Operators live in namespaces. CREATE/DROP/COMMENT ON OPERATOR take

qualified operator names directly, for example CREATE OPERATOR myschema.+
( ... ).  To qualify an operator name in an expression you need to write
OPERATOR(myschema.+) (thanks to Peter for suggesting an escape hatch).
I also took advantage of having to reformat pg_operator to fix something
that'd been bugging me for a while: mergejoinable operators should have
explicit links to the associated cross-data-type comparison operators,
rather than hardwiring an assumption that they are named < and >.

src/include/nodes/makefuncs.h

@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $Id: makefuncs.h,v 1.34 2002/03/29 19:06:23 tgl Exp $
+ * $Id: makefuncs.h,v 1.35 2002/04/16 23:08:12 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -16,6 +16,11 @@
 
 #include "nodes/parsenodes.h"
 
+extern A_Expr *makeA_Expr(int oper, List *name, Node *lexpr, Node *rexpr);
+
+extern A_Expr *makeSimpleA_Expr(int oper, const char *name,
+								Node *lexpr, Node *rexpr);
+
 extern Oper *makeOper(Oid opno,
 		 Oid opid,
 		 Oid opresulttype);