Correct coredump in ALTER TABLE foo ADD(). Accept explicit NULL in

typecasts, eg 'NULL::text'.  Later parts of the parser don't like this
yet, but I'll work on that next.

diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index ce16f9e9f3cbe29d6c2a821ecb49f1f3ce033dec..b7724b74a8efe41867dcf158ccd390bca4e56c8c 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 2.117 1999/12/06 18:02:43 wieck Exp $
+ *   $Header: /cvsroot/pgsql/src/backend/parser/gram.y,v 2.118 1999/12/10 03:01:05 tgl Exp $
  *
  * HISTORY
  *   AUTHOR            DATE            MAJOR EVENT
@@ -362,7 +362,7 @@ static Node *doNegate(Node *n);
 %right     UMINUS
 %left      '.'
 %left      '[' ']'
-%nonassoc  TYPECAST
+%left      TYPECAST
 %left      UNION INTERSECT EXCEPT
 %%
 
@@ -759,11 +759,9 @@ alter_clause:  ADD opt_column columnDef
                }
            | ADD '(' OptTableElementList ')'
                {
-                   Node *lp = lfirst($3);
-
                    if (length($3) != 1)
                        elog(ERROR,"ALTER TABLE/ADD() allows one column only");
-                   $$ = lp;
+                   $$ = (Node *) lfirst($3);
                }
            | DROP opt_column ColId
                {   elog(ERROR,"ALTER TABLE/DROP COLUMN not yet implemented"); }
@@ -1532,7 +1530,7 @@ ConstraintTimeSpec: INITIALLY IMMEDIATE
        | INITIALLY DEFERRED
            { $$ = 2; }
        ;
-       
+
 
 DropTrigStmt:  DROP TRIGGER name ON relation_name
                {
@@ -1758,7 +1756,7 @@ comment_tg:   TRIGGER { $$ = TRIGGER; }
        ; 
 
 comment_text:  Sconst { $$ = $1; }
-       | NULL_P { $$ = 0; }
+       | NULL_P { $$ = NULL; }
        ;
        
 /*****************************************************************************
@@ -3807,6 +3805,17 @@ a_expr:  com_expr
                        $$ = (Node *)n;
                    }
                }
+       /*
+        * Can't collapse this into prior rule by using a_expr_or_null;
+        * that creates reduce/reduce conflicts.  Grumble.
+        */
+       | NULL_P TYPECAST Typename
+               {
+                   A_Const *n = makeNode(A_Const);
+                   n->val.type = T_Null;
+                   n->typename = $3;
+                   $$ = (Node *)n;
+               }
        /*
         * These operators must be called out explicitly in order to make use
         * of yacc/bison's automatic operator-precedence handling.  All other
@@ -4041,6 +4050,13 @@ b_expr:  com_expr
                        $$ = (Node *)n;
                    }
                }
+       | NULL_P TYPECAST Typename
+               {
+                   A_Const *n = makeNode(A_Const);
+                   n->val.type = T_Null;
+                   n->typename = $3;
+                   $$ = (Node *)n;
+               }
        | '-' b_expr %prec UMINUS
                {   $$ = doNegate($2); }
        | '%' b_expr
@@ -4110,7 +4126,7 @@ com_expr:  attr
                {   $$ = $1;  }
        | '(' a_expr_or_null ')'
                {   $$ = $2; }
-       | CAST '(' a_expr AS Typename ')'
+       | CAST '(' a_expr_or_null AS Typename ')'
                {
                    $$ = (Node *)$3;
                    /* AexprConst can be either A_Const or ParamNo */
@@ -4870,7 +4886,7 @@ ColId:  IDENT                         { $$ = $1; }
        | STATEMENT                     { $$ = "statement"; }
        | STDIN                         { $$ = "stdin"; }
        | STDOUT                        { $$ = "stdout"; }
-                | SYSID                                                 { $$ = "sysid"; }
+       | SYSID                         { $$ = "sysid"; }
        | TIME                          { $$ = "time"; }
        | TIMESTAMP                     { $$ = "timestamp"; }
        | TIMEZONE_HOUR                 { $$ = "timezone_hour"; }