From 2c0fcdd857a73172daafe5f4ae12f07b2a7ed9e3 Mon Sep 17 00:00:00 2001
From: Oleg Kizeev <kizeev.ov@gmail.com>
Date: Fri, 28 Feb 2025 22:11:11 +0700
Subject: [PATCH] Named Arguments in Callbacks

---
 CHANGELOG.md                      |  1 +
 src/main/grammars/SlintParser.bnf |  5 ++-
 testData/ParsingTestData.slint    |  9 ++++
 testData/ParsingTestData.txt      | 73 ++++++++++++++++++++++++++++++-
 4 files changed, 85 insertions(+), 3 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index c017df8..0b83941 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,7 @@
 ### Features
 
 - Property Change Callbacks
+- Named Arguments in Callbacks
 
 ### Fixed
 
diff --git a/src/main/grammars/SlintParser.bnf b/src/main/grammars/SlintParser.bnf
index 92ed600..1383df7 100644
--- a/src/main/grammars/SlintParser.bnf
+++ b/src/main/grammars/SlintParser.bnf
@@ -208,9 +208,12 @@ private PropertyDefinitionInit::= (':' | '<=>') Expression
 private CallbackDefinition ::= PURE? CALLBACK Identifier (CallbackParametersDeclaration | CallbackBindingDeclaration)? ';' {
     pin=3
 }
-private CallbackParametersDeclaration ::= '(' Type? (',' (Type | &')'))* ')' CallbackReturnDeclaration? {
+private CallbackParametersDeclaration ::= '(' CallbackNamedParameter? (',' (CallbackNamedParameter | &')'))* ')' CallbackReturnDeclaration? {
     pin(".*")=1
 }
+private CallbackNamedParameter ::= Identifier ':' Type {
+    pin=3
+}
 private CallbackReturnDeclaration ::= '->' Type { pin=2 }
 private CallbackBindingDeclaration ::= '<=>' PropertyExpression
 
diff --git a/testData/ParsingTestData.slint b/testData/ParsingTestData.slint
index f0c7101..47d232c 100644
--- a/testData/ParsingTestData.slint
+++ b/testData/ParsingTestData.slint
@@ -126,4 +126,13 @@ export component Example inherits Window  {
         }
         t := Text {}
     }
+}
+
+// Named Arguments in Callbacks
+export component NamedCallbackExample inherits Rectangle {
+    // Declare a callback with named argument
+    callback hello(foo: int, bar: string);
+    // The names can be overridden with
+    // anything when setting a handler
+    hello(aa, bb) => { /* ... */ }
 }
\ No newline at end of file
diff --git a/testData/ParsingTestData.txt b/testData/ParsingTestData.txt
index e2193db..8ec8a2c 100644
--- a/testData/ParsingTestData.txt
+++ b/testData/ParsingTestData.txt
@@ -1,4 +1,4 @@
-SLINT_FILE(0,3330)
+SLINT_FILE(0,3627)
   SlintImportDefinitionImpl(IMPORT_DEFINITION)(0,85)
     PsiElement(import)('import')(0,6)
     PsiWhiteSpace(' ')(6,7)
@@ -1105,4 +1105,73 @@ SLINT_FILE(0,3330)
         PsiWhiteSpace('\n    ')(3322,3327)
         PsiElement(})('}')(3327,3328)
       PsiWhiteSpace('\n')(3328,3329)
-      PsiElement(})('}')(3329,3330)
\ No newline at end of file
+      PsiElement(})('}')(3329,3330)
+  PsiWhiteSpace('\n\n')(3330,3332)
+  PsiComment(LINE_COMMENT)('// Named Arguments in Callbacks')(3332,3363)
+  PsiWhiteSpace('\n')(3363,3364)
+  PsiElement(export)('export')(3364,3370)
+  PsiWhiteSpace(' ')(3370,3371)
+  SlintComponentDefinitionImpl(COMPONENT_DEFINITION)(3371,3627)
+    PsiElement(component)('component')(3371,3380)
+    PsiWhiteSpace(' ')(3380,3381)
+    SlintComponentNameImpl(COMPONENT_NAME)(3381,3401)
+      PsiElement(IDENTIFIER)('NamedCallbackExample')(3381,3401)
+    PsiWhiteSpace(' ')(3401,3402)
+    PsiElement(inherits)('inherits')(3402,3410)
+    PsiWhiteSpace(' ')(3410,3411)
+    SlintComponentNameImpl(COMPONENT_NAME)(3411,3420)
+      PsiElement(IDENTIFIER)('Rectangle')(3411,3420)
+    PsiWhiteSpace(' ')(3420,3421)
+    SlintComponentBodyImpl(COMPONENT_BODY)(3421,3627)
+      PsiElement({)('{')(3421,3422)
+      PsiWhiteSpace('\n    ')(3422,3427)
+      PsiComment(LINE_COMMENT)('// Declare a callback with named argument')(3427,3468)
+      PsiWhiteSpace('\n    ')(3468,3473)
+      PsiElement(callback)('callback')(3473,3481)
+      PsiWhiteSpace(' ')(3481,3482)
+      PsiElement(IDENTIFIER)('hello')(3482,3487)
+      PsiElement(()('(')(3487,3488)
+      PsiElement(IDENTIFIER)('foo')(3488,3491)
+      PsiElement(BAD_CHARACTER)(':')(3491,3492)
+      PsiWhiteSpace(' ')(3492,3493)
+      SlintTypeImpl(TYPE)(3493,3496)
+        SlintBuiltinTypeImpl(BUILTIN_TYPE)(3493,3496)
+          PsiElement(IDENTIFIER)('int')(3493,3496)
+      PsiElement(,)(',')(3496,3497)
+      PsiWhiteSpace(' ')(3497,3498)
+      PsiElement(IDENTIFIER)('bar')(3498,3501)
+      PsiElement(BAD_CHARACTER)(':')(3501,3502)
+      PsiWhiteSpace(' ')(3502,3503)
+      SlintTypeImpl(TYPE)(3503,3509)
+        SlintBuiltinTypeImpl(BUILTIN_TYPE)(3503,3509)
+          PsiElement(IDENTIFIER)('string')(3503,3509)
+      PsiElement())(')')(3509,3510)
+      PsiElement(;)(';')(3510,3511)
+      PsiWhiteSpace('\n    ')(3511,3516)
+      PsiComment(LINE_COMMENT)('// The names can be overridden with')(3516,3551)
+      PsiWhiteSpace('\n    ')(3551,3556)
+      PsiComment(LINE_COMMENT)('// anything when setting a handler')(3556,3590)
+      PsiWhiteSpace('\n    ')(3590,3595)
+      PsiElement(IDENTIFIER)('hello')(3595,3600)
+      PsiElement(()('(')(3600,3601)
+      SlintPropertyExpressionImpl(PROPERTY_EXPRESSION)(3601,3603)
+        SlintPropertyExpressionCompositeImpl(PROPERTY_EXPRESSION_COMPOSITE)(3601,3603)
+          PsiElement(IDENTIFIER)('aa')(3601,3603)
+      PsiElement(,)(',')(3603,3604)
+      PsiWhiteSpace(' ')(3604,3605)
+      SlintPropertyExpressionImpl(PROPERTY_EXPRESSION)(3605,3607)
+        SlintPropertyExpressionCompositeImpl(PROPERTY_EXPRESSION_COMPOSITE)(3605,3607)
+          PsiElement(IDENTIFIER)('bb')(3605,3607)
+      PsiElement())(')')(3607,3608)
+      PsiWhiteSpace(' ')(3608,3609)
+      PsiElement(=)('=')(3609,3610)
+      PsiElement(>)('>')(3610,3611)
+      PsiWhiteSpace(' ')(3611,3612)
+      SlintCallbackBodyImpl(CALLBACK_BODY)(3612,3625)
+        PsiElement({)('{')(3612,3613)
+        PsiWhiteSpace(' ')(3613,3614)
+        PsiComment(DOC_COMMENT)('/* ... */')(3614,3623)
+        PsiWhiteSpace(' ')(3623,3624)
+        PsiElement(})('}')(3624,3625)
+      PsiWhiteSpace('\n')(3625,3626)
+      PsiElement(})('}')(3626,3627)
\ No newline at end of file