src/parser/scopeTracker.ts

@@ -2,7 +2,7 @@ import { ContextTracker, InputStream } from '@lezer/lr'
 import * as terms from './shrimp.terms'
 
 export class Scope {
-  constructor(public parent: Scope | null, public vars = new Set<string>()) {}
+  constructor(public parent: Scope | null, public vars = new Set<string>()) { }
 
   has(name: string): boolean {
     return this.vars.has(name) || (this.parent?.has(name) ?? false)
@@ -42,7 +42,7 @@ export class Scope {
 
 // Tracker context that combines Scope with temporary pending identifiers
 class TrackerContext {
-  constructor(public scope: Scope, public pendingIds: string[] = []) {}
+  constructor(public scope: Scope, public pendingIds: string[] = []) { }
 }
 
 // Extract identifier text from input stream
@@ -75,6 +75,12 @@ export const trackScope = new ContextTracker<TrackerContext>({
       return new TrackerContext(context.scope, [...context.pendingIds, text])
     }
 
+    // Track identifiers in array destructuring: [ a b ] = ...
+    if (!inParams && term === terms.Identifier && isArrayDestructuring(input)) {
+      const text = readIdentifierText(input, input.pos, stack.pos)
+      return new TrackerContext(Scope.add(context.scope, text), context.pendingIds)
+    }
+
     return context
   },
 
@@ -98,3 +104,26 @@ export const trackScope = new ContextTracker<TrackerContext>({
 
   hash: (context) => context.scope.hash(),
 })
+
+// Check if we're parsing array destructuring: [ a b ] = ...
+const isArrayDestructuring = (input: InputStream): boolean => {
+  let pos = 0
+
+  // Find closing bracket
+  while (pos < 200 && input.peek(pos) !== 93 /* ] */) {
+    if (input.peek(pos) === -1) return false // EOF
+    pos++
+  }
+
+  if (input.peek(pos) !== 93 /* ] */) return false
+  pos++
+
+  // Skip whitespace
+  while (input.peek(pos) === 32 /* space */ ||
+    input.peek(pos) === 9 /* tab */ ||
+    input.peek(pos) === 10 /* \n */) {
+    pos++
+  }
+
+  return input.peek(pos) === 61 /* = */
+}

src/parser/tests/basics.test.ts

@@ -630,6 +630,24 @@ describe('Array destructuring', () => {
           Number 1
           Number 2`)
   })
+
+
+  test('works with dotget', () => {
+    expect('[ a ] = [ [1 2 3] ]; a.1').toMatchTree(`
+      Assign
+        Array
+          Identifier a
+        Eq =
+        Array
+          Array
+            Number 1
+            Number 2
+            Number 3
+      FunctionCallOrIdentifier
+        DotGet
+          IdentifierBeforeDot a
+          Number 1`)
+  })
 })
 
 describe('Conditional ops', () => {