From 16cb47ddccbd0f4ecc118d7c167dddd95ad74e97 Mon Sep 17 00:00:00 2001
From: Chris Wanstrath <2+defunkt@users.noreply.github.com>
Date: Tue, 25 Nov 2025 13:16:41 -0800
Subject: [PATCH] `do` allowed in arg/dict values

---
 src/parser/parser2.ts              | 36 ++++++++++++---------
 src/parser/tests/functions.test.ts | 52 ++++++++++++++++++++++++++++++
 src/parser/tests/literals.test.ts  | 16 +++++++++
 3 files changed, 88 insertions(+), 16 deletions(-)

diff --git a/src/parser/parser2.ts b/src/parser/parser2.ts
index 64f62bc..c0ea85c 100644
--- a/src/parser/parser2.ts
+++ b/src/parser/parser2.ts
@@ -241,6 +241,22 @@ export class Parser {
   // parse specific nodes
   //
 
+  // raw determines whether we just want the SyntaxNodes or we want to
+  // wrap them in a PositionalArg
+  arg(raw = false): SyntaxNode {
+    // 'do' is a special function arg - it doesn't need to be wrapped
+    // in parens. otherwise, args are regular value()s
+    const val = this.is($T.Keyword, 'do') ? this.do() : this.value()
+
+    if (raw) {
+      return val
+    } else {
+      const arg = new SyntaxNode('PositionalArg', val.from, val.to)
+      arg.add(val)
+      return arg
+    }
+  }
+
   // [ 1 2 3 ]
   array(): SyntaxNode {
     const open = this.expect($T.OpenBracket)
@@ -425,10 +441,7 @@ export class Parser {
         continue
       }
 
-      if (this.is($T.NamedArgPrefix))
-        values.push(this.namedArg())
-      else
-        values.push(this.value())
+      values.push(this.is($T.NamedArgPrefix) ? this.namedArg() : this.arg())
     }
 
     const close = this.expect($T.CloseBracket)
@@ -549,17 +562,8 @@ export class Parser {
     const ident = fn ?? this.identifier()
 
     const args: SyntaxNode[] = []
-    while (!this.isExprEnd() && !this.is($T.Operator, '|')) {
-      if (this.is($T.NamedArgPrefix)) {
-        args.push(this.namedArg())
-      } else {
-        // 'do' is the only keyword allowed as a function argument
-        const val = this.is($T.Keyword, 'do') ? this.do() : this.value()
-        const arg = new SyntaxNode('PositionalArg', val.from, val.to)
-        arg.add(val)
-        args.push(arg)
-      }
-    }
+    while (!this.isExprEnd() && !this.is($T.Operator, '|'))
+      args.push(this.is($T.NamedArgPrefix) ? this.namedArg() : this.arg())
 
     const node = new SyntaxNode('FunctionCall', ident.from, (args.at(-1) || ident).to)
     node.push(ident, ...args)
@@ -669,7 +673,7 @@ export class Parser {
   // abc= true
   namedArg(): SyntaxNode {
     const prefix = SyntaxNode.from(this.expect($T.NamedArgPrefix))
-    const val = this.value()
+    const val = this.arg(true)
     const node = new SyntaxNode('NamedArg', prefix.from, val.to)
     return node.push(prefix, val)
   }
diff --git a/src/parser/tests/functions.test.ts b/src/parser/tests/functions.test.ts
index d2d7f9f..ff39870 100644
--- a/src/parser/tests/functions.test.ts
+++ b/src/parser/tests/functions.test.ts
@@ -43,6 +43,58 @@ describe('calling functions', () => {
     `)
   })
 
+  test('call with function', () => {
+    expect(`tail do x: x end`).toMatchTree(`
+      FunctionCall
+        Identifier tail
+        PositionalArg
+          FunctionDef
+            Do do
+            Params
+              Identifier x
+            colon :
+            FunctionCallOrIdentifier
+              Identifier x
+            keyword end
+    `)
+  })
+
+  test('call with arg and function', () => {
+    expect(`tail true do x: x end`).toMatchTree(`
+      FunctionCall
+        Identifier tail
+        PositionalArg
+          Boolean true
+        PositionalArg
+          FunctionDef
+            Do do
+            Params
+              Identifier x
+            colon :
+            FunctionCallOrIdentifier
+              Identifier x
+            keyword end
+    `)
+  })
+
+  test('call with function in named arg', () => {
+    expect(`tail callback=do x: x end`).toMatchTree(`
+      FunctionCall
+        Identifier tail
+        NamedArg
+          NamedArgPrefix callback=
+          FunctionDef
+            Do do
+            Params
+              Identifier x
+            colon :
+            FunctionCallOrIdentifier
+              Identifier x
+            keyword end
+      `)
+  })
+
+
   test('command with arg that is also a command', () => {
     expect('tail tail').toMatchTree(`
       FunctionCall
diff --git a/src/parser/tests/literals.test.ts b/src/parser/tests/literals.test.ts
index 9173232..ba423ab 100644
--- a/src/parser/tests/literals.test.ts
+++ b/src/parser/tests/literals.test.ts
@@ -336,6 +336,22 @@ describe('dict literals', () => {
     `)
   })
 
+  test('work with functions', () => {
+    expect(`[trap=do x: x end]`).toMatchTree(`
+      Dict
+        NamedArg
+          NamedArgPrefix trap=
+          FunctionDef
+            Do do
+            Params
+              Identifier x
+            colon :
+            FunctionCallOrIdentifier
+              Identifier x
+            keyword end
+    `)
+  })
+
   test('can be nested', () => {
     expect('[a=one b=[two [c=three]]]').toMatchTree(`
       Dict