns Set of property names like 'index', 'first', 'last', etc.
+        def self.detect_forloop_properties(body)
+          props = Set.new
+          collect_forloop_properties(body, props)
+          props
+        end
+
+        def self.collect_forloop_properties(body, props)
+          return if body.nil?
+          nodelist = body.nodelist
+          return if nodelist.nil?
+
+          nodelist.each do |node|
+            case node
+            when Variable
+              collect_forloop_from_variable(node, props)
+            when Tag
+              collect_forloop_from_tag(node, props)
+            end
+          end
+        end
+
+        def self.collect_forloop_from_variable(var, props)
+          lookup = var.name
+          if lookup.is_a?(VariableLookup) && lookup.name == 'forloop'
+            lookup.lookups.each do |prop|
+              props << prop if prop.is_a?(String)
+            end
+          end
+        end
+
+        def self.collect_forloop_from_tag(tag, props)
+          # Check block bodies
+          [:@for_block, :@else_block, :@body, :@consequent, :@alternative].each do |ivar|
+            if tag.instance_variable_defined?(ivar)
+              collect_forloop_properties(tag.instance_variable_get(ivar), props)
+            end
+          end
+
+          # Check conditions
+          if tag.respond_to?(:blocks)
+            tag.blocks.each do |block|
+              collect_forloop_from_condition(block, props) if block.respond_to?(:left)
+              collect_forloop_properties(block.attachment, props) if block.respond_to?(:attachment)
+            end
+          end
+        end
+
+        def self.collect_forloop_from_condition(condition, props)
+          [condition.left, condition.right].compact.each do |expr|
+            if expr.is_a?(VariableLookup) && expr.name == 'forloop'
+              expr.lookups.each do |prop|
+                props << prop if prop.is_a?(String)
+              end
+            end
+          end
+          # Check child conditions
+          collect_forloop_from_condition(condition.child_condition, props) if condition.respond_to?(:child_condition) && condition.child_condition
+        end
+      end
+    end
+  end
+end

lib/liquid/compile/tags/if_compiler.rb

@@ -0,0 +1,34 @@
+# frozen_string_literal: true
+
+module Liquid
+  module Compile
+    module Tags
+      # Compiles {% if %} / {% elsif %} / {% else %} / {% endif %} tags
+      class IfCompiler
+        def self.compile(tag, compiler, code)
+          blocks = tag.blocks
+
+          blocks.each_with_index do |block, index|
+            condition_expr = ConditionCompiler.compile(block, compiler)
+
+            if index == 0
+              code.line "if #{condition_expr}"
+            elsif block.else?
+              code.line "else"
+            else
+              code.line "elsif #{condition_expr}"
+            end
+
+            code.indent do
+              if block.attachment
+                BlockBodyCompiler.compile(block.attachment, compiler, code)
+              end
+            end
+          end
+
+          code.line "end"
+        end
+      end
+    end
+  end
+end

lib/liquid/compile/tags/ifchanged_compiler.rb

@@ -0,0 +1,40 @@
+# frozen_string_literal: true
+
+module Liquid
+  module Compile
+    module Tags
+      # Compiles {% ifchanged %}...{% endifchanged %} tags
+      #
+      # Only outputs if the content has changed since last render
+      class IfchangedCompiler
+        def self.compile(tag, compiler, code)
+          capture_var = compiler.generate_var_name("ifchanged")
+
+          # Capture the block output
+          code.line "#{capture_var} = +''"
+          code.line "begin"
+          code.indent do
+            code.line "__saved_output__ = __output__"
+            code.line "__output__ = #{capture_var}"
+
+            # Compile the body
+            tag.nodelist.each do |body|
+              BlockBodyCompiler.compile(body, compiler, code)
+            end
+
+            code.line "__output__ = __saved_output__"
+          end
+          code.line "end"
+
+          # Only output if changed
+          code.line "if #{capture_var} != assigns[:__ifchanged__]"
+          code.indent do
+            code.line "assigns[:__ifchanged__] = #{capture_var}"
+            code.line "__output__ << #{capture_var}"
+          end
+          code.line "end"
+        end
+      end
+    end
+  end
+end

lib/liquid/compile/tags/include_compiler.rb

@@ -0,0 +1,119 @@
+# frozen_string_literal: true
+
+module Liquid
+  module Compile
+    module Tags
+      # Compiles {% include 'partial' %} tags
+      #
+      # Include is deprecated in favor of render, but we support it for compatibility.
+      # Unlike render, include shares the outer scope with the partial.
+      #
+      # For static template names, the partial is loaded and inlined at compile time.
+      # For dynamic template names, a runtime fallback is generated.
+      class IncludeCompiler
+        def self.compile(tag, compiler, code)
+          template_name_expr = tag.template_name_expr
+          variable_name_expr = tag.variable_name_expr
+          attributes = tag.attributes
+          alias_name = tag.instance_variable_get(:@alias_name)
+
+          # Check if the template name is a static string
+          if template_name_expr.is_a?(String)
+            compile_static_include(tag, template_name_expr, compiler, code)
+          else
+            compile_dynamic_include(tag, compiler, code)
+          end
+        end
+
+        private
+
+        def self.compile_static_include(tag, template_name, compiler, code)
+          variable_name_expr = tag.variable_name_expr
+          attributes = tag.attributes
+          alias_name = tag.instance_variable_get(:@alias_name)
+
+          # Try to load the partial at compile time
+          partial_source = compiler.load_partial(template_name)
+
+          if partial_source
+            if compiler.debug?
+              code.line "# Inlined partial #{template_name.inspect} at compile time"
+              code.line "$stderr.puts '* WARN: Liquid file system access - inlined partial ' + #{template_name.inspect} + ' at compile time' if $VERBOSE"
+            end
+            # Generate a unique method name for this partial
+            method_name = compiler.register_partial(template_name, partial_source)
+            context_var_name = alias_name || template_name.split('/').last
+
+            # Include shares scope, so we just set variables directly
+            code.line "# Include: #{template_name}"
+
+            # Set attributes
+            attributes.each do |key, value|
+              value_expr = ExpressionCompiler.compile(value, compiler)
+              code.line "assigns[#{key.inspect}] = #{value_expr}"
+            end
+
+            # Set the context variable
+            if variable_name_expr
+              var_expr = ExpressionCompiler.compile(variable_name_expr, compiler)
+              var_var = compiler.generate_var_name("incvar")
+              code.line "#{var_var} = #{var_expr}"
+
+              # If it's an array, loop through it
+              code.line "if #{var_var}.is_a?(Array)"
+              code.indent do
+                code.line "#{var_var}.each do |__include_item__|"
+                code.indent do
+                  code.line "assigns[#{context_var_name.inspect}] = __include_item__"
+                  code.line "__output__ << #{method_name}({})"
+                end
+                code.line "end"
+              end
+              code.line "else"
+              code.indent do
+                code.line "assigns[#{context_var_name.inspect}] = #{var_var}"
+                code.line "__output__ << #{method_name}({})"
+              end
+              code.line "end"
+            else
+              # Try to find a variable with the same name as the template
+              code.line "assigns[#{context_var_name.inspect}] = assigns[#{template_name.inspect}] if assigns.key?(#{template_name.inspect})"
+              code.line "__output__ << #{method_name}({})"
+            end
+          else
+            # Partial not found at compile time
+            code.line "# Partial '#{template_name}' not found at compile time"
+            compile_dynamic_include(tag, compiler, code)
+          end
+        end
+
+        def self.compile_dynamic_include(tag, compiler, code)
+          template_name_expr = tag.template_name_expr
+          variable_name_expr = tag.variable_name_expr
+          attributes = tag.attributes
+          alias_name = tag.instance_variable_get(:@alias_name)
+
+          if compiler.debug?
+            code.line "# Dynamic include (template name from variable)"
+          end
+
+          name_expr = ExpressionCompiler.compile(template_name_expr, compiler)
+
+          # Build attributes hash
+          attrs_var = compiler.generate_var_name("attrs")
+          code.line "#{attrs_var} = {}"
+          attributes.each do |key, value|
+            value_expr = ExpressionCompiler.compile(value, compiler)
+            code.line "#{attrs_var}[#{key.inspect}] = #{value_expr}"
+          end
+
+          var_expr = variable_name_expr ? ExpressionCompiler.compile(variable_name_expr, compiler) : "nil"
+          alias_expr = alias_name ? alias_name.inspect : "nil"
+
+          # Call the external handler for dynamic includes
+          code.line "__output__ << __external__.call(:include, #{name_expr}, #{var_expr}, #{attrs_var}, #{alias_expr}, assigns, __context__)"
+        end
+      end
+    end
+  end
+end

lib/liquid/compile/tags/increment_compiler.rb

@@ -0,0 +1,26 @@
+# frozen_string_literal: true
+
+module Liquid
+  module Compile
+    module Tags
+      # Compiles {% increment var %} tags
+      #
+      # Outputs the current counter value, then increments it.
+      # Uses a separate namespace from regular assigns (shares with decrement).
+      class IncrementCompiler
+        def self.compile(tag, compiler, code)
+          var_name = tag.variable_name
+
+          # Initialize counter storage if needed
+          code.line "assigns[:__counters__] ||= {}"
+
+          # Get current value (default 0), output it, then increment
+          inc_var = compiler.generate_var_name("inc")
+          code.line "#{inc_var} = assigns[:__counters__][#{var_name.inspect}] || 0"
+          code.line "__output__ << #{inc_var}.to_s"
+          code.line "assigns[:__counters__][#{var_name.inspect}] = #{inc_var} + 1"
+        end
+      end
+    end
+  end
+end

lib/liquid/compile/tags/raw_compiler.rb

@@ -0,0 +1,19 @@
+# frozen_string_literal: true
+
+module Liquid
+  module Compile
+    module Tags
+      # Compiles {% raw %}...{% endraw %} tags
+      #
+      # Outputs the content as-is without parsing Liquid syntax
+      class RawCompiler
+        def self.compile(tag, compiler, code)
+          body = tag.instance_variable_get(:@body)
+          return if body.nil? || body.empty?
+
+          code.line "__output__ << #{body.inspect}"
+        end
+      end
+    end
+  end
+end

lib/liquid/compile/tags/render_compiler.rb

@@ -0,0 +1,176 @@
+# frozen_string_literal: true
+
+module Liquid
+  module Compile
+    module Tags
+      # Compiles {% render 'partial' %} tags
+      #
+      # For static template names (string literals), the partial is loaded at
+      # compile time and inlined as a method.
+      #
+      # For dynamic template names (variables), a runtime fallback is generated
+      # that calls __render_dynamic__ which must be provided by the runtime.
+      class RenderCompiler
+        def self.compile(tag, compiler, code)
+          template_name_expr = tag.template_name_expr
+          variable_name_expr = tag.variable_name_expr
+          attributes = tag.attributes
+          alias_name = tag.alias_name
+          is_for_loop = tag.for_loop?
+
+          # Check if the template name is a static string
+          if template_name_expr.is_a?(String)
+            compile_static_render(tag, template_name_expr, compiler, code)
+          else
+            compile_dynamic_render(tag, compiler, code)
+          end
+        end
+
+        private
+
+        def self.compile_static_render(tag, template_name, compiler, code)
+          variable_name_expr = tag.variable_name_expr
+          attributes = tag.attributes
+          alias_name = tag.alias_name
+          is_for_loop = tag.for_loop?
+
+          # Try to load the partial at compile time
+          partial_source = compiler.load_partial(template_name)
+
+          if partial_source
+            if compiler.debug?
+              code.line "# Inlined partial #{template_name.inspect} at compile time"
+              code.line "$stderr.puts '* WARN: Liquid file system access - inlined partial ' + #{template_name.inspect} + ' at compile time' if $VERBOSE"
+            end
+            # Generate a unique method name for this partial
+            method_name = compiler.register_partial(template_name, partial_source)
+            context_var_name = alias_name || template_name.split('/').last
+
+            if is_for_loop && variable_name_expr
+              # Render for each item in collection
+              compile_for_loop_render(tag, method_name, context_var_name, compiler, code)
+            else
+              # Single render
+              compile_single_render(tag, method_name, context_var_name, compiler, code)
+            end
+          else
+            # Partial not found at compile time - generate runtime fallback
+            code.line "# Partial '#{template_name}' not found at compile time"
+            compile_dynamic_render(tag, compiler, code)
+          end
+        end
+
+        def self.compile_single_render(tag, method_name, context_var_name, compiler, code)
+          variable_name_expr = tag.variable_name_expr
+          attributes = tag.attributes
+
+          # Build the inner assigns hash
+          inner_assigns_var = compiler.generate_var_name("inner")
+          code.line "#{inner_assigns_var} = {}"
+
+          # Copy attributes
+          attributes.each do |key, value|
+            value_expr = ExpressionCompiler.compile(value, compiler)
+            code.line "#{inner_assigns_var}[#{key.inspect}] = #{value_expr}"
+          end
+
+          # Set the context variable if provided
+          if variable_name_expr
+            var_expr = ExpressionCompiler.compile(variable_name_expr, compiler)
+            code.line "#{inner_assigns_var}[#{context_var_name.inspect}] = #{var_expr}"
+          end
+
+          # Call the partial method
+          code.line "__output__ << #{method_name}(#{inner_assigns_var})"
+        end
+
+        def self.compile_for_loop_render(tag, method_name, context_var_name, compiler, code)
+          variable_name_expr = tag.variable_name_expr
+          attributes = tag.attributes
+          template_name = tag.template_name_expr
+
+          coll_var = compiler.generate_var_name("coll")
+          coll_expr = ExpressionCompiler.compile(variable_name_expr, compiler)
+          code.line "#{coll_var} = #{coll_expr}"
+
+          code.line "if #{coll_var}.respond_to?(:each) && #{coll_var}.respond_to?(:count)"
+          code.indent do
+            len_var = compiler.generate_var_name("len")
+            idx_var = compiler.generate_var_name("idx")
+            code.line "#{len_var} = #{coll_var}.count"
+            code.line "#{idx_var} = 0"
+
+            code.line "#{coll_var}.each do |__item__|"
+            code.indent do
+              inner_assigns_var = compiler.generate_var_name("inner")
+              code.line "#{inner_assigns_var} = {}"
+
+              # Copy attributes
+              attributes.each do |key, value|
+                value_expr = ExpressionCompiler.compile(value, compiler)
+                code.line "#{inner_assigns_var}[#{key.inspect}] = #{value_expr}"
+              end
+
+              # Set the context variable
+              code.line "#{inner_assigns_var}[#{context_var_name.inspect}] = __item__"
+
+              # Set forloop
+              code.line "#{inner_assigns_var}['forloop'] = {"
+              code.indent do
+                code.line "'name' => #{template_name.inspect},"
+                code.line "'length' => #{len_var},"
+                code.line "'index' => #{idx_var} + 1,"
+                code.line "'index0' => #{idx_var},"
+                code.line "'rindex' => #{len_var} - #{idx_var},"
+                code.line "'rindex0' => #{len_var} - #{idx_var} - 1,"
+                code.line "'first' => #{idx_var} == 0,"
+                code.line "'last' => #{idx_var} == #{len_var} - 1,"
+              end
+              code.line "}"
+
+              # Call the partial method
+              code.line "__output__ << #{method_name}(#{inner_assigns_var})"
+
+              code.line "#{idx_var} += 1"
+            end
+            code.line "end"
+          end
+          code.line "else"
+          code.indent do
+            # Single render if not a collection
+            compile_single_render(tag, method_name, context_var_name, compiler, code)
+          end
+          code.line "end"
+        end
+
+        def self.compile_dynamic_render(tag, compiler, code)
+          template_name_expr = tag.template_name_expr
+          variable_name_expr = tag.variable_name_expr
+          attributes = tag.attributes
+          alias_name = tag.alias_name
+          is_for_loop = tag.for_loop?
+
+          if compiler.debug?
+            code.line "# Dynamic render (template name from variable)"
+          end
+
+          name_expr = ExpressionCompiler.compile(template_name_expr, compiler)
+
+          # Build attributes hash
+          attrs_var = compiler.generate_var_name("attrs")
+          code.line "#{attrs_var} = {}"
+          attributes.each do |key, value|
+            value_expr = ExpressionCompiler.compile(value, compiler)
+            code.line "#{attrs_var}[#{key.inspect}] = #{value_expr}"
+          end
+
+          var_expr = variable_name_expr ? ExpressionCompiler.compile(variable_name_expr, compiler) : "nil"
+          alias_expr = alias_name ? alias_name.inspect : "nil"
+
+          # Call the external handler for dynamic renders
+          code.line "__output__ << __external__.call(:render, #{name_expr}, #{var_expr}, #{attrs_var}, #{alias_expr}, #{is_for_loop}, __context__)"
+        end
+      end
+    end
+  end
+end

lib/liquid/compile/tags/tablerow_compiler.rb

@@ -0,0 +1,117 @@
+# frozen_string_literal: true
+
+module Liquid
+  module Compile
+    module Tags
+      # Compiles {% tablerow %} tags
+      #
+      # Creates HTML table rows from a collection
+      class TableRowCompiler
+        def self.compile(tag, compiler, code)
+          var_name = tag.variable_name
+          collection_expr = ExpressionCompiler.compile(tag.collection_name, compiler)
+          attributes = tag.attributes
+
+          # Generate unique variable names
+          coll_var = compiler.generate_var_name("coll")
+          idx_var = compiler.generate_var_name("idx")
+          len_var = compiler.generate_var_name("len")
+          cols_var = compiler.generate_var_name("cols")
+          row_var = compiler.generate_var_name("row")
+          col_var = compiler.generate_var_name("col")
+
+          # Get parameters from attributes hash
+          cols = attributes['cols']
+          cols_expr = cols ? ExpressionCompiler.compile(cols, compiler) : "nil"
+
+          # Evaluate the collection
+          code.line "#{coll_var} = #{collection_expr}"
+          code.line "#{coll_var} = #{coll_var}.to_a if #{coll_var}.is_a?(Range)"
+
+          # Handle limit and offset from attributes
+          offset = attributes['offset']
+          limit = attributes['limit']
+          if offset || limit
+            if offset
+              offset_expr = ExpressionCompiler.compile(offset, compiler)
+              if limit
+                limit_expr = ExpressionCompiler.compile(limit, compiler)
+                code.line "#{coll_var} = #{coll_var}.slice(LR.to_integer(#{offset_expr}), LR.to_integer(#{limit_expr})) || []"
+              else
+                code.line "#{coll_var} = #{coll_var}.drop(LR.to_integer(#{offset_expr}))"
+              end
+            elsif limit
+              limit_expr = ExpressionCompiler.compile(limit, compiler)
+              code.line "#{coll_var} = #{coll_var}.first(LR.to_integer(#{limit_expr}))"
+            end
+          end
+
+          # Setup loop variables
+          code.line "#{len_var} = #{coll_var}.respond_to?(:length) ? #{coll_var}.length : 0"
+          code.line "#{cols_var} = #{cols_expr} || #{len_var}"
+          code.line "#{idx_var} = 0"
+          code.line "#{row_var} = 1"
+          code.line "#{col_var} = 0"
+
+          body = tag.instance_variable_get(:@body)
+
+          # Output initial row (matches interpreter behavior: outputs before loop)
+          code.line "__output__ << \"<tr class=\\\"row1\\\">\\n\""
+
+          # The loop
+          code.line "(#{coll_var}.respond_to?(:each) ? #{coll_var} : []).each do |__item__|"
+          code.indent do
+            code.line "#{col_var} += 1"
+
+            # Output cell start
+            code.line "__output__ << \"<td class=\\\"col\#{#{col_var}}\\\">\""
+
+            # Set loop variables
+            code.line "assigns[#{var_name.inspect}] = __item__"
+            code.line "assigns['tablerowloop'] = {"
+            code.indent do
+              code.line "'length' => #{len_var},"
+              code.line "'index' => #{idx_var} + 1,"
+              code.line "'index0' => #{idx_var},"
+              code.line "'rindex' => #{len_var} - #{idx_var},"
+              code.line "'rindex0' => #{len_var} - #{idx_var} - 1,"
+              code.line "'first' => #{idx_var} == 0,"
+              code.line "'last' => #{idx_var} == #{len_var} - 1,"
+              code.line "'col' => #{col_var},"
+              code.line "'col0' => #{col_var} - 1,"
+              code.line "'row' => #{row_var},"
+              code.line "'col_first' => #{col_var} == 1,"
+              code.line "'col_last' => #{col_var} == #{cols_var},"
+            end
+            code.line "}"
+
+            # Compile the body
+            BlockBodyCompiler.compile(body, compiler, code)
+
+            # Output cell end
+            code.line "__output__ << '</td>'"
+
+            # End row and start new row if needed (but not on last item)
+            code.line "if #{col_var} == #{cols_var} && #{idx_var} != #{len_var} - 1"
+            code.indent do
+              code.line "__output__ << \"</tr>\\n<tr class=\\\"row\#{#{row_var} + 1}\\\">\""
+              code.line "#{col_var} = 0"
+              code.line "#{row_var} += 1"
+            end
+            code.line "end"
+
+            code.line "#{idx_var} += 1"
+          end
+          code.line "end"
+
+          # Close the final row
+          code.line "__output__ << \"</tr>\\n\""
+
+          # Clean up
+          code.line "assigns.delete(#{var_name.inspect})"
+          code.line "assigns.delete('tablerowloop')"
+        end
+      end
+    end
+  end
+end

lib/liquid/compile/tags/unless_compiler.rb

@@ -0,0 +1,38 @@
+# frozen_string_literal: true
+
+module Liquid
+  module Compile
+    module Tags
+      # Compiles {% unless %} / {% elsif %} / {% else %} / {% endunless %} tags
+      #
+      # Unless is like if, but the first condition is negated
+      class UnlessCompiler
+        def self.compile(tag, compiler, code)
+          blocks = tag.blocks
+
+          blocks.each_with_index do |block, index|
+            condition_expr = ConditionCompiler.compile(block, compiler)
+
+            if index == 0
+              # First block is negated (unless = if not)
+              code.line "unless #{condition_expr}"
+            elsif block.else?
+              code.line "else"
+            else
+              # Subsequent blocks (elsif) are normal
+              code.line "elsif #{condition_expr}"
+            end
+
+            code.indent do
+              if block.attachment
+                BlockBodyCompiler.compile(block.attachment, compiler, code)
+              end
+            end
+          end
+
+          code.line "end"
+        end
+      end
+    end
+  end
+end

lib/liquid/compile/variable_compiler.rb

@@ -0,0 +1,37 @@
+# frozen_string_literal: true
+
+module Liquid
+  module Compile
+    # VariableCompiler compiles Liquid variable expressions ({{ ... }}) to Ruby code.
+    #
+    # A Variable consists of:
+    # - A name expression (the value to output)
+    # - Zero or more filters to apply
+    class VariableCompiler
+      # Compile a Variable node and append the result to the output buffer
+      # @param variable [Liquid::Variable] The variable node
+      # @param compiler [RubyCompiler] The main compiler instance
+      # @param code [CodeGenerator] The code generator
+      def self.compile(variable, compiler, code)
+        value_expr = compile_to_expression(variable, compiler)
+        code.line "__output__ << LR.output(#{value_expr})"
+      end
+
+      # Compile a Variable node to a Ruby expression (without output)
+      # @param variable [Liquid::Variable] The variable node
+      # @param compiler [RubyCompiler] The main compiler instance
+      # @return [String] Ruby code expression
+      def self.compile_to_expression(variable, compiler)
+        # Compile the base name expression
+        base_expr = ExpressionCompiler.compile(variable.name, compiler)
+
+        # Apply filters if any
+        if variable.filters && !variable.filters.empty?
+          FilterCompiler.compile(base_expr, variable.filters, compiler)
+        else
+          base_expr
+        end
+      end
+    end
+  end
+end

lib/liquid/condition.rb

@@ -24,6 +24,9 @@ module Liquid
         else
           false
         end
+      rescue Encoding::CompatibilityError
+        # "✅".b.include?("✅") raises Encoding::CompatibilityError despite being materially equal
+        left.b.include?(right.b)
       end,
     }
 
@@ -61,7 +64,7 @@ module Liquid
       @child_condition = nil
     end
 
-    def evaluate(context = Context.new)
+    def evaluate(context = deprecated_default_context)
       condition = self
       result = nil
       loop do
@@ -69,9 +72,9 @@ module Liquid
 
         case condition.child_relation
         when :or
-          break if result
+          break if Liquid::Utils.to_liquid_value(result)
         when :and
-          break unless result
+          break unless Liquid::Utils.to_liquid_value(result)
         else
           break
         end
@@ -150,11 +153,19 @@ module Liquid
       end
     end
 
+    def deprecated_default_context
+      warn("DEPRECATION WARNING: Condition#evaluate without a context argument is deprecated" \
+        " and will be removed from Liquid 6.0.0.")
+      Context.new
+    end
+
     class ParseTreeVisitor < Liquid::ParseTreeVisitor
       def children
         [
-          @node.left, @node.right,
-          @node.child_condition, @node.attachment
+          @node.left,
+          @node.right,
+          @node.child_condition,
+          @node.attachment
         ].compact
       end
     end

lib/liquid/const.rb

@@ -0,0 +1,8 @@
+# frozen_string_literal: true
+
+module Liquid
+  module Const
+    EMPTY_HASH = {}.freeze
+    EMPTY_ARRAY = [].freeze
+  end
+end

lib/liquid/context.rb

@@ -15,31 +15,40 @@ module Liquid
   #   context['bob']  #=> nil  class Context
   class Context
     attr_reader :scopes, :errors, :registers, :environments, :resource_limits, :static_registers, :static_environments
-    attr_accessor :exception_renderer, :template_name, :partial, :global_filter, :strict_variables, :strict_filters
+    attr_accessor :exception_renderer, :template_name, :partial, :global_filter, :strict_variables, :strict_filters, :environment
 
     # rubocop:disable Metrics/ParameterLists
-    def self.build(environments: {}, outer_scope: {}, registers: {}, rethrow_errors: false, resource_limits: nil, static_environments: {}, &block)
-      new(environments, outer_scope, registers, rethrow_errors, resource_limits, static_environments, &block)
+    def self.build(environment: Environment.default, environments: {}, outer_scope: {}, registers: {}, rethrow_errors: false, resource_limits: nil, static_environments: {}, &block)
+      new(environments, outer_scope, registers, rethrow_errors, resource_limits, static_environments, environment, &block)
     end
 
-    def initialize(environments = {}, outer_scope = {}, registers = {}, rethrow_errors = false, resource_limits = nil, static_environments = {})
+    def initialize(environments = {}, outer_scope = {}, registers = {}, rethrow_errors = false, resource_limits = nil, static_environments = {}, environment = Environment.default)
+      @environment = environment
       @environments = [environments]
       @environments.flatten!
 
-      @static_environments = [static_environments].flat_map(&:freeze).freeze
-      @scopes              = [(outer_scope || {})]
-      @registers           = registers
+      @static_environments = [static_environments].flatten(1).freeze
+      @scopes              = [outer_scope || {}]
+      @registers           = registers.is_a?(Registers) ? registers : Registers.new(registers)
       @errors              = []
       @partial             = false
       @strict_variables    = false
-      @resource_limits     = resource_limits || ResourceLimits.new(Template.default_resource_limits)
+      @resource_limits     = resource_limits || ResourceLimits.new(environment.default_resource_limits)
       @base_scope_depth    = 0
       @interrupts          = []
       @filters             = []
       @global_filter       = nil
       @disabled_tags       = {}
 
-      self.exception_renderer = Template.default_exception_renderer
+      # Instead of constructing new StringScanner objects for each Expression parse,
+      # we recycle the same one.
+      @string_scanner = StringScanner.new("")
+
+      @registers.static[:cached_partials] ||= {}
+      @registers.static[:file_system] ||= environment.file_system
+      @registers.static[:template_factory] ||= Liquid::TemplateFactory.new
+
+      self.exception_renderer = environment.exception_renderer
       if rethrow_errors
         self.exception_renderer = Liquid::RAISE_EXCEPTION_LAMBDA
       end
@@ -56,7 +65,7 @@ module Liquid
     end
 
     def strainer
-      @strainer ||= StrainerFactory.create(self, @filters)
+      @strainer ||= @environment.create_strainer(self, @filters)
     end
 
     # Adds filters to this context.
@@ -138,9 +147,10 @@ module Liquid
       check_overflow
 
       self.class.build(
+        environment: @environment,
         resource_limits: resource_limits,
         static_environments: static_environments,
-        registers: StaticRegisters.new(registers)
+        registers: Registers.new(registers),
       ).tap do |subcontext|
         subcontext.base_scope_depth   = base_scope_depth + 1
         subcontext.exception_renderer = exception_renderer
@@ -170,7 +180,7 @@ module Liquid
     # Example:
     #   products == empty #=> products.empty?
     def [](expression)
-      evaluate(Expression.parse(expression))
+      evaluate(Expression.parse(expression, @string_scanner))
     end
 
     def key?(key)
@@ -193,10 +203,14 @@ module Liquid
         try_variable_find_in_environments(key, raise_on_not_found: raise_on_not_found)
       end
 
-      variable         = variable.to_liquid
+      # update variable's context before invoking #to_liquid
       variable.context = self if variable.respond_to?(:context=)
 
-      variable
+      liquid_variable = variable.to_liquid
+
+      liquid_variable.context = self if variable != liquid_variable && liquid_variable.respond_to?(:context=)
+
+      liquid_variable
     end
 
     def lookup_and_evaluate(obj, key, raise_on_not_found: true)

lib/liquid/deprecations.rb

@@ -0,0 +1,22 @@
+# frozen_string_literal: true
+
+require "set"
+
+module Liquid
+  class Deprecations
+    class << self
+      attr_accessor :warned
+
+      Deprecations.warned = Set.new
+
+      def warn(name, alternative)
+        return if warned.include?(name)
+
+        warned << name
+
+        caller_location = caller_locations(2, 1).first
+        Warning.warn("[DEPRECATION] #{name} is deprecated. Use #{alternative} instead. Called from #{caller_location}\n")
+      end
+    end
+  end
+end

lib/liquid/drop.rb

@@ -25,6 +25,10 @@ module Liquid
   class Drop
     attr_writer :context
 
+    def initialize
+      @context = nil
+    end
+
     # Catch all for the method
     def liquid_method_missing(method)
       return nil unless @context&.strict_variables

lib/liquid/environment.rb

@@ -0,0 +1,159 @@
+# frozen_string_literal: true
+
+module Liquid
+  # The Environment is the container for all configuration options of Liquid, such as
+  # the registered tags, filters, and the default error mode.
+  class Environment
+    # The default error mode for all templates. This can be overridden on a
+    # per-template basis.
+    attr_accessor :error_mode
+
+    # The tags that are available to use in the template.
+    attr_accessor :tags
+
+    # The strainer template which is used to store filters that are available to
+    # use in templates.
+    attr_accessor :strainer_template
+
+    # The exception renderer that is used to render exceptions that are raised
+    # when rendering a template
+    attr_accessor :exception_renderer
+
+    # The default file system that is used to load templates from.
+    attr_accessor :file_system
+
+    # The default resource limits that are used to limit the resources that a
+    # template can consume.
+    attr_accessor :default_resource_limits
+
+    class << self
+      # Creates a new environment instance.
+      #
+      # @param tags [Hash] The tags that are available to use in
+      #  the template.
+      # @param file_system The default file system that is used
+      #  to load templates from.
+      # @param error_mode [Symbol] The default error mode for all templates
+      #  (either :strict, :warn, or :lax).
+      # @param exception_renderer [Proc] The exception renderer that is used to
+      #   render exceptions.
+      # @yieldparam environment [Environment] The environment instance that is being built.
+      # @return [Environment] The new environment instance.
+      def build(tags: nil, file_system: nil, error_mode: nil, exception_renderer: nil)
+        ret = new
+        ret.tags = tags if tags
+        ret.file_system = file_system if file_system
+        ret.error_mode = error_mode if error_mode
+        ret.exception_renderer = exception_renderer if exception_renderer
+        yield ret if block_given?
+        ret.freeze
+      end
+
+      # Returns the default environment instance.
+      #
+      # @return [Environment] The default environment instance.
+      def default
+        @default ||= new
+      end
+
+      # Sets the default environment instance for the duration of the block
+      #
+      # @param environment [Environment] The environment instance to use as the default for the
+      #   duration of the block.
+      # @yield
+      # @return [Object] The return value of the block.
+      def dangerously_override(environment)
+        original_default = @default
+        @default = environment
+        yield
+      ensure
+        @default = original_default
+      end
+    end
+
+    # Initializes a new environment instance.
+    # @api private
+    def initialize
+      @tags = Tags::STANDARD_TAGS.dup
+      @error_mode = :lax
+      @strainer_template = Class.new(StrainerTemplate).tap do |klass|
+        klass.add_filter(StandardFilters)
+      end
+      @exception_renderer = ->(exception) { exception }
+      @file_system = BlankFileSystem.new
+      @default_resource_limits = Const::EMPTY_HASH
+      @strainer_template_class_cache = {}
+    end
+
+    # Registers a new tag with the environment.
+    #
+    # @param name [String] The name of the tag.
+    # @param klass [Liquid::Tag] The class that implements the tag.
+    # @return [void]
+    def register_tag(name, klass)
+      @tags[name] = klass
+    end
+
+    # Registers a new filter with the environment.
+    #
+    # @param filter [Module] The module that contains the filter methods.
+    # @return [void]
+    def register_filter(filter)
+      @strainer_template_class_cache.clear
+      @strainer_template.add_filter(filter)
+    end
+
+    # Registers multiple filters with this environment.
+    #
+    # @param filters [Array<Module>] The modules that contain the filter methods.
+    # @return [self]
+    def register_filters(filters)
+      @strainer_template_class_cache.clear
+      filters.each { |f| @strainer_template.add_filter(f) }
+      self
+    end
+
+    # Creates a new strainer instance with the given filters, caching the result
+    # for faster lookup.
+    #
+    # @param context [Liquid::Context] The context that the strainer will be
+    #   used in.
+    # @param filters [Array<Module>] The filters that the strainer will have
+    #   access to.
+    # @return [Liquid::Strainer] The new strainer instance.
+    def create_strainer(context, filters = Const::EMPTY_ARRAY)
+      return @strainer_template.new(context) if filters.empty?
+
+      strainer_template = @strainer_template_class_cache[filters] ||= begin
+        klass = Class.new(@strainer_template)
+        filters.each { |f| klass.add_filter(f) }
+        klass
+      end
+
+      strainer_template.new(context)
+    end
+
+    # Returns the names of all the filter methods that are available to use in
+    # the strainer template.
+    #
+    # @return [Array<String>] The names of all the filter methods.
+    def filter_method_names
+      @strainer_template.filter_method_names
+    end
+
+    # Returns the tag class for the given tag name.
+    #
+    # @param name [String] The name of the tag.
+    # @return [Liquid::Tag] The tag class.
+    def tag_for_name(name)
+      @tags[name]
+    end
+
+    def freeze
+      @tags.freeze
+      # TODO: freeze the tags, currently this is not possible because of liquid-c
+      # @strainer_template.freeze
+      super
+    end
+  end
+end

lib/liquid/errors.rb

@@ -40,19 +40,20 @@ module Liquid
     end
   end
 
-  ArgumentError       = Class.new(Error)
-  ContextError        = Class.new(Error)
-  FileSystemError     = Class.new(Error)
-  StandardError       = Class.new(Error)
-  SyntaxError         = Class.new(Error)
-  StackLevelError     = Class.new(Error)
-  MemoryError         = Class.new(Error)
-  ZeroDivisionError   = Class.new(Error)
-  FloatDomainError    = Class.new(Error)
-  UndefinedVariable   = Class.new(Error)
-  UndefinedDropMethod = Class.new(Error)
-  UndefinedFilter     = Class.new(Error)
-  MethodOverrideError = Class.new(Error)
-  DisabledError       = Class.new(Error)
-  InternalError       = Class.new(Error)
+  ArgumentError         = Class.new(Error)
+  ContextError          = Class.new(Error)
+  FileSystemError       = Class.new(Error)
+  StandardError         = Class.new(Error)
+  SyntaxError           = Class.new(Error)
+  StackLevelError       = Class.new(Error)
+  MemoryError           = Class.new(Error)
+  ZeroDivisionError     = Class.new(Error)
+  FloatDomainError      = Class.new(Error)
+  UndefinedVariable     = Class.new(Error)
+  UndefinedDropMethod   = Class.new(Error)
+  UndefinedFilter       = Class.new(Error)
+  MethodOverrideError   = Class.new(Error)
+  DisabledError         = Class.new(Error)
+  InternalError         = Class.new(Error)
+  TemplateEncodingError = Class.new(Error)
 end

lib/liquid/expression.rb

@@ -3,40 +3,120 @@
 module Liquid
   class Expression
     LITERALS = {
-      nil => nil, 'nil' => nil, 'null' => nil, '' => nil,
+      nil => nil,
+      'nil' => nil,
+      'null' => nil,
+      '' => nil,
       'true' => true,
       'false' => false,
       'blank' => '',
-      'empty' => ''
+      'empty' => '',
+      # in lax mode, minus sign can be a VariableLookup
+      # For simplicity and performace, we treat it like a literal
+      '-' => VariableLookup.parse("-", nil).freeze,
     }.freeze
 
-    SINGLE_QUOTED_STRING = /\A\s*'(.*)'\s*\z/m
-    DOUBLE_QUOTED_STRING = /\A\s*"(.*)"\s*\z/m
-    INTEGERS_REGEX       = /\A\s*(-?\d+)\s*\z/
-    FLOATS_REGEX         = /\A\s*(-?\d[\d\.]+)\s*\z/
+    DOT = ".".ord
+    ZERO = "0".ord
+    NINE = "9".ord
+    DASH = "-".ord
 
     # Use an atomic group (?>...) to avoid pathological backtracing from
     # malicious input as described in https://github.com/Shopify/liquid/issues/1357
-    RANGES_REGEX         = /\A\s*\(\s*(?>(\S+)\s*\.\.)\s*(\S+)\s*\)\s*\z/
+    RANGES_REGEX = /\A\(\s*(?>(\S+)\s*\.\.)\s*(\S+)\s*\)\z/
+    INTEGER_REGEX = /\A(-?\d+)\z/
+    FLOAT_REGEX = /\A(-?\d+)\.\d+\z/
 
-    def self.parse(markup)
-      case markup
-      when nil
-        nil
-      when SINGLE_QUOTED_STRING, DOUBLE_QUOTED_STRING
-        Regexp.last_match(1)
-      when INTEGERS_REGEX
-        Regexp.last_match(1).to_i
-      when RANGES_REGEX
-        RangeLookup.parse(Regexp.last_match(1), Regexp.last_match(2))
-      when FLOATS_REGEX
-        Regexp.last_match(1).to_f
-      else
-        markup = markup.strip
-        if LITERALS.key?(markup)
-          LITERALS[markup]
+    class << self
+      def parse(markup, ss = StringScanner.new(""), cache = nil)
+        return unless markup
+
+        markup = markup.strip # markup can be a frozen string
+
+        if (markup.start_with?('"') && markup.end_with?('"')) ||
+          (markup.start_with?("'") && markup.end_with?("'"))
+          return markup[1..-2]
+        elsif LITERALS.key?(markup)
+          return LITERALS[markup]
+        end
+
+        # Cache only exists during parsing
+        if cache
+          return cache[markup] if cache.key?(markup)
+
+          cache[markup] = inner_parse(markup, ss, cache).freeze
         else
-          VariableLookup.parse(markup)
+          inner_parse(markup, ss, nil).freeze
+        end
+      end
+
+      def inner_parse(markup, ss, cache)
+        if (markup.start_with?("(") && markup.end_with?(")")) && markup =~ RANGES_REGEX
+          return RangeLookup.parse(
+            Regexp.last_match(1),
+            Regexp.last_match(2),
+            ss,
+            cache,
+          )
+        end
+
+        if (num = parse_number(markup, ss))
+          num
+        else
+          VariableLookup.parse(markup, ss, cache)
+        end
+      end
+
+      def parse_number(markup, ss)
+        # check if the markup is simple integer or float
+        case markup
+        when INTEGER_REGEX
+          return Integer(markup, 10)
+        when FLOAT_REGEX
+          return markup.to_f
+        end
+
+        ss.string = markup
+        # the first byte must be a digit or  a dash
+        byte = ss.scan_byte
+
+        return false if byte != DASH && (byte < ZERO || byte > NINE)
+
+        if byte == DASH
+          peek_byte = ss.peek_byte
+
+          # if it starts with a dash, the next byte must be a digit
+          return false if peek_byte.nil? || !(peek_byte >= ZERO && peek_byte <= NINE)
+        end
+
+        # The markup could be a float with multiple dots
+        first_dot_pos = nil
+        num_end_pos = nil
+
+        while (byte = ss.scan_byte)
+          return false if byte != DOT && (byte < ZERO || byte > NINE)
+
+          # we found our number and now we are just scanning the rest of the string
+          next if num_end_pos
+
+          if byte == DOT
+            if first_dot_pos.nil?
+              first_dot_pos = ss.pos
+            else
+              # we found another dot, so we know that the number ends here
+              num_end_pos = ss.pos - 1
+            end
+          end
+        end
+
+        num_end_pos = markup.length if ss.eos?
+
+        if num_end_pos
+          # number ends with a number "123.123"
+          markup.byteslice(0, num_end_pos).to_f
+        else
+          # number ends with a dot "123."
+          markup.byteslice(0, first_dot_pos).to_f
         end
       end
     end

lib/liquid/forloop_drop.rb

@@ -1,6 +1,11 @@
 # frozen_string_literal: true
 
 module Liquid
+  # @liquid_public_docs
+  # @liquid_type object
+  # @liquid_name forloop
+  # @liquid_summary
+  #   Information about a parent [`for` loop](/docs/api/liquid/tags/for).
   class ForloopDrop < Drop
     def initialize(name, length, parentloop)
       @name       = name
@@ -9,33 +14,68 @@ module Liquid
       @index      = 0
     end
 
-    attr_reader :length, :parentloop
+    # @liquid_public_docs
+    # @liquid_name length
+    # @liquid_summary
+    #   The total number of iterations in the loop.
+    # @liquid_return [number]
+    attr_reader :length
 
-    def name
-      Usage.increment('forloop_drop_name')
-      @name
-    end
+    # @liquid_public_docs
+    # @liquid_name parentloop
+    # @liquid_summary
+    #   The parent `forloop` object.
+    # @liquid_description
+    #   If the current `for` loop isn't nested inside another `for` loop, then `nil` is returned.
+    # @liquid_return [forloop]
+    attr_reader :parentloop
 
+    attr_reader :name
+
+    # @liquid_public_docs
+    # @liquid_summary
+    #   The 1-based index of the current iteration.
+    # @liquid_return [number]
     def index
       @index + 1
     end
 
+    # @liquid_public_docs
+    # @liquid_summary
+    #   The 0-based index of the current iteration.
+    # @liquid_return [number]
     def index0
       @index
     end
 
+    # @liquid_public_docs
+    # @liquid_summary
+    #   The 1-based index of the current iteration, in reverse order.
+    # @liquid_return [number]
     def rindex
       @length - @index
     end
 
+    # @liquid_public_docs
+    # @liquid_summary
+    #   The 0-based index of the current iteration, in reverse order.
+    # @liquid_return [number]
     def rindex0
       @length - @index - 1
     end
 
+    # @liquid_public_docs
+    # @liquid_summary
+    #   Returns `true` if the current iteration is the first. Returns `false` if not.
+    # @liquid_return [boolean]
     def first
       @index == 0
     end
 
+    # @liquid_public_docs
+    # @liquid_summary
+    #   Returns `true` if the current iteration is the last. Returns `false` if not.
+    # @liquid_return [boolean]
     def last
       @index == @length - 1
     end

lib/liquid/lexer.rb

@@ -1,62 +1,179 @@
 # frozen_string_literal: true
 
-require "strscan"
 module Liquid
   class Lexer
-    SPECIALS = {
-      '|' => :pipe,
-      '.' => :dot,
-      ':' => :colon,
-      ',' => :comma,
-      '[' => :open_square,
-      ']' => :close_square,
-      '(' => :open_round,
-      ')' => :close_round,
-      '?' => :question,
-      '-' => :dash,
-    }.freeze
-    IDENTIFIER            = /[a-zA-Z_][\w-]*\??/
-    SINGLE_STRING_LITERAL = /'[^\']*'/
+    CLOSE_ROUND = [:close_round, ")"].freeze
+    CLOSE_SQUARE = [:close_square, "]"].freeze
+    COLON = [:colon, ":"].freeze
+    COMMA = [:comma, ","].freeze
+    COMPARISION_NOT_EQUAL = [:comparison, "!="].freeze
+    COMPARISON_CONTAINS = [:comparison, "contains"].freeze
+    COMPARISON_EQUAL = [:comparison, "=="].freeze
+    COMPARISON_GREATER_THAN = [:comparison, ">"].freeze
+    COMPARISON_GREATER_THAN_OR_EQUAL = [:comparison, ">="].freeze
+    COMPARISON_LESS_THAN = [:comparison, "<"].freeze
+    COMPARISON_LESS_THAN_OR_EQUAL = [:comparison, "<="].freeze
+    COMPARISON_NOT_EQUAL_ALT = [:comparison, "<>"].freeze
+    DASH = [:dash, "-"].freeze
+    DOT = [:dot, "."].freeze
+    DOTDOT = [:dotdot, ".."].freeze
+    DOT_ORD = ".".ord
     DOUBLE_STRING_LITERAL = /"[^\"]*"/
+    EOS = [:end_of_string].freeze
+    IDENTIFIER            = /[a-zA-Z_][\w-]*\??/
     NUMBER_LITERAL        = /-?\d+(\.\d+)?/
-    DOTDOT                = /\.\./
-    COMPARISON_OPERATOR   = /==|!=|<>|<=?|>=?|contains(?=\s)/
+    OPEN_ROUND = [:open_round, "("].freeze
+    OPEN_SQUARE = [:open_square, "["].freeze
+    PIPE = [:pipe, "|"].freeze
+    QUESTION = [:question, "?"].freeze
+    RUBY_WHITESPACE = [" ", "\t", "\r", "\n", "\f"].freeze
+    SINGLE_STRING_LITERAL = /'[^\']*'/
     WHITESPACE_OR_NOTHING = /\s*/
 
-    def initialize(input)
-      @ss = StringScanner.new(input)
+    SINGLE_COMPARISON_TOKENS = [].tap do |table|
+      table["<".ord] = COMPARISON_LESS_THAN
+      table[">".ord] = COMPARISON_GREATER_THAN
+      table.freeze
     end
 
-    def tokenize
-      @output = []
+    TWO_CHARS_COMPARISON_JUMP_TABLE = [].tap do |table|
+      table["=".ord] = [].tap do |sub_table|
+        sub_table["=".ord] = COMPARISON_EQUAL
+        sub_table.freeze
+      end
+      table["!".ord] = [].tap do |sub_table|
+        sub_table["=".ord] = COMPARISION_NOT_EQUAL
+        sub_table.freeze
+      end
+      table.freeze
+    end
 
-      until @ss.eos?
-        @ss.skip(WHITESPACE_OR_NOTHING)
-        break if @ss.eos?
-        tok      = if (t = @ss.scan(COMPARISON_OPERATOR))
-          [:comparison, t]
-        elsif (t = @ss.scan(SINGLE_STRING_LITERAL))
-          [:string, t]
-        elsif (t = @ss.scan(DOUBLE_STRING_LITERAL))
-          [:string, t]
-        elsif (t = @ss.scan(NUMBER_LITERAL))
-          [:number, t]
-        elsif (t = @ss.scan(IDENTIFIER))
-          [:id, t]
-        elsif (t = @ss.scan(DOTDOT))
-          [:dotdot, t]
-        else
-          c     = @ss.getch
-          if (s = SPECIALS[c])
-            [s, c]
+    COMPARISON_JUMP_TABLE = [].tap do |table|
+      table["<".ord] = [].tap do |sub_table|
+        sub_table["=".ord] = COMPARISON_LESS_THAN_OR_EQUAL
+        sub_table[">".ord] = COMPARISON_NOT_EQUAL_ALT
+        sub_table.freeze
+      end
+      table[">".ord] = [].tap do |sub_table|
+        sub_table["=".ord] = COMPARISON_GREATER_THAN_OR_EQUAL
+        sub_table.freeze
+      end
+      table.freeze
+    end
+
+    NEXT_MATCHER_JUMP_TABLE = [].tap do |table|
+      "a".upto("z") do |c|
+        table[c.ord] = [:id, IDENTIFIER].freeze
+        table[c.upcase.ord] = [:id, IDENTIFIER].freeze
+      end
+      table["_".ord] = [:id, IDENTIFIER].freeze
+
+      "0".upto("9") do |c|
+        table[c.ord] = [:number, NUMBER_LITERAL].freeze
+      end
+      table["-".ord] = [:number, NUMBER_LITERAL].freeze
+
+      table["'".ord] = [:string, SINGLE_STRING_LITERAL].freeze
+      table["\"".ord] = [:string, DOUBLE_STRING_LITERAL].freeze
+      table.freeze
+    end
+
+    SPECIAL_TABLE = [].tap do |table|
+      table["|".ord] = PIPE
+      table[".".ord] = DOT
+      table[":".ord] = COLON
+      table[",".ord] = COMMA
+      table["[".ord] = OPEN_SQUARE
+      table["]".ord] = CLOSE_SQUARE
+      table["(".ord] = OPEN_ROUND
+      table[")".ord] = CLOSE_ROUND
+      table["?".ord] = QUESTION
+      table["-".ord] = DASH
+    end
+
+    NUMBER_TABLE = [].tap do |table|
+      "0".upto("9") do |c|
+        table[c.ord] = true
+      end
+      table.freeze
+    end
+
+    # rubocop:disable Metrics/BlockNesting
+    class << self
+      def tokenize(ss)
+        output = []
+
+        until ss.eos?
+          ss.skip(WHITESPACE_OR_NOTHING)
+
+          break if ss.eos?
+
+          start_pos = ss.pos
+          peeked = ss.peek_byte
+
+          if (special = SPECIAL_TABLE[peeked])
+            ss.scan_byte
+            # Special case for ".."
+            if special == DOT && ss.peek_byte == DOT_ORD
+              ss.scan_byte
+              output << DOTDOT
+            elsif special == DASH
+              # Special case for negative numbers
+              if (peeked_byte = ss.peek_byte) && NUMBER_TABLE[peeked_byte]
+                ss.pos -= 1
+                output << [:number, ss.scan(NUMBER_LITERAL)]
+              else
+                output << special
+              end
+            else
+              output << special
+            end
+          elsif (sub_table = TWO_CHARS_COMPARISON_JUMP_TABLE[peeked])
+            ss.scan_byte
+            if (peeked_byte = ss.peek_byte) && (found = sub_table[peeked_byte])
+              output << found
+              ss.scan_byte
+            else
+              raise_syntax_error(start_pos, ss)
+            end
+          elsif (sub_table = COMPARISON_JUMP_TABLE[peeked])
+            ss.scan_byte
+            if (peeked_byte = ss.peek_byte) && (found = sub_table[peeked_byte])
+              output << found
+              ss.scan_byte
+            else
+              output << SINGLE_COMPARISON_TOKENS[peeked]
+            end
           else
-            raise SyntaxError, "Unexpected character #{c}"
+            type, pattern = NEXT_MATCHER_JUMP_TABLE[peeked]
+
+            if type && (t = ss.scan(pattern))
+              # Special case for "contains"
+              output << if type == :id && t == "contains" && output.last&.first != :dot
+                COMPARISON_CONTAINS
+              else
+                [type, t]
+              end
+            else
+              raise_syntax_error(start_pos, ss)
+            end
           end
         end
-        @output << tok
+        # rubocop:enable Metrics/BlockNesting
+        output << EOS
+      rescue ::ArgumentError => e
+        if e.message == "invalid byte sequence in #{ss.string.encoding}"
+          raise SyntaxError, "Invalid byte sequence in #{ss.string.encoding}"
+        else
+          raise
+        end
       end
 
-      @output << [:end_of_string]
+      def raise_syntax_error(start_pos, ss)
+        ss.pos = start_pos
+        # the character could be a UTF-8 character, use getch to get all the bytes
+        raise SyntaxError, "Unexpected character #{ss.getch}"
+      end
     end
   end
 end

lib/liquid/locales/en.yml

@@ -2,26 +2,30 @@
   errors:
     syntax:
       tag_unexpected_args: "Syntax Error in '%{tag}' - Valid syntax: %{tag}"
+      block_tag_unexpected_args: "Syntax Error in '%{tag}' - Valid syntax: {% %{tag} %}{% end%{tag} %}"
       assign: "Syntax Error in 'assign' - Valid syntax: assign [var] = [source]"
       capture: "Syntax Error in 'capture' - Valid syntax: capture [var]"
       case: "Syntax Error in 'case' - Valid syntax: case [condition]"
       case_invalid_when: "Syntax Error in tag 'case' - Valid when condition: {% when [condition] [or condition2...] %}"
       case_invalid_else: "Syntax Error in tag 'case' - Valid else condition: {% else %} (no parameters) "
       cycle: "Syntax Error in 'cycle' - Valid syntax: cycle [name :] var [, var2, var3 ...]"
+      doc_invalid_nested: "Syntax Error in 'doc' - Nested doc tags are not allowed"
       for: "Syntax Error in 'for loop' - Valid syntax: for [item] in [collection]"
       for_invalid_in: "For loops require an 'in' clause"
       for_invalid_attribute: "Invalid attribute in for loop. Valid attributes are limit and offset"
       if: "Syntax Error in tag 'if' - Valid syntax: if [expression]"
       include: "Error in tag 'include' - Valid syntax: include '[template]' (with|for) [object|collection]"
-      unknown_tag: "Unknown tag '%{tag}'"
+      inline_comment_invalid: "Syntax error in tag '#' - Each line of comments must be prefixed by the '#' character"
       invalid_delimiter: "'%{tag}' is not a valid delimiter for %{block_name} tags. use %{block_delimiter}"
+      invalid_template_encoding: "Invalid template encoding"
+      render: "Syntax error in tag 'render' - Template name must be a quoted string"
+      table_row: "Syntax Error in 'table_row loop' - Valid syntax: table_row [item] in [collection] cols=3"
+      tag_never_closed: "'%{block_name}' tag was never closed"
+      tag_termination: "Tag '%{token}' was not properly terminated with regexp: %{tag_end}"
       unexpected_else: "%{block_name} tag does not expect 'else' tag"
       unexpected_outer_tag: "Unexpected outer '%{tag}' tag"
-      tag_termination: "Tag '%{token}' was not properly terminated with regexp: %{tag_end}"
+      unknown_tag: "Unknown tag '%{tag}'"
       variable_termination: "Variable '%{token}' was not properly terminated with regexp: %{tag_end}"
-      tag_never_closed: "'%{block_name}' tag was never closed"
-      table_row: "Syntax Error in 'table_row loop' - Valid syntax: table_row [item] in [collection] cols=3"
-      render: "Syntax error in tag 'render' - Template name must be a quoted string"
     argument:
       include: "Argument error in tag 'include' - Illegal template name"
     disabled:

lib/liquid/parse_context.rb

@@ -3,14 +3,27 @@
 module Liquid
   class ParseContext
     attr_accessor :locale, :line_number, :trim_whitespace, :depth
-    attr_reader :partial, :warnings, :error_mode
+    attr_reader :partial, :warnings, :error_mode, :environment
 
-    def initialize(options = {})
+    def initialize(options = Const::EMPTY_HASH)
+      @environment = options.fetch(:environment, Environment.default)
       @template_options = options ? options.dup : {}
 
       @locale   = @template_options[:locale] ||= I18n.new
       @warnings = []
 
+      # constructing new StringScanner in Lexer, Tokenizer, etc is expensive
+      # This StringScanner will be shared by all of them
+      @string_scanner = StringScanner.new("")
+
+      @expression_cache = if options[:expression_cache].nil?
+        {}
+      elsif options[:expression_cache].respond_to?(:[]) && options[:expression_cache].respond_to?(:[]=)
+        options[:expression_cache]
+      elsif options[:expression_cache]
+        {}
+      end
+
       self.depth   = 0
       self.partial = false
     end
@@ -23,19 +36,29 @@ module Liquid
       Liquid::BlockBody.new
     end
 
-    def new_tokenizer(markup, start_line_number: nil, for_liquid_tag: false)
-      Tokenizer.new(markup, line_number: start_line_number, for_liquid_tag: for_liquid_tag)
+    def new_parser(input)
+      @string_scanner.string = input
+      Parser.new(@string_scanner)
+    end
+
+    def new_tokenizer(source, start_line_number: nil, for_liquid_tag: false)
+      Tokenizer.new(
+        source: source,
+        string_scanner: @string_scanner,
+        line_number: start_line_number,
+        for_liquid_tag: for_liquid_tag,
+      )
     end
 
     def parse_expression(markup)
-      Expression.parse(markup)
+      Expression.parse(markup, @string_scanner, @expression_cache)
     end
 
     def partial=(value)
       @partial = value
       @options = value ? partial_options : @template_options
 
-      @error_mode = @options[:error_mode] || Template.error_mode
+      @error_mode = @options[:error_mode] || @environment.error_mode
     end
 
     def partial_options

lib/liquid/parse_tree_visitor.rb

@@ -36,7 +36,7 @@ module Liquid
     protected
 
     def children
-      @node.respond_to?(:nodelist) ? Array(@node.nodelist) : []
+      @node.respond_to?(:nodelist) ? Array(@node.nodelist) : Const::EMPTY_ARRAY
     end
   end
 end

lib/liquid/parser.rb

@@ -3,8 +3,8 @@
 module Liquid
   class Parser
     def initialize(input)
-      l       = Lexer.new(input)
-      @tokens = l.tokenize
+      ss = input.is_a?(StringScanner) ? input : StringScanner.new(input)
+      @tokens = Lexer.tokenize(ss)
       @p      = 0 # pointer to current location
     end
 
@@ -53,7 +53,7 @@ module Liquid
         str = consume
         str << variable_lookups
       when :open_square
-        str = consume
+        str = consume.dup
         str << expression
         str << consume(:close_square)
         str << variable_lookups

lib/liquid/partial_cache.rb

@@ -3,20 +3,29 @@
 module Liquid
   class PartialCache
     def self.load(template_name, context:, parse_context:)
-      cached_partials = (context.registers[:cached_partials] ||= {})
-      cached = cached_partials[template_name]
+      cached_partials = context.registers[:cached_partials]
+      cache_key = "#{template_name}:#{parse_context.error_mode}"
+      cached = cached_partials[cache_key]
       return cached if cached
 
-      file_system = (context.registers[:file_system] ||= Liquid::Template.file_system)
+      file_system = context.registers[:file_system]
       source      = file_system.read_template_file(template_name)
 
       parse_context.partial = true
 
-      template_factory = (context.registers[:template_factory] ||= Liquid::TemplateFactory.new)
+      template_factory = context.registers[:template_factory]
       template = template_factory.for(template_name)
 
-      partial = template.parse(source, parse_context)
-      cached_partials[template_name] = partial
+      begin
+        partial = template.parse(source, parse_context)
+      rescue Liquid::Error => e
+        e.template_name = template&.name || template_name
+        raise e
+      end
+
+      partial.name ||= template_name
+
+      cached_partials[cache_key] = partial
     ensure
       parse_context.partial = false
     end

lib/liquid/range_lookup.rb

@@ -2,13 +2,23 @@
 
 module Liquid
   class RangeLookup
-    def self.parse(start_markup, end_markup)
-      start_obj = Expression.parse(start_markup)
-      end_obj   = Expression.parse(end_markup)
+    def self.parse(start_markup, end_markup, string_scanner, cache = nil)
+      start_obj = Expression.parse(start_markup, string_scanner, cache)
+      end_obj   = Expression.parse(end_markup, string_scanner, cache)
       if start_obj.respond_to?(:evaluate) || end_obj.respond_to?(:evaluate)
         new(start_obj, end_obj)
       else
-        start_obj.to_i..end_obj.to_i
+        begin
+          start_obj.to_i..end_obj.to_i
+        rescue NoMethodError
+          invalid_expr = start_markup unless start_obj.respond_to?(:to_i)
+          invalid_expr ||= end_markup unless end_obj.respond_to?(:to_i)
+          if invalid_expr
+            raise Liquid::SyntaxError, "Invalid expression type '#{invalid_expr}' in range expression"
+          end
+
+          raise
+        end
       end
     end
 

lib/liquid/register.rb

@@ -1,6 +0,0 @@
-# frozen_string_literal: true
-
-module Liquid
-  class Register
-  end
-end

lib/liquid/registers.rb

@@ -0,0 +1,51 @@
+# frozen_string_literal: true
+
+module Liquid
+  class Registers
+    attr_reader :static
+
+    def initialize(registers = {})
+      @static = registers.is_a?(Registers) ? registers.static : registers
+      @changes = {}
+    end
+
+    def []=(key, value)
+      @changes[key] = value
+    end
+
+    def [](key)
+      if @changes.key?(key)
+        @changes[key]
+      else
+        @static[key]
+      end
+    end
+
+    def delete(key)
+      @changes.delete(key)
+    end
+
+    UNDEFINED = Object.new
+
+    def fetch(key, default = UNDEFINED, &block)
+      if @changes.key?(key)
+        @changes.fetch(key)
+      elsif default != UNDEFINED
+        if block_given?
+          @static.fetch(key, &block)
+        else
+          @static.fetch(key, default)
+        end
+      else
+        @static.fetch(key, &block)
+      end
+    end
+
+    def key?(key)
+      @changes.key?(key) || @static.key?(key)
+    end
+  end
+
+  # Alias for backwards compatibility
+  StaticRegisters = Registers
+end

lib/liquid/static_registers.rb

@@ -1,44 +0,0 @@
-# frozen_string_literal: true
-
-module Liquid
-  class StaticRegisters
-    attr_reader :static
-
-    def initialize(registers = {})
-      @static    = registers.is_a?(StaticRegisters) ? registers.static : registers
-      @registers = {}
-    end
-
-    def []=(key, value)
-      @registers[key] = value
-    end
-
-    def [](key)
-      if @registers.key?(key)
-        @registers[key]
-      else
-        @static[key]
-      end
-    end
-
-    def delete(key)
-      @registers.delete(key)
-    end
-
-    UNDEFINED = Object.new
-
-    def fetch(key, default = UNDEFINED, &block)
-      if @registers.key?(key)
-        @registers.fetch(key)
-      elsif default != UNDEFINED
-        @static.fetch(key, default, &block)
-      else
-        @static.fetch(key, &block)
-      end
-    end
-
-    def key?(key)
-      @registers.key?(key) || @static.key?(key)
-    end
-  end
-end

lib/liquid/strainer_factory.rb

@@ -1,36 +0,0 @@
-# frozen_string_literal: true
-
-module Liquid
-  # StrainerFactory is the factory for the filters system.
-  module StrainerFactory
-    extend self
-
-    def add_global_filter(filter)
-      strainer_class_cache.clear
-      global_filters << filter
-    end
-
-    def create(context, filters = [])
-      strainer_from_cache(filters).new(context)
-    end
-
-    private
-
-    def global_filters
-      @global_filters ||= []
-    end
-
-    def strainer_from_cache(filters)
-      strainer_class_cache[filters] ||= begin
-        klass = Class.new(StrainerTemplate)
-        global_filters.each { |f| klass.add_filter(f) }
-        filters.each { |f| klass.add_filter(f) }
-        klass
-      end
-    end
-
-    def strainer_class_cache
-      @strainer_class_cache ||= {}
-    end
-  end
-end

lib/liquid/strainer_template.rb

@@ -31,6 +31,15 @@ module Liquid
         filter_methods.include?(method.to_s)
       end
 
+      def inherited(subclass)
+        super
+        subclass.instance_variable_set(:@filter_methods, @filter_methods.dup)
+      end
+
+      def filter_method_names
+        filter_methods.map(&:to_s).to_a
+      end
+
       private
 
       def filter_methods

lib/liquid/tablerowloop_drop.rb

@@ -1,6 +1,11 @@
 # frozen_string_literal: true
 
 module Liquid
+  # @liquid_public_docs
+  # @liquid_type object
+  # @liquid_name tablerowloop
+  # @liquid_summary
+  #   Information about a parent [`tablerow` loop](/docs/api/liquid/tags/tablerow).
   class TablerowloopDrop < Drop
     def initialize(length, cols)
       @length = length
@@ -10,40 +15,92 @@ module Liquid
       @index  = 0
     end
 
-    attr_reader :length, :col, :row
+    # @liquid_public_docs
+    # @liquid_summary
+    #   The total number of iterations in the loop.
+    # @liquid_return [number]
+    attr_reader :length
 
+    # @liquid_public_docs
+    # @liquid_summary
+    #   The 1-based index of the current column.
+    # @liquid_return [number]
+    attr_reader :col
+
+    # @liquid_public_docs
+    # @liquid_summary
+    #   The 1-based index of current row.
+    # @liquid_return [number]
+    attr_reader :row
+
+    # @liquid_public_docs
+    # @liquid_summary
+    #   The 1-based index of the current iteration.
+    # @liquid_return [number]
     def index
       @index + 1
     end
 
+    # @liquid_public_docs
+    # @liquid_summary
+    #   The 0-based index of the current iteration.
+    # @liquid_return [number]
     def index0
       @index
     end
 
+    # @liquid_public_docs
+    # @liquid_summary
+    #   The 0-based index of the current column.
+    # @liquid_return [number]
     def col0
       @col - 1
     end
 
+    # @liquid_public_docs
+    # @liquid_summary
+    #   The 1-based index of the current iteration, in reverse order.
+    # @liquid_return [number]
     def rindex
       @length - @index
     end
 
+    # @liquid_public_docs
+    # @liquid_summary
+    #   The 0-based index of the current iteration, in reverse order.
+    # @liquid_return [number]
     def rindex0
       @length - @index - 1
     end
 
+    # @liquid_public_docs
+    # @liquid_summary
+    #   Returns `true` if the current iteration is the first. Returns `false` if not.
+    # @liquid_return [boolean]
     def first
       @index == 0
     end
 
+    # @liquid_public_docs
+    # @liquid_summary
+    #   Returns `true` if the current iteration is the last. Returns `false` if not.
+    # @liquid_return [boolean]
     def last
       @index == @length - 1
     end
 
+    # @liquid_public_docs
+    # @liquid_summary
+    #   Returns `true` if the current column is the first in the row. Returns `false` if not.
+    # @liquid_return [boolean]
     def col_first
       @col == 1
     end
 
+    # @liquid_public_docs
+    # @liquid_summary
+    #   Returns `true` if the current column is the last in the row. Returns `false` if not.
+    # @liquid_return [boolean]
     def col_last
       @col == @cols
     end

lib/liquid/tag.rb

@@ -1,5 +1,8 @@
 # frozen_string_literal: true
 
+require 'liquid/tag/disabler'
+require 'liquid/tag/disableable'
+
 module Liquid
   class Tag
     attr_reader :nodelist, :tag_name, :line_number, :parse_context
@@ -14,12 +17,18 @@ module Liquid
       end
 
       def disable_tags(*tag_names)
-        @disabled_tags ||= []
-        @disabled_tags.concat(tag_names)
+        tag_names += disabled_tags
+        define_singleton_method(:disabled_tags) { tag_names }
         prepend(Disabler)
       end
 
       private :new
+
+      protected
+
+      def disabled_tags
+        []
+      end
     end
 
     def initialize(tag_name, markup, parse_context)
@@ -48,7 +57,8 @@ module Liquid
     # of the `render_to_output_buffer` method will become the default and the `render`
     # method will be removed.
     def render_to_output_buffer(context, output)
-      output << render(context)
+      render_result = render(context)
+      output << render_result if render_result
       output
     end
 

lib/liquid/tag/disabler.rb

@@ -3,14 +3,6 @@
 module Liquid
   class Tag
     module Disabler
-      module ClassMethods
-        attr_reader :disabled_tags
-      end
-
-      def self.prepended(base)
-        base.extend(ClassMethods)
-      end
-
       def render_to_output_buffer(context, output)
         context.with_disabled_tags(self.class.disabled_tags) do
           super

lib/liquid/tags.rb

@@ -0,0 +1,49 @@
+# frozen_string_literal: true
+
+require_relative "tags/table_row"
+require_relative "tags/echo"
+require_relative "tags/if"
+require_relative "tags/break"
+require_relative "tags/inline_comment"
+require_relative "tags/for"
+require_relative "tags/assign"
+require_relative "tags/ifchanged"
+require_relative "tags/case"
+require_relative "tags/include"
+require_relative "tags/continue"
+require_relative "tags/capture"
+require_relative "tags/decrement"
+require_relative "tags/unless"
+require_relative "tags/increment"
+require_relative "tags/comment"
+require_relative "tags/raw"
+require_relative "tags/render"
+require_relative "tags/cycle"
+require_relative "tags/doc"
+
+module Liquid
+  module Tags
+    STANDARD_TAGS = {
+      'cycle' => Cycle,
+      'render' => Render,
+      'raw' => Raw,
+      'comment' => Comment,
+      'increment' => Increment,
+      'unless' => Unless,
+      'decrement' => Decrement,
+      'capture' => Capture,
+      'continue' => Continue,
+      'include' => Include,
+      'case' => Case,
+      'ifchanged' => Ifchanged,
+      'assign' => Assign,
+      'for' => For,
+      '#' => InlineComment,
+      'break' => Break,
+      'if' => If,
+      'echo' => Echo,
+      'tablerow' => TableRow,
+      'doc' => Doc,
+    }.freeze
+  end
+end

lib/liquid/tags/assign.rb

@@ -1,14 +1,18 @@
 # frozen_string_literal: true
 
 module Liquid
-  # Assign sets a variable in your template.
-  #
-  #   {% assign foo = 'monkey' %}
-  #
-  # You can then use the variable later in the page.
-  #
-  #  {{ foo }}
-  #
+  # @liquid_public_docs
+  # @liquid_type tag
+  # @liquid_category variable
+  # @liquid_name assign
+  # @liquid_summary
+  #   Creates a new variable.
+  # @liquid_description
+  #   You can create variables of any [basic type](/docs/api/liquid/basics#types), [object](/docs/api/liquid/objects), or object property.
+  # @liquid_syntax
+  #   {% assign variable_name = value %}
+  # @liquid_syntax_keyword variable_name The name of the variable being created.
+  # @liquid_syntax_keyword value The value you want to assign to the variable.
   class Assign < Tag
     Syntax = /(#{VariableSignature}+)\s*=\s*(.*)\s*/om
 
@@ -68,6 +72,4 @@ module Liquid
       end
     end
   end
-
-  Template.register_tag('assign', Assign)
 end

lib/liquid/tags/break.rb

@@ -10,6 +10,14 @@ module Liquid
   #      {% endif %}
   #    {% endfor %}
   #
+  # @liquid_public_docs
+  # @liquid_type tag
+  # @liquid_category iteration
+  # @liquid_name break
+  # @liquid_summary
+  #   Stops a [`for` loop](/docs/api/liquid/tags/for) from iterating.
+  # @liquid_syntax
+  #   {% break %}
   class Break < Tag
     INTERRUPT = BreakInterrupt.new.freeze
 
@@ -18,6 +26,4 @@ module Liquid
       output
     end
   end
-
-  Template.register_tag('break', Break)
 end

lib/liquid/tags/capture.rb

@@ -1,17 +1,20 @@
 # frozen_string_literal: true
 
 module Liquid
-  # Capture stores the result of a block into a variable without rendering it inplace.
-  #
-  #   {% capture heading %}
-  #     Monkeys!
+  # @liquid_public_docs
+  # @liquid_type tag
+  # @liquid_category variable
+  # @liquid_name capture
+  # @liquid_summary
+  #   Creates a new variable with a string value.
+  # @liquid_description
+  #   You can create complex strings with Liquid logic and variables.
+  # @liquid_syntax
+  #   {% capture variable %}
+  #     value
   #   {% endcapture %}
-  #   ...
-  #   <h1>{{ heading }}</h1>
-  #
-  # Capture is useful for saving content for use later in your template, such as
-  # in a sidebar or footer.
-  #
+  # @liquid_syntax_keyword variable The name of the variable being created.
+  # @liquid_syntax_keyword value The value you want to assign to the variable.
   class Capture < Block
     Syntax = /(#{VariableSignature}+)/o
 
@@ -36,6 +39,4 @@ module Liquid
       true
     end
   end
-
-  Template.register_tag('capture', Capture)
 end

lib/liquid/tags/case.rb

@@ -1,6 +1,27 @@
 # frozen_string_literal: true
 
 module Liquid
+  # @liquid_public_docs
+  # @liquid_type tag
+  # @liquid_category conditional
+  # @liquid_name case
+  # @liquid_summary
+  #   Renders a specific expression depending on the value of a specific variable.
+  # @liquid_syntax
+  #   {% case variable %}
+  #     {% when first_value %}
+  #       first_expression
+  #     {% when second_value %}
+  #       second_expression
+  #     {% else %}
+  #       third_expression
+  #   {% endcase %}
+  # @liquid_syntax_keyword variable The name of the variable you want to base your case statement on.
+  # @liquid_syntax_keyword first_value A specific value to check for.
+  # @liquid_syntax_keyword second_value A specific value to check for.
+  # @liquid_syntax_keyword first_expression An expression to be rendered when the variable's value matches `first_value`.
+  # @liquid_syntax_keyword second_expression An expression to be rendered when the variable's value matches `second_value`.
+  # @liquid_syntax_keyword third_expression An expression to be rendered when the variable's value has no match.
   class Case < Block
     Syntax     = /(#{QuotedFragment})/o
     WhenSyntax = /(#{QuotedFragment})(?:(?:\s+or\s+|\s*\,\s*)(#{QuotedFragment}.*))?/om
@@ -56,7 +77,7 @@ module Liquid
         end
 
         result = Liquid::Utils.to_liquid_value(
-          block.evaluate(context)
+          block.evaluate(context),
         )
 
         if result
@@ -102,6 +123,4 @@ module Liquid
       end
     end
   end
-
-  Template.register_tag('case', Case)
 end

lib/liquid/tags/comment.rb

@@ -1,20 +1,20 @@
 # frozen_string_literal: true
 
 module Liquid
+  # @liquid_public_docs
+  # @liquid_type tag
+  # @liquid_category syntax
+  # @liquid_name comment
+  # @liquid_summary
+  #   Prevents an expression from being rendered or output.
+  # @liquid_description
+  #   Any text inside `comment` tags won't be output, and any Liquid code will be parsed, but not executed.
+  # @liquid_syntax
+  #   {% comment %}
+  #     content
+  #   {% endcomment %}
+  # @liquid_syntax_keyword content The content of the comment.
   class Comment < Block
-    # Potential fix
-    FullTokenPossiblyInvalid = /\A(.*)#{TagStart}#{WhitespaceControl}?\s*(\w+)\s*(.*)?#{WhitespaceControl}?#{TagEnd}\z/om
-
-    def parse(tokens)
-      while (token = tokens.shift)
-        if token =~ FullTokenPossiblyInvalid && block_delimiter == Regexp.last_match(2)
-          return
-        end
-      end
-
-      raise_tag_never_closed(block_name)
-    end
-
     def render_to_output_buffer(_context, output)
       output
     end
@@ -25,7 +25,64 @@ module Liquid
     def blank?
       true
     end
-  end
 
-  Template.register_tag('comment', Comment)
+    private
+
+    def parse_body(body, tokenizer)
+      if parse_context.depth >= MAX_DEPTH
+        raise StackLevelError, "Nesting too deep"
+      end
+
+      parse_context.depth += 1
+      comment_tag_depth = 1
+
+      begin
+        # Consume tokens without creating child nodes.
+        # The children tag doesn't require to be a valid Liquid except the comment and raw tag.
+        # The child comment and raw tag must be closed.
+        while (token = tokenizer.send(:shift))
+          tag_name = if tokenizer.for_liquid_tag
+            next if token.empty? || token.match?(BlockBody::WhitespaceOrNothing)
+
+            tag_name_match = BlockBody::LiquidTagToken.match(token)
+
+            next if tag_name_match.nil?
+
+            tag_name_match[1]
+          else
+            token =~ BlockBody::FullToken
+            Regexp.last_match(2)
+          end
+
+          case tag_name
+          when "raw"
+            parse_raw_tag_body(tokenizer)
+          when "comment"
+            comment_tag_depth += 1
+          when "endcomment"
+            comment_tag_depth -= 1
+          end
+
+          if comment_tag_depth.zero?
+            parse_context.trim_whitespace = (token[-3] == WhitespaceControl) unless tokenizer.for_liquid_tag
+            return false
+          end
+        end
+
+        raise_tag_never_closed(block_name)
+      ensure
+        parse_context.depth -= 1
+      end
+
+      false
+    end
+
+    def parse_raw_tag_body(tokenizer)
+      while (token = tokenizer.send(:shift))
+        return if token =~ BlockBody::FullTokenPossiblyInvalid && "endraw" == Regexp.last_match(2)
+      end
+
+      raise_tag_never_closed("raw")
+    end
+  end
 end

lib/liquid/tags/continue.rb

@@ -1,15 +1,14 @@
 # frozen_string_literal: true
 
 module Liquid
-  # Continue tag to be used to break out of a for loop.
-  #
-  # == Basic Usage:
-  #    {% for item in collection %}
-  #      {% if item.condition %}
-  #        {% continue %}
-  #      {% endif %}
-  #    {% endfor %}
-  #
+  # @liquid_public_docs
+  # @liquid_type tag
+  # @liquid_category iteration
+  # @liquid_name continue
+  # @liquid_summary
+  #   Causes a [`for` loop](/docs/api/liquid/tags/for) to skip to the next iteration.
+  # @liquid_syntax
+  #   {% continue %}
   class Continue < Tag
     INTERRUPT = ContinueInterrupt.new.freeze
 
@@ -18,6 +17,4 @@ module Liquid
       output
     end
   end
-
-  Template.register_tag('continue', Continue)
 end

lib/liquid/tags/cycle.rb

@@ -1,18 +1,19 @@
 # frozen_string_literal: true
 
 module Liquid
-  # Cycle is usually used within a loop to alternate between values, like colors or DOM classes.
-  #
-  #   {% for item in items %}
-  #     <div class="{% cycle 'red', 'green', 'blue' %}"> {{ item }} </div>
-  #   {% end %}
-  #
-  #    <div class="red"> Item one </div>
-  #    <div class="green"> Item two </div>
-  #    <div class="blue"> Item three </div>
-  #    <div class="red"> Item four </div>
-  #    <div class="green"> Item five</div>
+  # @liquid_public_docs
+  # @liquid_type tag
+  # @liquid_category iteration
+  # @liquid_name cycle
+  # @liquid_summary
+  #   Loops through a group of strings and outputs them one at a time for each iteration of a [`for` loop](/docs/api/liquid/tags/for).
+  # @liquid_description
+  #   The `cycle` tag must be used inside a `for` loop.
   #
+  #   > Tip:
+  #   > Use the `cycle` tag to output text in a predictable pattern. For example, to apply odd/even classes to rows in a table.
+  # @liquid_syntax
+  #   {% cycle string, string, ... %}
   class Cycle < Tag
     SimpleSyntax = /\A#{QuotedFragment}+/o
     NamedSyntax  = /\A(#{QuotedFragment})\s*\:\s*(.*)/om
@@ -25,14 +26,20 @@ module Liquid
       when NamedSyntax
         @variables = variables_from_string(Regexp.last_match(2))
         @name      = parse_expression(Regexp.last_match(1))
+        @is_named = true
       when SimpleSyntax
         @variables = variables_from_string(markup)
         @name      = @variables.to_s
+        @is_named = !@name.match?(/\w+:0x\h{8}/)
       else
         raise SyntaxError, options[:locale].t("errors.syntax.cycle")
       end
     end
 
+    def named?
+      @is_named
+    end
+
     def render_to_output_buffer(context, output)
       context.registers[:cycle] ||= {}
 
@@ -61,7 +68,13 @@ module Liquid
     def variables_from_string(markup)
       markup.split(',').collect do |var|
         var =~ /\s*(#{QuotedFragment})\s*/o
-        Regexp.last_match(1) ? parse_expression(Regexp.last_match(1)) : nil
+        next unless Regexp.last_match(1)
+
+        # Expression Parser returns cached objects, and we need to dup them to
+        # start the cycle over for each new cycle call.
+        # Liquid-C does not have a cache, so we don't need to dup the object.
+        var = parse_expression(Regexp.last_match(1))
+        var.is_a?(VariableLookup) ? var.dup : var
       end.compact
     end
 
@@ -71,6 +84,4 @@ module Liquid
       end
     end
   end
-
-  Template.register_tag('cycle', Cycle)
 end

lib/liquid/tags/decrement.rb

@@ -1,38 +1,38 @@
 # frozen_string_literal: true
 
 module Liquid
-  # decrement is used in a place where one needs to insert a counter
-  #     into a template, and needs the counter to survive across
-  #     multiple instantiations of the template.
-  #     NOTE: decrement is a pre-decrement, --i,
-  #           while increment is post:      i++.
-  #
-  #     (To achieve the survival, the application must keep the context)
-  #
-  #     if the variable does not exist, it is created with value 0.
-
-  #   Hello: {% decrement variable %}
-  #
-  # gives you:
-  #
-  #    Hello: -1
-  #    Hello: -2
-  #    Hello: -3
+  # @liquid_public_docs
+  # @liquid_type tag
+  # @liquid_category variable
+  # @liquid_name decrement
+  # @liquid_summary
+  #   Creates a new variable, with a default value of -1, that's decreased by 1 with each subsequent call.
+  # @liquid_description
+  #   Variables that are declared with `decrement` are unique to the [layout](/themes/architecture/layouts), [template](/themes/architecture/templates),
+  #   or [section](/themes/architecture/sections) file that they're created in. However, the variable is shared across
+  #   [snippets](/themes/architecture/snippets) included in the file.
   #
+  #   Similarly, variables that are created with `decrement` are independent from those created with [`assign`](/docs/api/liquid/tags/assign)
+  #   and [`capture`](/docs/api/liquid/tags/capture). However, `decrement` and [`increment`](/docs/api/liquid/tags/increment) share
+  #   variables.
+  # @liquid_syntax
+  #   {% decrement variable_name %}
+  # @liquid_syntax_keyword variable_name The name of the variable being decremented.
   class Decrement < Tag
+    attr_reader :variable_name
+
     def initialize(tag_name, markup, options)
       super
-      @variable = markup.strip
+      @variable_name = markup.strip
     end
 
     def render_to_output_buffer(context, output)
-      value = context.environments.first[@variable] ||= 0
+      counter_environment = context.environments.first
+      value = counter_environment[@variable_name] || 0
       value -= 1
-      context.environments.first[@variable] = value
+      counter_environment[@variable_name] = value
       output << value.to_s
       output
     end
   end
-
-  Template.register_tag('decrement', Decrement)
 end

lib/liquid/tags/doc.rb

@@ -0,0 +1,77 @@
+# frozen_string_literal: true
+
+module Liquid
+  # @liquid_public_docs
+  # @liquid_type tag
+  # @liquid_category syntax
+  # @liquid_name doc
+  # @liquid_summary
+  #   Documents template elements with annotations.
+  # @liquid_description
+  #   The `doc` tag allows developers to include documentation within Liquid
+  #   templates. Any content inside `doc` tags is not rendered or outputted.
+  #   Liquid code inside will be parsed but not executed. This facilitates
+  #   tooling support for features like code completion, linting, and inline
+  #   documentation.
+  #
+  #   For detailed documentation syntax and examples, see the
+  #   [`LiquidDoc` reference](/docs/storefronts/themes/tools/liquid-doc).
+  #
+  # @liquid_syntax
+  #   {% doc %}
+  #     Renders a message.
+  #
+  #     @param {string} foo - A string value.
+  #     @param {string} [bar] - An optional string value.
+  #
+  #     @example
+  #     {% render 'message', foo: 'Hello', bar: 'World' %}
+  #   {% enddoc %}
+  class Doc < Block
+    NO_UNEXPECTED_ARGS = /\A\s*\z/
+
+    def initialize(tag_name, markup, parse_context)
+      super
+      ensure_valid_markup(tag_name, markup, parse_context)
+    end
+
+    def parse(tokens)
+      while (token = tokens.shift)
+        tag_name = token =~ BlockBody::FullTokenPossiblyInvalid && Regexp.last_match(2)
+
+        raise_nested_doc_error if tag_name == @tag_name
+
+        if tag_name == block_delimiter
+          parse_context.trim_whitespace = (token[-3] == WhitespaceControl)
+          return
+        end
+      end
+
+      raise_tag_never_closed(block_name)
+    end
+
+    def render_to_output_buffer(_context, output)
+      output
+    end
+
+    def blank?
+      true
+    end
+
+    def nodelist
+      []
+    end
+
+    private
+
+    def ensure_valid_markup(tag_name, markup, parse_context)
+      unless NO_UNEXPECTED_ARGS.match?(markup)
+        raise SyntaxError, parse_context.locale.t("errors.syntax.block_tag_unexpected_args", tag: tag_name)
+      end
+    end
+
+    def raise_nested_doc_error
+      raise SyntaxError, parse_context.locale.t("errors.syntax.doc_invalid_nested")
+    end
+  end
+end

lib/liquid/tags/echo.rb

@@ -1,38 +1,39 @@
 # frozen_string_literal: true
 
 module Liquid
-  # Echo outputs an expression
-  #
-  #   {% echo monkey %}
-  #   {% echo user.name %}
-  #
-  # This is identical to variable output syntax, like {{ foo }}, but works
-  # inside {% liquid %} tags. The full syntax is supported, including filters:
-  #
-  #   {% echo user | link %}
+  # @liquid_public_docs
+  # @liquid_type tag
+  # @liquid_category syntax
+  # @liquid_name echo
+  # @liquid_summary
+  #   Outputs an expression.
+  # @liquid_description
+  #   Using the `echo` tag is the same as wrapping an expression in curly brackets (`{{` and `}}`). However, unlike the curly
+  #   bracket method, you can use the `echo` tag inside [`liquid` tags](/docs/api/liquid/tags/liquid).
   #
+  #   > Tip:
+  #   > You can use [filters](/docs/api/liquid/filters) on expressions inside `echo` tags.
+  # @liquid_syntax
+  #   {% liquid
+  #     echo expression
+  #   %}
+  # @liquid_syntax_keyword expression The expression to be output.
   class Echo < Tag
     attr_reader :variable
 
     def initialize(tag_name, markup, parse_context)
-      puts "Initializing Echo tag"
       super
       @variable = Variable.new(markup, parse_context)
     end
 
     def render(context)
-      puts "Render Echo tag"
       @variable.render_to_output_buffer(context, +'')
     end
 
     class ParseTreeVisitor < Liquid::ParseTreeVisitor
-      puts "ParseTreeVisitor Echo tag"
-
       def children
         [@node.variable]
       end
     end
   end
-
-  Template.register_tag('echo', Echo)
 end

lib/liquid/tags/for.rb

@@ -1,50 +1,29 @@
 # frozen_string_literal: true
 
 module Liquid
-  # "For" iterates over an array or collection.
-  # Several useful variables are available to you within the loop.
-  #
-  # == Basic usage:
-  #    {% for item in collection %}
-  #      {{ forloop.index }}: {{ item.name }}
-  #    {% endfor %}
-  #
-  # == Advanced usage:
-  #    {% for item in collection %}
-  #      <div {% if forloop.first %}class="first"{% endif %}>
-  #        Item {{ forloop.index }}: {{ item.name }}
-  #      </div>
-  #    {% else %}
-  #      There is nothing in the collection.
-  #    {% endfor %}
-  #
-  # You can also define a limit and offset much like SQL.  Remember
-  # that offset starts at 0 for the first item.
-  #
-  #    {% for item in collection limit:5 offset:10 %}
-  #      {{ item.name }}
-  #    {% end %}
-  #
-  #  To reverse the for loop simply use {% for item in collection reversed %} (note that the flag's spelling is different to the filter `reverse`)
-  #
-  # == Available variables:
-  #
-  # forloop.name:: 'item-collection'
-  # forloop.length:: Length of the loop
-  # forloop.index:: The current item's position in the collection;
-  #                 forloop.index starts at 1.
-  #                 This is helpful for non-programmers who start believe
-  #                 the first item in an array is 1, not 0.
-  # forloop.index0:: The current item's position in the collection
-  #                  where the first item is 0
-  # forloop.rindex:: Number of items remaining in the loop
-  #                  (length - index) where 1 is the last item.
-  # forloop.rindex0:: Number of items remaining in the loop
-  #                   where 0 is the last item.
-  # forloop.first:: Returns true if the item is the first item.
-  # forloop.last:: Returns true if the item is the last item.
-  # forloop.parentloop:: Provides access to the parent loop, if present.
+  # @liquid_public_docs
+  # @liquid_type tag
+  # @liquid_category iteration
+  # @liquid_name for
+  # @liquid_summary
+  #   Renders an expression for every item in an array.
+  # @liquid_description
+  #   You can do a maximum of 50 iterations with a `for` loop. If you need to iterate over more than 50 items, then use the
+  #   [`paginate` tag](/docs/api/liquid/tags/paginate) to split the items over multiple pages.
   #
+  #   > Tip:
+  #   > Every `for` loop has an associated [`forloop` object](/docs/api/liquid/objects/forloop) with information about the loop.
+  # @liquid_syntax
+  #   {% for variable in array %}
+  #     expression
+  #   {% endfor %}
+  # @liquid_syntax_keyword variable The current item in the array.
+  # @liquid_syntax_keyword array The array to iterate over.
+  # @liquid_syntax_keyword expression The expression to render for each iteration.
+  # @liquid_optional_param limit [number] The number of iterations to perform.
+  # @liquid_optional_param offset [number] The 1-based index to start iterating at.
+  # @liquid_optional_param range [untyped] A custom numeric range to iterate over.
+  # @liquid_optional_param reversed [untyped] Iterate in reverse order.
   class For < Block
     Syntax = /\A(#{VariableSegment}+)\s+in\s+(#{QuotedFragment}+)\s*(reversed)?/o
 
@@ -109,7 +88,7 @@ module Liquid
     end
 
     def strict_parse(markup)
-      p = Parser.new(markup)
+      p = @parse_context.new_parser(markup)
       @variable_name = p.consume(:id)
       raise SyntaxError, options[:locale].t("errors.syntax.for_invalid_in") unless p.id?('in')
 
@@ -119,11 +98,12 @@ module Liquid
       @name     = "#{@variable_name}-#{collection_name}"
       @reversed = p.id?('reversed')
 
-      while p.look(:id) && p.look(:colon, 1)
+      while p.look(:comma) || p.look(:id)
+        p.consume?(:comma)
         unless (attribute = p.id?('limit') || p.id?('offset'))
           raise SyntaxError, options[:locale].t("errors.syntax.for_invalid_attribute")
         end
-        p.consume
+        p.consume(:colon)
         set_attribute(attribute, p.expression)
       end
       p.consume(:end_of_string)
@@ -198,7 +178,6 @@ module Liquid
       case key
       when 'offset'
         @from = if expr == 'continue'
-          Usage.increment('for_offset_continue')
           :continue
         else
           parse_expression(expr)
@@ -222,6 +201,4 @@ module Liquid
       end
     end
   end
-
-  Template.register_tag('for', For)
 end

lib/liquid/tags/if.rb

@@ -1,16 +1,18 @@
 # frozen_string_literal: true
 
 module Liquid
-  # If is the conditional block
-  #
-  #   {% if user.admin %}
-  #     Admin user!
-  #   {% else %}
-  #     Not admin user
+  # @liquid_public_docs
+  # @liquid_type tag
+  # @liquid_category conditional
+  # @liquid_name if
+  # @liquid_summary
+  #   Renders an expression if a specific condition is `true`.
+  # @liquid_syntax
+  #   {% if condition %}
+  #     expression
   #   {% endif %}
-  #
-  #    There are {% if count < 5 %} less {% else %} more {% endif %} items than you need.
-  #
+  # @liquid_syntax_keyword condition The condition to evaluate.
+  # @liquid_syntax_keyword expression The expression to render if the condition is met.
   class If < Block
     Syntax                  = /(#{QuotedFragment})\s*([=!<>a-z_]+)?\s*(#{QuotedFragment})?/o
     ExpressionsAndOperators = /(?:\b(?:\s?and\s?|\s?or\s?)\b|(?:\s*(?!\b(?:\s?and\s?|\s?or\s?)\b)(?:#{QuotedFragment}|\S+)\s*)+)/o
@@ -51,7 +53,7 @@ module Liquid
     def render_to_output_buffer(context, output)
       @blocks.each do |block|
         result = Liquid::Utils.to_liquid_value(
-          block.evaluate(context)
+          block.evaluate(context),
         )
 
         if result
@@ -100,7 +102,7 @@ module Liquid
     end
 
     def strict_parse(markup)
-      p = Parser.new(markup)
+      p = @parse_context.new_parser(markup)
       condition = parse_binary_comparisons(p)
       p.consume(:end_of_string)
       condition
@@ -109,7 +111,7 @@ module Liquid
     def parse_binary_comparisons(p)
       condition = parse_comparison(p)
       first_condition = condition
-      while (op = (p.id?('and') || p.id?('or')))
+      while (op = p.id?('and') || p.id?('or'))
         child_condition = parse_comparison(p)
         condition.send(op, child_condition)
         condition = child_condition
@@ -133,6 +135,4 @@ module Liquid
       end
     end
   end
-
-  Template.register_tag('if', If)
 end

lib/liquid/tags/ifchanged.rb

@@ -14,6 +14,4 @@ module Liquid
       output
     end
   end
-
-  Template.register_tag('ifchanged', Ifchanged)
 end

lib/liquid/tags/include.rb

@@ -1,20 +1,22 @@
 # frozen_string_literal: true
 
 module Liquid
-  # Include allows templates to relate with other templates
-  #
-  # Simply include another template:
-  #
-  #   {% include 'product' %}
-  #
-  # Include a template with a local variable:
-  #
-  #   {% include 'product' with products[0] %}
-  #
-  # Include a template for a collection:
-  #
-  #   {% include 'product' for products %}
+  # @liquid_public_docs
+  # @liquid_type tag
+  # @liquid_category theme
+  # @liquid_name include
+  # @liquid_summary
+  #   Renders a [snippet](/themes/architecture/snippets).
+  # @liquid_description
+  #   Inside the snippet, you can access and alter variables that are [created](/docs/api/liquid/tags/variable-tags) outside of the
+  #   snippet.
+  # @liquid_syntax
+  #   {% include 'filename' %}
+  # @liquid_syntax_keyword filename The name of the snippet to render, without the `.liquid` extension.
+  # @liquid_deprecated
+  #   Deprecated because the way that variables are handled reduces performance and makes code harder to both read and maintain.
   #
+  #   The `include` tag has been replaced by [`render`](/docs/api/liquid/tags/render).
   class Include < Tag
     prepend Tag::Disableable
 
@@ -50,12 +52,12 @@ module Liquid
 
     def render_to_output_buffer(context, output)
       template_name = context.evaluate(@template_name_expr)
-      raise ArgumentError, options[:locale].t("errors.argument.include") unless template_name
+      raise ArgumentError, options[:locale].t("errors.argument.include") unless template_name.is_a?(String)
 
       partial = PartialCache.load(
         template_name,
         context: context,
-        parse_context: parse_context
+        parse_context: parse_context,
       )
 
       context_variable_name = @alias_name || template_name.split('/').last
@@ -68,9 +70,11 @@ module Liquid
 
       old_template_name = context.template_name
       old_partial       = context.partial
+
       begin
-        context.template_name = template_name
-        context.partial       = true
+        context.template_name = partial.name
+        context.partial = true
+
         context.stack do
           @attributes.each do |key, value|
             context[key] = context.evaluate(value)
@@ -106,6 +110,4 @@ module Liquid
       end
     end
   end
-
-  Template.register_tag('include', Include)
 end

lib/liquid/tags/increment.rb

@@ -1,35 +1,38 @@
 # frozen_string_literal: true
 
 module Liquid
-  # increment is used in a place where one needs to insert a counter
-  #     into a template, and needs the counter to survive across
-  #     multiple instantiations of the template.
-  #     (To achieve the survival, the application must keep the context)
-  #
-  #     if the variable does not exist, it is created with value 0.
-  #
-  #   Hello: {% increment variable %}
-  #
-  # gives you:
-  #
-  #    Hello: 0
-  #    Hello: 1
-  #    Hello: 2
+  # @liquid_public_docs
+  # @liquid_type tag
+  # @liquid_category variable
+  # @liquid_name increment
+  # @liquid_summary
+  #   Creates a new variable, with a default value of 0, that's increased by 1 with each subsequent call.
+  # @liquid_description
+  #   Variables that are declared with `increment` are unique to the [layout](/themes/architecture/layouts), [template](/themes/architecture/templates),
+  #   or [section](/themes/architecture/sections) file that they're created in. However, the variable is shared across
+  #   [snippets](/themes/architecture/snippets) included in the file.
   #
+  #   Similarly, variables that are created with `increment` are independent from those created with [`assign`](/docs/api/liquid/tags/assign)
+  #   and [`capture`](/docs/api/liquid/tags/capture). However, `increment` and [`decrement`](/docs/api/liquid/tags/decrement) share
+  #   variables.
+  # @liquid_syntax
+  #   {% increment variable_name %}
+  # @liquid_syntax_keyword variable_name The name of the variable being incremented.
   class Increment < Tag
+    attr_reader :variable_name
+
     def initialize(tag_name, markup, options)
       super
-      @variable = markup.strip
+      @variable_name = markup.strip
     end
 
     def render_to_output_buffer(context, output)
-      value = context.environments.first[@variable] ||= 0
-      context.environments.first[@variable] = value + 1
+      counter_environment = context.environments.first
+      value = counter_environment[@variable_name] || 0
+      counter_environment[@variable_name] = value + 1
 
       output << value.to_s
       output
     end
   end
-
-  Template.register_tag('increment', Increment)
 end

lib/liquid/tags/inline_comment.rb

@@ -0,0 +1,28 @@
+# frozen_string_literal: true
+
+module Liquid
+  class InlineComment < Tag
+    def initialize(tag_name, markup, options)
+      super
+
+      # Semantically, a comment should only ignore everything after it on the line.
+      # Currently, this implementation doesn't support mixing a comment with another tag
+      # but we need to reserve future support for this and prevent the introduction
+      # of inline comments from being backward incompatible change.
+      #
+      # As such, we're forcing users to put a # symbol on every line otherwise this
+      # tag will throw an error.
+      if markup.match?(/\n\s*[^#\s]/)
+        raise SyntaxError, options[:locale].t("errors.syntax.inline_comment_invalid")
+      end
+    end
+
+    def render_to_output_buffer(_context, output)
+      output
+    end
+
+    def blank?
+      true
+    end
+  end
+end

lib/liquid/tags/raw.rb

@@ -1,9 +1,19 @@
 # frozen_string_literal: true
 
 module Liquid
+  # @liquid_public_docs
+  # @liquid_type tag
+  # @liquid_category syntax
+  # @liquid_name raw
+  # @liquid_summary
+  #   Outputs any Liquid code as text instead of rendering it.
+  # @liquid_syntax
+  #   {% raw %}
+  #     expression
+  #   {% endraw %}
+  # @liquid_syntax_keyword expression The expression to be output without being rendered.
   class Raw < Block
     Syntax = /\A\s*\z/
-    FullTokenPossiblyInvalid = /\A(.*)#{TagStart}\s*(\w+)\s*(.*)?#{TagEnd}\z/om
 
     def initialize(tag_name, markup, parse_context)
       super
@@ -14,7 +24,8 @@ module Liquid
     def parse(tokens)
       @body = +''
       while (token = tokens.shift)
-        if token =~ FullTokenPossiblyInvalid && block_delimiter == Regexp.last_match(2)
+        if token =~ BlockBody::FullTokenPossiblyInvalid && block_delimiter == Regexp.last_match(2)
+          parse_context.trim_whitespace = (token[-3] == WhitespaceControl)
           @body << Regexp.last_match(1) if Regexp.last_match(1) != ""
           return
         end
@@ -45,6 +56,4 @@ module Liquid
       end
     end
   end
-
-  Template.register_tag('raw', Raw)
 end

lib/liquid/tags/render.rb

@@ -1,13 +1,37 @@
 # frozen_string_literal: true
 
 module Liquid
+  # @liquid_public_docs
+  # @liquid_type tag
+  # @liquid_category theme
+  # @liquid_name render
+  # @liquid_summary
+  #   Renders a [snippet](/themes/architecture/snippets) or [app block](/themes/architecture/sections/section-schema#render-app-blocks).
+  # @liquid_description
+  #   Inside snippets and app blocks, you can't directly access variables that are [created](/docs/api/liquid/tags/variable-tags) outside
+  #   of the snippet or app block. However, you can [specify variables as parameters](/docs/api/liquid/tags/render#render-passing-variables-to-a-snippet)
+  #   to pass outside variables to snippets.
+  #
+  #   While you can't directly access created variables, you can access global objects, as well as any objects that are
+  #   directly accessible outside the snippet or app block. For example, a snippet or app block inside the [product template](/themes/architecture/templates/product)
+  #   can access the [`product` object](/docs/api/liquid/objects/product), and a snippet or app block inside a [section](/themes/architecture/sections)
+  #   can access the [`section` object](/docs/api/liquid/objects/section).
+  #
+  #   Outside a snippet or app block, you can't access variables created inside the snippet or app block.
+  #
+  #   > Note:
+  #   > When you render a snippet using the `render` tag, you can't use the [`include` tag](/docs/api/liquid/tags/include)
+  #   > inside the snippet.
+  # @liquid_syntax
+  #   {% render 'filename' %}
+  # @liquid_syntax_keyword filename The name of the snippet to render, without the `.liquid` extension.
   class Render < Tag
     FOR = 'for'
     SYNTAX = /(#{QuotedString}+)(\s+(with|#{FOR})\s+(#{QuotedFragment}+))?(\s+(?:as)\s+(#{VariableSegment}+))?/o
 
     disable_tags "include"
 
-    attr_reader :template_name_expr, :attributes
+    attr_reader :template_name_expr, :variable_name_expr, :attributes, :alias_name
 
     def initialize(tag_name, markup, options)
       super
@@ -21,7 +45,7 @@ module Liquid
       @alias_name = Regexp.last_match(6)
       @variable_name_expr = variable_name ? parse_expression(variable_name) : nil
       @template_name_expr = parse_expression(template_name)
-      @for = (with_or_for == FOR)
+      @is_for_loop = (with_or_for == FOR)
 
       @attributes = {}
       markup.scan(TagAttributes) do |key, value|
@@ -29,26 +53,30 @@ module Liquid
       end
     end
 
+    def for_loop?
+      @is_for_loop
+    end
+
     def render_to_output_buffer(context, output)
       render_tag(context, output)
     end
 
     def render_tag(context, output)
-      # Though we evaluate this here we will only ever parse it as a string literal.
-      template_name = context.evaluate(@template_name_expr)
-      raise ArgumentError, options[:locale].t("errors.argument.include") unless template_name
+      # The expression should be a String literal, which parses to a String object
+      template_name = @template_name_expr
+      raise ::ArgumentError unless template_name.is_a?(String)
 
       partial = PartialCache.load(
         template_name,
         context: context,
-        parse_context: parse_context
+        parse_context: parse_context,
       )
 
       context_variable_name = @alias_name || template_name.split('/').last
 
       render_partial_func = ->(var, forloop) {
         inner_context               = context.new_isolated_subcontext
-        inner_context.template_name = template_name
+        inner_context.template_name = partial.name
         inner_context.partial       = true
         inner_context['forloop']    = forloop if forloop
 
@@ -61,7 +89,7 @@ module Liquid
       }
 
       variable = @variable_name_expr ? context.evaluate(@variable_name_expr) : nil
-      if @for && variable.respond_to?(:each) && variable.respond_to?(:count)
+      if @is_for_loop && variable.respond_to?(:each) && variable.respond_to?(:count)
         forloop = Liquid::ForloopDrop.new(template_name, variable.count, nil)
         variable.each { |var| render_partial_func.call(var, forloop) }
       else
@@ -75,10 +103,9 @@ module Liquid
       def children
         [
           @node.template_name_expr,
+          @node.variable_name_expr,
         ] + @node.attributes.values
       end
     end
   end
-
-  Template.register_tag('render', Render)
 end

lib/liquid/tags/table_row.rb

@@ -1,6 +1,28 @@
 # frozen_string_literal: true
 
 module Liquid
+  # @liquid_public_docs
+  # @liquid_type tag
+  # @liquid_category iteration
+  # @liquid_name tablerow
+  # @liquid_summary
+  #   Generates HTML table rows for every item in an array.
+  # @liquid_description
+  #   The `tablerow` tag must be wrapped in HTML `<table>` and `</table>` tags.
+  #
+  #   > Tip:
+  #   > Every `tablerow` loop has an associated [`tablerowloop` object](/docs/api/liquid/objects/tablerowloop) with information about the loop.
+  # @liquid_syntax
+  #   {% tablerow variable in array %}
+  #     expression
+  #   {% endtablerow %}
+  # @liquid_syntax_keyword variable The current item in the array.
+  # @liquid_syntax_keyword array The array to iterate over.
+  # @liquid_syntax_keyword expression The expression to render.
+  # @liquid_optional_param cols [number] The number of columns that the table should have.
+  # @liquid_optional_param limit [number] The number of iterations to perform.
+  # @liquid_optional_param offset [number] The 1-based index to start iterating at.
+  # @liquid_optional_param range [untyped] A custom numeric range to iterate over.
   class TableRow < Block
     Syntax = /(\w+)\s+in\s+(#{QuotedFragment}+)/o
 
@@ -23,13 +45,13 @@ module Liquid
     def render_to_output_buffer(context, output)
       (collection = context.evaluate(@collection_name)) || (return '')
 
-      from = @attributes.key?('offset') ? context.evaluate(@attributes['offset']).to_i : 0
-      to   = @attributes.key?('limit')  ? from + context.evaluate(@attributes['limit']).to_i : nil
+      from = @attributes.key?('offset') ? to_integer(context.evaluate(@attributes['offset'])) : 0
+      to = @attributes.key?('limit') ? from + to_integer(context.evaluate(@attributes['limit'])) : nil
 
       collection = Utils.slice_collection(collection, from, to)
       length     = collection.length
 
-      cols = context.evaluate(@attributes['cols']).to_i
+      cols = @attributes.key?('cols') ? to_integer(context.evaluate(@attributes['cols'])) : length
 
       output << "<tr class=\"row1\">\n"
       context.stack do
@@ -43,6 +65,12 @@ module Liquid
           super
           output << '</td>'
 
+          # Handle any interrupts if they exist.
+          if context.interrupt?
+            interrupt = context.pop_interrupt
+            break if interrupt.is_a?(BreakInterrupt)
+          end
+
           if tablerowloop.col_last && !tablerowloop.last
             output << "</tr>\n<tr class=\"row#{tablerowloop.row + 1}\">"
           end
@@ -60,7 +88,13 @@ module Liquid
         super + @node.attributes.values + [@node.collection_name]
       end
     end
-  end
 
-  Template.register_tag('tablerow', TableRow)
+    private
+
+    def to_integer(value)
+      value.to_i
+    rescue NoMethodError
+      raise Liquid::ArgumentError, "invalid integer"
+    end
+  end
 end

lib/liquid/tags/unless.rb

@@ -3,16 +3,27 @@
 require_relative 'if'
 
 module Liquid
-  # Unless is a conditional just like 'if' but works on the inverse logic.
-  #
-  #   {% unless x < 0 %} x is greater than zero {% endunless %}
-  #
+  # @liquid_public_docs
+  # @liquid_type tag
+  # @liquid_category conditional
+  # @liquid_name unless
+  # @liquid_summary
+  #   Renders an expression unless a specific condition is `true`.
+  # @liquid_description
+  #   > Tip:
+  #   > Similar to the [`if` tag](/docs/api/liquid/tags/if), you can use `elsif` to add more conditions to an `unless` tag.
+  # @liquid_syntax
+  #   {% unless condition %}
+  #     expression
+  #   {% endunless %}
+  # @liquid_syntax_keyword condition The condition to evaluate.
+  # @liquid_syntax_keyword expression The expression to render unless the condition is met.
   class Unless < If
     def render_to_output_buffer(context, output)
       # First condition is interpreted backwards ( if not )
       first_block = @blocks.first
       result = Liquid::Utils.to_liquid_value(
-        first_block.evaluate(context)
+        first_block.evaluate(context),
       )
 
       unless result
@@ -22,7 +33,7 @@ module Liquid
       # After the first condition unless works just like if
       @blocks[1..-1].each do |block|
         result = Liquid::Utils.to_liquid_value(
-          block.evaluate(context)
+          block.evaluate(context),
         )
 
         if result
@@ -33,6 +44,4 @@ module Liquid
       output
     end
   end
-
-  Template.register_tag('unless', Unless)
 end

lib/liquid/template.rb

@@ -15,45 +15,9 @@ module Liquid
   #   template.render('user_name' => 'bob')
   #
   class Template
-    attr_accessor :root
+    attr_accessor :root, :name
     attr_reader :resource_limits, :warnings
 
-    class TagRegistry
-      include Enumerable
-
-      def initialize
-        @tags  = {}
-        @cache = {}
-      end
-
-      def [](tag_name)
-        return nil unless @tags.key?(tag_name)
-        return @cache[tag_name] if Liquid.cache_classes
-
-        lookup_class(@tags[tag_name]).tap { |o| @cache[tag_name] = o }
-      end
-
-      def []=(tag_name, klass)
-        @tags[tag_name]  = klass.name
-        @cache[tag_name] = klass
-      end
-
-      def delete(tag_name)
-        @tags.delete(tag_name)
-        @cache.delete(tag_name)
-      end
-
-      def each(&block)
-        @tags.each(&block)
-      end
-
-      private
-
-      def lookup_class(name)
-        Object.const_get(name)
-      end
-    end
-
     attr_reader :profiler
 
     class << self
@@ -61,52 +25,83 @@ module Liquid
       # :lax acts like liquid 2.5 and silently ignores malformed tags in most cases.
       # :warn is the default and will give deprecation warnings when invalid syntax is used.
       # :strict will enforce correct syntax.
-      attr_accessor :error_mode
-      Template.error_mode = :lax
-
-      attr_accessor :default_exception_renderer
-      Template.default_exception_renderer = lambda do |exception|
-        exception
+      def error_mode=(mode)
+        Deprecations.warn("Template.error_mode=", "Environment#error_mode=")
+        Environment.default.error_mode = mode
       end
 
-      attr_accessor :file_system
-      Template.file_system = BlankFileSystem.new
+      def error_mode
+        Environment.default.error_mode
+      end
 
-      attr_accessor :tags
-      Template.tags = TagRegistry.new
-      private :tags=
+      def default_exception_renderer=(renderer)
+        Deprecations.warn("Template.default_exception_renderer=", "Environment#exception_renderer=")
+        Environment.default.exception_renderer = renderer
+      end
+
+      def default_exception_renderer
+        Environment.default.exception_renderer
+      end
+
+      def file_system=(file_system)
+        Deprecations.warn("Template.file_system=", "Environment#file_system=")
+        Environment.default.file_system = file_system
+      end
+
+      def file_system
+        Environment.default.file_system
+      end
+
+      def tags
+        Environment.default.tags
+      end
 
       def register_tag(name, klass)
-        tags[name.to_s] = klass
+        Deprecations.warn("Template.register_tag", "Environment#register_tag")
+        Environment.default.register_tag(name, klass)
       end
 
       # Pass a module with filter methods which should be available
       # to all liquid views. Good for registering the standard library
       def register_filter(mod)
-        StrainerFactory.add_global_filter(mod)
+        Deprecations.warn("Template.register_filter", "Environment#register_filter")
+        Environment.default.register_filter(mod)
       end
 
-      attr_accessor :default_resource_limits
-      Template.default_resource_limits = {}
-      private :default_resource_limits=
+      private def default_resource_limits=(limits)
+        Deprecations.warn("Template.default_resource_limits=", "Environment#default_resource_limits=")
+        Environment.default.default_resource_limits = limits
+      end
+
+      def default_resource_limits
+        Environment.default.default_resource_limits
+      end
 
       # creates a new <tt>Template</tt> object from liquid source code
       # To enable profiling, pass in <tt>profile: true</tt> as an option.
       # See Liquid::Profiler for more information
       def parse(source, options = {})
-        new.parse(source, options)
+        environment = options[:environment] || Environment.default
+        new(environment: environment).parse(source, options)
       end
     end
 
-    def initialize
+    def initialize(environment: Environment.default)
+      @environment = environment
       @rethrow_errors  = false
-      @resource_limits = ResourceLimits.new(Template.default_resource_limits)
+      @resource_limits = ResourceLimits.new(environment.default_resource_limits)
     end
 
     # Parse source code.
     # Returns self for easy chaining
     def parse(source, options = {})
       parse_context = configure_options(options)
+      source = source.to_s.to_str
+
+      unless source.valid_encoding?
+        raise TemplateEncodingError, parse_context.locale.t("errors.syntax.invalid_template_encoding")
+      end
+
       tokenizer     = parse_context.new_tokenizer(source, start_line_number: @line_numbers && 1)
       @root         = Document.parse(tokenizer, parse_context)
       self
@@ -156,26 +151,25 @@ module Liquid
         c
       when Liquid::Drop
         drop         = args.shift
-        drop.context = Context.new([drop, assigns], instance_assigns, registers, @rethrow_errors, @resource_limits)
+        drop.context = Context.new([drop, assigns], instance_assigns, registers, @rethrow_errors, @resource_limits, {}, @environment)
       when Hash
-        Context.new([args.shift, assigns], instance_assigns, registers, @rethrow_errors, @resource_limits)
+        Context.new([args.shift, assigns], instance_assigns, registers, @rethrow_errors, @resource_limits, {}, @environment)
       when nil
-        Context.new(assigns, instance_assigns, registers, @rethrow_errors, @resource_limits)
+        Context.new(assigns, instance_assigns, registers, @rethrow_errors, @resource_limits, {}, @environment)
       else
         raise ArgumentError, "Expected Hash or Liquid::Context as parameter"
       end
 
       output = nil
 
-      context_register = context.registers.is_a?(StaticRegisters) ? context.registers.static : context.registers
-
       case args.last
       when Hash
         options = args.pop
         output  = options[:output] if options[:output]
+        static_registers = context.registers.static
 
         options[:registers]&.each do |key, register|
-          context_register[key] = register
+          static_registers[key] = register
         end
 
         apply_options_to_context(context, options)
@@ -190,6 +184,8 @@ module Liquid
         @profiler = context.profiler = Liquid::Profiler.new
       end
 
+      context.template_name ||= name
+
       begin
         # render the nodelist.
         @root.render_to_output_buffer(context, output || +'')
@@ -209,6 +205,68 @@ module Liquid
       render(context, output: output)
     end
 
+    # Compile the template to Ruby code for fast, secure execution.
+    #
+    # Returns a CompiledTemplate that can be rendered repeatedly. On Ruby 4.0+,
+    # rendering happens in a secure sandbox. On earlier versions, a security
+    # warning is printed to STDERR.
+    #
+    # == Example
+    #
+    #   template = Liquid::Template.parse("Hello, {{ name }}!")
+    #   compiled = template.compile_to_ruby
+    #
+    #   # Render (fast, secure on Ruby 4.0+)
+    #   result = compiled.render({ "name" => "World" })
+    #   # => "Hello, World!"
+    #
+    #   # Access the generated Ruby source
+    #   puts compiled.source
+    #
+    #   # Check if execution is sandboxed
+    #   compiled.secure?  # => true on Ruby 4.0+
+    #
+    # == Options
+    #
+    # * <tt>:strict_variables</tt> - Raise on undefined variables (default: false)
+    # * <tt>:include_filters</tt> - Include helper methods for filters (default: true)
+    # * <tt>:debug</tt> - Include source comments in generated code (default: false)
+    #
+    # == Performance
+    #
+    # Compiled templates are ~1.5x faster than interpreted Liquid:
+    # * No Context object overhead
+    # * No filter invocation overhead (direct method calls)
+    # * No resource limits tracking
+    # * No stack-based scoping (uses Ruby's native scoping)
+    # * Direct string concatenation
+    #
+    # == Security
+    #
+    # On Ruby 4.0+, templates execute in a Ruby::Box sandbox that blocks:
+    # * File/network access
+    # * System calls (exec, spawn, fork)
+    # * Code loading (require, eval)
+    # * Dangerous metaprogramming
+    #
+    # On Ruby < 4.0, templates execute WITHOUT sandboxing.
+    # A warning is printed to STDERR on first execution.
+    #
+    # == Limitations
+    #
+    # * {% render %} and {% include %} resolved at compile time when possible
+    # * Custom tags need explicit compiler implementations
+    # * Custom filters must be available at runtime
+    #
+    def compile_to_ruby(options = {})
+      return nil if @root.nil?
+
+      require 'liquid/compile'
+      compiler = Compile::RubyCompiler.new(self, options)
+      code = compiler.compile
+      Compile::CompiledTemplate.new(code, compiler.external_tags, compiler.has_external_filters?)
+    end
+
     private
 
     def configure_options(options)
@@ -219,8 +277,14 @@ module Liquid
       @options      = options
       @profiling    = profiling
       @line_numbers = options[:line_numbers] || @profiling
-      parse_context = options.is_a?(ParseContext) ? options : ParseContext.new(options)
-      @warnings     = parse_context.warnings
+      parse_context = if options.is_a?(ParseContext)
+        options
+      else
+        opts = options.key?(:environment) ? options : options.merge(environment: @environment)
+        ParseContext.new(opts)
+      end
+
+      @warnings = parse_context.warnings
       parse_context
     end
 

lib/liquid/tokenizer.rb

@@ -1,18 +1,45 @@
 # frozen_string_literal: true
 
+require "strscan"
+
 module Liquid
   class Tokenizer
     attr_reader :line_number, :for_liquid_tag
 
-    def initialize(source, line_numbers = false, line_number: nil, for_liquid_tag: false)
-      @source         = source.to_s.to_str
-      @line_number    = line_number || (line_numbers ? 1 : nil)
+    TAG_END = /%\}/
+    TAG_OR_VARIABLE_START = /\{[\{\%]/
+    NEWLINE = /\n/
+
+    OPEN_CURLEY = "{".ord
+    CLOSE_CURLEY = "}".ord
+    PERCENTAGE = "%".ord
+
+    def initialize(
+      source:,
+      string_scanner:,
+      line_numbers: false,
+      line_number: nil,
+      for_liquid_tag: false
+    )
+      @line_number = line_number || (line_numbers ? 1 : nil)
       @for_liquid_tag = for_liquid_tag
-      @tokens         = tokenize
+      @source = source.to_s.to_str
+      @offset = 0
+      @tokens = []
+
+      if @source
+        @ss = string_scanner
+        @ss.string = @source
+        tokenize
+      end
     end
 
     def shift
-      (token = @tokens.shift) || return
+      token = @tokens[@offset]
+
+      return unless token
+
+      @offset += 1
 
       if @line_number
         @line_number += @for_liquid_tag ? 1 : token.count("\n")
@@ -24,16 +51,111 @@ module Liquid
     private
 
     def tokenize
-      return [] if @source.empty?
+      if @for_liquid_tag
+        @tokens = @source.split("\n")
+      else
+        @tokens << shift_normal until @ss.eos?
+      end
 
-      return @source.split("\n") if @for_liquid_tag
+      @source = nil
+      @ss = nil
+    end
 
-      tokens = @source.split(TemplateParser)
+    def shift_normal
+      token = next_token
 
-      # removes the rogue empty element at the beginning of the array
-      tokens.shift if tokens[0]&.empty?
+      return unless token
 
-      tokens
+      token
+    end
+
+    def next_token
+      # possible states: :text, :tag, :variable
+      byte_a = @ss.peek_byte
+
+      if byte_a == OPEN_CURLEY
+        @ss.scan_byte
+
+        byte_b = @ss.peek_byte
+
+        if byte_b == PERCENTAGE
+          @ss.scan_byte
+          return next_tag_token
+        elsif byte_b == OPEN_CURLEY
+          @ss.scan_byte
+          return next_variable_token
+        end
+
+        @ss.pos -= 1
+      end
+
+      next_text_token
+    end
+
+    def next_text_token
+      start = @ss.pos
+
+      unless @ss.skip_until(TAG_OR_VARIABLE_START)
+        token = @ss.rest
+        @ss.terminate
+        return token
+      end
+
+      pos = @ss.pos -= 2
+      @source.byteslice(start, pos - start)
+    rescue ::ArgumentError => e
+      if e.message == "invalid byte sequence in #{@ss.string.encoding}"
+        raise SyntaxError, "Invalid byte sequence in #{@ss.string.encoding}"
+      else
+        raise
+      end
+    end
+
+    def next_variable_token
+      start = @ss.pos - 2
+
+      byte_a = byte_b = @ss.scan_byte
+
+      while byte_b
+        byte_a = @ss.scan_byte while byte_a && (byte_a != CLOSE_CURLEY && byte_a != OPEN_CURLEY)
+
+        break unless byte_a
+
+        if @ss.eos?
+          return byte_a == CLOSE_CURLEY ? @source.byteslice(start, @ss.pos - start) : "{{"
+        end
+
+        byte_b = @ss.scan_byte
+
+        if byte_a == CLOSE_CURLEY
+          if byte_b == CLOSE_CURLEY
+            return @source.byteslice(start, @ss.pos - start)
+          elsif byte_b != CLOSE_CURLEY
+            @ss.pos -= 1
+            return @source.byteslice(start, @ss.pos - start)
+          end
+        elsif byte_a == OPEN_CURLEY && byte_b == PERCENTAGE
+          return next_tag_token_with_start(start)
+        end
+
+        byte_a = byte_b
+      end
+
+      "{{"
+    end
+
+    def next_tag_token
+      start = @ss.pos - 2
+      if (len = @ss.skip_until(TAG_END))
+        @source.byteslice(start, len + 2)
+      else
+        "{%"
+      end
+    end
+
+    def next_tag_token_with_start(start)
+      @ss.skip_until(TAG_END)
+      @source.byteslice(start, @ss.pos - start)
     end
   end
 end

lib/liquid/utils.rb

@@ -89,5 +89,101 @@ module Liquid
       # Otherwise return the object itself
       obj
     end
+
+    def self.to_s(obj, seen = {})
+      case obj
+      when Hash
+        # If the custom hash implementation overrides `#to_s`, use their
+        # custom implementation. Otherwise we use Liquid's default
+        # implementation.
+        if obj.class.instance_method(:to_s) == HASH_TO_S_METHOD
+          hash_inspect(obj, seen)
+        else
+          obj.to_s
+        end
+      when Array
+        array_inspect(obj, seen)
+      else
+        obj.to_s
+      end
+    end
+
+    def self.inspect(obj, seen = {})
+      case obj
+      when Hash
+        # If the custom hash implementation overrides `#inspect`, use their
+        # custom implementation. Otherwise we use Liquid's default
+        # implementation.
+        if obj.class.instance_method(:inspect) == HASH_INSPECT_METHOD
+          hash_inspect(obj, seen)
+        else
+          obj.inspect
+        end
+      when Array
+        array_inspect(obj, seen)
+      else
+        obj.inspect
+      end
+    end
+
+    def self.array_inspect(arr, seen = {})
+      if seen[arr.object_id]
+        return "[...]"
+      end
+
+      seen[arr.object_id] = true
+      str = +"["
+      cursor = 0
+      len = arr.length
+
+      while cursor < len
+        if cursor > 0
+          str << ", "
+        end
+
+        item_str = inspect(arr[cursor], seen)
+        str << item_str
+        cursor += 1
+      end
+
+      str << "]"
+      str
+    ensure
+      seen.delete(arr.object_id)
+    end
+
+    def self.hash_inspect(hash, seen = {})
+      if seen[hash.object_id]
+        return "{...}"
+      end
+      seen[hash.object_id] = true
+
+      str = +"{"
+      first = true
+      hash.each do |key, value|
+        if first
+          first = false
+        else
+          str << ", "
+        end
+
+        key_str = inspect(key, seen)
+        str << key_str
+        str << "=>"
+
+        value_str = inspect(value, seen)
+        str << value_str
+      end
+      str << "}"
+      str
+    ensure
+      seen.delete(hash.object_id)
+    end
+
+    HASH_TO_S_METHOD = Hash.instance_method(:to_s)
+    private_constant :HASH_TO_S_METHOD
+
+    HASH_INSPECT_METHOD = Hash.instance_method(:inspect)
+    private_constant :HASH_INSPECT_METHOD
   end
 end

lib/liquid/variable.rb

@@ -47,7 +47,7 @@ module Liquid
 
       name_markup   = Regexp.last_match(1)
       filter_markup = Regexp.last_match(2)
-      @name         = Expression.parse(name_markup)
+      @name         = parse_context.parse_expression(name_markup)
       if filter_markup =~ FilterMarkupRegex
         filters = Regexp.last_match(1).scan(FilterParser)
         filters.each do |f|
@@ -61,14 +61,14 @@ module Liquid
 
     def strict_parse(markup)
       @filters = []
-      p = Parser.new(markup)
+      p = @parse_context.new_parser(markup)
 
       return if p.look(:end_of_string)
 
-      @name = Expression.parse(p.expression)
+      @name = parse_context.parse_expression(p.expression)
       while p.consume?(:pipe)
         filtername = p.consume(:id)
-        filterargs = p.consume?(:colon) ? parse_filterargs(p) : []
+        filterargs = p.consume?(:colon) ? parse_filterargs(p) : Const::EMPTY_ARRAY
         @filters << parse_filter_expressions(filtername, filterargs)
       end
       p.consume(:end_of_string)
@@ -95,17 +95,23 @@ module Liquid
 
     def render_to_output_buffer(context, output)
       obj = render(context)
-
-      if obj.is_a?(Array)
-        output << obj.join
-      elsif obj.nil?
-      else
-        output << obj.to_s
-      end
-
+      render_obj_to_output(obj, output)
       output
     end
 
+    def render_obj_to_output(obj, output)
+      case obj
+      when NilClass
+        # Do nothing
+      when Array
+        obj.each do |o|
+          render_obj_to_output(o, output)
+        end
+      else
+        output << Liquid::Utils.to_s(obj)
+      end
+    end
+
     def disabled?(_context)
       false
     end
@@ -122,9 +128,9 @@ module Liquid
       unparsed_args.each do |a|
         if (matches = a.match(JustTagAttributes))
           keyword_args           ||= {}
-          keyword_args[matches[1]] = Expression.parse(matches[2])
+          keyword_args[matches[1]] = parse_context.parse_expression(matches[2])
         else
-          filter_args << Expression.parse(a)
+          filter_args << parse_context.parse_expression(a)
         end
       end
       result = [filter_name, filter_args]

lib/liquid/variable_lookup.rb

@@ -2,21 +2,24 @@
 
 module Liquid
   class VariableLookup
-    SQUARE_BRACKETED = /\A\[(.*)\]\z/m
-    COMMAND_METHODS  = ['size', 'first', 'last'].freeze
+    COMMAND_METHODS = ['size', 'first', 'last'].freeze
 
     attr_reader :name, :lookups
 
-    def self.parse(markup)
-      new(markup)
+    def self.parse(markup, string_scanner = StringScanner.new(""), cache = nil)
+      new(markup, string_scanner, cache)
     end
 
-    def initialize(markup)
+    def initialize(markup, string_scanner = StringScanner.new(""), cache = nil)
       lookups = markup.scan(VariableParser)
 
       name = lookups.shift
-      if name =~ SQUARE_BRACKETED
-        name = Expression.parse(Regexp.last_match(1))
+      if name&.start_with?('[') && name&.end_with?(']')
+        name = Expression.parse(
+          name[1..-2],
+          string_scanner,
+          cache,
+        )
       end
       @name = name
 
@@ -25,14 +28,22 @@ module Liquid
 
       @lookups.each_index do |i|
         lookup = lookups[i]
-        if lookup =~ SQUARE_BRACKETED
-          lookups[i] = Expression.parse(Regexp.last_match(1))
+        if lookup&.start_with?('[') && lookup&.end_with?(']')
+          lookups[i] = Expression.parse(
+            lookup[1..-2],
+            string_scanner,
+            cache,
+          )
         elsif COMMAND_METHODS.include?(lookup)
           @command_flags |= 1 << i
         end
       end
     end
 
+    def lookup_command?(lookup_index)
+      @command_flags & (1 << lookup_index) != 0
+    end
+
     def evaluate(context)
       name   = context.evaluate(@name)
       object = context.find_variable(name)
@@ -56,7 +67,7 @@ module Liquid
           # Some special cases. If the part wasn't in square brackets and
           # no key with the same name was found we interpret following calls
           # as commands and call them on the current object
-        elsif @command_flags & (1 << i) != 0 && object.respond_to?(key)
+        elsif lookup_command?(i) && object.respond_to?(key)
           object = object.send(key).to_liquid
 
           # No key was present with the desired value and it wasn't one of the directly supported

lib/liquid/version.rb

@@ -2,5 +2,5 @@
 # frozen_string_literal: true
 
 module Liquid
-  VERSION = "5.1.0"
+  VERSION = "5.8.6"
 end