Clean up plantree representation of SubPlan-s --- SubLink does not appear

in the planned representation of a subplan at all any more, only SubPlan.
This means subselect.c doesn't scribble on its input anymore, which seems
like a good thing; and there are no longer three different possible
interpretations of a SubLink.  Simplify node naming and improve comments
in primnodes.h.  No change to stored rules, though.

4 files changed, 51 insertions, 63 deletions

diff --git a/src/backend/executor/execAmi.c b/src/backend/executor/execAmi.c
index fa95ad6d992..c55e5ecd149 100644
--- a/src/backend/executor/execAmi.c
+++ b/src/backend/executor/execAmi.c
@@ -6,7 +6,7 @@
  * Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- *	$Header: /cvsroot/pgsql/src/backend/executor/execAmi.c,v 1.67 2002/12/13 19:45:52 tgl Exp $
+ *	$Header: /cvsroot/pgsql/src/backend/executor/execAmi.c,v 1.68 2002/12/14 00:17:50 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -61,7 +61,7 @@ ExecReScan(PlanState *node, ExprContext *exprCtxt)
 
 		foreach(lst, node->initPlan)
 		{
-			SubPlanExprState  *sstate = (SubPlanExprState *) lfirst(lst);
+			SubPlanState  *sstate = (SubPlanState *) lfirst(lst);
 			PlanState  *splan = sstate->planstate;
 
 			if (splan->plan->extParam != NIL)	/* don't care about child
@@ -72,7 +72,7 @@ ExecReScan(PlanState *node, ExprContext *exprCtxt)
 		}
 		foreach(lst, node->subPlan)
 		{
-			SubPlanExprState  *sstate = (SubPlanExprState *) lfirst(lst);
+			SubPlanState  *sstate = (SubPlanState *) lfirst(lst);
 			PlanState  *splan = sstate->planstate;
 
 			if (splan->plan->extParam != NIL)
diff --git a/src/backend/executor/execProcnode.c b/src/backend/executor/execProcnode.c
index 59c798b267a..dc5a3085ead 100644
--- a/src/backend/executor/execProcnode.c
+++ b/src/backend/executor/execProcnode.c
@@ -12,7 +12,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/executor/execProcnode.c,v 1.33 2002/12/13 19:45:52 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/executor/execProcnode.c,v 1.34 2002/12/14 00:17:50 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -228,10 +228,10 @@ ExecInitNode(Plan *node, EState *estate)
 	subps = NIL;
 	foreach(subp, node->initPlan)
 	{
-		SubPlanExpr *subplan = (SubPlanExpr *) lfirst(subp);
-		SubPlanExprState *sstate;
+		SubPlan	   *subplan = (SubPlan *) lfirst(subp);
+		SubPlanState *sstate;
 
-		Assert(IsA(subplan, SubPlanExpr));
+		Assert(IsA(subplan, SubPlan));
 		sstate = ExecInitExprInitPlan(subplan, result);
 		ExecInitSubPlan(sstate, estate);
 		subps = lappend(subps, sstate);
@@ -247,9 +247,9 @@ ExecInitNode(Plan *node, EState *estate)
 	subps = NIL;
 	foreach(subp, result->subPlan)
 	{
-		SubPlanExprState *sstate = (SubPlanExprState *) lfirst(subp);
+		SubPlanState *sstate = (SubPlanState *) lfirst(subp);
 
-		Assert(IsA(sstate, SubPlanExprState));
+		Assert(IsA(sstate, SubPlanState));
 		ExecInitSubPlan(sstate, estate);
 		subps = lappend(subps, sstate);
 	}
@@ -500,9 +500,9 @@ ExecEndNode(PlanState *node)
 
 	/* Clean up initPlans and subPlans */
 	foreach(subp, node->initPlan)
-		ExecEndSubPlan((SubPlanExprState *) lfirst(subp));
+		ExecEndSubPlan((SubPlanState *) lfirst(subp));
 	foreach(subp, node->subPlan)
-		ExecEndSubPlan((SubPlanExprState *) lfirst(subp));
+		ExecEndSubPlan((SubPlanState *) lfirst(subp));
 
 	if (node->chgParam != NIL)
 	{
diff --git a/src/backend/executor/execQual.c b/src/backend/executor/execQual.c
index b529d045c4d..a3f79c3ac80 100644
--- a/src/backend/executor/execQual.c
+++ b/src/backend/executor/execQual.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/executor/execQual.c,v 1.119 2002/12/13 19:45:52 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/executor/execQual.c,v 1.120 2002/12/14 00:17:50 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1794,8 +1794,8 @@ ExecEvalExpr(ExprState *expression,
 				}
 				break;
 			}
-		case T_SubPlanExpr:
-			retDatum = ExecSubPlan((SubPlanExprState *) expression,
+		case T_SubPlan:
+			retDatum = ExecSubPlan((SubPlanState *) expression,
 								   econtext,
 								   isNull);
 			break;
@@ -1883,7 +1883,7 @@ ExecEvalExprSwitchContext(ExprState *expression,
  * executions of the expression are needed.  Typically the context will be
  * the same as the per-query context of the associated ExprContext.
  *
- * Any Aggref and SubplanExpr nodes found in the tree are added to the lists
+ * Any Aggref and SubPlan nodes found in the tree are added to the lists
  * of such nodes held by the parent PlanState.  Otherwise, we do very little
  * initialization here other than building the state-node tree.  Any nontrivial
  * work associated with initializing runtime info for a node should happen
@@ -2003,31 +2003,26 @@ ExecInitExpr(Expr *node, PlanState *parent)
 				state = (ExprState *) bstate;
 			}
 			break;
-		case T_SubPlanExpr:
+		case T_SubPlan:
 			{
 				/* Keep this in sync with ExecInitExprInitPlan, below */
-				SubPlanExpr *subplanexpr = (SubPlanExpr *) node;
-				SubLink *sublink = subplanexpr->sublink;
-				SubPlanExprState *sstate = makeNode(SubPlanExprState);
+				SubPlan *subplan = (SubPlan *) node;
+				SubPlanState *sstate = makeNode(SubPlanState);
 
-				Assert(IsA(sublink, SubLink));
 				if (!parent)
-					elog(ERROR, "ExecInitExpr: SubPlanExpr not expected here");
+					elog(ERROR, "ExecInitExpr: SubPlan not expected here");
 
 				/*
-				 * Here we just add the SubPlanExprState nodes to
+				 * Here we just add the SubPlanState nodes to
 				 * parent->subPlan.  The subplans will be initialized later.
 				 */
 				parent->subPlan = lcons(sstate, parent->subPlan);
 				sstate->planstate = NULL;
 
-				sstate->args = (List *)
-					ExecInitExpr((Expr *) subplanexpr->args, parent);
-
-				if (sublink->lefthand)
-					elog(ERROR, "ExecInitExpr: sublink has not been transformed");
 				sstate->oper = (List *)
-					ExecInitExpr((Expr *) sublink->oper, parent);
+					ExecInitExpr((Expr *) subplan->oper, parent);
+				sstate->args = (List *)
+					ExecInitExpr((Expr *) subplan->args, parent);
 
 				state = (ExprState *) sstate;
 			}
@@ -2145,26 +2140,20 @@ ExecInitExpr(Expr *node, PlanState *parent)
  * subplan expr, except we do NOT want to add the node to the parent's
  * subplan list.
  */
-SubPlanExprState *
-ExecInitExprInitPlan(SubPlanExpr *node, PlanState *parent)
+SubPlanState *
+ExecInitExprInitPlan(SubPlan *node, PlanState *parent)
 {
-	SubLink *sublink = node->sublink;
-	SubPlanExprState *sstate = makeNode(SubPlanExprState);
+	SubPlanState *sstate = makeNode(SubPlanState);
 
-	Assert(IsA(sublink, SubLink));
 	if (!parent)
-		elog(ERROR, "ExecInitExpr: SubPlanExpr not expected here");
+		elog(ERROR, "ExecInitExpr: SubPlan not expected here");
 
 	/* The subplan's state will be initialized later */
 	sstate->planstate = NULL;
 
+	sstate->oper = (List *) ExecInitExpr((Expr *) node->oper, parent);
 	sstate->args = (List *) ExecInitExpr((Expr *) node->args, parent);
 
-	if (sublink->lefthand)
-		elog(ERROR, "ExecInitExpr: sublink has not been transformed");
-
-	sstate->oper = (List *) ExecInitExpr((Expr *) sublink->oper, parent);
-
 	sstate->xprstate.expr = (Expr *) node;
 
 	return sstate;
diff --git a/src/backend/executor/nodeSubplan.c b/src/backend/executor/nodeSubplan.c
index 69fcc58e079..3a2ca974aee 100644
--- a/src/backend/executor/nodeSubplan.c
+++ b/src/backend/executor/nodeSubplan.c
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/executor/nodeSubplan.c,v 1.37 2002/12/13 19:45:55 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/executor/nodeSubplan.c,v 1.38 2002/12/14 00:17:50 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -30,15 +30,14 @@
  * ----------------------------------------------------------------
  */
 Datum
-ExecSubPlan(SubPlanExprState *node,
+ExecSubPlan(SubPlanState *node,
 			ExprContext *econtext,
 			bool *isNull)
 {
+	SubPlan	   *subplan = (SubPlan *) node->xprstate.expr;
 	PlanState  *planstate = node->planstate;
-	SubPlanExpr *subplan = (SubPlanExpr *) node->xprstate.expr;
-	SubLink    *sublink = subplan->sublink;
-	SubLinkType subLinkType = sublink->subLinkType;
-	bool		useor = sublink->useor;
+	SubLinkType subLinkType = subplan->subLinkType;
+	bool		useor = subplan->useor;
 	MemoryContext oldcontext;
 	TupleTableSlot *slot;
 	Datum		result;
@@ -292,56 +291,56 @@ ExecSubPlan(SubPlanExprState *node,
  * ----------------------------------------------------------------
  */
 void
-ExecInitSubPlan(SubPlanExprState *sstate, EState *estate)
+ExecInitSubPlan(SubPlanState *node, EState *estate)
 {
-	SubPlanExpr *expr = (SubPlanExpr *) sstate->xprstate.expr;
+	SubPlan	   *subplan = (SubPlan *) node->xprstate.expr;
 	EState	   *sp_estate;
 
 	/*
 	 * Do access checking on the rangetable entries in the subquery.
 	 * Here, we assume the subquery is a SELECT.
 	 */
-	ExecCheckRTPerms(expr->rtable, CMD_SELECT);
+	ExecCheckRTPerms(subplan->rtable, CMD_SELECT);
 
 	/*
 	 * initialize state
 	 */
-	sstate->needShutdown = false;
-	sstate->curTuple = NULL;
+	node->needShutdown = false;
+	node->curTuple = NULL;
 
 	/*
 	 * create an EState for the subplan
 	 */
 	sp_estate = CreateExecutorState();
 
-	sp_estate->es_range_table = expr->rtable;
+	sp_estate->es_range_table = subplan->rtable;
 	sp_estate->es_param_list_info = estate->es_param_list_info;
 	sp_estate->es_param_exec_vals = estate->es_param_exec_vals;
 	sp_estate->es_tupleTable =
-		ExecCreateTupleTable(ExecCountSlotsNode(expr->plan) + 10);
+		ExecCreateTupleTable(ExecCountSlotsNode(subplan->plan) + 10);
 	sp_estate->es_snapshot = estate->es_snapshot;
 	sp_estate->es_instrument = estate->es_instrument;
 
 	/*
 	 * Start up the subplan
 	 */
-	sstate->planstate = ExecInitNode(expr->plan, sp_estate);
+	node->planstate = ExecInitNode(subplan->plan, sp_estate);
 
-	sstate->needShutdown = true;	/* now we need to shutdown the subplan */
+	node->needShutdown = true;	/* now we need to shutdown the subplan */
 
 	/*
 	 * If this plan is un-correlated or undirect correlated one and want
 	 * to set params for parent plan then prepare parameters.
 	 */
-	if (expr->setParam != NIL)
+	if (subplan->setParam != NIL)
 	{
 		List	   *lst;
 
-		foreach(lst, expr->setParam)
+		foreach(lst, subplan->setParam)
 		{
 			ParamExecData *prm = &(estate->es_param_exec_vals[lfirsti(lst)]);
 
-			prm->execPlan = sstate;
+			prm->execPlan = node;
 		}
 
 		/*
@@ -366,11 +365,11 @@ ExecInitSubPlan(SubPlanExprState *sstate, EState *estate)
  * ----------------------------------------------------------------
  */
 void
-ExecSetParamPlan(SubPlanExprState *node, ExprContext *econtext)
+ExecSetParamPlan(SubPlanState *node, ExprContext *econtext)
 {
+	SubPlan	   *subplan = (SubPlan *) node->xprstate.expr;
 	PlanState  *planstate = node->planstate;
-	SubPlanExpr *subplan = (SubPlanExpr *) node->xprstate.expr;
-	SubLinkType	subLinkType = subplan->sublink->subLinkType;
+	SubLinkType	subLinkType = subplan->subLinkType;
 	MemoryContext oldcontext;
 	TupleTableSlot *slot;
 	List	   *lst;
@@ -473,7 +472,7 @@ ExecSetParamPlan(SubPlanExprState *node, ExprContext *econtext)
  * ----------------------------------------------------------------
  */
 void
-ExecEndSubPlan(SubPlanExprState *node)
+ExecEndSubPlan(SubPlanState *node)
 {
 	if (node->needShutdown)
 	{
@@ -488,10 +487,10 @@ ExecEndSubPlan(SubPlanExprState *node)
 }
 
 void
-ExecReScanSetParamPlan(SubPlanExprState *node, PlanState *parent)
+ExecReScanSetParamPlan(SubPlanState *node, PlanState *parent)
 {
 	PlanState  *planstate = node->planstate;
-	SubPlanExpr *subplan = (SubPlanExpr *) node->xprstate.expr;
+	SubPlan	   *subplan = (SubPlan *) node->xprstate.expr;
 	EState	   *estate = parent->state;
 	List	   *lst;