Only allow NULL in the prpoer places.

diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index d412e4db23e3896a150596968d98c4b81f92fff7..af0e6c5c67e7c86ffd764df4d8eeacdda6e0ca60 100644 (file)
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -10,7 +10,7 @@
  *
  *
  * IDENTIFICATION
- *    $Header: /cvsroot/pgsql/src/backend/parser/gram.y,v 1.25 1997/01/16 14:56:05 momjian Exp $
+ *    $Header: /cvsroot/pgsql/src/backend/parser/gram.y,v 1.26 1997/02/13 15:40:03 momjian Exp $
  *
  * HISTORY
  *    AUTHOR           DATE            MAJOR EVENT
@@ -149,7 +149,8 @@ static Node *makeA_Expr(int oper, char *opname, Node *lexpr, Node *rexpr);
 %type <coldef> columnDef
 %type <defelt> def_elem
 %type <node>   def_arg, columnElem, where_clause, 
-               a_expr, AexprConst, in_expr_nodes, not_in_expr_nodes,
+               a_expr, a_expr_or_null, AexprConst,
+               in_expr_nodes, not_in_expr_nodes,
                having_clause
 %type <value>  NumConst
 %type <attr>   event_object, attr
@@ -1751,6 +1752,15 @@ Typename:  typname opt_array_bounds
  *
  *****************************************************************************/
 
+a_expr_or_null: a_expr
+               { $$ = $1;}
+       | Pnull
+               {       
+                   A_Const *n = makeNode(A_Const);
+                   n->val.type = T_Null;
+                   $$ = (Node *)n;
+               }
+               
 a_expr:  attr opt_indirection
                {
                    $1->indirection = $2;
@@ -1800,7 +1810,7 @@ a_expr:  attr opt_indirection
                    }
                    $$ = (Node *)$2;
                }
-       | '(' a_expr ')'
+       | '(' a_expr_or_null ')'
                {   $$ = $2; }
        | a_expr Op a_expr
                {   $$ = makeA_Expr(OP, $2, $1, $3); }
@@ -1892,9 +1902,9 @@ opt_indirection:  '[' a_expr ']' opt_indirection
                {   $$ = NIL; }
        ;
    
-expr_list: a_expr
+expr_list: a_expr_or_null
                { $$ = lcons($1, NIL); }
-       |  expr_list ',' a_expr
+       |  expr_list ',' a_expr_or_null
                { $$ = lappend($1, $3); }
        ;
 
@@ -1966,7 +1976,7 @@ res_target_list:  res_target_list ',' res_target_el
                }
        ;
 
-res_target_el: Id opt_indirection '=' a_expr
+res_target_el: Id opt_indirection '=' a_expr_or_null
                {
                    $$ = makeNode(ResTarget);
                    $$->name = $1;
@@ -2014,7 +2024,7 @@ res_target_el2: a_expr AS Id
                    $$->indirection = NULL;
                    $$->val = (Node *)$1;
                }
-       | a_expr
+       | a_expr_or_null
                {
                    $$ = makeNode(ResTarget);
                    $$->name = NULL;
@@ -2108,12 +2118,6 @@ AexprConst:  Iconst
                }
        | ParamNo
                {   $$ = (Node *)$1;  }
-       | Pnull         
-               {       
-                   A_Const *n = makeNode(A_Const);
-                   n->val.type = T_Null;
-                   $$ = (Node *)n;
-               }
        ;
 
 ParamNo:  PARAM