Promote row expressions to full-fledged citizens of the expression syntax,

rather than allowing them only in a few special cases as before.  In
particular you can now pass a ROW() construct to a function that accepts
a rowtype parameter.  Internal generation of RowExprs fixes a number of
corner cases that used to not work very well, such as referencing the
whole-row result of a JOIN or subquery.  This represents a further step in
the work I started a month or so back to make rowtype values into
first-class citizens.

src/pl/plpgsql/src/pl_exec.c

@@ -3,7 +3,7 @@
  *			  procedural language
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/pl/plpgsql/src/pl_exec.c,v 1.99 2004/04/01 21:28:46 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/pl/plpgsql/src/pl_exec.c,v 1.100 2004/05/10 22:44:49 tgl Exp $
  *
  *	  This software is copyrighted by Jan Wieck - Hamburg.
  *
@@ -3752,6 +3752,16 @@ exec_simple_check_node(Node *node)
 				return TRUE;
 			}
 
+		case T_RowExpr:
+			{
+				RowExpr  *expr = (RowExpr *) node;
+
+				if (!exec_simple_check_node((Node *) expr->args))
+					return FALSE;
+
+				return TRUE;
+			}
+
 		case T_CoalesceExpr:
 			{
 				CoalesceExpr *expr = (CoalesceExpr *) node;