Replace TupleTableSlot convention for whole-row variables and function

results with tuples as ordinary varlena Datums.  This commit does not
in itself do much for us, except eliminate the horrid memory leak
associated with evaluation of whole-row variables.  However, it lays the
groundwork for allowing composite types as table columns, and perhaps
some other useful features as well.  Per my proposal of a few days ago.

src/backend/parser/parse_func.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/parser/parse_func.c,v 1.165 2004/01/07 18:56:27 neilc Exp $
+ *	  $PostgreSQL: pgsql/src/backend/parser/parse_func.c,v 1.166 2004/04/01 21:28:44 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -170,9 +170,7 @@ ParseFuncOrColumn(ParseState *pstate, List *funcname, List *fargs,
 			 * tuple from the relation.  We build a special VarNode to
 			 * reflect this -- it has varno set to the correct range table
 			 * entry, but has varattno == 0 to signal that the whole tuple
-			 * is the argument.  Also, it has typmod set to
-			 * sizeof(Pointer) to signal that the runtime representation
-			 * will be a pointer not an Oid.
+			 * is the argument.
 			 */
 			switch (rte->rtekind)
 			{
@@ -185,7 +183,7 @@ ParseFuncOrColumn(ParseState *pstate, List *funcname, List *fargs,
 					lfirst(i) = makeVar(vnum,
 										InvalidAttrNumber,
 										toid,
-										sizeof(Pointer),
+										-1,
 										sublevels_up);
 					break;
 				case RTE_FUNCTION:
@@ -196,7 +194,7 @@ ParseFuncOrColumn(ParseState *pstate, List *funcname, List *fargs,
 						lfirst(i) = makeVar(vnum,
 											InvalidAttrNumber,
 											toid,
-											sizeof(Pointer),
+											-1,
 											sublevels_up);
 					}
 					else
@@ -214,6 +212,8 @@ ParseFuncOrColumn(ParseState *pstate, List *funcname, List *fargs,
 					/*
 					 * RTE is a join or subselect; must fail for lack of a
 					 * named tuple type
+					 *
+					 * XXX FIXME
 					 */
 					if (is_column)
 						unknown_attribute(schemaname, relname,