WIP - Support {% render obj %}

Fix Shopify documentation link

README.md

@@ -5,7 +5,7 @@
 
 * [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/api/liquid)
 * [Liquid Wiki at GitHub](https://github.com/Shopify/liquid/wiki)
 * [Website](http://liquidmarkup.org/)
 
@@ -56,7 +56,7 @@ For standard use you can just pass it the content of a file and call render with
 
 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:

lib/liquid.rb

@@ -64,6 +64,7 @@ require 'liquid/strainer_template'
 require 'liquid/expression'
 require 'liquid/context'
 require 'liquid/parser_switching'
+require 'liquid/renderabledrop'
 require 'liquid/tag'
 require 'liquid/tag/disabler'
 require 'liquid/tag/disableable'

lib/liquid/locales/en.yml

@@ -24,5 +24,6 @@
       render: "Syntax error in tag 'render' - Template name must be a quoted string"
     argument:
       include: "Argument error in tag 'include' - Illegal template name"
+      render: "Argument error in tag 'render' - Illegal template name"
     disabled:
       tag: "usage is not allowed in this context"

lib/liquid/renderabledrop.rb

@@ -0,0 +1,9 @@
+# frozen_string_literal: true
+
+module Liquid
+  class RenderableDrop < Drop
+    def render(_context, _output)
+      raise NotImplementedError, "render must be implemented for #{self.class.name}"
+    end
+  end
+end

lib/liquid/tags/comment.rb

@@ -2,19 +2,6 @@
 
 module Liquid
   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

lib/liquid/tags/echo.rb

@@ -15,19 +15,15 @@ module Liquid
     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

lib/liquid/tags/render.rb

@@ -3,7 +3,20 @@
 module Liquid
   class Render < Tag
     FOR = 'for'
-    SYNTAX = /(#{QuotedString}+)(\s+(with|#{FOR})\s+(#{QuotedFragment}+))?(\s+(?:as)\s+(#{VariableSegment}+))?/o
+    SYNTAX = %r{
+      (
+        ## for {% render "snippet" %}
+        #{Liquid::QuotedString}+ |
+        ## for {% render block %}
+        \A#{Liquid::VariableSegment}+
+      )
+      ## for {% render "snippet" with product as p %}
+      ## or  {% render "snippet" for products p %}
+      (\s+(with|#{Liquid::Render::FOR})\s+(#{Liquid::QuotedFragment}+))?
+      (\s+(?:as)\s+(#{Liquid::VariableSegment}+))?
+      ## variables passed into the tag (e.g. {% render "snippet", var1: value1, var2: value2 %}
+      ## are not matched by this regex and are handled by .initialize
+    }xo
 
     disable_tags "include"
 
@@ -14,13 +27,13 @@ module Liquid
 
       raise SyntaxError, options[:locale].t("errors.syntax.render") unless markup =~ SYNTAX
 
-      template_name = Regexp.last_match(1)
+      @template_name = Regexp.last_match(1)
       with_or_for = Regexp.last_match(3)
       variable_name = Regexp.last_match(4)
 
       @alias_name = Regexp.last_match(6)
       @variable_name_expr = variable_name ? parse_expression(variable_name) : nil
-      @template_name_expr = parse_expression(template_name)
+      @template_name_expr = parse_expression(@template_name)
       @for = (with_or_for == FOR)
 
       @attributes = {}
@@ -34,9 +47,21 @@ module Liquid
     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
+      render_target = context.evaluate(@template_name_expr)
+      raise ArgumentError, options[:locale].t("errors.argument.render") unless render_target
+
+      # Check to see if this is a renderable drop
+      if render_target.is_a?(Liquid::RenderableDrop)
+        return render_target.render(context, output)
+      end
+
+      # Otherwise it must be a quoted string
+      unless /#{Liquid::QuotedString}+/.match?(@template_name)
+        output << "<!-- #{options[:locale].t('errors.syntax.render')} -->"
+        return
+      end
+
+      template_name = render_target
 
       partial = PartialCache.load(
         template_name,

test/integration/tags/comment_tag_test.rb

@@ -1,25 +0,0 @@
-# frozen_string_literal: true
-
-require 'test_helper'
-
-class CommentTagTest < Minitest::Test
-  include Liquid
-
-  def test_single_line_comments_parse
-    assert_template_result('Before comment', <<~LIQUID)
-      Before comment
-      {%- comment -%}
-        Regular text comment
-        Liquid in comment: {% echo 'Hi from comment' %}
-      {%- endcomment -%}
-    LIQUID
-  end
-
-  def test_multi_line_comments_parse
-    assert_template_result('Before comment', <<~LIQUID)
-      Before comment
-      {%- comment -%} Regular text comment {%- endcomment -%}
-      {%- comment -%} Liquid in comment: {% echo 'Hi from comment' %} {%- endcomment -%}
-    LIQUID
-  end
-end # CommentTagTest

test/integration/tags/render_tag_test.rb

@@ -75,9 +75,8 @@ class RenderTagTest < Minitest::Test
   def test_dynamically_choosen_templates_are_not_allowed
     Liquid::Template.file_system = StubFileSystem.new('snippet' => 'should not be rendered')
 
-    assert_raises(Liquid::SyntaxError) do
-      Liquid::Template.parse("{% assign name = 'snippet' %}{% render name %}")
-    end
+    assert_equal("<!-- Syntax error in tag 'render' - Template name must be a quoted string -->",
+      Liquid::Template.parse("{% assign name = 'snippet' %}{% render name %}").render!)
   end
 
   def test_include_tag_caches_second_read_of_same_partial