pg_cast table, and standards-compliant CREATE/DROP CAST commands, plus

extension to create binary compatible casts.  Includes dependency tracking
as well.

pg_proc.proimplicit is now defunct, but will be removed in a separate
commit.

pg_dump provides a migration path from the previous scheme to declare
casts.  Dumping binary compatible casts is currently impossible, though.

src/backend/parser/keywords.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/parser/keywords.c,v 1.121 2002/07/18 17:14:19 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/parser/keywords.c,v 1.122 2002/07/18 23:11:28 petere Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -142,7 +142,6 @@ static const ScanKeyword ScanKeywords[] = {
 	{"ilike", ILIKE},
 	{"immediate", IMMEDIATE},
 	{"immutable", IMMUTABLE},
-	{"implicit", IMPLICIT},
 	{"in", IN_P},
 	{"increment", INCREMENT},
 	{"index", INDEX},