analyze.c

/*-------------------------------------------------------------------------
 *
 * analyze.c--
 *	  transform the parse tree into a query tree
 *
 * Copyright (c) 1994, Regents of the University of California
 *
 *
 * IDENTIFICATION
 *	  $Header: /cvsroot/pgsql/src/backend/parser/analyze.c,v 1.45 1997/10/12 07:09:20 vadim Exp $
 *
 *-------------------------------------------------------------------------
 */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "postgres.h"
#include "nodes/nodes.h"
#include "nodes/params.h"
#include "nodes/primnodes.h"
#include "nodes/parsenodes.h"
#include "nodes/relation.h"
#include "parse.h"				/* for AND, OR, etc. */
#include "catalog/pg_type.h"	/* for INT4OID, etc. */
#include "catalog/pg_proc.h"
#include "utils/elog.h"
#include "utils/builtins.h"		/* namecmp(), textout() */
#include "utils/lsyscache.h"
#include "utils/palloc.h"
#include "utils/mcxt.h"
#include "utils/syscache.h"
#include "utils/acl.h"
#include "parser/parse_query.h"
#include "parser/parse_state.h"
#include "nodes/makefuncs.h"	/* for makeResdom(), etc. */
#include "nodes/nodeFuncs.h"
#include "commands/sequence.h"

#include "optimizer/clauses.h"
#include "access/heapam.h"

#include "miscadmin.h"

#include "port-protos.h"		/* strdup() */

/* convert the parse tree into a query tree */
static Query *transformStmt(ParseState *pstate, Node *stmt);

static Query *transformDeleteStmt(ParseState *pstate, DeleteStmt *stmt);
static Query *transformInsertStmt(ParseState *pstate, AppendStmt *stmt);
static Query *transformIndexStmt(ParseState *pstate, IndexStmt *stmt);
static Query *transformExtendStmt(ParseState *pstate, ExtendStmt *stmt);
static Query *transformRuleStmt(ParseState *query, RuleStmt *stmt);
static Query *transformSelectStmt(ParseState *pstate, RetrieveStmt *stmt);
static Query *transformUpdateStmt(ParseState *pstate, ReplaceStmt *stmt);
static Query *transformCursorStmt(ParseState *pstate, CursorStmt *stmt);
static Node *handleNestedDots(ParseState *pstate, Attr *attr, int *curr_resno);

#define EXPR_COLUMN_FIRST	 1
#define EXPR_RELATION_FIRST  2
static Node *transformExpr(ParseState *pstate, Node *expr, int precedence);
static Node *transformIdent(ParseState *pstate, Node *expr, int precedence);

static void makeRangeTable(ParseState *pstate, char *relname, List *frmList);
static List *expandAllTables(ParseState *pstate);
static char *figureColname(Node *expr, Node *resval);
static List *makeTargetNames(ParseState *pstate, List *cols);
static List *transformTargetList(ParseState *pstate, List *targetlist);
static TargetEntry *
make_targetlist_expr(ParseState *pstate,
					 char *colname, Node *expr,
					 List *arrayRef);
static bool inWhereClause = false;
static Node *transformWhereClause(ParseState *pstate, Node *a_expr);
static List *
transformGroupClause(ParseState *pstate, List *grouplist,
					 List *targetlist);
static List *
transformSortClause(ParseState *pstate,
					List *orderlist, List *targetlist,
					char *uniqueFlag);

static void parseFromClause(ParseState *pstate, List *frmList);
static Node *
ParseFunc(ParseState *pstate, char *funcname,
		  List *fargs, int *curr_resno);
static List *setup_tlist(char *attname, Oid relid);
static List *setup_base_tlist(Oid typeid);
static void
make_arguments(int nargs, List *fargs, Oid *input_typeids,
			   Oid *function_typeids);
static void AddAggToParseState(ParseState *pstate, Aggreg *aggreg);
static void finalizeAggregates(ParseState *pstate, Query *qry);
static void parseCheckAggregates(ParseState *pstate, Query *qry);
static ParseState *makeParseState(void);

/*****************************************************************************
 *
 *****************************************************************************/

/*
 * makeParseState() --
 *	  allocate and initialize a new ParseState.
 *	the CALLERS is responsible for freeing the ParseState* returned
 *
 */

static ParseState *
makeParseState(void)
{
	ParseState *pstate;

	pstate = malloc(sizeof(ParseState));
	pstate->p_last_resno = 1;
	pstate->p_rtable = NIL;
	pstate->p_numAgg = 0;
	pstate->p_aggs = NIL;
	pstate->p_is_insert = false;
	pstate->p_insert_columns = NIL;
	pstate->p_is_update = false;
	pstate->p_is_rule = false;
	pstate->p_target_relation = NULL;
	pstate->p_target_rangetblentry = NULL;

	return (pstate);
}

/*
 * parse_analyze -
 *	  analyze a list of parse trees and transform them if necessary.
 *
 * Returns a list of transformed parse trees. Optimizable statements are
 * all transformed to Query while the rest stays the same.
 *
 * CALLER is responsible for freeing the QueryTreeList* returned
 */
QueryTreeList *
parse_analyze(List *pl)
{
	QueryTreeList *result;
	ParseState *pstate;
	int			i = 0;

	result = malloc(sizeof(QueryTreeList));
	result->len = length(pl);
	result->qtrees = (Query **) malloc(result->len * sizeof(Query *));

	inWhereClause = false;		/* to avoid nextval(sequence) in WHERE */

	while (pl != NIL)
	{
		pstate = makeParseState();
		result->qtrees[i++] = transformStmt(pstate, lfirst(pl));
		pl = lnext(pl);
		if (pstate->p_target_relation != NULL)
			heap_close(pstate->p_target_relation);
		free(pstate);
	}

	return result;
}

/*
 * transformStmt -
 *	  transform a Parse tree. If it is an optimizable statement, turn it
 *	  into a Query tree.
 */
static Query *
transformStmt(ParseState *pstate, Node *parseTree)
{
	Query	   *result = NULL;

	switch (nodeTag(parseTree))
	{
			/*------------------------
			 *	Non-optimizable statements
			 *------------------------
			 */
		case T_IndexStmt:
			result = transformIndexStmt(pstate, (IndexStmt *) parseTree);
			break;

		case T_ExtendStmt:
			result = transformExtendStmt(pstate, (ExtendStmt *) parseTree);
			break;

		case T_RuleStmt:
			result = transformRuleStmt(pstate, (RuleStmt *) parseTree);
			break;

		case T_ViewStmt:
			{
				ViewStmt   *n = (ViewStmt *) parseTree;

				n->query = (Query *) transformStmt(pstate, (Node *) n->query);
				result = makeNode(Query);
				result->commandType = CMD_UTILITY;
				result->utilityStmt = (Node *) n;
			}
			break;

		case T_VacuumStmt:
			{
				MemoryContext oldcontext;

				/*
				 * make sure that this Query is allocated in TopMemory
				 * context because vacuum spans transactions and we don't
				 * want to lose the vacuum Query due to end-of-transaction
				 * free'ing
				 */
				oldcontext = MemoryContextSwitchTo(TopMemoryContext);
				result = makeNode(Query);
				result->commandType = CMD_UTILITY;
				result->utilityStmt = (Node *) parseTree;
				MemoryContextSwitchTo(oldcontext);
				break;

			}
		case T_ExplainStmt:
			{
				ExplainStmt *n = (ExplainStmt *) parseTree;

				result = makeNode(Query);
				result->commandType = CMD_UTILITY;
				n->query = transformStmt(pstate, (Node *) n->query);
				result->utilityStmt = (Node *) parseTree;
			}
			break;

			/*------------------------
			 *	Optimizable statements
			 *------------------------
			 */
		case T_AppendStmt:
			result = transformInsertStmt(pstate, (AppendStmt *) parseTree);
			break;

		case T_DeleteStmt:
			result = transformDeleteStmt(pstate, (DeleteStmt *) parseTree);
			break;

		case T_ReplaceStmt:
			result = transformUpdateStmt(pstate, (ReplaceStmt *) parseTree);
			break;

		case T_CursorStmt:
			result = transformCursorStmt(pstate, (CursorStmt *) parseTree);
			break;

		case T_RetrieveStmt:
			result = transformSelectStmt(pstate, (RetrieveStmt *) parseTree);
			break;

		default:

			/*
			 * other statments don't require any transformation-- just
			 * return the original parsetree
			 */
			result = makeNode(Query);
			result->commandType = CMD_UTILITY;
			result->utilityStmt = (Node *) parseTree;
			break;
	}
	return result;
}

/*
 * transformDeleteStmt -
 *	  transforms a Delete Statement
 */
static Query *
transformDeleteStmt(ParseState *pstate, DeleteStmt *stmt)
{
	Query	   *qry = makeNode(Query);

	qry->commandType = CMD_DELETE;

	/* set up a range table */
	makeRangeTable(pstate, stmt->relname, NULL);

	qry->uniqueFlag = NULL;

	/* fix where clause */
	qry->qual = transformWhereClause(pstate, stmt->whereClause);

	qry->rtable = pstate->p_rtable;
	qry->resultRelation = refnameRangeTablePosn(pstate->p_rtable, stmt->relname);

	/* make sure we don't have aggregates in the where clause */
	if (pstate->p_numAgg > 0)
		parseCheckAggregates(pstate, qry);

	return (Query *) qry;
}

/*
 * transformInsertStmt -
 *	  transform an Insert Statement
 */
static Query *
transformInsertStmt(ParseState *pstate, AppendStmt *stmt)
{
	Query	   *qry = makeNode(Query);	/* make a new query tree */
	List	   *icolumns;

	qry->commandType = CMD_INSERT;
	pstate->p_is_insert = true;

	/* set up a range table */
	makeRangeTable(pstate, stmt->relname, stmt->fromClause);

	qry->uniqueFlag = NULL;

	/* fix the target list */
	icolumns = pstate->p_insert_columns = makeTargetNames(pstate, stmt->cols);
	
	qry->targetList = transformTargetList(pstate, stmt->targetList);
	
	/* DEFAULT handling */
	if (length(qry->targetList) < pstate->p_target_relation->rd_att->natts &&
		pstate->p_target_relation->rd_att->constr &&
		pstate->p_target_relation->rd_att->constr->num_defval > 0)
	{
		AttributeTupleForm	   *att = pstate->p_target_relation->rd_att->attrs;
		AttrDefault			   *defval = pstate->p_target_relation->rd_att->constr->defval;
		int						ndef = pstate->p_target_relation->rd_att->constr->num_defval;
		
		/* 
		 * if stmt->cols == NIL then makeTargetNames returns list of all 
		 * attrs: have to shorter icolumns list...
		 */
		if (stmt->cols == NIL)
		{
			List   *extrl;
			int		i = length(qry->targetList);
			
			foreach (extrl, icolumns)
			{
				if (--i <= 0)
					break;
			}
			freeList (lnext(extrl));
			lnext(extrl) = NIL;
		}
		
		while (ndef-- > 0)
		{
			List		   *tl;
			Ident		   *id;
			TargetEntry	   *te;
			
			foreach (tl, icolumns)
			{
				id = (Ident *) lfirst(tl);
				if (!namestrcmp(&(att[defval[ndef].adnum - 1]->attname), id->name))
					break;
			}
			if (tl != NIL)		/* something given for this attr */
				continue;
			/* 
			 * Nothing given for this attr with DEFAULT expr, so
			 * add new TargetEntry to qry->targetList. 
			 * Note, that we set resno to defval[ndef].adnum:
			 * it's what transformTargetList()->make_targetlist_expr()
			 * does for INSERT ... SELECT. But for INSERT ... VALUES
			 * pstate->p_last_resno is used. It doesn't matter for 
			 * "normal" using (planner creates proper target list
			 * in preptlist.c), but may break RULEs in some way.
			 * It seems better to create proper target list here...
			 */
			te = makeNode(TargetEntry);
			te->resdom = makeResdom(defval[ndef].adnum,
									att[defval[ndef].adnum - 1]->atttypid,
									att[defval[ndef].adnum - 1]->attlen,
									pstrdup(nameout(&(att[defval[ndef].adnum - 1]->attname))),
									0, 0, 0);
			te->fjoin = NULL;
			te->expr = (Node *) stringToNode(defval[ndef].adbin);
			qry->targetList = lappend (qry->targetList, te);
		}
	}
	
	/* fix where clause */
	qry->qual = transformWhereClause(pstate, stmt->whereClause);

	/* now the range table will not change */
	qry->rtable = pstate->p_rtable;
	qry->resultRelation = refnameRangeTablePosn(pstate->p_rtable, stmt->relname);

	if (pstate->p_numAgg > 0)
		finalizeAggregates(pstate, qry);

	return (Query *) qry;
}

/*
 * transformIndexStmt -
 *	  transforms the qualification of the index statement
 */
static Query *
transformIndexStmt(ParseState *pstate, IndexStmt *stmt)
{
	Query	   *q;

	q = makeNode(Query);
	q->commandType = CMD_UTILITY;

	/* take care of the where clause */
	stmt->whereClause = transformWhereClause(pstate, stmt->whereClause);
	stmt->rangetable = pstate->p_rtable;

	q->utilityStmt = (Node *) stmt;

	return q;
}

/*
 * transformExtendStmt -
 *	  transform the qualifications of the Extend Index Statement
 *
 */
static Query *
transformExtendStmt(ParseState *pstate, ExtendStmt *stmt)
{
	Query	   *q;

	q = makeNode(Query);
	q->commandType = CMD_UTILITY;

	/* take care of the where clause */
	stmt->whereClause = transformWhereClause(pstate, stmt->whereClause);
	stmt->rangetable = pstate->p_rtable;

	q->utilityStmt = (Node *) stmt;
	return q;
}

/*
 * transformRuleStmt -
 *	  transform a Create Rule Statement. The actions is a list of parse
 *	  trees which is transformed into a list of query trees.
 */
static Query *
transformRuleStmt(ParseState *pstate, RuleStmt *stmt)
{
	Query	   *q;
	List	   *actions;

	q = makeNode(Query);
	q->commandType = CMD_UTILITY;

	actions = stmt->actions;

	/*
	 * transform each statment, like parse_analyze()
	 */
	while (actions != NIL)
	{

		/*
		 * NOTE: 'CURRENT' must always have a varno equal to 1 and 'NEW'
		 * equal to 2.
		 */
		addRangeTableEntry(pstate, stmt->object->relname, "*CURRENT*",
						   FALSE, FALSE, NULL);
		addRangeTableEntry(pstate, stmt->object->relname, "*NEW*",
						   FALSE, FALSE, NULL);

		pstate->p_last_resno = 1;
		pstate->p_is_rule = true;		/* for expand all */
		pstate->p_numAgg = 0;
		pstate->p_aggs = NULL;

		lfirst(actions) = transformStmt(pstate, lfirst(actions));
		actions = lnext(actions);
	}

	/* take care of the where clause */
	stmt->whereClause = transformWhereClause(pstate, stmt->whereClause);

	q->utilityStmt = (Node *) stmt;
	return q;
}


/*
 * transformSelectStmt -
 *	  transforms a Select Statement
 *
 */
static Query *
transformSelectStmt(ParseState *pstate, RetrieveStmt *stmt)
{
	Query	   *qry = makeNode(Query);

	qry->commandType = CMD_SELECT;

	/* set up a range table */
	makeRangeTable(pstate, NULL, stmt->fromClause);

	qry->uniqueFlag = stmt->unique;

	qry->into = stmt->into;
	qry->isPortal = FALSE;

	/* fix the target list */
	qry->targetList = transformTargetList(pstate, stmt->targetList);

	/* fix where clause */
	qry->qual = transformWhereClause(pstate, stmt->whereClause);

	/* check subselect clause */
	if (stmt->selectClause)
		elog(NOTICE, "UNION not yet supported; using first SELECT only", NULL);

	/* check subselect clause */
	if (stmt->havingClause)
		elog(NOTICE, "HAVING not yet supported; ignore clause", NULL);

	/* fix order clause */
	qry->sortClause = transformSortClause(pstate,
										  stmt->sortClause,
										  qry->targetList,
										  qry->uniqueFlag);

	/* fix group by clause */
	qry->groupClause = transformGroupClause(pstate,
											stmt->groupClause,
											qry->targetList);
	qry->rtable = pstate->p_rtable;

	if (pstate->p_numAgg > 0)
		finalizeAggregates(pstate, qry);

	return (Query *) qry;
}

/*
 * transformUpdateStmt -
 *	  transforms an update statement
 *
 */
static Query *
transformUpdateStmt(ParseState *pstate, ReplaceStmt *stmt)
{
	Query	   *qry = makeNode(Query);

	qry->commandType = CMD_UPDATE;
	pstate->p_is_update = true;

	/*
	 * the FROM clause is non-standard SQL syntax. We used to be able to
	 * do this with REPLACE in POSTQUEL so we keep the feature.
	 */
	makeRangeTable(pstate, stmt->relname, stmt->fromClause);

	/* fix the target list */
	qry->targetList = transformTargetList(pstate, stmt->targetList);

	/* fix where clause */
	qry->qual = transformWhereClause(pstate, stmt->whereClause);

	qry->rtable = pstate->p_rtable;
	qry->resultRelation = refnameRangeTablePosn(pstate->p_rtable, stmt->relname);

	/* make sure we don't have aggregates in the where clause */
	if (pstate->p_numAgg > 0)
		parseCheckAggregates(pstate, qry);

	return (Query *) qry;
}

/*
 * transformCursorStmt -
 *	  transform a Create Cursor Statement
 *
 */
static Query *
transformCursorStmt(ParseState *pstate, CursorStmt *stmt)
{
	Query	   *qry = makeNode(Query);

	/*
	 * in the old days, a cursor statement is a 'retrieve into portal'; If
	 * you change the following, make sure you also go through the code in
	 * various places that tests the kind of operation.
	 */
	qry->commandType = CMD_SELECT;

	/* set up a range table */
	makeRangeTable(pstate, NULL, stmt->fromClause);

	qry->uniqueFlag = stmt->unique;

	qry->into = stmt->portalname;
	qry->isPortal = TRUE;
	qry->isBinary = stmt->binary;		/* internal portal */

	/* fix the target list */
	qry->targetList = transformTargetList(pstate, stmt->targetList);

	/* fix where clause */
	qry->qual = transformWhereClause(pstate, stmt->whereClause);

	/* fix order clause */
	qry->sortClause = transformSortClause(pstate,
										  stmt->sortClause,
										  qry->targetList,
										  qry->uniqueFlag);
	/* fix group by clause */
	qry->groupClause = transformGroupClause(pstate,
											stmt->groupClause,
											qry->targetList);

	qry->rtable = pstate->p_rtable;

	if (pstate->p_numAgg > 0)
		finalizeAggregates(pstate, qry);

	return (Query *) qry;
}

/*****************************************************************************
 *
 * Transform Exprs, Aggs, etc.
 *
 *****************************************************************************/

/*
 * transformExpr -
 *	  analyze and transform expressions. Type checking and type casting is
 *	  done here. The optimizer and the executor cannot handle the original
 *	  (raw) expressions collected by the parse tree. Hence the transformation
 *	  here.
 */
static Node *
transformExpr(ParseState *pstate, Node *expr, int precedence)
{
	Node	   *result = NULL;

	if (expr == NULL)
		return NULL;

	switch (nodeTag(expr))
	{
		case T_Attr:
			{
				Attr	   *att = (Attr *) expr;
				Node	   *temp;

				/* what if att.attrs == "*"?? */
				temp = handleNestedDots(pstate, att, &pstate->p_last_resno);
				if (att->indirection != NIL)
				{
					List	   *idx = att->indirection;

					while (idx != NIL)
					{
						A_Indices  *ai = (A_Indices *) lfirst(idx);
						Node	   *lexpr = NULL,
								   *uexpr;

						uexpr = transformExpr(pstate, ai->uidx, precedence);	/* must exists */
						if (exprType(uexpr) != INT4OID)
							elog(WARN, "array index expressions must be int4's");
						if (ai->lidx != NULL)
						{
							lexpr = transformExpr(pstate, ai->lidx, precedence);
							if (exprType(lexpr) != INT4OID)
								elog(WARN, "array index expressions must be int4's");
						}
#if 0
						pfree(ai->uidx);
						if (ai->lidx != NULL)
							pfree(ai->lidx);
#endif
						ai->lidx = lexpr;
						ai->uidx = uexpr;

						/*
						 * note we reuse the list of indices, make sure we
						 * don't free them! Otherwise, make a new list
						 * here
						 */
						idx = lnext(idx);
					}
					result = (Node *) make_array_ref(temp, att->indirection);
				}
				else
				{
					result = temp;
				}
				break;
			}
		case T_A_Const:
			{
				A_Const    *con = (A_Const *) expr;
				Value	   *val = &con->val;

				if (con->typename != NULL)
				{
					result = parser_typecast(val, con->typename, -1);
				}
				else
				{
					result = (Node *) make_const(val);
				}
				break;
			}
		case T_ParamNo:
			{
				ParamNo    *pno = (ParamNo *) expr;
				Oid			toid;
				int			paramno;
				Param	   *param;

				paramno = pno->number;
				toid = param_type(paramno);
				if (!OidIsValid(toid))
				{
					elog(WARN, "Parameter '$%d' is out of range",
						 paramno);
				}
				param = makeNode(Param);
				param->paramkind = PARAM_NUM;
				param->paramid = (AttrNumber) paramno;
				param->paramname = "<unnamed>";
				param->paramtype = (Oid) toid;
				param->param_tlist = (List *) NULL;

				result = (Node *) param;
				break;
			}
		case T_A_Expr:
			{
				A_Expr	   *a = (A_Expr *) expr;

				switch (a->oper)
				{
					case OP:
						{
							Node	   *lexpr = transformExpr(pstate, a->lexpr, precedence);
							Node	   *rexpr = transformExpr(pstate, a->rexpr, precedence);

							result = (Node *) make_op(a->opname, lexpr, rexpr);
						}
						break;
					case ISNULL:
						{
							Node	   *lexpr = transformExpr(pstate, a->lexpr, precedence);

							result = ParseFunc(pstate,
										  "nullvalue", lcons(lexpr, NIL),
											   &pstate->p_last_resno);
						}
						break;
					case NOTNULL:
						{
							Node	   *lexpr = transformExpr(pstate, a->lexpr, precedence);

							result = ParseFunc(pstate,
									   "nonnullvalue", lcons(lexpr, NIL),
											   &pstate->p_last_resno);
						}
						break;
					case AND:
						{
							Expr	   *expr = makeNode(Expr);
							Node	   *lexpr = transformExpr(pstate, a->lexpr, precedence);
							Node	   *rexpr = transformExpr(pstate, a->rexpr, precedence);

							if (exprType(lexpr) != BOOLOID)
								elog(WARN,
									 "left-hand side of AND is type '%s', not bool",
									 tname(get_id_type(exprType(lexpr))));
							if (exprType(rexpr) != BOOLOID)
								elog(WARN,
									 "right-hand side of AND is type '%s', not bool",
									 tname(get_id_type(exprType(rexpr))));
							expr->typeOid = BOOLOID;
							expr->opType = AND_EXPR;
							expr->args = makeList(lexpr, rexpr, -1);
							result = (Node *) expr;
						}
						break;
					case OR:
						{
							Expr	   *expr = makeNode(Expr);
							Node	   *lexpr = transformExpr(pstate, a->lexpr, precedence);
							Node	   *rexpr = transformExpr(pstate, a->rexpr, precedence);

							if (exprType(lexpr) != BOOLOID)
								elog(WARN,
									 "left-hand side of OR is type '%s', not bool",
									 tname(get_id_type(exprType(lexpr))));
							if (exprType(rexpr) != BOOLOID)
								elog(WARN,
									 "right-hand side of OR is type '%s', not bool",
									 tname(get_id_type(exprType(rexpr))));
							expr->typeOid = BOOLOID;
							expr->opType = OR_EXPR;
							expr->args = makeList(lexpr, rexpr, -1);
							result = (Node *) expr;
						}
						break;
					case NOT:
						{
							Expr	   *expr = makeNode(Expr);
							Node	   *rexpr = transformExpr(pstate, a->rexpr, precedence);

							if (exprType(rexpr) != BOOLOID)
								elog(WARN,
								"argument to NOT is type '%s', not bool",
									 tname(get_id_type(exprType(rexpr))));
							expr->typeOid = BOOLOID;
							expr->opType = NOT_EXPR;
							expr->args = makeList(rexpr, -1);
							result = (Node *) expr;
						}
						break;
				}
				break;
			}
		case T_Ident:
			{

				/*
				 * look for a column name or a relation name (the default
				 * behavior)
				 */
				result = transformIdent(pstate, expr, precedence);
				break;
			}
		case T_FuncCall:
			{
				FuncCall   *fn = (FuncCall *) expr;
				List	   *args;

				/* transform the list of arguments */
				foreach(args, fn->args)
					lfirst(args) = transformExpr(pstate, (Node *) lfirst(args), precedence);
				result = ParseFunc(pstate,
						  fn->funcname, fn->args, &pstate->p_last_resno);
				break;
			}
		default:
			/* should not reach here */
			elog(WARN, "transformExpr: does not know how to transform %d\n",
				 nodeTag(expr));
			break;
	}

	return result;
}

static Node *
transformIdent(ParseState *pstate, Node *expr, int precedence)
{
	Ident	   *ident = (Ident *) expr;
	RangeTblEntry *rte;
	Node	   *column_result,
			   *relation_result,
			   *result;

	column_result = relation_result = result = 0;
	/* try to find the ident as a column */
	if ((rte = colnameRangeTableEntry(pstate, ident->name)) != NULL)
	{
		Attr	   *att = makeNode(Attr);

		att->relname = rte->refname;
		att->attrs = lcons(makeString(ident->name), NIL);
		column_result =
			(Node *) handleNestedDots(pstate, att, &pstate->p_last_resno);
	}

	/* try to find the ident as a relation */
	if (refnameRangeTableEntry(pstate->p_rtable, ident->name) != NULL)
	{
		ident->isRel = TRUE;
		relation_result = (Node *) ident;
	}

	/* choose the right result based on the precedence */
	if (precedence == EXPR_COLUMN_FIRST)
	{
		if (column_result)
			result = column_result;
		else
			result = relation_result;
	}
	else
	{
		if (relation_result)
			result = relation_result;
		else
			result = column_result;
	}

	if (result == NULL)
		elog(WARN, "attribute \"%s\" not found", ident->name);

	return result;
}

/*****************************************************************************
 *
 * From Clause
 *
 *****************************************************************************/

/*
 * parseFromClause -
 *	  turns the table references specified in the from-clause into a
 *	  range table. The range table may grow as we transform the expressions
 *	  in the target list. (Note that this happens because in POSTQUEL, we
 *	  allow references to relations not specified in the from-clause. We
 *	  also allow that in our POST-SQL)
 *
 */
static void
parseFromClause(ParseState *pstate, List *frmList)
{
	List	   *fl;

	foreach(fl, frmList)
	{
		RangeVar   *r = lfirst(fl);
		RelExpr    *baserel = r->relExpr;
		char	   *relname = baserel->relname;
		char	   *refname = r->name;
		RangeTblEntry *rte;

		if (refname == NULL)
			refname = relname;

		/*
		 * marks this entry to indicate it comes from the FROM clause. In
		 * SQL, the target list can only refer to range variables
		 * specified in the from clause but we follow the more powerful
		 * POSTQUEL semantics and automatically generate the range
		 * variable if not specified. However there are times we need to
		 * know whether the entries are legitimate.
		 *
		 * eg. select * from foo f where f.x = 1; will generate wrong answer
		 * if we expand * to foo.x.
		 */
		rte = addRangeTableEntry(pstate, relname, refname, baserel->inh, TRUE,
								 baserel->timeRange);
	}
}

/*
 * makeRangeTable -
 *	  make a range table with the specified relation (optional) and the
 *	  from-clause.
 */
static void
makeRangeTable(ParseState *pstate, char *relname, List *frmList)
{
	RangeTblEntry *rte;

	parseFromClause(pstate, frmList);

	if (relname == NULL)
		return;

	if (refnameRangeTablePosn(pstate->p_rtable, relname) < 1)
		rte = addRangeTableEntry(pstate, relname, relname, FALSE, FALSE, NULL);
	else
		rte = refnameRangeTableEntry(pstate->p_rtable, relname);

	pstate->p_target_rangetblentry = rte;
	Assert(pstate->p_target_relation == NULL);
	pstate->p_target_relation = heap_open(rte->relid);
	Assert(pstate->p_target_relation != NULL);
	/* will close relation later */
}

/*
 *	exprType -
 *	  returns the Oid of the type of the expression. (Used for typechecking.)
 */
Oid
exprType(Node *expr)
{
	Oid			type = (Oid) 0;

	switch (nodeTag(expr))
	{
		case T_Func:
			type = ((Func *) expr)->functype;
			break;
		case T_Iter:
			type = ((Iter *) expr)->itertype;
			break;
		case T_Var:
			type = ((Var *) expr)->vartype;
			break;
		case T_Expr:
			type = ((Expr *) expr)->typeOid;
			break;
		case T_Const:
			type = ((Const *) expr)->consttype;
			break;
		case T_ArrayRef:
			type = ((ArrayRef *) expr)->refelemtype;
			break;
		case T_Aggreg:
			type = ((Aggreg *) expr)->aggtype;
			break;
		case T_Param:
			type = ((Param *) expr)->paramtype;
			break;
		case T_Ident:
			/* is this right? */
			type = UNKNOWNOID;
			break;
		default:
			elog(WARN, "exprType: don't know how to get type for %d node",
				 nodeTag(expr));
			break;
	}
	return type;
}

/*
 * expandAllTables -
 *	  turns '*' (in the target list) into a list of attributes (of all
 *	  relations in the range table)
 */
static List *
expandAllTables(ParseState *pstate)
{
	List	   *target = NIL;
	List	   *legit_rtable = NIL;
	List	   *rt,
			   *rtable;

	rtable = pstate->p_rtable;
	if (pstate->p_is_rule)
	{

		/*
		 * skip first two entries, "*new*" and "*current*"
		 */
		rtable = lnext(lnext(pstate->p_rtable));
	}

	/* this should not happen */
	if (rtable == NULL)
		elog(WARN, "cannot expand: null p_rtable");

	/*
	 * go through the range table and make a list of range table entries
	 * which we will expand.
	 */
	foreach(rt, rtable)
	{
		RangeTblEntry *rte = lfirst(rt);

		/*
		 * we only expand those specify in the from clause. (This will
		 * also prevent us from using the wrong table in inserts: eg.
		 * tenk2 in "insert into tenk2 select * from tenk1;")
		 */
		if (!rte->inFromCl)
			continue;
		legit_rtable = lappend(legit_rtable, rte);
	}

	foreach(rt, legit_rtable)
	{
		RangeTblEntry *rte = lfirst(rt);
		List	   *temp = target;

		if (temp == NIL)
			target = expandAll(pstate, rte->relname, rte->refname,
							   &pstate->p_last_resno);
		else
		{
			while (temp != NIL && lnext(temp) != NIL)
				temp = lnext(temp);
			lnext(temp) = expandAll(pstate, rte->relname, rte->refname,
									&pstate->p_last_resno);
		}
	}
	return target;
}


/*
 * figureColname -
 *	  if the name of the resulting column is not specified in the target
 *	  list, we have to guess.
 *
 */
static char *
figureColname(Node *expr, Node *resval)
{
	switch (nodeTag(expr))
	{
			case T_Aggreg:
			return (char *)		/* XXX */
			((Aggreg *) expr)->aggname;
		case T_Expr:
			if (((Expr *) expr)->opType == FUNC_EXPR)
			{
				if (nodeTag(resval) == T_FuncCall)
					return ((FuncCall *) resval)->funcname;
			}
			break;
		default:
			break;
	}

	return "?column?";
}

/*****************************************************************************
 *
 * Target list
 *
 *****************************************************************************/

/*
 * makeTargetNames -
 *	  generate a list of column names if not supplied or
 *	  test supplied column names to make sure they are in target table
 *	  (used exclusively for inserts)
 */
static List *
makeTargetNames(ParseState *pstate, List *cols)
{
	List	   *tl = NULL;

	/* Generate ResTarget if not supplied */

	if (cols == NIL)
	{
		int			numcol;
		int			i;
		AttributeTupleForm *attr = pstate->p_target_relation->rd_att->attrs;

		numcol = pstate->p_target_relation->rd_rel->relnatts;
		for (i = 0; i < numcol; i++)
		{
			Ident	   *id = makeNode(Ident);

			id->name = palloc(NAMEDATALEN);
			strNcpy(id->name, attr[i]->attname.data, NAMEDATALEN - 1);
			id->indirection = NIL;
			id->isRel = false;
			if (tl == NIL)
				cols = tl = lcons(id, NIL);
			else
			{
				lnext(tl) = lcons(id, NIL);
				tl = lnext(tl);
			}
		}
	}
	else
	{
		foreach(tl, cols)
		{
			List	   *nxt;
			char	   *name = ((Ident *) lfirst(tl))->name;
		
			/* elog on failure */
			varattno(pstate->p_target_relation, name);
			foreach(nxt, lnext(tl))
				if (!strcmp(name, ((Ident *) lfirst(nxt))->name))
					elog (WARN, "Attribute %s should be specified only once", name);
		}
	}
	
	return cols;
}

/*
 * transformTargetList -
 *	  turns a list of ResTarget's into a list of TargetEntry's
 */
static List *
transformTargetList(ParseState *pstate, List *targetlist)
{
	List	   *p_target = NIL;
	List	   *tail_p_target = NIL;

	while (targetlist != NIL)
	{
		ResTarget  *res = (ResTarget *) lfirst(targetlist);
		TargetEntry *tent = makeNode(TargetEntry);

		switch (nodeTag(res->val))
		{
			case T_Ident:
				{
					Node	   *expr;
					Oid			type_id;
					int			type_len;
					char	   *identname;
					char	   *resname;

					identname = ((Ident *) res->val)->name;
					handleTargetColname(pstate, &res->name, NULL, identname);

					/*
					 * here we want to look for column names only, not
					 * relation
					 */

					/*
					 * names (even though they can be stored in Ident
					 * nodes,
					 */
					/* too)														*/
					expr = transformIdent(pstate, (Node *) res->val, EXPR_COLUMN_FIRST);
					type_id = exprType(expr);
					type_len = tlen(get_id_type(type_id));
					resname = (res->name) ? res->name : identname;
					tent->resdom = makeResdom((AttrNumber) pstate->p_last_resno++,
											  (Oid) type_id,
											  (Size) type_len,
											  resname,
											  (Index) 0,
											  (Oid) 0,
											  0);

					tent->expr = expr;
					break;
				}
			case T_ParamNo:
			case T_FuncCall:
			case T_A_Const:
			case T_A_Expr:
				{
					Node	   *expr = transformExpr(pstate, (Node *) res->val, EXPR_COLUMN_FIRST);

					handleTargetColname(pstate, &res->name, NULL, NULL);
					/* note indirection has not been transformed */
					if (pstate->p_is_insert && res->indirection != NIL)
					{
						/* this is an array assignment */
						char	   *val;
						char	   *str,
								   *save_str;
						List	   *elt;
						int			i = 0,
									ndims;
						int			lindx[MAXDIM],
									uindx[MAXDIM];
						int			resdomno;
						Relation	rd;
						Value	   *constval;

						if (exprType(expr) != UNKNOWNOID ||
							!IsA(expr, Const))
							elog(WARN, "yyparse: string constant expected");

						val = (char *) textout((struct varlena *)
										   ((Const *) expr)->constvalue);
						str = save_str = (char *) palloc(strlen(val) + MAXDIM * 25 + 2);
						foreach(elt, res->indirection)
						{
							A_Indices  *aind = (A_Indices *) lfirst(elt);

							aind->uidx = transformExpr(pstate, aind->uidx, EXPR_COLUMN_FIRST);
							if (!IsA(aind->uidx, Const))
								elog(WARN,
									 "Array Index for Append should be a constant");
							uindx[i] = ((Const *) aind->uidx)->constvalue;
							if (aind->lidx != NULL)
							{
								aind->lidx = transformExpr(pstate, aind->lidx, EXPR_COLUMN_FIRST);
								if (!IsA(aind->lidx, Const))
									elog(WARN,
										 "Array Index for Append should be a constant");
								lindx[i] = ((Const *) aind->lidx)->constvalue;
							}
							else
							{
								lindx[i] = 1;
							}
							if (lindx[i] > uindx[i])
								elog(WARN, "yyparse: lower index cannot be greater than upper index");
							sprintf(str, "[%d:%d]", lindx[i], uindx[i]);
							str += strlen(str);
							i++;
						}
						sprintf(str, "=%s", val);
						rd = pstate->p_target_relation;
						Assert(rd != NULL);
						resdomno = varattno(rd, res->name);
						ndims = att_attnelems(rd, resdomno);
						if (i != ndims)
							elog(WARN, "yyparse: array dimensions do not match");
						constval = makeNode(Value);
						constval->type = T_String;
						constval->val.str = save_str;
						tent = make_targetlist_expr(pstate, res->name,
										   (Node *) make_const(constval),
													NULL);
						pfree(save_str);
					}
					else
					{
						char	   *colname = res->name;

						/* this is not an array assignment */
						if (colname == NULL)
						{

							/*
							 * if you're wondering why this is here, look
							 * at the yacc grammar for why a name can be
							 * missing. -ay
							 */
							colname = figureColname(expr, res->val);
						}
						if (res->indirection)
						{
							List	   *ilist = res->indirection;

							while (ilist != NIL)
							{
								A_Indices  *ind = lfirst(ilist);

								ind->lidx = transformExpr(pstate, ind->lidx, EXPR_COLUMN_FIRST);
								ind->uidx = transformExpr(pstate, ind->uidx, EXPR_COLUMN_FIRST);
								ilist = lnext(ilist);
							}
						}
						res->name = colname;
						tent = make_targetlist_expr(pstate, res->name, expr,
													res->indirection);
					}
					break;
				}
			case T_Attr:
				{
					Oid			type_id;
					int			type_len;
					Attr	   *att = (Attr *) res->val;
					Node	   *result;
					char	   *attrname;
					char	   *resname;
					Resdom	   *resnode;
					List	   *attrs = att->attrs;

					/*
					 * Target item is a single '*', expand all tables (eg.
					 * SELECT * FROM emp)
					 */
					if (att->relname != NULL && !strcmp(att->relname, "*"))
					{
						if (tail_p_target == NIL)
							p_target = tail_p_target = expandAllTables(pstate);
						else
							lnext(tail_p_target) = expandAllTables(pstate);

						while (lnext(tail_p_target) != NIL)
							/* make sure we point to the last target entry */
							tail_p_target = lnext(tail_p_target);

						/*
						 * skip rest of while loop
						 */
						targetlist = lnext(targetlist);
						continue;
					}

					/*
					 * Target item is relation.*, expand the table (eg.
					 * SELECT emp.*, dname FROM emp, dept)
					 */
					attrname = strVal(lfirst(att->attrs));
					if (att->attrs != NIL && !strcmp(attrname, "*"))
					{

						/*
						 * tail_p_target is the target list we're building
						 * in the while loop. Make sure we fix it after
						 * appending more nodes.
						 */
						if (tail_p_target == NIL)
							p_target = tail_p_target = expandAll(pstate, att->relname,
									att->relname, &pstate->p_last_resno);
						else
							lnext(tail_p_target) =
								expandAll(pstate, att->relname, att->relname,
										  &pstate->p_last_resno);
						while (lnext(tail_p_target) != NIL)
							/* make sure we point to the last target entry */
							tail_p_target = lnext(tail_p_target);

						/*
						 * skip the rest of the while loop
						 */
						targetlist = lnext(targetlist);
						continue;
					}


					/*
					 * Target item is fully specified: ie.
					 * relation.attribute
					 */
					result = handleNestedDots(pstate, att, &pstate->p_last_resno);
					handleTargetColname(pstate, &res->name, att->relname, attrname);
					if (att->indirection != NIL)
					{
						List	   *ilist = att->indirection;

						while (ilist != NIL)
						{
							A_Indices  *ind = lfirst(ilist);

							ind->lidx = transformExpr(pstate, ind->lidx, EXPR_COLUMN_FIRST);
							ind->uidx = transformExpr(pstate, ind->uidx, EXPR_COLUMN_FIRST);
							ilist = lnext(ilist);
						}
						result = (Node *) make_array_ref(result, att->indirection);
					}
					type_id = exprType(result);
					type_len = tlen(get_id_type(type_id));
					/* move to last entry */
					while (lnext(attrs) != NIL)
						attrs = lnext(attrs);
					resname = (res->name) ? res->name : strVal(lfirst(attrs));
					resnode = makeResdom((AttrNumber) pstate->p_last_resno++,
										 (Oid) type_id,
										 (Size) type_len,
										 resname,
										 (Index) 0,
										 (Oid) 0,
										 0);
					tent->resdom = resnode;
					tent->expr = result;
					break;
				}
			default:
				/* internal error */
				elog(WARN,
					 "internal error: do not know how to transform targetlist");
				break;
		}

		if (p_target == NIL)
		{
			p_target = tail_p_target = lcons(tent, NIL);
		}
		else
		{
			lnext(tail_p_target) = lcons(tent, NIL);
			tail_p_target = lnext(tail_p_target);
		}
		targetlist = lnext(targetlist);
	}

	return p_target;
}


/*
 * make_targetlist_expr -
 *	  make a TargetEntry from an expression
 *
 * arrayRef is a list of transformed A_Indices
 */
static TargetEntry *
make_targetlist_expr(ParseState *pstate,
					 char *colname,
					 Node *expr,
					 List *arrayRef)
{
	Oid			type_id,
				attrtype;
	int			type_len,
				attrlen;
	int			resdomno;
	Relation	rd;
	bool		attrisset;
	TargetEntry *tent;
	Resdom	   *resnode;

	if (expr == NULL)
		elog(WARN, "make_targetlist_expr: invalid use of NULL expression");

	type_id = exprType(expr);
	if (type_id == InvalidOid)
	{
		type_len = 0;
	}
	else
		type_len = tlen(get_id_type(type_id));

	/* I have no idea what the following does! */
	/* It appears to process target columns that will be receiving results */
	if (pstate->p_is_insert || pstate->p_is_update)
	{

		/*
		 * append or replace query -- append, replace work only on one
		 * relation, so multiple occurence of same resdomno is bogus
		 */
		rd = pstate->p_target_relation;
		Assert(rd != NULL);
		resdomno = varattno(rd, colname);
		attrisset = varisset(rd, colname);
		attrtype = att_typeid(rd, resdomno);
		if ((arrayRef != NIL) && (lfirst(arrayRef) == NIL))
			attrtype = GetArrayElementType(attrtype);
		if (attrtype == BPCHAROID || attrtype == VARCHAROID)
		{
			attrlen = rd->rd_att->attrs[resdomno - 1]->attlen;
		}
		else
		{
			attrlen = tlen(get_id_type(attrtype));
		}
#if 0
		if (Input_is_string && Typecast_ok)
		{
			Datum		val;

			if (type_id == typeid(type("unknown")))
			{
				val = (Datum) textout((struct varlena *)
									  ((Const) lnext(expr))->constvalue);
			}
			else
			{
				val = ((Const) lnext(expr))->constvalue;
			}
			if (attrisset)
			{
				lnext(expr) = makeConst(attrtype,
										attrlen,
										val,
										false,
										true,
										true,	/* is set */
										false);
			}
			else
			{
				lnext(expr) =
					makeConst(attrtype,
							  attrlen,
							  (Datum) fmgr(typeid_get_retinfunc(attrtype),
										 val, get_typelem(attrtype), -1),
							  false,
							  true /* Maybe correct-- 80% chance */ ,
							  false,	/* is not a set */
							  false);
			}
		}
		else if ((Typecast_ok) && (attrtype != type_id))
		{
			lnext(expr) =
				parser_typecast2(expr, get_id_type(attrtype));
		}
		else if (attrtype != type_id)
		{
			if ((attrtype == INT2OID) && (type_id == INT4OID))
				lfirst(expr) = lispInteger(INT2OID);	/* handle CASHOID too */
			else if ((attrtype == FLOAT4OID) && (type_id == FLOAT8OID))
				lfirst(expr) = lispInteger(FLOAT4OID);
			else
				elog(WARN, "unequal type in tlist : %s \n", colname);
		}

		Input_is_string = false;
		Input_is_integer = false;
		Typecast_ok = true;
#endif

		if (attrtype != type_id)
		{
			if (IsA(expr, Const))
			{
				/* try to cast the constant */
				if (arrayRef && !(((A_Indices *) lfirst(arrayRef))->lidx))
				{
					/* updating a single item */
					Oid			typelem = get_typelem(attrtype);

					expr = (Node *) parser_typecast2(expr,
													 type_id,
													 get_id_type(typelem),
													 attrlen);
				}
				else
					expr = (Node *) parser_typecast2(expr,
													 type_id,
												   get_id_type(attrtype),
													 attrlen);
			}
			else
			{
				/* currently, we can't handle casting of expressions */
				elog(WARN, "parser: attribute '%s' is of type '%s' but expression is of type '%s'",
					 colname,
					 get_id_typname(attrtype),
					 get_id_typname(type_id));
			}
		}

		if (arrayRef != NIL)
		{
			Expr	   *target_expr;
			Attr	   *att = makeNode(Attr);
			List	   *ar = arrayRef;
			List	   *upperIndexpr = NIL;
			List	   *lowerIndexpr = NIL;

			att->relname = pstrdup(RelationGetRelationName(rd)->data);
			att->attrs = lcons(makeString(colname), NIL);
			target_expr = (Expr *) handleNestedDots(pstate, att,
												  &pstate->p_last_resno);
			while (ar != NIL)
			{
				A_Indices  *ind = lfirst(ar);

				if (lowerIndexpr || (!upperIndexpr && ind->lidx))
				{

					/*
					 * XXX assume all lowerIndexpr is non-null in this
					 * case
					 */
					lowerIndexpr = lappend(lowerIndexpr, ind->lidx);
				}
				upperIndexpr = lappend(upperIndexpr, ind->uidx);
				ar = lnext(ar);
			}

			expr = (Node *) make_array_set(target_expr,
										   upperIndexpr,
										   lowerIndexpr,
										   (Expr *) expr);
			attrtype = att_typeid(rd, resdomno);
			attrlen = tlen(get_id_type(attrtype));
		}
	}
	else
	{
		resdomno = pstate->p_last_resno++;
		attrtype = type_id;
		attrlen = type_len;
	}
	tent = makeNode(TargetEntry);

	resnode = makeResdom((AttrNumber) resdomno,
						 (Oid) attrtype,
						 (Size) attrlen,
						 colname,
						 (Index) 0,
						 (Oid) 0,
						 0);

	tent->resdom = resnode;
	tent->expr = expr;

	return tent;
}


/*****************************************************************************
 *
 * Where Clause
 *
 *****************************************************************************/

/*
 * transformWhereClause -
 *	  transforms the qualification and make sure it is of type Boolean
 *
 */
static Node *
transformWhereClause(ParseState *pstate, Node *a_expr)
{
	Node	   *qual;

	if (a_expr == NULL)
		return (Node *) NULL;	/* no qualifiers */

	inWhereClause = true;
	qual = transformExpr(pstate, a_expr, EXPR_COLUMN_FIRST);
	inWhereClause = false;
	if (exprType(qual) != BOOLOID)
	{
		elog(WARN,
			 "where clause must return type bool, not %s",
			 tname(get_id_type(exprType(qual))));
	}
	return qual;
}

/*****************************************************************************
 *
 * Sort Clause
 *
 *****************************************************************************/

/*
 *	find_targetlist_entry -
 *	  returns the Resdom in the target list matching the specified varname
 *	  and range
 *
 */
static TargetEntry *
find_targetlist_entry(ParseState *pstate, SortGroupBy *sortgroupby, List *tlist)
{
	List	   *i;
	int			real_rtable_pos = 0,
				target_pos = 0;
	TargetEntry *target_result = NULL;

	if (sortgroupby->range)
		real_rtable_pos = refnameRangeTablePosn(pstate->p_rtable,
												sortgroupby->range);

	foreach(i, tlist)
	{
		TargetEntry *target = (TargetEntry *) lfirst(i);
		Resdom	   *resnode = target->resdom;
		Var		   *var = (Var *) target->expr;
		char	   *resname = resnode->resname;
		int			test_rtable_pos = var->varno;

#ifdef PARSEDEBUG
		printf("find_targetlist_entry- target name is %s, position %d, resno %d\n",
			   (sortgroupby->name ? sortgroupby->name : "(null)"), target_pos + 1, sortgroupby->resno);
#endif

		if (!sortgroupby->name)
		{
			if (sortgroupby->resno == ++target_pos)
			{
				target_result = target;
				break;
			}
		}
		else
		{
			if (!strcmp(resname, sortgroupby->name))
			{
				if (sortgroupby->range)
				{
					if (real_rtable_pos == test_rtable_pos)
					{
						if (target_result != NULL)
							elog(WARN, "Order/Group By %s is ambiguous", sortgroupby->name);
						else
							target_result = target;
					}
				}
				else
				{
					if (target_result != NULL)
						elog(WARN, "Order/Group By %s is ambiguous", sortgroupby->name);
					else
						target_result = target;
				}
			}
		}
	}
	return target_result;
}

static Oid
any_ordering_op(int restype)
{
	Operator	order_op;
	Oid			order_opid;

	order_op = oper("<", restype, restype, false);
	order_opid = oprid(order_op);

	return order_opid;
}

/*
 * transformGroupClause -
 *	  transform a Group By clause
 *
 */
static List *
transformGroupClause(ParseState *pstate, List *grouplist, List *targetlist)
{
	List	   *glist = NIL,
			   *gl = NIL;

	while (grouplist != NIL)
	{
		GroupClause *grpcl = makeNode(GroupClause);
		TargetEntry *restarget;
		Resdom	   *resdom;

		restarget = find_targetlist_entry(pstate, lfirst(grouplist), targetlist);

		if (restarget == NULL)
			elog(WARN, "The field being grouped by must appear in the target list");

		grpcl->entry = restarget;
		resdom = restarget->resdom;
		grpcl->grpOpoid = oprid(oper("<",
									 resdom->restype,
									 resdom->restype, false));
		if (glist == NIL)
			gl = glist = lcons(grpcl, NIL);
		else
		{
			lnext(gl) = lcons(grpcl, NIL);
			gl = lnext(gl);
		}
		grouplist = lnext(grouplist);
	}

	return glist;
}

/*
 * transformSortClause -
 *	  transform an Order By clause
 *
 */
static List *
transformSortClause(ParseState *pstate,
					List *orderlist, List *targetlist,
					char *uniqueFlag)
{
	List	   *sortlist = NIL;
	List	   *s = NIL,
			   *i;

	while (orderlist != NIL)
	{
		SortGroupBy *sortby = lfirst(orderlist);
		SortClause *sortcl = makeNode(SortClause);
		TargetEntry *restarget;
		Resdom	   *resdom;

		restarget = find_targetlist_entry(pstate, sortby, targetlist);
		if (restarget == NULL)
			elog(WARN, "The field being ordered by must appear in the target list");

		sortcl->resdom = resdom = restarget->resdom;
		sortcl->opoid = oprid(oper(sortby->useOp,
								   resdom->restype,
								   resdom->restype, false));
		if (sortlist == NIL)
		{
			s = sortlist = lcons(sortcl, NIL);
		}
		else
		{
			lnext(s) = lcons(sortcl, NIL);
			s = lnext(s);
		}
		orderlist = lnext(orderlist);
	}

	if (uniqueFlag)
	{
		if (uniqueFlag[0] == '*')
		{

			/*
			 * concatenate all elements from target list that are not
			 * already in the sortby list
			 */
			foreach(i, targetlist)
			{
				TargetEntry *tlelt = (TargetEntry *) lfirst(i);

				s = sortlist;
				while (s != NIL)
				{
					SortClause *sortcl = lfirst(s);

					if (sortcl->resdom == tlelt->resdom)
						break;
					s = lnext(s);
				}
				if (s == NIL)
				{
					/* not a member of the sortclauses yet */
					SortClause *sortcl = makeNode(SortClause);

					sortcl->resdom = tlelt->resdom;
					sortcl->opoid = any_ordering_op(tlelt->resdom->restype);

					sortlist = lappend(sortlist, sortcl);
				}
			}
		}
		else
		{
			TargetEntry *tlelt = NULL;
			char	   *uniqueAttrName = uniqueFlag;

			/* only create sort clause with the specified unique attribute */
			foreach(i, targetlist)
			{
				tlelt = (TargetEntry *) lfirst(i);
				if (strcmp(tlelt->resdom->resname, uniqueAttrName) == 0)
					break;
			}
			if (i == NIL)
			{
				elog(WARN, "The field specified in the UNIQUE ON clause is not in the targetlist");
			}
			s = sortlist;
			foreach(s, sortlist)
			{
				SortClause *sortcl = lfirst(s);

				if (sortcl->resdom == tlelt->resdom)
					break;
			}
			if (s == NIL)
			{
				/* not a member of the sortclauses yet */
				SortClause *sortcl = makeNode(SortClause);

				sortcl->resdom = tlelt->resdom;
				sortcl->opoid = any_ordering_op(tlelt->resdom->restype);

				sortlist = lappend(sortlist, sortcl);
			}
		}

	}

	return sortlist;
}

/*
 ** HandleNestedDots --
 **    Given a nested dot expression (i.e. (relation func ... attr), build up
 ** a tree with of Iter and Func nodes.
 */
static Node *
handleNestedDots(ParseState *pstate, Attr *attr, int *curr_resno)
{
	List	   *mutator_iter;
	Node	   *retval = NULL;

	if (attr->paramNo != NULL)
	{
		Param	   *param = (Param *) transformExpr(pstate, (Node *) attr->paramNo, EXPR_RELATION_FIRST);

		retval =
			ParseFunc(pstate, strVal(lfirst(attr->attrs)),
					  lcons(param, NIL),
					  curr_resno);
	}
	else
	{
		Ident	   *ident = makeNode(Ident);

		ident->name = attr->relname;
		ident->isRel = TRUE;
		retval =
			ParseFunc(pstate, strVal(lfirst(attr->attrs)),
					  lcons(ident, NIL),
					  curr_resno);
	}

	foreach(mutator_iter, lnext(attr->attrs))
	{
		retval = ParseFunc(pstate, strVal(lfirst(mutator_iter)),
						   lcons(retval, NIL),
						   curr_resno);
	}

	return (retval);
}

/*
 ** make_arguments --
 **   Given the number and types of arguments to a function, and the
 **   actual arguments and argument types, do the necessary typecasting.
 */
static void
make_arguments(int nargs,
			   List *fargs,
			   Oid *input_typeids,
			   Oid *function_typeids)
{

	/*
	 * there are two ways an input typeid can differ from a function
	 * typeid : either the input type inherits the function type, so no
	 * typecasting is necessary, or the input type can be typecast into
	 * the function type. right now, we only typecast unknowns, and that
	 * is all we check for.
	 */

	List	   *current_fargs;
	int			i;

	for (i = 0, current_fargs = fargs;
		 i < nargs;
		 i++, current_fargs = lnext(current_fargs))
	{

		if (input_typeids[i] == UNKNOWNOID && function_typeids[i] != InvalidOid)
		{
			lfirst(current_fargs) =
				parser_typecast2(lfirst(current_fargs),
								 input_typeids[i],
								 get_id_type(function_typeids[i]),
								 -1);
		}
	}
}

/*
 ** setup_tlist --
 **		Build a tlist that says which attribute to project to.
 **		This routine is called by ParseFunc() to set up a target list
 **		on a tuple parameter or return value.  Due to a bug in 4.0,
 **		it's not possible to refer to system attributes in this case.
 */
static List *
setup_tlist(char *attname, Oid relid)
{
	TargetEntry *tle;
	Resdom	   *resnode;
	Var		   *varnode;
	Oid			typeid;
	int			attno;

	attno = get_attnum(relid, attname);
	if (attno < 0)
		elog(WARN, "cannot reference attribute %s of tuple params/return values for functions", attname);

	typeid = find_atttype(relid, attname);
	resnode = makeResdom(1,
						 typeid,
						 tlen(get_id_type(typeid)),
						 get_attname(relid, attno),
						 0,
						 (Oid) 0,
						 0);
	varnode = makeVar(-1, attno, typeid, -1, attno);

	tle = makeNode(TargetEntry);
	tle->resdom = resnode;
	tle->expr = (Node *) varnode;
	return (lcons(tle, NIL));
}

/*
 ** setup_base_tlist --
 **		Build a tlist that extracts a base type from the tuple
 **		returned by the executor.
 */
static List *
setup_base_tlist(Oid typeid)
{
	TargetEntry *tle;
	Resdom	   *resnode;
	Var		   *varnode;

	resnode = makeResdom(1,
						 typeid,
						 tlen(get_id_type(typeid)),
						 "<noname>",
						 0,
						 (Oid) 0,
						 0);
	varnode = makeVar(-1, 1, typeid, -1, 1);
	tle = makeNode(TargetEntry);
	tle->resdom = resnode;
	tle->expr = (Node *) varnode;

	return (lcons(tle, NIL));
}

/*
 * ParseComplexProjection -
 *	  handles function calls with a single argument that is of complex type.
 *	  This routine returns NULL if it can't handle the projection (eg. sets).
 */
static Node *
ParseComplexProjection(ParseState *pstate,
					   char *funcname,
					   Node *first_arg,
					   bool *attisset)
{
	Oid			argtype;
	Oid			argrelid;
	Name		relname;
	Relation	rd;
	Oid			relid;
	int			attnum;

	switch (nodeTag(first_arg))
	{
		case T_Iter:
			{
				Func	   *func;
				Iter	   *iter;

				iter = (Iter *) first_arg;
				func = (Func *) ((Expr *) iter->iterexpr)->oper;
				argtype = funcid_get_rettype(func->funcid);
				argrelid = typeid_get_relid(argtype);
				if (argrelid &&
					((attnum = get_attnum(argrelid, funcname))
					 != InvalidAttrNumber))
				{

					/*
					 * the argument is a function returning a tuple, so
					 * funcname may be a projection
					 */

					/* add a tlist to the func node and return the Iter */
					rd = heap_openr(tname(get_id_type(argtype)));
					if (RelationIsValid(rd))
					{
						relid = RelationGetRelationId(rd);
						relname = RelationGetRelationName(rd);
						heap_close(rd);
					}
					if (RelationIsValid(rd))
					{
						func->func_tlist =
							setup_tlist(funcname, argrelid);
						iter->itertype = att_typeid(rd, attnum);
						return ((Node *) iter);
					}
					else
					{
						elog(WARN,
							 "Function %s has bad returntype %d",
							 funcname, argtype);
					}
				}
				else
				{
					/* drop through */
					;
				}
				break;
			}
		case T_Var:
			{

				/*
				 * The argument is a set, so this is either a projection
				 * or a function call on this set.
				 */
				*attisset = true;
				break;
			}
		case T_Expr:
			{
				Expr	   *expr = (Expr *) first_arg;
				Func	   *funcnode;

				if (expr->opType != FUNC_EXPR)
					break;

				funcnode = (Func *) expr->oper;
				argtype = funcid_get_rettype(funcnode->funcid);
				argrelid = typeid_get_relid(argtype);

				/*
				 * the argument is a function returning a tuple, so
				 * funcname may be a projection
				 */
				if (argrelid &&
					(attnum = get_attnum(argrelid, funcname))
					!= InvalidAttrNumber)
				{

					/* add a tlist to the func node */
					rd = heap_openr(tname(get_id_type(argtype)));
					if (RelationIsValid(rd))
					{
						relid = RelationGetRelationId(rd);
						relname = RelationGetRelationName(rd);
						heap_close(rd);
					}
					if (RelationIsValid(rd))
					{
						Expr	   *newexpr;

						funcnode->func_tlist =
							setup_tlist(funcname, argrelid);
						funcnode->functype = att_typeid(rd, attnum);

						newexpr = makeNode(Expr);
						newexpr->typeOid = funcnode->functype;
						newexpr->opType = FUNC_EXPR;
						newexpr->oper = (Node *) funcnode;
						newexpr->args = lcons(first_arg, NIL);

						return ((Node *) newexpr);
					}

				}

				elog(WARN, "Function %s has bad returntype %d",
					 funcname, argtype);
				break;
			}
		case T_Param:
			{
				Param	   *param = (Param *) first_arg;

				/*
				 * If the Param is a complex type, this could be a
				 * projection
				 */
				rd = heap_openr(tname(get_id_type(param->paramtype)));
				if (RelationIsValid(rd))
				{
					relid = RelationGetRelationId(rd);
					relname = RelationGetRelationName(rd);
					heap_close(rd);
				}
				if (RelationIsValid(rd) &&
					(attnum = get_attnum(relid, funcname))
					!= InvalidAttrNumber)
				{

					param->paramtype = att_typeid(rd, attnum);
					param->param_tlist = setup_tlist(funcname, relid);
					return ((Node *) param);
				}
				break;
			}
		default:
			break;
	}

	return NULL;
}

static Node *
ParseFunc(ParseState *pstate, char *funcname, List *fargs, int *curr_resno)
{
	Oid			rettype = (Oid) 0;
	Oid			argrelid = (Oid) 0;
	Oid			funcid = (Oid) 0;
	List	   *i = NIL;
	Node	   *first_arg = NULL;
	char	   *relname = NULL;
	char	   *refname = NULL;
	Relation	rd;
	Oid			relid;
	int			nargs;
	Func	   *funcnode;
	Oid			oid_array[8];
	Oid		   *true_oid_array;
	Node	   *retval;
	bool		retset;
	bool		exists;
	bool		attisset = false;
	Oid			toid = (Oid) 0;
	Expr	   *expr;

	if (fargs)
	{
		first_arg = lfirst(fargs);
		if (first_arg == NULL)
			elog(WARN, "function %s does not allow NULL input", funcname);
	}

	/*
	 * * check for projection methods: if function takes one argument, and *
	 * that argument is a relation, param, or PQ function returning a
	 * complex * type, then the function could be a projection.
	 */
	if (length(fargs) == 1)
	{

		if (nodeTag(first_arg) == T_Ident && ((Ident *) first_arg)->isRel)
		{
			RangeTblEntry *rte;
			Ident	   *ident = (Ident *) first_arg;

			/*
			 * first arg is a relation. This could be a projection.
			 */
			refname = ident->name;

			rte = refnameRangeTableEntry(pstate->p_rtable, refname);
			if (rte == NULL)
				rte = addRangeTableEntry(pstate, refname, refname, FALSE, FALSE, NULL);

			relname = rte->relname;
			relid = rte->relid;

			/*
			 * If the attr isn't a set, just make a var for it.  If it is
			 * a set, treat it like a function and drop through.
			 */
			if (get_attnum(relid, funcname) != InvalidAttrNumber)
			{
				Oid			dummyTypeId;

				return
					((Node *) make_var(pstate,
									   refname,
									   funcname,
									   &dummyTypeId));
			}
			else
			{
				/* drop through - attr is a set */
				;
			}
		}
		else if (ISCOMPLEX(exprType(first_arg)))
		{

			/*
			 * Attempt to handle projection of a complex argument. If
			 * ParseComplexProjection can't handle the projection, we have
			 * to keep going.
			 */
			retval = ParseComplexProjection(pstate,
											funcname,
											first_arg,
											&attisset);
			if (attisset)
			{
				toid = exprType(first_arg);
				rd = heap_openr(tname(get_id_type(toid)));
				if (RelationIsValid(rd))
				{
					relname = RelationGetRelationName(rd)->data;
					heap_close(rd);
				}
				else
					elog(WARN,
						 "Type %s is not a relation type",
						 tname(get_id_type(toid)));
				argrelid = typeid_get_relid(toid);

				/*
				 * A projection contains either an attribute name or the
				 * "*".
				 */
				if ((get_attnum(argrelid, funcname) == InvalidAttrNumber)
					&& strcmp(funcname, "*"))
				{
					elog(WARN, "Functions on sets are not yet supported");
				}
			}

			if (retval)
				return retval;
		}
		else
		{

			/*
			 * Parsing aggregates.
			 */
			Oid			basetype;

			/*
			 * the aggregate count is a special case, ignore its base
			 * type.  Treat it as zero
			 */
			if (strcmp(funcname, "count") == 0)
				basetype = 0;
			else
				basetype = exprType(lfirst(fargs));
			if (SearchSysCacheTuple(AGGNAME,
									PointerGetDatum(funcname),
									ObjectIdGetDatum(basetype),
									0, 0))
			{
				Aggreg	   *aggreg = ParseAgg(funcname, basetype, lfirst(fargs));

				AddAggToParseState(pstate, aggreg);
				return (Node *) aggreg;
			}
		}
	}


	/*
	 * * If we dropped through to here it's really a function (or a set,
	 * which * is implemented as a function.) * extract arg type info and
	 * transform relation name arguments into * varnodes of the
	 * appropriate form.
	 */
	MemSet(&oid_array[0], 0, 8 * sizeof(Oid));

	nargs = 0;
	foreach(i, fargs)
	{
		int			vnum;
		RangeTblEntry *rte;
		Node	   *pair = lfirst(i);

		if (nodeTag(pair) == T_Ident && ((Ident *) pair)->isRel)
		{

			/*
			 * a relation
			 */
			refname = ((Ident *) pair)->name;

			rte = refnameRangeTableEntry(pstate->p_rtable, refname);
			if (rte == NULL)
				rte = addRangeTableEntry(pstate, refname, refname,
										 FALSE, FALSE, NULL);
			relname = rte->relname;

			vnum = refnameRangeTablePosn(pstate->p_rtable, rte->refname);

			/*
			 * for func(relname), the param to the function is the tuple
			 * under consideration.  we build a special VarNode to reflect
			 * this -- it has varno set to the correct range table entry,
			 * but has varattno == 0 to signal that the whole tuple is the
			 * argument.
			 */
			toid = typeid(type(relname));
			/* replace it in the arg list */
			lfirst(fargs) =
				makeVar(vnum, 0, toid, vnum, 0);
		}
		else if (!attisset)
		{						/* set functions don't have parameters */

			/*
			 * any functiona args which are typed "unknown", but aren't
			 * constants, we don't know what to do with, because we can't
			 * cast them	- jolly
			 */
			if (exprType(pair) == UNKNOWNOID &&
				!IsA(pair, Const))
			{
				elog(WARN, "ParseFunc: no function named %s that takes in an unknown type as argument #%d", funcname, nargs);
			}
			else
				toid = exprType(pair);
		}

		oid_array[nargs++] = toid;
	}

	/*
	 * func_get_detail looks up the function in the catalogs, does
	 * disambiguation for polymorphic functions, handles inheritance, and
	 * returns the funcid and type and set or singleton status of the
	 * function's return value.  it also returns the true argument types
	 * to the function.  if func_get_detail returns true, the function
	 * exists.	otherwise, there was an error.
	 */
	if (attisset)
	{							/* we know all of these fields already */

		/*
		 * We create a funcnode with a placeholder function SetEval.
		 * SetEval() never actually gets executed.	When the function
		 * evaluation routines see it, they use the funcid projected out
		 * from the relation as the actual function to call. Example:
		 * retrieve (emp.mgr.name) The plan for this will scan the emp
		 * relation, projecting out the mgr attribute, which is a funcid.
		 * This function is then called (instead of SetEval) and "name" is
		 * projected from its result.
		 */
		funcid = SetEvalRegProcedure;
		rettype = toid;
		retset = true;
		true_oid_array = oid_array;
		exists = true;
	}
	else
	{
		exists = func_get_detail(funcname, nargs, oid_array, &funcid,
								 &rettype, &retset, &true_oid_array);
	}

	if (!exists)
		elog(WARN, "no such attribute or function %s", funcname);

	/* got it */
	funcnode = makeNode(Func);
	funcnode->funcid = funcid;
	funcnode->functype = rettype;
	funcnode->funcisindex = false;
	funcnode->funcsize = 0;
	funcnode->func_fcache = NULL;
	funcnode->func_tlist = NIL;
	funcnode->func_planlist = NIL;

	/* perform the necessary typecasting */
	make_arguments(nargs, fargs, oid_array, true_oid_array);

	/*
	 * for functions returning base types, we want to project out the
	 * return value.  set up a target list to do that.	the executor will
	 * ignore these for c functions, and do the right thing for postquel
	 * functions.
	 */

	if (typeid_get_relid(rettype) == InvalidOid)
		funcnode->func_tlist = setup_base_tlist(rettype);

	/*
	 * For sets, we want to make a targetlist to project out this
	 * attribute of the set tuples.
	 */
	if (attisset)
	{
		if (!strcmp(funcname, "*"))
		{
			funcnode->func_tlist =
				expandAll(pstate, relname, refname, curr_resno);
		}
		else
		{
			funcnode->func_tlist = setup_tlist(funcname, argrelid);
			rettype = find_atttype(argrelid, funcname);
		}
	}

	/*
	 * Sequence handling.
	 */
	if (funcid == SeqNextValueRegProcedure ||
		funcid == SeqCurrValueRegProcedure)
	{
		Const	   *seq;
		char	   *seqrel;
		text	   *seqname;
		int32		aclcheck_result = -1;
		extern text *lower (text *string);

		Assert(length(fargs) == 1);
		seq = (Const *) lfirst(fargs);
		if (!IsA((Node *) seq, Const))
			elog(WARN, "%s: only constant sequence names are acceptable", funcname);
		seqname = lower ((text*)DatumGetPointer(seq->constvalue));
		pfree (DatumGetPointer(seq->constvalue));
		seq->constvalue = PointerGetDatum (seqname);
		seqrel = textout(seqname);

		if ((aclcheck_result = pg_aclcheck(seqrel, GetPgUserName(),
			   ((funcid == SeqNextValueRegProcedure) ? ACL_WR : ACL_RD)))
			!= ACLCHECK_OK)
			elog(WARN, "%s.%s: %s",
			  seqrel, funcname, aclcheck_error_strings[aclcheck_result]);

		pfree(seqrel);

		if (funcid == SeqNextValueRegProcedure && inWhereClause)
			elog(WARN, "nextval of a sequence in WHERE disallowed");
	}

	expr = makeNode(Expr);
	expr->typeOid = rettype;
	expr->opType = FUNC_EXPR;
	expr->oper = (Node *) funcnode;
	expr->args = fargs;
	retval = (Node *) expr;

	/*
	 * if the function returns a set of values, then we need to iterate
	 * over all the returned values in the executor, so we stick an iter
	 * node here.  if it returns a singleton, then we don't need the iter
	 * node.
	 */

	if (retset)
	{
		Iter	   *iter = makeNode(Iter);

		iter->itertype = rettype;
		iter->iterexpr = retval;
		retval = (Node *) iter;
	}

	return (retval);
}

/*****************************************************************************
 *
 *****************************************************************************/

/*
 * AddAggToParseState -
 *	  add the aggregate to the list of unique aggregates in pstate.
 *
 * SIDE EFFECT: aggno in target list entry will be modified
 */
static void
AddAggToParseState(ParseState *pstate, Aggreg *aggreg)
{
	List	   *ag;
	int			i;

	/*
	 * see if we have the aggregate already (we only need to record the
	 * aggregate once)
	 */
	i = 0;
	foreach(ag, pstate->p_aggs)
	{
		Aggreg	   *a = lfirst(ag);

		if (!strcmp(a->aggname, aggreg->aggname) &&
			equal(a->target, aggreg->target))
		{

			/* fill in the aggno and we're done */
			aggreg->aggno = i;
			return;
		}
		i++;
	}

	/* not found, new aggregate */
	aggreg->aggno = i;
	pstate->p_numAgg++;
	pstate->p_aggs = lappend(pstate->p_aggs, aggreg);
	return;
}

/*
 * finalizeAggregates -
 *	  fill in qry_aggs from pstate. Also checks to make sure that aggregates
 *	  are used in the proper place.
 */
static void
finalizeAggregates(ParseState *pstate, Query *qry)
{
	List	   *l;
	int			i;

	parseCheckAggregates(pstate, qry);

	qry->qry_numAgg = pstate->p_numAgg;
	qry->qry_aggs =
		(Aggreg **) palloc(sizeof(Aggreg *) * qry->qry_numAgg);
	i = 0;
	foreach(l, pstate->p_aggs)
		qry->qry_aggs[i++] = (Aggreg *) lfirst(l);
}

/*
 * contain_agg_clause--
 *	  Recursively find aggreg nodes from a clause.
 *
 *	  Returns true if any aggregate found.
 */
static bool
contain_agg_clause(Node *clause)
{
	if (clause == NULL)
		return FALSE;
	else if (IsA(clause, Aggreg))
		return TRUE;
	else if (IsA(clause, Iter))
		return contain_agg_clause(((Iter *) clause)->iterexpr);
	else if (single_node(clause))
		return FALSE;
	else if (or_clause(clause))
	{
		List	   *temp;

		foreach(temp, ((Expr *) clause)->args)
			if (contain_agg_clause(lfirst(temp)))
			return TRUE;
		return FALSE;
	}
	else if (is_funcclause(clause))
	{
		List	   *temp;

		foreach(temp, ((Expr *) clause)->args)
			if (contain_agg_clause(lfirst(temp)))
			return TRUE;
		return FALSE;
	}
	else if (IsA(clause, ArrayRef))
	{
		List	   *temp;

		foreach(temp, ((ArrayRef *) clause)->refupperindexpr)
			if (contain_agg_clause(lfirst(temp)))
			return TRUE;
		foreach(temp, ((ArrayRef *) clause)->reflowerindexpr)
			if (contain_agg_clause(lfirst(temp)))
			return TRUE;
		if (contain_agg_clause(((ArrayRef *) clause)->refexpr))
			return TRUE;
		if (contain_agg_clause(((ArrayRef *) clause)->refassgnexpr))
			return TRUE;
		return FALSE;
	}
	else if (not_clause(clause))
		return contain_agg_clause((Node *) get_notclausearg((Expr *) clause));
	else if (is_opclause(clause))
		return (contain_agg_clause((Node *) get_leftop((Expr *) clause)) ||
			  contain_agg_clause((Node *) get_rightop((Expr *) clause)));

	return FALSE;
}

/*
 * exprIsAggOrGroupCol -
 *	  returns true if the expression does not contain non-group columns.
 */
static bool
exprIsAggOrGroupCol(Node *expr, List *groupClause)
{
	List	   *gl;

	if (expr == NULL || IsA(expr, Const) ||
		IsA(expr, Param) ||IsA(expr, Aggreg))
		return TRUE;

	foreach(gl, groupClause)
	{
		GroupClause *grpcl = lfirst(gl);

		if (equal(expr, grpcl->entry->expr))
			return TRUE;
	}

	if (IsA(expr, Expr))
	{
		List	   *temp;

		foreach(temp, ((Expr *) expr)->args)
			if (!exprIsAggOrGroupCol(lfirst(temp), groupClause))
			return FALSE;
		return TRUE;
	}

	return FALSE;
}

/*
 * tleIsAggOrGroupCol -
 *	  returns true if the TargetEntry is Agg or GroupCol.
 */
static bool
tleIsAggOrGroupCol(TargetEntry *tle, List *groupClause)
{
	Node	   *expr = tle->expr;
	List	   *gl;

	if (expr == NULL || IsA(expr, Const) ||IsA(expr, Param))
		return TRUE;

	foreach(gl, groupClause)
	{
		GroupClause *grpcl = lfirst(gl);

		if (tle->resdom->resno == grpcl->entry->resdom->resno)
		{
			if (contain_agg_clause((Node *) expr))
				elog(WARN, "parser: aggregates not allowed in GROUP BY clause");
			return TRUE;
		}
	}

	if (IsA(expr, Aggreg))
		return TRUE;

	if (IsA(expr, Expr))
	{
		List	   *temp;

		foreach(temp, ((Expr *) expr)->args)
			if (!exprIsAggOrGroupCol(lfirst(temp), groupClause))
			return FALSE;
		return TRUE;
	}

	return FALSE;
}

/*
 * parseCheckAggregates -
 *	  this should really be done earlier but the current grammar
 *	  cannot differentiate functions from aggregates. So we have do check
 *	  here when the target list and the qualifications are finalized.
 */
static void
parseCheckAggregates(ParseState *pstate, Query *qry)
{
	List	   *tl;

	Assert(pstate->p_numAgg > 0);

	/*
	 * aggregates never appear in WHERE clauses. (we have to check where
	 * clause first because if there is an aggregate, the check for
	 * non-group column in target list may fail.)
	 */
	if (contain_agg_clause(qry->qual))
		elog(WARN, "parser: aggregates not allowed in WHERE clause");

	/*
	 * the target list can only contain aggregates, group columns and
	 * functions thereof.
	 */
	foreach(tl, qry->targetList)
	{
		TargetEntry *tle = lfirst(tl);

		if (!tleIsAggOrGroupCol(tle, qry->groupClause))
			elog(WARN,
				 "parser: illegal use of aggregates or non-group column in target list");
	}

	/*
	 * the expression specified in the HAVING clause has the same
	 * restriction as those in the target list.
	 */
/*
 * Need to change here when we get HAVING works. Currently
 * qry->havingQual is NULL.		- vadim 04/05/97
	if (!exprIsAggOrGroupCol(qry->havingQual, qry->groupClause))
		elog(WARN,
			 "parser: illegal use of aggregates or non-group column in HAVING clause");
 */
	return;
}