Get rid of long-since-vestigial Iter node type, in favor of adding a

returns-set boolean field in Func and Oper nodes.  This allows cleaner,
more reliable tests for expressions returning sets in the planner and
parser.  For example, a WHERE clause returning a set is now detected
and complained of in the parser, not only at runtime.

src/backend/nodes/copyfuncs.c

@@ -15,7 +15,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/nodes/copyfuncs.c,v 1.183 2002/05/12 20:10:02 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/nodes/copyfuncs.c,v 1.184 2002/05/12 23:43:02 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -764,6 +764,7 @@ _copyOper(Oper *from)
 	newnode->opno = from->opno;
 	newnode->opid = from->opid;
 	newnode->opresulttype = from->opresulttype;
+	newnode->opretset = from->opretset;
 	/* Do not copy the run-time state, if any */
 	newnode->op_fcache = NULL;
 
@@ -852,7 +853,8 @@ _copyFunc(Func *from)
 	 * copy remainder of node
 	 */
 	newnode->funcid = from->funcid;
-	newnode->functype = from->functype;
+	newnode->funcresulttype = from->funcresulttype;
+	newnode->funcretset = from->funcretset;
 	/* Do not copy the run-time state, if any */
 	newnode->func_fcache = NULL;
 
@@ -1433,17 +1435,6 @@ _copyJoinInfo(JoinInfo *from)
 	return newnode;
 }
 
-static Iter *
-_copyIter(Iter *from)
-{
-	Iter	   *newnode = makeNode(Iter);
-
-	Node_Copy(from, newnode, iterexpr);
-	newnode->itertype = from->itertype;
-
-	return newnode;
-}
-
 static Stream *
 _copyStream(Stream *from)
 {
@@ -2729,9 +2720,6 @@ copyObject(void *from)
 		case T_ArrayRef:
 			retval = _copyArrayRef(from);
 			break;
-		case T_Iter:
-			retval = _copyIter(from);
-			break;
 		case T_FieldSelect:
 			retval = _copyFieldSelect(from);
 			break;

src/backend/nodes/equalfuncs.c

@@ -20,7 +20,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/nodes/equalfuncs.c,v 1.131 2002/05/12 20:10:03 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/nodes/equalfuncs.c,v 1.132 2002/05/12 23:43:02 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -130,6 +130,8 @@ _equalOper(Oper *a, Oper *b)
 		return false;
 	if (a->opresulttype != b->opresulttype)
 		return false;
+	if (a->opretset != b->opretset)
+		return false;
 
 	/*
 	 * We do not examine opid or op_fcache, since these are logically
@@ -139,7 +141,8 @@ _equalOper(Oper *a, Oper *b)
 	 * (Besides, op_fcache is executor state, which we don't check --- see
 	 * notes at head of file.)
 	 *
-	 * It's probably not really necessary to check opresulttype either...
+	 * It's probably not really necessary to check opresulttype or opretset,
+	 * either...
 	 */
 
 	return true;
@@ -210,7 +213,9 @@ _equalFunc(Func *a, Func *b)
 {
 	if (a->funcid != b->funcid)
 		return false;
-	if (a->functype != b->functype)
+	if (a->funcresulttype != b->funcresulttype)
+		return false;
+	if (a->funcretset != b->funcretset)
 		return false;
 	/* Note we do not look at func_fcache; see notes for _equalOper */
 
@@ -538,12 +543,6 @@ _equalJoinInfo(JoinInfo *a, JoinInfo *b)
 	return true;
 }
 
-static bool
-_equalIter(Iter *a, Iter *b)
-{
-	return equal(a->iterexpr, b->iterexpr);
-}
-
 static bool
 _equalStream(Stream *a, Stream *b)
 {
@@ -1884,9 +1883,6 @@ equal(void *a, void *b)
 		case T_ArrayRef:
 			retval = _equalArrayRef(a, b);
 			break;
-		case T_Iter:
-			retval = _equalIter(a, b);
-			break;
 		case T_RelabelType:
 			retval = _equalRelabelType(a, b);
 			break;

src/backend/nodes/makefuncs.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/nodes/makefuncs.c,v 1.31 2002/04/16 23:08:10 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/nodes/makefuncs.c,v 1.32 2002/05/12 23:43:02 tgl Exp $
  */
 #include "postgres.h"
 
@@ -56,13 +56,15 @@ makeSimpleA_Expr(int oper, const char *name,
 Oper *
 makeOper(Oid opno,
 		 Oid opid,
-		 Oid opresulttype)
+		 Oid opresulttype,
+		 bool opretset)
 {
 	Oper	   *oper = makeNode(Oper);
 
 	oper->opno = opno;
 	oper->opid = opid;
 	oper->opresulttype = opresulttype;
+	oper->opretset = opretset;
 	oper->op_fcache = NULL;
 	return oper;
 }

src/backend/nodes/outfuncs.c

@@ -5,7 +5,7 @@
  * Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- *	$Header: /cvsroot/pgsql/src/backend/nodes/outfuncs.c,v 1.158 2002/05/12 20:10:03 tgl Exp $
+ *	$Header: /cvsroot/pgsql/src/backend/nodes/outfuncs.c,v 1.159 2002/05/12 23:43:02 tgl Exp $
  *
  * NOTES
  *	  Every (plan) node in POSTGRES has an associated "out" routine which
@@ -850,9 +850,11 @@ _outArrayRef(StringInfo str, ArrayRef *node)
 static void
 _outFunc(StringInfo str, Func *node)
 {
-	appendStringInfo(str, " FUNC :funcid %u :functype %u ",
+	appendStringInfo(str,
+					 " FUNC :funcid %u :funcresulttype %u :funcretset %s ",
 					 node->funcid,
-					 node->functype);
+					 node->funcresulttype,
+					 booltostr(node->funcretset));
 }
 
 /*
@@ -862,10 +864,11 @@ static void
 _outOper(StringInfo str, Oper *node)
 {
 	appendStringInfo(str,
-					 " OPER :opno %u :opid %u :opresulttype %u ",
+					 " OPER :opno %u :opid %u :opresulttype %u :opretset %s ",
 					 node->opno,
 					 node->opid,
-					 node->opresulttype);
+					 node->opresulttype,
+					 booltostr(node->opretset));
 }
 
 /*
@@ -1246,13 +1249,6 @@ _outDatum(StringInfo str, Datum value, int typlen, bool typbyval)
 	}
 }
 
-static void
-_outIter(StringInfo str, Iter *node)
-{
-	appendStringInfo(str, " ITER :iterexpr ");
-	_outNode(str, node->iterexpr);
-}
-
 static void
 _outStream(StringInfo str, Stream *node)
 {
@@ -1731,9 +1727,6 @@ _outNode(StringInfo str, void *obj)
 			case T_JoinInfo:
 				_outJoinInfo(str, obj);
 				break;
-			case T_Iter:
-				_outIter(str, obj);
-				break;
 			case T_Stream:
 				_outStream(str, obj);
 				break;

src/backend/nodes/readfuncs.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/nodes/readfuncs.c,v 1.121 2002/05/12 20:10:03 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/nodes/readfuncs.c,v 1.122 2002/05/12 23:43:02 tgl Exp $
  *
  * NOTES
  *	  Most of the read functions for plan nodes are tested. (In fact, they
@@ -1083,9 +1083,13 @@ _readFunc(void)
 	token = pg_strtok(&length); /* now read it */
 	local_node->funcid = atooid(token);
 
-	token = pg_strtok(&length); /* get :functype */
+	token = pg_strtok(&length); /* get :funcresulttype */
 	token = pg_strtok(&length); /* now read it */
-	local_node->functype = atooid(token);
+	local_node->funcresulttype = atooid(token);
+
+	token = pg_strtok(&length); /* get :funcretset */
+	token = pg_strtok(&length); /* now read it */
+	local_node->funcretset = strtobool(token);
 
 	local_node->func_fcache = NULL;
 
@@ -1119,6 +1123,10 @@ _readOper(void)
 	token = pg_strtok(&length); /* now read it */
 	local_node->opresulttype = atooid(token);
 
+	token = pg_strtok(&length); /* get :opretset */
+	token = pg_strtok(&length); /* now read it */
+	local_node->opretset = strtobool(token);
+
 	local_node->op_fcache = NULL;
 
 	return local_node;
@@ -1991,26 +1999,6 @@ _readJoinInfo(void)
 	return local_node;
 }
 
-/* ----------------
- *		_readIter()
- *
- * ----------------
- */
-static Iter *
-_readIter(void)
-{
-	Iter	   *local_node;
-	char	   *token;
-	int			length;
-
-	local_node = makeNode(Iter);
-
-	token = pg_strtok(&length); /* eat :iterexpr */
-	local_node->iterexpr = nodeRead(true);		/* now read it */
-
-	return local_node;
-}
-
 
 /* ----------------
  *		parsePlanString
@@ -2124,8 +2112,6 @@ parsePlanString(void)
 		return_value = _readRestrictInfo();
 	else if (length == 8 && strncmp(token, "JOININFO", length) == 0)
 		return_value = _readJoinInfo();
-	else if (length == 4 && strncmp(token, "ITER", length) == 0)
-		return_value = _readIter();
 	else if (length == 5 && strncmp(token, "QUERY", length) == 0)
 		return_value = _readQuery();
 	else if (length == 6 && strncmp(token, "NOTIFY", length) == 0)