feat: Add support of inner expressions enclosed by parentheses (#863)

* Add support of inner expressions enclosed by parentheses

* Add support of inner expressions enclosed by parentheses

Made-with: Cursor

* simplify implementation

* fix lint

* fix test

* Enhance tests for parenthesized filter chains in Liquid tags. Added scenarios for enabled and disabled grouped expressions in case, for, if, unless tags, ensuring proper handling of expressions and error throwing for invalid syntax.

* test: remove duplicate readGroupedExpression test block

The readGroupedExpression() test suite was duplicated twice in the spec file. Removed the duplicate block to avoid redundant test execution.

* refactor: extract extractGroupedExpressionTokenVariables helper

Extract inline grouped expression variable extraction logic into a dedicated
function for consistency with other extractors (extractFilteredValueVariables,
extractPropertyAccessVariable).

This addresses PR #863 comment 7 - improves code organization and
maintainability.

* refactor(types): explicit type for collection in for tag

collection: ValueToken | GroupedExpressionToken

Addresses PR #863 comment 5.

* refactor: evaluate grouped expressions at render time with resolvedFilters

Addresses PR review comments 4, 6, 8, 9 - moves grouped expression evaluation
from parse-time resolution to render-time lazy evaluation following the
generator-based async/sync duality pattern used throughout liquidjs.

Key changes:
- Replace resolvedValue (Value instance) with resolvedFilters (Filter[])
- Rename resolveGroupedExpressions() to resolveGroupedExpressionFilters()
- Move evaluation logic to evalGroupedExpressionToken() at render time
- Build Filter instances at parse time (carry liquid reference for render)
- Evaluate expression and apply filters lazily via generators
- Add support for tablerow tag with grouped expressions
- Remove duplicate getFilter() method in Value class

Maintains proper layering (tokens → render → templates) and consistency
with Value.value() pattern. Filter resolution still happens at parse time
since it requires liquid.filters access, but actual evaluation is deferred
to render time.

Tags that store raw ValueToken (for, case when-values, tablerow) still need
explicit resolveGroupedExpressionFilters() calls. Tags that wrap with
new Value() get automatic recursive resolution via Value constructor.

* refactor: reuse FilteredValueToken and fix architectural layering

Replace GroupedExpressionToken with existing FilteredValueToken to avoid
code duplication and fix layering violation where tokens depended on
templates (Filter instances).

Key changes:
- Reuse FilteredValueToken instead of GroupedExpressionToken
- Simplify readGroupOrRange() to return FilteredValueToken | RangeToken
- Add liquid reference to Context for runtime filter resolution
- Build Filter instances at render time in evalFilteredValueToken()
- Remove resolveGroupedExpressionFilters() and parse-time resolution
- Remove explicit resolution calls from tag constructors

This maintains proper architectural layering (tokens → render → templates)
with no backward dependencies, as requested in PR review feedback.

All 1537 tests pass.

* revert redundant'

* refactor: make getFilter private and improve code organization

* test: fix test name in case.spec.ts for when disabled block

* refactor: no need for Deprecated flag

* test: fix test name and logic to properly test if tag with nested expressions

* feat: support real parenthesis grouping in grouped expressions

Allow arbitrary expressions inside parentheses (e.g. ((a | upcase) > 3)
and (1 < 3)) when groupedExpressions is enabled, reusing readFilteredValue
for the general case while keeping range and filter-chain fast paths.

* feat: enhance expression tokenization with new generator methods

Added `readExpressionTokensFromHere` and `readGroupedExpressionTokens` methods to improve the handling of expression tokens. This refactor simplifies the token reading process and maintains compatibility with existing grouped expressions, ensuring proper evaluation and filtering.

* add tests

* address comments

---------

Co-authored-by: Omri Rosner <[email protected]>

src/context/context.ts

@@ -31,6 +31,10 @@ export class Context {
    * The normalized liquid options object
    */
   public opts: NormalizedFullOptions
+  /**
+   * Reference to the Liquid instance for filter resolution
+   */
+  public liquid?: any
   /**
    * Throw when accessing undefined variable?
    */
@@ -38,7 +42,7 @@ export class Context {
   public ownPropertyOnly: boolean;
   public memoryLimit: Limiter;
   public renderLimit: Limiter;
-  public constructor (env: object = {}, opts: NormalizedFullOptions = defaultOptions, renderOptions: RenderOptions = {}, { memoryLimit, renderLimit }: { [key: string]: Limiter } = {}) {
+  public constructor (env: object = {}, opts: NormalizedFullOptions = defaultOptions, renderOptions: RenderOptions = {}, { memoryLimit, renderLimit, liquid }: { memoryLimit?: Limiter, renderLimit?: Limiter, liquid?: any } = {}) {
     this.sync = !!renderOptions.sync
     this.opts = opts
     this.globals = renderOptions.globals ?? opts.globals
@@ -47,6 +51,7 @@ export class Context {
     this.ownPropertyOnly = renderOptions.ownPropertyOnly ?? opts.ownPropertyOnly
     this.memoryLimit = memoryLimit ?? new Limiter('memory alloc', renderOptions.memoryLimit ?? opts.memoryLimit)
     this.renderLimit = renderLimit ?? new Limiter('template render', getPerformance().now() + (renderOptions.renderLimit ?? opts.renderLimit))
+    this.liquid = liquid
   }
   public getRegister<T> (key: string, defaultValue: T = undefined as T): T {
     return (this.registers[key] = this.registers[key] || defaultValue)
@@ -110,7 +115,8 @@ export class Context {
       ownPropertyOnly: this.ownPropertyOnly
     }, {
       renderLimit: this.renderLimit,
-      memoryLimit: this.memoryLimit
+      memoryLimit: this.memoryLimit,
+      liquid: this.liquid
     })
   }
   private findScope (key: string | number) {

src/index.ts

@@ -11,7 +11,7 @@ export { Context, Scope } from './context'
 export { Value, Hash, Template, FilterImplOptions, Tag, Filter, Output, Variable, VariableLocation, VariableSegments, Variables, StaticAnalysis, StaticAnalysisOptions, analyze, analyzeSync, Arguments, PartialScope } from './template'
 export type { TagRenderReturn } from './template'
 export { Token, TopLevelToken, TagToken, ValueToken } from './tokens'
-export type { RangeToken, LiteralToken, QuotedToken, PropertyAccessToken, NumberToken } from './tokens'
+export type { RangeToken, LiteralToken, QuotedToken, PropertyAccessToken, NumberToken, FilteredValueToken } from './tokens'
 export { TokenKind, Tokenizer, ParseStream, Parser } from './parser'
 export { filters } from './filters'
 export * from './tags'

src/liquid-options.ts

@@ -87,6 +87,8 @@ export interface LiquidOptions {
   operators?: Operators;
   /** Respect parameter order when using filters like "for ... reversed limit", Defaults to `false`. */
   orderedFilterParameters?: boolean;
+  /** Allow parenthesized expressions as operands in conditions and loops, e.g. `{% if (foo | upcase) == "BAR" %}`. This is a non-standard extension to Liquid. Defaults to `false`. */
+  groupedExpressions?: boolean;
   /** For DoS handling, limit total length of templates parsed in one `parse()` call. A typical PC can handle 1e8 (100M) characters without issues. */
   parseLimit?: number;
   /** For DoS handling, limit total time (in ms) for each `render()` call. */
@@ -162,6 +164,7 @@ export interface NormalizedFullOptions extends NormalizedOptions {
   globals: object;
   keepOutputType: boolean;
   operators: Operators;
+  groupedExpressions: boolean;
   parseLimit: number;
   renderLimit: number;
   memoryLimit: number;
@@ -198,6 +201,7 @@ export const defaultOptions: NormalizedFullOptions = {
   globals: {},
   keepOutputType: false,
   operators: defaultOperators,
+  groupedExpressions: false,
   memoryLimit: Infinity,
   parseLimit: Infinity,
   renderLimit: Infinity

src/liquid.ts

@@ -31,7 +31,7 @@ export class Liquid {
   }
 
   public _render (tpl: Template[], scope: Context | object | undefined, renderOptions: RenderOptions): IterableIterator<any> {
-    const ctx = scope instanceof Context ? scope : new Context(scope, this.options, renderOptions)
+    const ctx = scope instanceof Context ? scope : new Context(scope, this.options, renderOptions, { liquid: this })
     return this.renderer.renderTemplates(tpl, ctx)
   }
   public async render (tpl: Template[], scope?: object, renderOptions?: RenderOptions): Promise<any> {
@@ -41,7 +41,7 @@ export class Liquid {
     return toValueSync(this._render(tpl, scope, { ...renderOptions, sync: true }))
   }
   public renderToNodeStream (tpl: Template[], scope?: object, renderOptions: RenderOptions = {}): NodeJS.ReadableStream {
-    const ctx = new Context(scope, this.options, renderOptions)
+    const ctx = new Context(scope, this.options, renderOptions, { liquid: this })
     return this.renderer.renderTemplatesToNodeStream(tpl, ctx)
   }
 
@@ -88,7 +88,7 @@ export class Liquid {
 
   public _evalValue (str: string, scope?: object | Context): IterableIterator<any> {
     const value = new Value(str, this)
-    const ctx = scope instanceof Context ? scope : new Context(scope, this.options)
+    const ctx = scope instanceof Context ? scope : new Context(scope, this.options, {}, { liquid: this })
     return value.value(ctx)
   }
   public async evalValue (str: string, scope?: object | Context): Promise<any> {

src/parser/parser.ts

@@ -33,7 +33,7 @@ export class Parser {
   public parse (html: string, filepath?: string): Template[] {
     html = String(html)
     this.parseLimit.use(html.length)
-    const tokenizer = new Tokenizer(html, this.liquid.options.operators, filepath)
+    const tokenizer = new Tokenizer(html, this.liquid.options.operators, filepath, undefined, this.liquid.options.groupedExpressions)
     const tokens = tokenizer.readTopLevelTokens(this.liquid.options)
     return this.parseTokens(tokens)
   }

src/parser/token-kind.ts

@@ -12,5 +12,6 @@ export enum TokenKind {
   Quoted = 1024,
   Operator = 2048,
   FilteredValue = 4096,
+  GroupedExpression = 8192,
   Delimited = Tag | Output
 }

src/parser/tokenizer.spec.ts

@@ -1,4 +1,4 @@
-import { LiquidTagToken, HTMLToken, QuotedToken, OutputToken, TagToken, OperatorToken, RangeToken, PropertyAccessToken, NumberToken, IdentifierToken } from '../tokens'
+import { LiquidTagToken, HTMLToken, QuotedToken, OutputToken, TagToken, OperatorToken, RangeToken, PropertyAccessToken, NumberToken, IdentifierToken, FilteredValueToken } from '../tokens'
 import { Tokenizer } from './tokenizer'
 import { defaultOperators } from '../render/operator'
 import { createTrie } from '../util/operator-trie'
@@ -229,24 +229,115 @@ describe('Tokenizer', function () {
   })
   describe('#readRange()', () => {
     it('should read `(1..3)`', () => {
-      const range = new Tokenizer('(1..3)').readRange()
+      const range = new Tokenizer('(1..3)').readGroupOrRange()
+      expect(range).toBeDefined()
       expect(range).toBeInstanceOf(RangeToken)
       expect(range!.getText()).toEqual('(1..3)')
-      const { lhs, rhs } = range!
+      expect((range as RangeToken).lhs).toBeInstanceOf(NumberToken)
-      expect(lhs).toBeInstanceOf(NumberToken)
+      expect((range as RangeToken).lhs.getText()).toBe('1')
-      expect(lhs.getText()).toBe('1')
+      expect((range as RangeToken).rhs).toBeInstanceOf(NumberToken)
-      expect(rhs).toBeInstanceOf(NumberToken)
+      expect((range as RangeToken).rhs.getText()).toBe('3')
-      expect(rhs.getText()).toBe('3')
     })
     it('should throw for `(..3)`', () => {
-      expect(() => new Tokenizer('(..3)').readRange()).toThrow('unexpected token "..3)", value expected')
+      expect(() => new Tokenizer('(..3)').readGroupOrRange()).toThrow('unexpected token "..3)", value expected')
     })
     it('should read `(a.b..c["..d"])`', () => {
-      const range = new Tokenizer('(a.b..c["..d"])').readRange()
+      const range = new Tokenizer('(a.b..c["..d"])').readGroupOrRange()
+      expect(range).toBeDefined()
       expect(range).toBeInstanceOf(RangeToken)
       expect(range!.getText()).toEqual('(a.b..c["..d"])')
     })
   })
+  describe('#readGroupedExpression()', () => {
+    function createGrouped (input: string): Tokenizer {
+      const t = new Tokenizer(input, defaultOperators)
+      t.groupedExpressions = true
+      return t
+    }
+    it('should read `(foo | upcase)` as FilteredValueToken', () => {
+      const token = createGrouped('(foo | upcase)').readValue()
+      expect(token).toBeInstanceOf(FilteredValueToken)
+      const grouped = token as FilteredValueToken
+      expect(grouped.getText()).toBe('(foo | upcase)')
+      expect(grouped.initial.postfix).toHaveLength(1)
+      expect(grouped.filters).toHaveLength(1)
+      expect(grouped.filters[0].name).toBe('upcase')
+    })
+    it('should read `(foo | append: "!")` with filter argument', () => {
+      const token = createGrouped('(foo | append: "!")').readValue()
+      expect(token).toBeInstanceOf(FilteredValueToken)
+      const grouped = token as FilteredValueToken
+      expect(grouped.filters).toHaveLength(1)
+      expect(grouped.filters[0].name).toBe('append')
+      expect(grouped.filters[0].args).toHaveLength(1)
+    })
+    it('should read nested `((foo | append: "!") | upcase)`', () => {
+      const token = createGrouped('((foo | append: "!") | upcase)').readValue()
+      expect(token).toBeInstanceOf(FilteredValueToken)
+      const grouped = token as FilteredValueToken
+      expect(grouped.filters).toHaveLength(1)
+      expect(grouped.filters[0].name).toBe('upcase')
+      expect(grouped.initial.postfix).toHaveLength(1)
+      expect(grouped.initial.postfix[0]).toBeInstanceOf(FilteredValueToken)
+    })
+    it('should parse `(a | upcase) == "BAR"` as expression', () => {
+      const exp = [...createGrouped('(a | upcase) == "BAR"').readExpressionTokens()]
+      expect(exp).toHaveLength(3)
+      expect(exp[0]).toBeInstanceOf(FilteredValueToken)
+      expect(exp[1]).toBeInstanceOf(OperatorToken)
+      expect(exp[1].getText()).toBe('==')
+      expect(exp[2]).toBeInstanceOf(QuotedToken)
+    })
+    it('should read `((a | upcase) > 3)` as outer FilteredValueToken with comparison inside parens', () => {
+      const token = createGrouped('((a | upcase) > 3)').readValue()
+      expect(token).toBeInstanceOf(FilteredValueToken)
+      const outer = token as FilteredValueToken
+      expect(outer.filters).toHaveLength(0)
+      expect(outer.getText()).toBe('((a | upcase) > 3)')
+      const [first, second, third] = outer.initial.postfix
+      expect(first).toBeInstanceOf(FilteredValueToken)
+      expect(second).toBeInstanceOf(NumberToken)
+      expect(third).toBeInstanceOf(OperatorToken)
+      expect((first as FilteredValueToken).filters[0].name).toBe('upcase')
+    })
+    it('should read `(1 < 3)` as grouped comparison with no filters', () => {
+      const token = createGrouped('(1 < 3)').readValue() as FilteredValueToken
+      expect(token.filters).toHaveLength(0)
+      expect(token.initial.postfix).toHaveLength(3)
+      expect(token.initial.postfix[0]).toBeInstanceOf(NumberToken)
+      expect(token.initial.postfix[1]).toBeInstanceOf(NumberToken)
+      expect((token.initial.postfix[2] as OperatorToken).operator).toBe('<')
+    })
+    it('should read redundant parens `(x)` as FilteredValueToken', () => {
+      const token = createGrouped('(x)').readValue() as FilteredValueToken
+      expect(token.filters).toHaveLength(0)
+      expect(token.initial.postfix).toHaveLength(1)
+    })
+    it('should read expression plus filters inside parens `(a == b | default: "x")`', () => {
+      const token = createGrouped('(a == b | default: "x")').readValue() as FilteredValueToken
+      expect(token.filters).toHaveLength(1)
+      expect(token.filters[0].name).toBe('default')
+      expect(token.initial.postfix.map((t) => t.getText()).join(' ')).toMatch(/a.*b.*==/)
+    })
+    it('should parse `((a | upcase) > 3) and (1 < 3)` as three expression tokens', () => {
+      const exp = [...createGrouped('((a | upcase) > 3) and (1 < 3)').readExpressionTokens()]
+      expect(exp).toHaveLength(3)
+      expect(exp[0]).toBeInstanceOf(FilteredValueToken)
+      expect(exp[1]).toBeInstanceOf(OperatorToken)
+      expect(exp[1].getText()).toBe('and')
+      expect(exp[2]).toBeInstanceOf(FilteredValueToken)
+    })
+    it('should still parse `(1..3)` as RangeToken', () => {
+      const token = createGrouped('(1..3)').readValue()
+      expect(token).toBeInstanceOf(RangeToken)
+    })
+    it('should throw for unclosed parens', () => {
+      expect(() => createGrouped('(foo | upcase').readValue()).toThrow('unbalanced parentheses')
+    })
+    it('should fall back to readRange when flag is off', () => {
+      expect(() => new Tokenizer('(foo | upcase)', defaultOperators).readValue()).toThrow('invalid range syntax')
+    })
+  })
   describe('#readFilter()', () => {
     it('should read a simple filter', function () {
       const tokenizer = new Tokenizer('| plus')

src/parser/tokenizer.ts

@@ -9,6 +9,7 @@ import { whiteSpaceCtrl } from './whitespace-ctrl'
 export class Tokenizer {
   p: number
   N: number
+  public groupedExpressions: boolean
   private rawBeginAt = -1
   private opTrie: Trie<OperatorHandler>
   private literalTrie: Trie<LiteralValue>
@@ -17,12 +18,14 @@ export class Tokenizer {
     public input: string,
     operators: Operators = defaultOptions.operators,
     public file?: string,
-    range?: [number, number]
+    range?: [number, number],
+    groupedExpressions = false
   ) {
     this.p = range ? range[0] : 0
     this.N = range ? range[1] : input.length
     this.opTrie = createTrie(operators)
     this.literalTrie = createTrie(literalValues)
+    this.groupedExpressions = groupedExpressions
   }
 
   readExpression () {
@@ -80,6 +83,7 @@ export class Tokenizer {
   readFilter (): FilterToken | null {
     this.skipBlank()
     if (this.end()) return null
+    if (this.peek() === ')') return null
     this.assert(this.read() === '|', `expected "|" before filter`)
     const name = this.readIdentifier()
     if (!name.size()) {
@@ -94,9 +98,9 @@ export class Tokenizer {
         const arg = this.readFilterArg()
         arg && args.push(arg)
         this.skipBlank()
-        this.assert(this.end() || this.peek() === ',' || this.peek() === '|', () => `unexpected character ${this.snapshot()}`)
+        this.assert(this.end() || this.peek() === ',' || this.peek() === '|' || this.peek() === ')', () => `unexpected character ${this.snapshot()}`)
       } while (this.peek() === ',')
-    } else if (this.peek() === '|' || this.end()) {
+    } else if (this.peek() === '|' || this.peek() === ')' || this.end()) {
       // do nothing
     } else {
       throw this.error('expected ":" after filter name')
@@ -307,10 +311,13 @@ export class Tokenizer {
     return -1
   }
 
-  readValue (): ValueToken | undefined {
+  readValue (): ValueToken | FilteredValueToken | undefined {
     this.skipBlank()
     const begin = this.p
-    const variable = this.readLiteral() || this.readQuoted() || this.readRange() || this.readNumber()
+    let variable: ValueToken | FilteredValueToken | undefined = this.readLiteral() || this.readQuoted() || this.readNumber()
+    if (!variable && this.peek() === '(') {
+      variable = this.readGroupOrRange()
+    }
     const props = this.readProperties(!variable)
     if (!props.length) return variable
     return new PropertyAccessToken(variable, props, this.input, begin, this.p)
@@ -385,20 +392,34 @@ export class Tokenizer {
     return literal
   }
 
-  readRange (): RangeToken | undefined {
+  readGroupOrRange (): FilteredValueToken | RangeToken | undefined {
     this.skipBlank()
     const begin = this.p
     if (this.peek() !== '(') return
     ++this.p
     const lhs = this.readValueOrThrow()
     this.skipBlank()
-    this.assert(this.read() === '.' && this.read() === '.', 'invalid range syntax')
+
+    if (this.peek() === '.' && this.peek(1) === '.') {
+      this.p += 2
       const rhs = this.readValueOrThrow()
       this.skipBlank()
       this.assert(this.read() === ')', 'invalid range syntax')
       return new RangeToken(this.input, begin, this.p, lhs, rhs, this.file)
     }
 
+    if (this.groupedExpressions) {
+      const initial = new Expression([lhs, ...this.readExpressionTokens()])
+      this.assert(initial.valid(), () => `invalid value expression: ${this.snapshot()}`)
+      const filters = this.readFilters()
+      this.skipBlank()
+      this.assert(this.read() === ')', 'unbalanced parentheses')
+      return new FilteredValueToken(initial, filters, this.input, begin, this.p, this.file)
+    }
+
+    throw this.error('invalid range syntax')
+  }
+
   readValueOrThrow (): ValueToken {
     const value = this.readValue()
     this.assert(value, () => `unexpected token ${this.snapshot()}, value expected`)

src/render/expression.ts

@@ -1,13 +1,14 @@
-import { QuotedToken, RangeToken, OperatorToken, Token, PropertyAccessToken, OperatorType, operatorTypes } from '../tokens'
+import { QuotedToken, RangeToken, OperatorToken, Token, PropertyAccessToken, OperatorType, operatorTypes, FilteredValueToken } from '../tokens'
-import { isRangeToken, isPropertyAccessToken, UndefinedVariableError, range, isOperatorToken, assert } from '../util'
+import { isRangeToken, isPropertyAccessToken, isFilteredValueToken, UndefinedVariableError, range, isOperatorToken, assert } from '../util'
 import type { Context } from '../context'
 import type { UnaryOperatorHandler } from '../render'
 import { Drop } from '../drop'
+import { Filter } from '../template/filter'
 
 export class Expression {
   readonly postfix: Token[]
 
-  public constructor (tokens: IterableIterator<Token>) {
+  public constructor (tokens: Iterable<Token>) {
     this.postfix = [...toPostfix(tokens)]
   }
   public * evaluate (ctx: Context, lenient?: boolean): Generator<unknown, unknown, unknown> {
@@ -40,6 +41,22 @@ export function * evalToken (token: Token | undefined, ctx: Context, lenient = f
   if ('content' in token) return token.content
   if (isPropertyAccessToken(token)) return yield evalPropertyAccessToken(token, ctx, lenient)
   if (isRangeToken(token)) return yield evalRangeToken(token, ctx)
+  if (isFilteredValueToken(token)) return yield evalFilteredValueToken(token, ctx, lenient)
+}
+
+function * evalFilteredValueToken (token: FilteredValueToken, ctx: Context, lenient: boolean): IterableIterator<unknown> {
+  assert(ctx.liquid, 'FilteredValueToken evaluation requires liquid instance in context')
+  lenient = lenient || (ctx.opts.lenientIf && token.filters.length > 0 && token.filters[0].name === 'default')
+  let val = yield token.initial.evaluate(ctx, lenient)
+
+  for (const filterToken of token.filters) {
+    const filterImpl = ctx.liquid.filters[filterToken.name]
+    assert(filterImpl || !ctx.liquid.options.strictFilters, () => `undefined filter: ${filterToken.name}`)
+    const filter = new Filter(filterToken, filterImpl, ctx.liquid)
+    val = yield filter.render(val, ctx)
+  }
+
+  return val
 }
 
 function * evalPropertyAccessToken (token: PropertyAccessToken, ctx: Context, lenient: boolean): IterableIterator<unknown> {
@@ -71,7 +88,7 @@ function * evalRangeToken (token: RangeToken, ctx: Context) {
   return range(+low, +high + 1)
 }
 
-function * toPostfix (tokens: IterableIterator<Token>): IterableIterator<Token> {
+function * toPostfix (tokens: Iterable<Token>): IterableIterator<Token> {
   const ops: OperatorToken[] = []
   for (const token of tokens) {
     if (isOperatorToken(token)) {

src/tags/case.ts

@@ -1,11 +1,11 @@
-import { ValueToken, Liquid, toValue, evalToken, Value, Emitter, TagToken, TopLevelToken, Context, Template, Tag, ParseStream } from '..'
+import { ValueToken, Liquid, toValue, evalToken, Value, Emitter, TagToken, TopLevelToken, Context, Template, Tag, ParseStream, FilteredValueToken } from '..'
 import { Parser } from '../parser'
 import { equals } from '../render'
 import { Arguments } from '../template'
 
 export default class extends Tag {
   value: Value
-  branches: { values: ValueToken[], templates: Template[] }[] = []
+  branches: { values: (ValueToken | FilteredValueToken)[], templates: Template[] }[] = []
   elseTemplates: Template[] = []
   constructor (tagToken: TagToken, remainTokens: TopLevelToken[], liquid: Liquid, parser: Parser) {
     super(tagToken, remainTokens, liquid)
@@ -22,7 +22,7 @@ export default class extends Tag {
 
         p = []
 
-        const values: ValueToken[] = []
+        const values: (ValueToken | FilteredValueToken)[] = []
         while (!token.tokenizer.end()) {
           values.push(token.tokenizer.readValueOrThrow())
           token.tokenizer.skipBlank()

src/tags/for.ts

@@ -1,4 +1,4 @@
-import { Hash, ValueToken, Liquid, Tag, evalToken, Emitter, TagToken, TopLevelToken, Context, Template, ParseStream } from '..'
+import { Hash, ValueToken, Liquid, Tag, evalToken, Emitter, TagToken, TopLevelToken, Context, Template, ParseStream, FilteredValueToken } from '..'
 import { assertEmpty, isValueToken, toEnumerable } from '../util'
 import { createScope } from '../context/scope'
 import { ForloopDrop } from '../drop/forloop-drop'
@@ -11,7 +11,7 @@ type valueOf<T> = T[keyof T]
 
 export default class extends Tag {
   variable: string
-  collection: ValueToken
+  collection: ValueToken | FilteredValueToken
   hash: Hash
   templates: Template[]
   elseTemplates: Template[]

src/tags/tablerow.ts

@@ -1,6 +1,6 @@
 import { isValueToken, toEnumerable } from '../util'
 import { createScope } from '../context/scope'
-import { ValueToken, Liquid, Tag, evalToken, Emitter, Hash, TagToken, TopLevelToken, Context, Template, ParseStream } from '..'
+import { ValueToken, Liquid, Tag, evalToken, Emitter, Hash, TagToken, TopLevelToken, Context, Template, ParseStream, FilteredValueToken } from '..'
 import { TablerowloopDrop } from '../drop/tablerowloop-drop'
 import { Parser } from '../parser'
 import { Arguments } from '../template'
@@ -9,7 +9,7 @@ export default class extends Tag {
   variable: string
   args: Hash
   templates: Template[]
-  collection: ValueToken
+  collection: ValueToken | FilteredValueToken
   constructor (tagToken: TagToken, remainTokens: TopLevelToken[], liquid: Liquid, parser: Parser) {
     super(tagToken, remainTokens, liquid)
     const variable = this.tokenizer.readIdentifier()

src/template/analysis.ts

@@ -2,6 +2,7 @@ import { Argument, Template, Value } from '.'
 import { isKeyValuePair } from '../parser/filter-arg'
 import { PropertyAccessToken, ValueToken } from '../tokens'
 import {
+  isFilteredValueToken,
   isNumberToken,
   isPropertyAccessToken,
   isQuotedToken,
@@ -371,11 +372,31 @@ function * extractValueTokenVariables (token: ValueToken): Generator<Variable> {
   if (isRangeToken(token)) {
     yield * extractValueTokenVariables(token.lhs)
     yield * extractValueTokenVariables(token.rhs)
+  } else if (isFilteredValueToken(token)) {
+    yield * extractGroupedExpressionTokenVariables(token)
   } else if (isPropertyAccessToken(token)) {
     yield extractPropertyAccessVariable(token)
   }
 }
 
+function * extractGroupedExpressionTokenVariables (token: ValueToken): Generator<Variable> {
+  if (!isFilteredValueToken(token)) return
+
+  for (const t of token.initial.postfix) {
+    if (isValueToken(t)) yield * extractValueTokenVariables(t)
+  }
+
+  for (const filter of token.filters) {
+    for (const arg of filter.args) {
+      if (isKeyValuePair(arg) && arg[1]) {
+        yield * extractValueTokenVariables(arg[1])
+      } else if (isValueToken(arg)) {
+        yield * extractValueTokenVariables(arg)
+      }
+    }
+  }
+}
+
 function extractPropertyAccessVariable (token: PropertyAccessToken): Variable {
   const segments: VariableSegments = []
 

src/template/output.ts

@@ -12,7 +12,7 @@ export class Output extends TemplateImpl<OutputToken> implements Template {
   value: Value
   public constructor (token: OutputToken, liquid: Liquid) {
     super(token)
-    const tokenizer = new Tokenizer(token.input, liquid.options.operators, token.file, token.contentRange)
+    const tokenizer = new Tokenizer(token.input, liquid.options.operators, token.file, token.contentRange, liquid.options.groupedExpressions)
     this.value = new Value(tokenizer.readFilteredValue(), liquid)
     const filters = this.value.filters
     const outputEscape = liquid.options.outputEscape

src/template/value.ts

@@ -15,7 +15,7 @@ export class Value {
    */
   public constructor (input: string | FilteredValueToken, liquid: Liquid) {
     const token: FilteredValueToken = typeof input === 'string'
-      ? new Tokenizer(input, liquid.options.operators).readFilteredValue()
+      ? new Tokenizer(input, liquid.options.operators, undefined, undefined, liquid.options.groupedExpressions).readFilteredValue()
       : input
     this.initial = token.initial
     this.filters = token.filters.map(token => new Filter(token, this.getFilter(liquid, token.name), liquid))

src/tokens/liquid-tag-token.ts

@@ -16,7 +16,7 @@ export class LiquidTagToken extends DelimitedToken {
     file?: string
   ) {
     super(TokenKind.Tag, [begin, end], input, begin, end, false, false, file)
-    this.tokenizer = new Tokenizer(input, options.operators, file, this.contentRange)
+    this.tokenizer = new Tokenizer(input, options.operators, file, this.contentRange, options.groupedExpressions)
     this.name = this.tokenizer.readTagName()
     this.tokenizer.assert(this.name, 'illegal liquid tag syntax')
     this.tokenizer.skipBlank()

src/tokens/property-access-token.ts

@@ -5,11 +5,12 @@ import { IdentifierToken } from './identifier-token'
 import { NumberToken } from './number-token'
 import { RangeToken } from './range-token'
 import { QuotedToken } from './quoted-token'
+import { FilteredValueToken } from './filtered-value-token'
 import { TokenKind } from '../parser'
 
 export class PropertyAccessToken extends Token {
   constructor (
-    public variable: QuotedToken | RangeToken | LiteralToken | NumberToken | undefined,
+    public variable: QuotedToken | RangeToken | LiteralToken | NumberToken | FilteredValueToken | undefined,
     public props: (ValueToken | IdentifierToken)[],
     input: string,
     begin: number,

src/tokens/tag-token.ts

@@ -17,7 +17,7 @@ export class TagToken extends DelimitedToken {
     const [valueBegin, valueEnd] = [begin + tagDelimiterLeft.length, end - tagDelimiterRight.length]
     super(TokenKind.Tag, [valueBegin, valueEnd], input, begin, end, trimTagLeft, trimTagRight, file)
 
-    this.tokenizer = new Tokenizer(input, options.operators, file, this.contentRange)
+    this.tokenizer = new Tokenizer(input, options.operators, file, this.contentRange, options.groupedExpressions)
     this.name = this.tokenizer.readTagName()
     this.tokenizer.assert(this.name, `illegal tag syntax, tag name expected`)
     this.tokenizer.skipBlank()

src/tokens/value-token.ts

@@ -3,5 +3,6 @@ import { LiteralToken } from './literal-token'
 import { NumberToken } from './number-token'
 import { QuotedToken } from './quoted-token'
 import { PropertyAccessToken } from './property-access-token'
+import { FilteredValueToken } from './filtered-value-token'
 
-export type ValueToken = RangeToken | LiteralToken | QuotedToken | PropertyAccessToken | NumberToken
+export type ValueToken = RangeToken | LiteralToken | QuotedToken | PropertyAccessToken | NumberToken | FilteredValueToken

src/util/type-guards.ts

@@ -1,4 +1,4 @@
-import { RangeToken, NumberToken, QuotedToken, LiteralToken, PropertyAccessToken, OutputToken, HTMLToken, TagToken, IdentifierToken, DelimitedToken, OperatorToken, ValueToken } from '../tokens'
+import { RangeToken, NumberToken, QuotedToken, LiteralToken, PropertyAccessToken, OutputToken, HTMLToken, TagToken, IdentifierToken, DelimitedToken, OperatorToken, ValueToken, FilteredValueToken } from '../tokens'
 import { TokenKind } from '../parser'
 
 export function isDelimitedToken (val: any): val is DelimitedToken {
@@ -45,9 +45,13 @@ export function isRangeToken (val: any): val is RangeToken {
   return getKind(val) === TokenKind.Range
 }
 
+export function isFilteredValueToken (val: any): val is FilteredValueToken {
+  return getKind(val) === TokenKind.FilteredValue
+}
+
 export function isValueToken (val: any): val is ValueToken {
-  // valueTokenBitMask = TokenKind.Number | TokenKind.Literal | TokenKind.Quoted | TokenKind.PropertyAccess | TokenKind.Range
+  // valueTokenBitMask = TokenKind.Number | TokenKind.Literal | TokenKind.Quoted | TokenKind.PropertyAccess | TokenKind.Range | TokenKind.FilteredValue
-  return (getKind(val) & 1667) > 0
+  return (getKind(val) & 5763) > 0
 }
 
 function getKind (val: any) {

test/integration/static_analysis/variables.spec.ts

@@ -1085,4 +1085,24 @@ describe('Variable analysis', () => {
       locals: { y: [new Variable(['y'], { row: 1, col: 11, file: 'a' })] }
     })
   })
+
+  describe('grouped expressions', () => {
+    const ge = new Liquid({ groupedExpressions: true })
+
+    it('should report variables inside a grouped output expression', () => {
+      const analysis = analyzeSync(ge.parse('{{ (a | append: b) }}'))
+      expect(Object.keys(analysis.variables).sort()).toStrictEqual(['a', 'b'])
+    })
+
+    it('should report variables inside a grouped condition', () => {
+      const analysis = analyzeSync(ge.parse('{% if (a | append: b) == c %}{% endif %}'))
+      expect(Object.keys(analysis.globals).sort()).toStrictEqual(['a', 'b', 'c'])
+    })
+
+    it('should separate locals from globals for grouped assign', () => {
+      const analysis = analyzeSync(ge.parse('{% assign x = (a | upcase) %}{{ x }}'))
+      expect(Object.keys(analysis.globals)).toStrictEqual(['a'])
+      expect(Object.keys(analysis.locals)).toStrictEqual(['x'])
+    })
+  })
 })

test/integration/tags/assign.spec.ts

@@ -99,4 +99,13 @@ describe('tags/assign', function () {
     const html = liquid.parseAndRenderSync(src)
     return expect(html).toBe('bar')
   })
+  describe('grouped expressions', function () {
+    const ge = new Liquid({ groupedExpressions: true })
+    it('should assign a grouped expression', async () => {
+      expect(await ge.parseAndRender('{% assign x = (name | upcase) %}{{ x }}', { name: 'bar' })).toBe('BAR')
+    })
+    it('should assign a grouped range', async () => {
+      expect(await ge.parseAndRender('{% assign x = (1..(items | size)) %}{{ x }}', { items: ['a', 'b', 'c'] })).toBe('123')
+    })
+  })
 })

test/integration/tags/case.spec.ts

@@ -132,4 +132,30 @@ describe('tags/case', function () {
       TRUE
     `)
   })
+  describe('parenthesized filter chains', function () {
+    describe('when enabled', () => {
+      const ge = new Liquid({ groupedExpressions: true })
+      it('should support grouped expression in case value', () => {
+        const src = '{% case (status | downcase) %}{% when "active" %}active{% when "pending" %}pending{% else %}other{% endcase %}'
+        const html = ge.parseAndRenderSync(src, { status: 'ACTIVE' })
+        expect(html).toBe('active')
+      })
+      it('should support grouped expression in when value', () => {
+        const src = '{% case status %}{% when (expected | downcase) %}match{% else %}no match{% endcase %}'
+        const html = ge.parseAndRenderSync(src, { status: 'active', expected: 'ACTIVE' })
+        expect(html).toBe('match')
+      })
+    })
+    describe('when disabled', () => {
+      const ge = new Liquid({ groupedExpressions: false })
+      it('should throw error for grouped expression in case value', () => {
+        const src = '{% case (status | downcase) %}{% when "active" %}active{% when "pending" %}pending{% else %}other{% endcase %}'
+        expect(() => ge.parseAndRenderSync(src, { status: 'ACTIVE' })).toThrow('invalid range syntax')
+      })
+      it('should throw error for grouped expression in when value', () => {
+        const src = '{% case status %}{% when (expected | downcase) %}match{% else %}no match{% endcase %}'
+        expect(() => ge.parseAndRenderSync(src, { status: 'active', expected: 'ACTIVE' })).toThrow('invalid range syntax')
+      })
+    })
+  })
 })

test/integration/tags/echo.spec.ts

@@ -36,4 +36,14 @@ describe('tags/echo', function () {
     const html = await liquid.parseAndRender(src, { user: { name: 'Sally' } })
     return expect(html).toBe('Hello, SALLY!')
   })
+
+  describe('grouped expressions', function () {
+    const ge = new Liquid({ groupedExpressions: true })
+    it('should echo a grouped expression', async () => {
+      expect(await ge.parseAndRender('{% echo (name | upcase) %}', { name: 'bar' })).toBe('BAR')
+    })
+    it('should render a grouped expression in an output statement', async () => {
+      expect(await ge.parseAndRender('{{ (name | upcase | append: "!") }}', { name: 'bar' })).toBe('BAR!')
+    })
+  })
 })

test/integration/tags/for.spec.ts

@@ -426,4 +426,21 @@ describe('tags/for', function () {
       return expect(html).toBe('i-someDrop i-someDrop i-someDrop ')
     })
   })
+  describe('parenthesized filter chains', function () {
+    describe('when enabled', function () {
+      const ge = new Liquid({ groupedExpressions: true })
+      it('should support range with filtered RHS', function () {
+        const src = '{% for i in (1..(items | size)) %}{{i}} {% endfor %}'
+        const html = ge.parseAndRenderSync(src, { items: ['a', 'b', 'c'] })
+        expect(html).toBe('1 2 3 ')
+      })
+    })
+    describe('when disabled', function () {
+      const ge = new Liquid({ groupedExpressions: false })
+      it('should throw for range with filtered RHS', function () {
+        const src = '{% for i in (1..(items | size)) %}{{i}} {% endfor %}'
+        expect(() => ge.parseAndRenderSync(src, { items: ['a', 'b', 'c'] })).toThrow('invalid range syntax')
+      })
+    })
+  })
 })

test/integration/tags/if.spec.ts

@@ -169,4 +169,84 @@ describe('tags/if', function () {
     expect(() => liquid.parseAndRenderSync('{% if false %}{% else %}{% elsif true %}{% endif %}'))
       .toThrow(`unexpected elsif after else`)
   })
+  describe('parenthesized filter chains', function () {
+    describe('when enabled', function () {
+      const ge = new Liquid({ groupedExpressions: true })
+      it('should support (foo | upcase) == "BAR"', async function () {
+        const src = '{% if (foo | upcase) == "BAR" %}yes{% else %}no{% endif %}'
+        const html = await ge.parseAndRender(src, { foo: 'bar' })
+        return expect(html).toBe('yes')
+      })
+      it('should support both sides parenthesized', async function () {
+        const src = '{% if (a | upcase) == (b | upcase) %}yes{% else %}no{% endif %}'
+        const html = await ge.parseAndRender(src, { a: 'hi', b: 'hi' })
+        return expect(html).toBe('yes')
+      })
+      it('should support with logical operators', async function () {
+        const src = '{% if (a | upcase) == "FOO" and (b | downcase) == "bar" %}yes{% else %}no{% endif %}'
+        const html = await ge.parseAndRender(src, { a: 'foo', b: 'BAR' })
+        return expect(html).toBe('yes')
+      })
+      it('should support standalone parenthesized filter via evalValueSync', function () {
+        const result = ge.evalValueSync('(foo | upcase)', { foo: 'bar' })
+        return expect(result).toBe('BAR')
+      })
+      it('should support comparison via evalValueSync', function () {
+        const result = ge.evalValueSync('(foo | upcase) == "BAR"', { foo: 'bar' })
+        return expect(result).toBe(true)
+      })
+      it('should keep range syntax working', function () {
+        const result = ge.evalValueSync('(1..5)', {})
+        return expect(result).toEqual([1, 2, 3, 4, 5])
+      })
+      it('should support chained filters in condition', async function () {
+        const src = '{% if (name | downcase | size) > 3 %}long{% else %}short{% endif %}'
+        const html = await ge.parseAndRender(src, { name: 'Alice' })
+        return expect(html).toBe('long')
+      })
+      it('should support real parenthesis grouping with comparisons and and', async function () {
+        const src = '{% if (((name | downcase | size) > 3) and (one < three)) %}long{% else %}short{% endif %}'
+        const html = await ge.parseAndRender(src, { name: 'Alice', one: 1, three: 3 })
+        return expect(html).toBe('long')
+      })
+      it('should support nested parenthesized expressions in if condition', async function () {
+        const src = '{% if ((foo | append: "!") | upcase) == "BAR!" %}match{% else %}no match{% endif %}'
+        const html = await ge.parseAndRender(src, { foo: 'bar' })
+        return expect(html).toBe('match')
+      })
+      it('should support or with grouped operands', async function () {
+        const src = '{% if (a | upcase) == "X" or (b | upcase) == "B" %}yes{% else %}no{% endif %}'
+        expect(await ge.parseAndRender(src, { a: 'z', b: 'b' })).toBe('yes')
+      })
+      it('should support not with a grouped operand', async function () {
+        const src = '{% if not (a | upcase) == "B" %}no{% else %}yes{% endif %}'
+        expect(await ge.parseAndRender(src, { a: 'b' })).toBe('yes')
+      })
+      it('should support contains with a grouped operand', async function () {
+        const src = '{% if (csv | split: ",") contains "b" %}yes{% else %}no{% endif %}'
+        expect(await ge.parseAndRender(src, { csv: 'a,b,c' })).toBe('yes')
+      })
+      it('should support property access on a grouped result', function () {
+        expect(ge.evalValueSync('(items | first).name', { items: [{ name: 'Sally' }] })).toBe('Sally')
+      })
+      it('should support a grouped expression inside a bracket index', function () {
+        expect(ge.evalValueSync('arr[(i | plus: 1)]', { arr: [10, 20, 30], i: 1 })).toBe(30)
+      })
+      it('should support an async filter inside a grouped expression', async function () {
+        ge.registerFilter('asyncUpcase', (v: string) => Promise.resolve(String(v).toUpperCase()))
+        const src = '{% if (name | asyncUpcase) == "BAR" %}yes{% else %}no{% endif %}'
+        expect(await ge.parseAndRender(src, { name: 'bar' })).toBe('yes')
+      })
+    })
+    describe('when disabled', function () {
+      const ge = new Liquid({ groupedExpressions: false })
+      it('should throw for parenthesized filter in condition', () => {
+        const src = '{% if (foo | upcase) == "BAR" %}yes{% else %}no{% endif %}'
+        expect(() => ge.parseAndRenderSync(src, { foo: 'bar' })).toThrow('invalid range syntax')
+      })
+      it('should throw for parenthesized filter via evalValueSync', () => {
+        expect(() => ge.evalValueSync('(foo | upcase)', { foo: 'bar' })).toThrow('invalid range syntax')
+      })
+    })
+  })
 })

test/integration/tags/unless.spec.ts

@@ -83,4 +83,21 @@ describe('tags/unless', function () {
       expect(html).toBe('yes')
     })
   })
+  describe('parenthesized filter chains', function () {
+    describe('when enabled', function () {
+      const ge = new Liquid({ groupedExpressions: true })
+      it('should support grouped expression in unless condition', function () {
+        const src = '{% unless (content | size) == 0 %}has content{% else %}empty{% endunless %}'
+        const html = ge.parseAndRenderSync(src, { content: 'hello' })
+        expect(html).toBe('has content')
+      })
+    })
+    describe('when disabled', function () {
+      const ge = new Liquid({ groupedExpressions: false })
+      it('should throw for grouped expression in unless condition', function () {
+        const src = '{% unless (content | size) == 0 %}has content{% else %}empty{% endunless %}'
+        expect(() => ge.parseAndRenderSync(src, { content: 'hello' })).toThrow('invalid range syntax')
+      })
+    })
+  })
 })