From: gaoyunzhong@gmail.com   
      
   Richard,   
   Consider changing these rules:   
   exp_list => expression;   
   expression => '(' query_specification ')';   
   query_list => '(' query_list ')';   
   query_list => query_specification;   
      
   Whether the query_spec in your statement #3 should reduce to exp_list   
   or query_list will depend on the particular SQL dialect you are   
   working with, especially the treatment of redundant parentheses. You   
   may also consider creating an extra nonterminal such as   
   exp_or_query_list.   
      
   Hope it helps.   
   Y.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)