void-payloads, multi-pattern arms, and range patterns (match statements)

2026-06-29 19:52:05 +02:00
parent 462632554c
commit c82f070d55
8 changed files with 499 additions and 106 deletions
@@ -477,14 +477,18 @@ parse_struct_literal :: proc(
 			break
 		}
 		advance(parser)
-		if _, ok := allow(parser, .Equal); !ok {
-			source.add(parser.diagnostics, current(parser).span, "expected '=' after struct field name")
+		// A bare key (`T{ variant }`, no `= value`) constructs a void-payload union
+		// variant; the checker validates that the field actually has a void type.
+		value := ast.INVALID_EXPR
+		key_end := field.span
+		if _, ok := allow(parser, .Equal); ok {
+			skip_newlines(parser)
+			value = parse_expression_bp(parser, 0, nesting+1)
+			key_end = parser.module.exprs[value].span
 		}
-		skip_newlines(parser)
-		value := parse_expression_bp(parser, 0, nesting+1)
 		append(&args, add_expr(parser, ast.Expr{
 			kind=.Keyed,
-			span=span_from(field.span, parser.module.exprs[value].span),
+			span=span_from(field.span, key_end),
 			name=field.symbol,
 			left=value,
 			right=ast.INVALID_EXPR,
@@ -1544,20 +1548,33 @@ parse_arm_body :: proc(parser: ^Parser) -> []ast.Stmt_Id {
 	return single
 }

-// parse_match_arm parses one `<pattern> [|capture|]: <body>` arm (or `else: <body>`).
-// The pattern is `INVALID_EXPR` for `else`; `captures` holds the optional 0-or-1
-// payload capture name (tagged-union variants only).
+// parse_match_arm parses one `<pattern,...> [|[@]capture|]: <body>` arm (or
+// `else: <body>`). `patterns` is empty for `else`, one expr for a single pattern, or
+// several for a multi-pattern arm; `captures` holds the optional 0-or-1 payload capture
+// name with `pointer_capture` set for the `|@cap|` form (validated in the checker).
 parse_match_arm :: proc(parser: ^Parser) -> ast.Stmt_Id {
 	start := current(parser).span
-	pattern := ast.INVALID_EXPR
+	patterns: [dynamic]ast.Expr_Id
+	patterns.allocator = parser.module.allocator
 	captures: [dynamic]symbol.Id
 	captures.allocator = parser.module.allocator
+	pointer_capture := false
 	if _, is_else := allow(parser, .Keyword_Else); !is_else {
 		saved := parser.no_struct_literal
 		parser.no_struct_literal = true
-		pattern = parse_expression(parser)
+		append(&patterns, parse_expression(parser))
+		for {
+			if _, ok := allow(parser, .Comma); !ok {
+				break
+			}
+			skip_newlines(parser)
+			append(&patterns, parse_expression(parser))
+		}
 		parser.no_struct_literal = saved
 		if _, ok := allow(parser, .Pipe); ok {
+			if _, at_ok := allow(parser, .At); at_ok {
+				pointer_capture = true
+			}
 			name_tok := current(parser)
 			if name_tok.kind == .Identifier || name_tok.kind == .Underscore {
 				advance(parser)
@@ -1578,8 +1595,10 @@ parse_match_arm :: proc(parser: ^Parser) -> ast.Stmt_Id {
 	append(&parser.module.statements, ast.Stmt{
 		kind=.Match_Arm,
 		span=span_from(start, previous(parser).span),
-		expr=pattern,
+		expr=ast.INVALID_EXPR,
+		patterns=patterns[:],
 		captures=captures[:],
+		pointer_capture=pointer_capture,
 		body=body,
 		target=ast.INVALID_EXPR,
 		update=ast.INVALID_STMT,