diff --git a/parse.leg b/parse.leg
index 28a2ee0..6ec147c 100644
--- a/parse.leg
+++ b/parse.leg
@@ -309,7 +309,7 @@ postfix		= s:atom ( "?" -		{ s = mkQuery(s) }
 			 | "+" -		{ s = mkPlus(s) }
 			 )?			{ $$ = s }
 
-atom		= string | class | dot | rule
+atom		= string | class | dot | rule | '(' -expression')'-
 
 rule		= i:id !'='        		{ $$ = mkId(intern(yytext)) }