diff --git a/brag/brag/rules/parser.rkt b/brag/brag/rules/parser.rkt
index a5ea573..9d25117 100755
--- a/brag/brag/rules/parser.rkt
+++ b/brag/brag/rules/parser.rkt
@@ -59,7 +59,7 @@
 (define hide-char #\/)
 (define splice-char #\@)
 
-(define id-separators-pattern "((:)|(::=))")
+(define id-separators-pattern "(:|::=)")
 
 ;; grammar-parser: (-> token) -> (listof rule)
 (define grammar-parser