allow keywords as values in enums (and tagged unions)

2026-07-13 17:51:59 +02:00
parent de56dc7315
commit 5a958d9bfd
5 changed files with 156 additions and 18 deletions
@@ -39,6 +39,34 @@ roadmap and milestone history.
 - native sum composition with `A | B` for unbacked enums and tagged unions, using program-global `u16` variant ids
 - fallible channel types `T ! E`, where `E` is a native enum/tagged union or supported sum composition

+#### keyword member names
+
+Reserved keywords are valid native enum members and tagged-union variants when used in an
+unambiguous member context:
+
+```bro
+TokenKind :: enum {
+    if
+    else
+    return
+}
+
+Token :: union(TokenKind) {
+    if i32
+    else void
+    return i32
+}
+
+conditional func() TokenKind { return TokenKind.if }
+fallback func() TokenKind { return .else }
+token func() Token { return Token{ if = 1 } }
+```
+
+Keyword variants also work with field access and `.variant` match patterns; `.else:` remains
+distinct from the `else:` catch-all arm. No escaping syntax is required. Keywords remain reserved
+for ordinary declarations, struct fields, untagged-union fields, and anonymous payload-struct
+fields. `_` is not a keyword member name.
+
 ### expressions and control flow

 - checked integer `+ - *`, unary `-`, float-only `/`, IEEE float arithmetic, comparisons, `!`, `and`, and `or`