Remove unnecessary syntactic predicates.

libwccl/parser/grammar.g

@@ -487,11 +487,11 @@ bool_variable
 symset_operator
 	[const Corpus2::Tagset& tagset, Variables& vars]
 	returns [boost::shared_ptr<Function<TSet> > ret]
-	: (symset_condition[tagset, vars]) => (ret = symset_condition [tagset, vars])
-	| (symset_getsymbol[tagset, vars]) => (ret = symset_getsymbol [tagset, vars])
-	| (symset_var_val  [tagset, vars]) => (ret = symset_var_val   [tagset, vars])
-	| (symset_class    [tagset, vars]) => (ret = symset_class     [tagset, vars])
-	| (symset_range    [tagset, vars]) => (ret = symset_range     [tagset, vars])
+	: ret = symset_condition [tagset, vars]
+	| (SYMBOL LBRACKET) => (ret = symset_getsymbol [tagset, vars])
+	| ret = symset_var_val   [tagset, vars]
+	| ret = symset_class     [tagset, vars]
+	| ret = symset_range     [tagset, vars]
 	//
 	| LPAREN ret = symset_operator [tagset, vars] RPAREN
 ;