Make match guards accept a test, not just and expression

marijnh · marijnh · commit 0daf785f1153 · 2025-04-17T08:00:20.000+02:00
FIX: Fix parsing of match guards with conditional tests. Closes #28
diff --git a/src/python.grammar b/src/python.grammar
@@ -42,7 +42,7 @@ MatchStatement {
 }
 
 MatchClause {
-  skw<"case"> commaSep<pattern> Guard { kw<"if"> expression }? Body
+  skw<"case"> commaSep<pattern> Guard { kw<"if"> test }? Body
 }
 
 pattern[@isGroup=Pattern] {
diff --git a/test/statement.txt b/test/statement.txt
@@ -368,6 +368,8 @@ match foo:
     pass
   case [a, b, *rest] | (p, q):
     pass
+  case (1, 2) if bar == 2:
+    pass
 
 ==>
 
@@ -392,6 +394,10 @@ Script(MatchStatement(match,VariableName,MatchBody(
         StarPattern(CapturePattern(VariableName))),
       LogicOp,
       SequencePattern(CapturePattern(VariableName),CapturePattern(VariableName))),
+    Body(PassStatement(pass))),
+  MatchClause(case,
+    SequencePattern(LiteralPattern(Number),LiteralPattern(Number)),
+    Guard(if,BinaryExpression(VariableName,CompareOp,Number)),
     Body(PassStatement(pass))))))
 
 # Type Params

Original file line number	Diff line number	Diff line change
`@@ -42,7 +42,7 @@ MatchStatement {`
`42`	`42`	`}`
`43`	`43`
`44`	`44`	`MatchClause {`
`45`		`- skw<"case"> commaSep<pattern> Guard { kw<"if"> expression }? Body`
	`45`	`+ skw<"case"> commaSep<pattern> Guard { kw<"if"> test }? Body`
`46`	`46`	`}`
`47`	`47`
`48`	`48`	`pattern[@isGroup=Pattern] {`