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/backend/optimizer/path/clausesel.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/optimizer/path/clausesel.c,v 1.64 2004/01/05 16:44:40 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/optimizer/path/clausesel.c,v 1.65 2004/05/10 22:44:45 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -27,11 +27,6 @@
 #include "utils/selfuncs.h"
 
 
-/* note that pg_type.h hardwires size of bool as 1 ... duplicate it */
-#define MAKEBOOLCONST(val,isnull) \
-	((Node *) makeConst(BOOLOID, 1, (Datum) (val), (isnull), true))
-
-
 /*
  * Data structure for accumulating info about possible range-query
  * clause pairs in clauselist_selectivity.
@@ -486,7 +481,7 @@ clause_selectivity(Query *root,
 				s1 = restriction_selectivity(root,
 											 BooleanEqualOperator,
 											 makeList2(var,
-													   MAKEBOOLCONST(true,
+													   makeBoolConst(true,
 																 false)),
 											 varRelid);
 			}