feat: static variable analysis

src/index.ts

@@ -6,7 +6,7 @@ export { Drop } from './drop'
 export { Emitter } from './emitters'
 export { defaultOperators, Operators, evalToken, evalQuotedToken, Expression, isFalsy, isTruthy } from './render'
 export { Context, Scope } from './context'
-export { Value, Hash, Template, FilterImplOptions, Tag, Filter, Output } from './template'
+export { Value, Hash, Template, FilterImplOptions, Tag, Filter, Output, Variable, VariableLocation, VariableSegments, Variables, analyze } from './template'
 export { Token, TopLevelToken, TagToken, ValueToken } from './tokens'
 export { TokenKind, Tokenizer, ParseStream } from './parser'
 export { filters } from './filters'

src/render/expression.ts

@@ -4,7 +4,7 @@ import type { Context } from '../context'
 import type { UnaryOperatorHandler } from '../render'
 
 export class Expression {
-  private postfix: Token[]
+  readonly postfix: Token[]
 
   public constructor (tokens: IterableIterator<Token>) {
     this.postfix = [...toPostfix(tokens)]

src/tags/assign.ts

@@ -1,4 +1,6 @@
 import { Value, Liquid, TopLevelToken, TagToken, Context, Tag } from '..'
+import { Arguments } from '../template'
+
 export default class extends Tag {
   private key: string
   private value: Value
@@ -17,4 +19,12 @@ export default class extends Tag {
   * render (ctx: Context): Generator<unknown, void, unknown> {
     ctx.bottom()[this.key] = yield this.value.value(ctx, this.liquid.options.lenientIf)
   }
+
+  public arguments (): Arguments {
+    return [this.value]
+  }
+
+  public localScope (): string[] {
+    return [this.key]
+  }
 }

src/tags/block.ts

@@ -42,4 +42,8 @@ export default class extends Tag {
       ? (superBlock: BlockDrop, emitter: Emitter) => renderChild(new BlockDrop(() => renderCurrent(superBlock, emitter)), emitter)
       : renderCurrent
   }
+
+  public children (): Template[] {
+    return this.templates
+  }
 }

src/tags/capture.ts

@@ -29,4 +29,12 @@ export default class extends Tag {
     if (quoted) return evalQuotedToken(quoted)
     throw this.tokenizer.error('invalid capture name')
   }
+
+  public children (): Template[] {
+    return this.templates
+  }
+
+  public localScope (): string[] {
+    return [this.variable]
+  }
 }

src/tags/case.ts

@@ -1,6 +1,7 @@
 import { ValueToken, Liquid, toValue, evalToken, Value, Emitter, TagToken, TopLevelToken, Context, Template, Tag, ParseStream } from '..'
 import { Parser } from '../parser'
 import { equals } from '../render'
+import { Arguments } from '../template'
 
 export default class extends Tag {
   value: Value
@@ -71,4 +72,18 @@ export default class extends Tag {
       yield r.renderTemplates(this.elseTemplates, ctx, emitter)
     }
   }
+
+  public arguments (): Arguments {
+    return this.branches.flatMap(b => b.values)
+  }
+
+  public children (): Template[] {
+    const children = this.branches.flatMap(b => b.templates)
+
+    if (this.elseTemplates) {
+      children.push(...this.elseTemplates)
+    }
+
+    return children
+  }
 }

src/tags/cycle.ts

@@ -1,4 +1,5 @@
 import { TopLevelToken, Liquid, ValueToken, evalToken, Emitter, TagToken, Context, Tag } from '..'
+import { Arguments } from '../template'
 
 export default class extends Tag {
   private candidates: ValueToken[] = []
@@ -38,4 +39,14 @@ export default class extends Tag {
     groups[fingerprint] = idx
     return yield evalToken(candidate, ctx)
   }
+
+  public arguments (): Arguments {
+    const args = this.candidates.slice()
+
+    if (this.group) {
+      args.push(this.group)
+    }
+
+    return args
+  }
 }

src/tags/decrement.ts

@@ -1,4 +1,5 @@
 import { Tag, Liquid, TopLevelToken, Emitter, TagToken, Context } from '..'
+import { Arguments } from '../template'
 import { isNumber, stringify } from '../util'
 
 export default class extends Tag {
@@ -14,4 +15,12 @@ export default class extends Tag {
     }
     emitter.write(stringify(--scope[this.variable]))
   }
+
+  public arguments (): Arguments {
+    return [this.variable]
+  }
+
+  public localScope (): string[] {
+    return [this.variable]
+  }
 }

src/tags/echo.ts

@@ -1,4 +1,5 @@
 import { Liquid, TopLevelToken, Emitter, Value, TagToken, Context, Tag } from '..'
+import { Arguments } from '../template'
 
 export default class extends Tag {
   private value?: Value
@@ -15,4 +16,8 @@ export default class extends Tag {
     const val = yield this.value.value(ctx, false)
     emitter.write(val)
   }
+
+  public arguments (): Arguments {
+    return this.value ? [this.value] : []
+  }
 }

src/tags/for.ts

@@ -1,7 +1,8 @@
 import { Hash, ValueToken, Liquid, Tag, evalToken, Emitter, TagToken, TopLevelToken, Context, Template, ParseStream } from '..'
-import { assertEmpty, toEnumerable } from '../util'
+import { assertEmpty, isValueToken, toEnumerable } from '../util'
 import { ForloopDrop } from '../drop/forloop-drop'
 import { Parser } from '../parser'
+import { Arguments } from '../template'
 
 const MODIFIERS = ['offset', 'limit', 'reversed']
 
@@ -78,6 +79,32 @@ export default class extends Tag {
     }
     ctx.pop()
   }
+
+  public children (): Template[] {
+    const children = [...this.templates]
+
+    if (this.elseTemplates) {
+      children.push(...this.elseTemplates)
+    }
+
+    return children
+  }
+
+  public arguments (): Arguments {
+    const args: Arguments = [this.collection]
+
+    for (const v of Object.values(this.hash.hash)) {
+      if (isValueToken(v)) {
+        args.push(v)
+      }
+    }
+
+    return args
+  }
+
+  public blockScope (): string[] {
+    return [this.variable, 'forloop']
+  }
 }
 
 function reversed<T> (arr: Array<T>) {

src/tags/if.ts

@@ -1,5 +1,6 @@
 import { Liquid, Tag, Value, Emitter, isTruthy, TagToken, TopLevelToken, Context, Template } from '..'
 import { Parser } from '../parser'
+import { Arguments } from '../template'
 import { assert, assertEmpty } from '../util'
 
 export default class extends Tag {
@@ -44,4 +45,18 @@ export default class extends Tag {
     }
     yield r.renderTemplates(this.elseTemplates || [], ctx, emitter)
   }
+
+  public children (): Template[] {
+    const children = this.branches.flatMap(b => b.templates)
+
+    if (this.elseTemplates) {
+      children.push(...this.elseTemplates)
+    }
+
+    return children
+  }
+
+  public arguments (): Arguments {
+    return this.branches.map(b => b.value)
+  }
 }

src/tags/include.ts

@@ -1,6 +1,8 @@
 import { Template, ValueToken, TopLevelToken, Liquid, Tag, assert, evalToken, Hash, Emitter, TagToken, Context } from '..'
 import { BlockMode, Scope } from '../context'
 import { Parser } from '../parser'
+import { Arguments } from '../template'
+import { isValueToken } from '../util'
 import { parseFilePath, renderFilePath } from './render'
 
 export default class extends Tag {
@@ -40,4 +42,36 @@ export default class extends Tag {
     ctx.pop()
     ctx.restoreRegister(saved)
   }
+
+  public arguments (): Arguments {
+    const args: Arguments = []
+
+    for (const v of Object.values(this.hash.hash)) {
+      if (isValueToken(v)) {
+        args.push(v)
+      }
+    }
+
+    if (isValueToken(this['file'])) {
+      args.push(this['file'])
+    }
+
+    if (isValueToken(this.withVar)) {
+      args.push(this.withVar)
+    }
+
+    return args
+  }
+
+  public blockScope (): string[] {
+    const names: string[] = []
+
+    for (const k of Object.keys(this.hash.hash)) {
+      names.push(k)
+    }
+
+    // TODO: withVar
+
+    return names
+  }
 }

src/tags/increment.ts

@@ -1,5 +1,6 @@
 import { isNumber, stringify } from '../util'
 import { Tag, Liquid, TopLevelToken, Emitter, TagToken, Context } from '..'
+import { Arguments } from '../template'
 
 export default class extends Tag {
   private variable: string
@@ -16,4 +17,12 @@ export default class extends Tag {
     scope[this.variable]++
     emitter.write(stringify(val))
   }
+
+  public arguments (): Arguments {
+    return [this.variable]
+  }
+
+  public localScope (): string[] {
+    return [this.variable]
+  }
 }

src/tags/layout.ts

@@ -3,6 +3,8 @@ import { BlockMode } from '../context'
 import { parseFilePath, renderFilePath, ParsedFileName } from './render'
 import { BlankDrop } from '../drop'
 import { Parser } from '../parser'
+import { Arguments } from '../template'
+import { isValueToken } from '../util'
 
 export default class extends Tag {
   args: Hash
@@ -41,4 +43,30 @@ export default class extends Tag {
     yield renderer.renderTemplates(templates, ctx, emitter)
     ctx.pop()
   }
+
+  public arguments (): Arguments {
+    const args: Arguments = []
+
+    for (const v of Object.values(this.args.hash)) {
+      if (isValueToken(v)) {
+        args.push(v)
+      }
+    }
+
+    if (isValueToken(this['file'])) {
+      args.push(this['file'])
+    }
+
+    return args
+  }
+
+  public blockScope (): string[] {
+    const names: string[] = []
+
+    for (const k of Object.keys(this.args.hash)) {
+      names.push(k)
+    }
+
+    return names
+  }
 }

src/tags/liquid.ts

@@ -11,4 +11,8 @@ export default class extends Tag {
   * render (ctx: Context, emitter: Emitter): Generator<unknown, void, unknown> {
     yield this.liquid.renderer.renderTemplates(this.templates, ctx, emitter)
   }
+
+  public children (): Template[] {
+    return this.templates
+  }
 }

src/tags/render.ts

@@ -1,8 +1,9 @@
 import { __assign } from 'tslib'
 import { ForloopDrop } from '../drop'
-import { toEnumerable } from '../util'
+import { isString, isValueToken, toEnumerable } from '../util'
 import { TopLevelToken, assert, Liquid, Token, Template, evalQuotedToken, TypeGuards, Tokenizer, evalToken, Hash, Emitter, TagToken, Context, Tag } from '..'
 import { Parser } from '../parser'
+import { Arguments } from '../template'
 
 export type ParsedFileName = Template[] | Token | string | undefined
 
@@ -75,6 +76,50 @@ export default class extends Tag {
       yield liquid.renderer.renderTemplates(templates, childCtx, emitter)
     }
   }
+
+  public arguments (): Arguments {
+    const args: Arguments = []
+
+    for (const v of Object.values(this.hash.hash)) {
+      if (isValueToken(v)) {
+        args.push(v)
+      }
+    }
+
+    if (isValueToken(this['file'])) {
+      args.push(this['file'])
+    }
+
+    if (this['for']) {
+      const { value } = this['for']
+      if (isValueToken(value)) {
+        args.push(value)
+      }
+    }
+
+    return args
+  }
+
+  public blockScope (): string[] {
+    const names: string[] = []
+
+    for (const k of Object.keys(this.hash.hash)) {
+      names.push(k)
+    }
+
+    if (this['for']) {
+      const { alias } = this['for']
+      if (isString(alias)) {
+        names.push(alias)
+      } else if (isString(this.file)) {
+        names.push(this.file)
+      }
+
+      names.push('forloop')
+    }
+
+    return names
+  }
 }
 
 /**