Restructure representation of aggregate functions so that they have pg_proc

entries, per pghackers discussion.  This fixes aggregates to live in
namespaces, and also simplifies/speeds up lookup in parse_func.c.
Also, add a 'proimplicit' flag to pg_proc that controls whether a type
coercion function may be invoked implicitly, or only explicitly.  The
current settings of these flags are more permissive than I would like,
but we will need to debate and refine the behavior; for now, I avoided
breaking regression tests as much as I could.

src/backend/utils/adt/ruleutils.c

@@ -3,7 +3,7 @@
  *				back to source text
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/utils/adt/ruleutils.c,v 1.95 2002/03/22 02:56:35 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/utils/adt/ruleutils.c,v 1.96 2002/04/11 20:00:04 tgl Exp $
  *
  *	  This software is copyrighted by Jan Wieck - Hamburg.
  *
@@ -130,6 +130,7 @@ static void get_names_for_var(Var *var, deparse_context *context,
 				  char **refname, char **attname);
 static void get_rule_expr(Node *node, deparse_context *context);
 static void get_func_expr(Expr *expr, deparse_context *context);
+static void get_agg_expr(Aggref *aggref, deparse_context *context);
 static Node *strip_type_coercion(Node *expr, Oid resultType);
 static void get_tle_expr(TargetEntry *tle, deparse_context *context);
 static void get_const_expr(Const *constval, deparse_context *context);
@@ -1694,18 +1695,7 @@ get_rule_expr(Node *node, deparse_context *context)
 			break;
 
 		case T_Aggref:
-			{
-				Aggref	   *aggref = (Aggref *) node;
-
-				appendStringInfo(buf, "%s(%s",
-								 quote_identifier(aggref->aggname),
-								 aggref->aggdistinct ? "DISTINCT " : "");
-				if (aggref->aggstar)
-					appendStringInfo(buf, "*");
-				else
-					get_rule_expr(aggref->target, context);
-				appendStringInfoChar(buf, ')');
-			}
+			get_agg_expr((Aggref *) node, context);
 			break;
 
 		case T_Iter:
@@ -2000,6 +1990,45 @@ get_func_expr(Expr *expr, deparse_context *context)
 	ReleaseSysCache(proctup);
 }
 
+/* ----------
+ * get_agg_expr			- Parse back an Aggref node
+ * ----------
+ */
+static void
+get_agg_expr(Aggref *aggref, deparse_context *context)
+{
+	StringInfo	buf = context->buf;
+	HeapTuple	proctup;
+	Form_pg_proc procStruct;
+	char	   *proname;
+
+	/*
+	 * Get the aggregate's pg_proc tuple
+	 */
+	proctup = SearchSysCache(PROCOID,
+							 ObjectIdGetDatum(aggref->aggfnoid),
+							 0, 0, 0);
+	if (!HeapTupleIsValid(proctup))
+		elog(ERROR, "cache lookup for proc %u failed", aggref->aggfnoid);
+
+	procStruct = (Form_pg_proc) GETSTRUCT(proctup);
+	proname = NameStr(procStruct->proname);
+
+	/*
+	 * Display it
+	 */
+	appendStringInfo(buf, "%s(%s",
+					 quote_identifier(proname),
+					 aggref->aggdistinct ? "DISTINCT " : "");
+	if (aggref->aggstar)
+		appendStringInfo(buf, "*");
+	else
+		get_rule_expr(aggref->target, context);
+	appendStringInfoChar(buf, ')');
+
+	ReleaseSysCache(proctup);
+}
+
 
 /*
  * strip_type_coercion

src/backend/utils/adt/sets.c

@@ -10,7 +10,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/utils/adt/Attic/sets.c,v 1.42 2002/04/05 00:31:29 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/utils/adt/Attic/sets.c,v 1.43 2002/04/11 20:00:05 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -58,16 +58,19 @@ SetDefine(char *querystr, Oid elemType)
 							 true,		/* returnsSet */
 							 elemType,	/* returnType */
 							 SQLlanguageId,	/* language */
-							 querystr,	/* sourceCode */
-							 fileName,	/* fileName */
+							 querystr,	/* prosrc */
+							 fileName,	/* probin */
+							 false,		/* not aggregate */
 							 true,		/* trusted */
+							 false,		/* not implicit coercion */
 							 false,		/* isStrict (irrelevant, no args) */
 							 PROVOLATILE_VOLATILE,	/* assume unsafe */
 							 100,		/* byte_pct */
 							 0, /* perbyte_cpu */
 							 0, /* percall_cpu */
 							 100,		/* outin_ratio */
-							 NIL);		/* argList */
+							 0,			/* parameterCount */
+							 NULL);		/* parameterTypes */
 
 	/*
 	 * Since we're still inside this command of the transaction, we can't

src/backend/utils/adt/varchar.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/utils/adt/varchar.c,v 1.88 2002/03/09 17:35:36 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/utils/adt/varchar.c,v 1.89 2002/04/11 20:00:05 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -307,19 +307,6 @@ _bpchar(PG_FUNCTION_ARGS)
 }
 
 
-/* bpchar_char()
- * Convert bpchar(1) to char.
- *
- * If input is multiple chars, only the first is returned.
- */
-Datum
-bpchar_char(PG_FUNCTION_ARGS)
-{
-	BpChar	   *s = PG_GETARG_BPCHAR_P(0);
-
-	PG_RETURN_CHAR(*VARDATA(s));
-}
-
 /* char_bpchar()
  * Convert char to bpchar(1).
  */