/*-------------------------------------------------------------------------
 *
 * equalfuncs.c
 *	  Equality functions to compare node trees.
 *
 * NOTE: we currently support comparing all node types found in parse
 * trees.  We do not support comparing executor state trees; there
 * is no need for that, and no point in maintaining all the code that
 * would be needed.  We also do not support comparing Path trees, mainly
 * because the circular linkages between RelOptInfo and Path nodes can't
 * be handled easily in a simple depth-first traversal.
 *
 * Currently, in fact, equal() doesn't know how to compare Plan trees
 * either.  This might need to be fixed someday.
 *
 *
 * Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 * IDENTIFICATION
 *	  $Header: /cvsroot/pgsql/src/backend/nodes/equalfuncs.c,v 1.194 2003/05/28 16:03:56 tgl Exp $
 *
 *-------------------------------------------------------------------------
 */

#include "postgres.h"

#include "nodes/params.h"
#include "nodes/parsenodes.h"
#include "nodes/relation.h"
#include "utils/datum.h"


/*
 * Macros to simplify comparison of different kinds of fields.  Use these
 * wherever possible to reduce the chance for silly typos.  Note that these
 * hard-wire the convention that the local variables in an Equal routine are
 * named 'a' and 'b'.
 */

/* Compare a simple scalar field (int, float, bool, enum, etc) */
#define COMPARE_SCALAR_FIELD(fldname) \
	do { \
		if (a->fldname != b->fldname) \
			return false; \
	} while (0)

/* Compare a field that is a pointer to some kind of Node or Node tree */
#define COMPARE_NODE_FIELD(fldname) \
	do { \
		if (!equal(a->fldname, b->fldname)) \
			return false; \
	} while (0)

/* Compare a field that is a pointer to a list of integers */
#define COMPARE_INTLIST_FIELD(fldname) \
	do { \
		if (!equali(a->fldname, b->fldname)) \
			return false; \
	} while (0)

/* Compare a field that is a pointer to a list of Oids */
#define COMPARE_OIDLIST_FIELD(fldname) \
	do { \
		if (!equalo(a->fldname, b->fldname)) \
			return false; \
	} while (0)

/* Compare a field that is a pointer to a Bitmapset */
#define COMPARE_BITMAPSET_FIELD(fldname) \
	do { \
		if (!bms_equal(a->fldname, b->fldname)) \
			return false; \
	} while (0)

/* Compare a field that is a pointer to a C string, or perhaps NULL */
#define COMPARE_STRING_FIELD(fldname) \
	do { \
		if (!equalstr(a->fldname, b->fldname)) \
			return false; \
	} while (0)

/* Macro for comparing string fields that might be NULL */
#define equalstr(a, b)	\
	(((a) != NULL && (b) != NULL) ? (strcmp(a, b) == 0) : (a) == (b))

/* Compare a field that is a pointer to a simple palloc'd object of size sz */
#define COMPARE_POINTER_FIELD(fldname, sz) \
	do { \
		if (memcmp(a->fldname, b->fldname, (sz)) != 0) \
			return false; \
	} while (0)


/*
 *	Stuff from primnodes.h
 */

static bool
_equalResdom(Resdom *a, Resdom *b)
{
	COMPARE_SCALAR_FIELD(resno);
	COMPARE_SCALAR_FIELD(restype);
	COMPARE_SCALAR_FIELD(restypmod);
	COMPARE_STRING_FIELD(resname);
	COMPARE_SCALAR_FIELD(ressortgroupref);
	COMPARE_SCALAR_FIELD(resorigtbl);
	COMPARE_SCALAR_FIELD(resorigcol);
	COMPARE_SCALAR_FIELD(resjunk);

	return true;
}

static bool
_equalAlias(Alias *a, Alias *b)
{
	COMPARE_STRING_FIELD(aliasname);
	COMPARE_NODE_FIELD(colnames);

	return true;
}

static bool
_equalRangeVar(RangeVar *a, RangeVar *b)
{
	COMPARE_STRING_FIELD(catalogname);
	COMPARE_STRING_FIELD(schemaname);
	COMPARE_STRING_FIELD(relname);
	COMPARE_SCALAR_FIELD(inhOpt);
	COMPARE_SCALAR_FIELD(istemp);
	COMPARE_NODE_FIELD(alias);

	return true;
}

/*
 * We don't need an _equalExpr because Expr is an abstract supertype which
 * should never actually get instantiated.  Also, since it has no common
 * fields except NodeTag, there's no need for a helper routine to factor
 * out comparing the common fields...
 */

static bool
_equalVar(Var *a, Var *b)
{
	COMPARE_SCALAR_FIELD(varno);
	COMPARE_SCALAR_FIELD(varattno);
	COMPARE_SCALAR_FIELD(vartype);
	COMPARE_SCALAR_FIELD(vartypmod);
	COMPARE_SCALAR_FIELD(varlevelsup);
	COMPARE_SCALAR_FIELD(varnoold);
	COMPARE_SCALAR_FIELD(varoattno);

	return true;
}

static bool
_equalConst(Const *a, Const *b)
{
	COMPARE_SCALAR_FIELD(consttype);
	COMPARE_SCALAR_FIELD(constlen);
	COMPARE_SCALAR_FIELD(constisnull);
	COMPARE_SCALAR_FIELD(constbyval);

	/*
	 * We treat all NULL constants of the same type as equal. Someday this
	 * might need to change?  But datumIsEqual doesn't work on nulls,
	 * so...
	 */
	if (a->constisnull)
		return true;
	return datumIsEqual(a->constvalue, b->constvalue,
						a->constbyval, a->constlen);
}

static bool
_equalParam(Param *a, Param *b)
{
	COMPARE_SCALAR_FIELD(paramkind);
	COMPARE_SCALAR_FIELD(paramtype);

	switch (a->paramkind)
	{
		case PARAM_NAMED:
			COMPARE_STRING_FIELD(paramname);
			break;
		case PARAM_NUM:
		case PARAM_EXEC:
			COMPARE_SCALAR_FIELD(paramid);
			break;
		default:
			elog(ERROR, "_equalParam: Invalid paramkind value: %d",
				 a->paramkind);
	}

	return true;
}

static bool
_equalAggref(Aggref *a, Aggref *b)
{
	COMPARE_SCALAR_FIELD(aggfnoid);
	COMPARE_SCALAR_FIELD(aggtype);
	COMPARE_NODE_FIELD(target);
	COMPARE_SCALAR_FIELD(aggstar);
	COMPARE_SCALAR_FIELD(aggdistinct);

	return true;
}

static bool
_equalArrayRef(ArrayRef *a, ArrayRef *b)
{
	COMPARE_SCALAR_FIELD(refrestype);
	COMPARE_SCALAR_FIELD(refarraytype);
	COMPARE_SCALAR_FIELD(refelemtype);
	COMPARE_NODE_FIELD(refupperindexpr);
	COMPARE_NODE_FIELD(reflowerindexpr);
	COMPARE_NODE_FIELD(refexpr);
	COMPARE_NODE_FIELD(refassgnexpr);

	return true;
}

static bool
_equalFuncExpr(FuncExpr *a, FuncExpr *b)
{
	COMPARE_SCALAR_FIELD(funcid);
	COMPARE_SCALAR_FIELD(funcresulttype);
	COMPARE_SCALAR_FIELD(funcretset);
	/*
	 * Special-case COERCE_DONTCARE, so that pathkeys can build coercion
	 * nodes that are equal() to both explicit and implicit coercions.
	 */
	if (a->funcformat != b->funcformat &&
		a->funcformat != COERCE_DONTCARE &&
		b->funcformat != COERCE_DONTCARE)
		return false;

	COMPARE_NODE_FIELD(args);

	return true;
}

static bool
_equalOpExpr(OpExpr *a, OpExpr *b)
{
	COMPARE_SCALAR_FIELD(opno);
	/*
	 * Special-case opfuncid: it is allowable for it to differ if one
	 * node contains zero and the other doesn't.  This just means that the
	 * one node isn't as far along in the parse/plan pipeline and hasn't
	 * had the opfuncid cache filled yet.
	 */
	if (a->opfuncid != b->opfuncid &&
		a->opfuncid != 0 &&
		b->opfuncid != 0)
		return false;

	COMPARE_SCALAR_FIELD(opresulttype);
	COMPARE_SCALAR_FIELD(opretset);
	COMPARE_NODE_FIELD(args);

	return true;
}

static bool
_equalDistinctExpr(DistinctExpr *a, DistinctExpr *b)
{
	COMPARE_SCALAR_FIELD(opno);
	/*
	 * Special-case opfuncid: it is allowable for it to differ if one
	 * node contains zero and the other doesn't.  This just means that the
	 * one node isn't as far along in the parse/plan pipeline and hasn't
	 * had the opfuncid cache filled yet.
	 */
	if (a->opfuncid != b->opfuncid &&
		a->opfuncid != 0 &&
		b->opfuncid != 0)
		return false;

	COMPARE_SCALAR_FIELD(opresulttype);
	COMPARE_SCALAR_FIELD(opretset);
	COMPARE_NODE_FIELD(args);

	return true;
}

static bool
_equalBoolExpr(BoolExpr *a, BoolExpr *b)
{
	COMPARE_SCALAR_FIELD(boolop);
	COMPARE_NODE_FIELD(args);

	return true;
}

static bool
_equalSubLink(SubLink *a, SubLink *b)
{
	COMPARE_SCALAR_FIELD(subLinkType);
	COMPARE_SCALAR_FIELD(useOr);
	COMPARE_NODE_FIELD(lefthand);
	COMPARE_NODE_FIELD(operName);
	COMPARE_OIDLIST_FIELD(operOids);
	COMPARE_NODE_FIELD(subselect);

	return true;
}

static bool
_equalSubPlan(SubPlan *a, SubPlan *b)
{
	COMPARE_SCALAR_FIELD(subLinkType);
	COMPARE_SCALAR_FIELD(useOr);
	COMPARE_NODE_FIELD(exprs);
	COMPARE_INTLIST_FIELD(paramIds);
	/* should compare plans, but have to settle for comparing plan IDs */
	COMPARE_SCALAR_FIELD(plan_id);
	COMPARE_NODE_FIELD(rtable);
	COMPARE_SCALAR_FIELD(useHashTable);
	COMPARE_SCALAR_FIELD(unknownEqFalse);
	COMPARE_INTLIST_FIELD(setParam);
	COMPARE_INTLIST_FIELD(parParam);
	COMPARE_NODE_FIELD(args);

	return true;
}

static bool
_equalFieldSelect(FieldSelect *a, FieldSelect *b)
{
	COMPARE_NODE_FIELD(arg);
	COMPARE_SCALAR_FIELD(fieldnum);
	COMPARE_SCALAR_FIELD(resulttype);
	COMPARE_SCALAR_FIELD(resulttypmod);

	return true;
}

static bool
_equalRelabelType(RelabelType *a, RelabelType *b)
{
	COMPARE_NODE_FIELD(arg);
	COMPARE_SCALAR_FIELD(resulttype);
	COMPARE_SCALAR_FIELD(resulttypmod);
	/*
	 * Special-case COERCE_DONTCARE, so that pathkeys can build coercion
	 * nodes that are equal() to both explicit and implicit coercions.
	 */
	if (a->relabelformat != b->relabelformat &&
		a->relabelformat != COERCE_DONTCARE &&
		b->relabelformat != COERCE_DONTCARE)
		return false;

	return true;
}

static bool
_equalCaseExpr(CaseExpr *a, CaseExpr *b)
{
	COMPARE_SCALAR_FIELD(casetype);
	COMPARE_NODE_FIELD(arg);
	COMPARE_NODE_FIELD(args);
	COMPARE_NODE_FIELD(defresult);

	return true;
}

static bool
_equalCaseWhen(CaseWhen *a, CaseWhen *b)
{
	COMPARE_NODE_FIELD(expr);
	COMPARE_NODE_FIELD(result);

	return true;
}

static bool
_equalArrayExpr(ArrayExpr *a, ArrayExpr *b)
{
	COMPARE_SCALAR_FIELD(array_typeid);
	COMPARE_SCALAR_FIELD(element_typeid);
	COMPARE_NODE_FIELD(elements);
	COMPARE_SCALAR_FIELD(ndims);

	return true;
}

static bool
_equalCoalesceExpr(CoalesceExpr *a, CoalesceExpr *b)
{
	COMPARE_SCALAR_FIELD(coalescetype);
	COMPARE_NODE_FIELD(args);

	return true;
}

static bool
_equalNullIfExpr(NullIfExpr *a, NullIfExpr *b)
{
	COMPARE_SCALAR_FIELD(opno);
	/*
	 * Special-case opfuncid: it is allowable for it to differ if one
	 * node contains zero and the other doesn't.  This just means that the
	 * one node isn't as far along in the parse/plan pipeline and hasn't
	 * had the opfuncid cache filled yet.
	 */
	if (a->opfuncid != b->opfuncid &&
		a->opfuncid != 0 &&
		b->opfuncid != 0)
		return false;

	COMPARE_SCALAR_FIELD(opresulttype);
	COMPARE_SCALAR_FIELD(opretset);
	COMPARE_NODE_FIELD(args);

	return true;
}

static bool
_equalNullTest(NullTest *a, NullTest *b)
{
	COMPARE_NODE_FIELD(arg);
	COMPARE_SCALAR_FIELD(nulltesttype);

	return true;
}

static bool
_equalBooleanTest(BooleanTest *a, BooleanTest *b)
{
	COMPARE_NODE_FIELD(arg);
	COMPARE_SCALAR_FIELD(booltesttype);

	return true;
}

static bool
_equalCoerceToDomain(CoerceToDomain *a, CoerceToDomain *b)
{
	COMPARE_NODE_FIELD(arg);
	COMPARE_SCALAR_FIELD(resulttype);
	COMPARE_SCALAR_FIELD(resulttypmod);
	/*
	 * Special-case COERCE_DONTCARE, so that pathkeys can build coercion
	 * nodes that are equal() to both explicit and implicit coercions.
	 */
	if (a->coercionformat != b->coercionformat &&
		a->coercionformat != COERCE_DONTCARE &&
		b->coercionformat != COERCE_DONTCARE)
		return false;

	return true;
}

static bool
_equalCoerceToDomainValue(CoerceToDomainValue *a, CoerceToDomainValue *b)
{
	COMPARE_SCALAR_FIELD(typeId);
	COMPARE_SCALAR_FIELD(typeMod);

	return true;
}

static bool
_equalTargetEntry(TargetEntry *a, TargetEntry *b)
{
	COMPARE_NODE_FIELD(resdom);
	COMPARE_NODE_FIELD(expr);

	return true;
}

static bool
_equalRangeTblRef(RangeTblRef *a, RangeTblRef *b)
{
	COMPARE_SCALAR_FIELD(rtindex);

	return true;
}

static bool
_equalJoinExpr(JoinExpr *a, JoinExpr *b)
{
	COMPARE_SCALAR_FIELD(jointype);
	COMPARE_SCALAR_FIELD(isNatural);
	COMPARE_NODE_FIELD(larg);
	COMPARE_NODE_FIELD(rarg);
	COMPARE_NODE_FIELD(using);
	COMPARE_NODE_FIELD(quals);
	COMPARE_NODE_FIELD(alias);
	COMPARE_SCALAR_FIELD(rtindex);

	return true;
}

static bool
_equalFromExpr(FromExpr *a, FromExpr *b)
{
	COMPARE_NODE_FIELD(fromlist);
	COMPARE_NODE_FIELD(quals);

	return true;
}


/*
 * Stuff from relation.h
 */

static bool
_equalPathKeyItem(PathKeyItem *a, PathKeyItem *b)
{
	COMPARE_NODE_FIELD(key);
	COMPARE_SCALAR_FIELD(sortop);

	return true;
}

static bool
_equalRestrictInfo(RestrictInfo *a, RestrictInfo *b)
{
	COMPARE_NODE_FIELD(clause);
	COMPARE_SCALAR_FIELD(ispusheddown);
	/*
	 * We ignore subclauseindices, eval_cost, this_selec, left/right_relids,
	 * left/right_pathkey, and left/right_bucketsize, since they may not be
	 * set yet, and should be derivable from the clause anyway.  Probably it's
	 * not really necessary to compare any of these remaining fields ...
	 */
	COMPARE_SCALAR_FIELD(mergejoinoperator);
	COMPARE_SCALAR_FIELD(left_sortop);
	COMPARE_SCALAR_FIELD(right_sortop);
	COMPARE_SCALAR_FIELD(hashjoinoperator);

	return true;
}

static bool
_equalJoinInfo(JoinInfo *a, JoinInfo *b)
{
	COMPARE_BITMAPSET_FIELD(unjoined_relids);
	COMPARE_NODE_FIELD(jinfo_restrictinfo);

	return true;
}

static bool
_equalInClauseInfo(InClauseInfo *a, InClauseInfo *b)
{
	COMPARE_BITMAPSET_FIELD(lefthand);
	COMPARE_BITMAPSET_FIELD(righthand);
	COMPARE_NODE_FIELD(sub_targetlist);

	return true;
}


/*
 * Stuff from parsenodes.h
 */

static bool
_equalQuery(Query *a, Query *b)
{
	COMPARE_SCALAR_FIELD(commandType);
	COMPARE_SCALAR_FIELD(querySource);
	COMPARE_SCALAR_FIELD(canSetTag);
	COMPARE_NODE_FIELD(utilityStmt);
	COMPARE_SCALAR_FIELD(resultRelation);
	COMPARE_NODE_FIELD(into);
	COMPARE_SCALAR_FIELD(hasAggs);
	COMPARE_SCALAR_FIELD(hasSubLinks);
	COMPARE_NODE_FIELD(rtable);
	COMPARE_NODE_FIELD(jointree);
	COMPARE_INTLIST_FIELD(rowMarks);
	COMPARE_NODE_FIELD(targetList);
	COMPARE_NODE_FIELD(groupClause);
	COMPARE_NODE_FIELD(havingQual);
	COMPARE_NODE_FIELD(distinctClause);
	COMPARE_NODE_FIELD(sortClause);
	COMPARE_NODE_FIELD(limitOffset);
	COMPARE_NODE_FIELD(limitCount);
	COMPARE_NODE_FIELD(setOperations);
	COMPARE_INTLIST_FIELD(resultRelations);
	COMPARE_NODE_FIELD(in_info_list);
	COMPARE_SCALAR_FIELD(hasJoinRTEs);

	/*
	 * We do not check the other planner internal fields: base_rel_list,
	 * other_rel_list, join_rel_list, equi_key_list, query_pathkeys.
	 * They might not be set yet, and in any case they should be derivable
	 * from the other fields.
	 */
	return true;
}

static bool
_equalInsertStmt(InsertStmt *a, InsertStmt *b)
{
	COMPARE_NODE_FIELD(relation);
	COMPARE_NODE_FIELD(cols);
	COMPARE_NODE_FIELD(targetList);
	COMPARE_NODE_FIELD(selectStmt);

	return true;
}

static bool
_equalDeleteStmt(DeleteStmt *a, DeleteStmt *b)
{
	COMPARE_NODE_FIELD(relation);
	COMPARE_NODE_FIELD(whereClause);

	return true;
}

static bool
_equalUpdateStmt(UpdateStmt *a, UpdateStmt *b)
{
	COMPARE_NODE_FIELD(relation);
	COMPARE_NODE_FIELD(targetList);
	COMPARE_NODE_FIELD(whereClause);
	COMPARE_NODE_FIELD(fromClause);

	return true;
}

static bool
_equalSelectStmt(SelectStmt *a, SelectStmt *b)
{
	COMPARE_NODE_FIELD(distinctClause);
	COMPARE_NODE_FIELD(into);
	COMPARE_NODE_FIELD(intoColNames);
	COMPARE_NODE_FIELD(targetList);
	COMPARE_NODE_FIELD(fromClause);
	COMPARE_NODE_FIELD(whereClause);
	COMPARE_NODE_FIELD(groupClause);
	COMPARE_NODE_FIELD(havingClause);
	COMPARE_NODE_FIELD(sortClause);
	COMPARE_NODE_FIELD(limitOffset);
	COMPARE_NODE_FIELD(limitCount);
	COMPARE_NODE_FIELD(forUpdate);
	COMPARE_SCALAR_FIELD(op);
	COMPARE_SCALAR_FIELD(all);
	COMPARE_NODE_FIELD(larg);
	COMPARE_NODE_FIELD(rarg);

	return true;
}

static bool
_equalSetOperationStmt(SetOperationStmt *a, SetOperationStmt *b)
{
	COMPARE_SCALAR_FIELD(op);
	COMPARE_SCALAR_FIELD(all);
	COMPARE_NODE_FIELD(larg);
	COMPARE_NODE_FIELD(rarg);
	COMPARE_OIDLIST_FIELD(colTypes);

	return true;
}

static bool
_equalAlterTableStmt(AlterTableStmt *a, AlterTableStmt *b)
{
	COMPARE_SCALAR_FIELD(subtype);
	COMPARE_NODE_FIELD(relation);
	COMPARE_STRING_FIELD(name);
	COMPARE_NODE_FIELD(def);
	COMPARE_SCALAR_FIELD(behavior);

	return true;
}

static bool
_equalAlterDomainStmt(AlterDomainStmt *a, AlterDomainStmt *b)
{
	COMPARE_SCALAR_FIELD(subtype);
	COMPARE_NODE_FIELD(typename);
	COMPARE_STRING_FIELD(name);
	COMPARE_NODE_FIELD(def);
	COMPARE_SCALAR_FIELD(behavior);

	return true;
}

static bool
_equalGrantStmt(GrantStmt *a, GrantStmt *b)
{
	COMPARE_SCALAR_FIELD(is_grant);
	COMPARE_SCALAR_FIELD(objtype);
	COMPARE_NODE_FIELD(objects);
	COMPARE_INTLIST_FIELD(privileges);
	COMPARE_NODE_FIELD(grantees);
	COMPARE_SCALAR_FIELD(grant_option);
	COMPARE_SCALAR_FIELD(behavior);

	return true;
}

static bool
_equalPrivGrantee(PrivGrantee *a, PrivGrantee *b)
{
	COMPARE_STRING_FIELD(username);
	COMPARE_STRING_FIELD(groupname);

	return true;
}

static bool
_equalFuncWithArgs(FuncWithArgs *a, FuncWithArgs *b)
{
	COMPARE_NODE_FIELD(funcname);
	COMPARE_NODE_FIELD(funcargs);

	return true;
}

static bool
_equalInsertDefault(InsertDefault *a, InsertDefault *b)
{
	return true;
}

static bool
_equalDeclareCursorStmt(DeclareCursorStmt *a, DeclareCursorStmt *b)
{
	COMPARE_STRING_FIELD(portalname);
	COMPARE_SCALAR_FIELD(options);
	COMPARE_NODE_FIELD(query);

	return true;
}

static bool
_equalClosePortalStmt(ClosePortalStmt *a, ClosePortalStmt *b)
{
	COMPARE_STRING_FIELD(portalname);

	return true;
}

static bool
_equalClusterStmt(ClusterStmt *a, ClusterStmt *b)
{
	COMPARE_NODE_FIELD(relation);
	COMPARE_STRING_FIELD(indexname);

	return true;
}

static bool
_equalCopyStmt(CopyStmt *a, CopyStmt *b)
{
	COMPARE_NODE_FIELD(relation);
	COMPARE_NODE_FIELD(attlist);
	COMPARE_SCALAR_FIELD(is_from);
	COMPARE_STRING_FIELD(filename);
	COMPARE_NODE_FIELD(options);

	return true;
}

static bool
_equalCreateStmt(CreateStmt *a, CreateStmt *b)
{
	COMPARE_NODE_FIELD(relation);
	COMPARE_NODE_FIELD(tableElts);
	COMPARE_NODE_FIELD(inhRelations);
	COMPARE_NODE_FIELD(constraints);
	COMPARE_SCALAR_FIELD(hasoids);
	COMPARE_SCALAR_FIELD(oncommit);

	return true;
}

static bool
_equalDefineStmt(DefineStmt *a, DefineStmt *b)
{
	COMPARE_SCALAR_FIELD(kind);
	COMPARE_NODE_FIELD(defnames);
	COMPARE_NODE_FIELD(definition);

	return true;
}

static bool
_equalDropStmt(DropStmt *a, DropStmt *b)
{
	COMPARE_NODE_FIELD(objects);
	COMPARE_SCALAR_FIELD(removeType);
	COMPARE_SCALAR_FIELD(behavior);

	return true;
}

static bool
_equalTruncateStmt(TruncateStmt *a, TruncateStmt *b)
{
	COMPARE_NODE_FIELD(relation);

	return true;
}

static bool
_equalCommentStmt(CommentStmt *a, CommentStmt *b)
{
	COMPARE_SCALAR_FIELD(objtype);
	COMPARE_NODE_FIELD(objname);
	COMPARE_NODE_FIELD(objargs);
	COMPARE_STRING_FIELD(comment);

	return true;
}

static bool
_equalFetchStmt(FetchStmt *a, FetchStmt *b)
{
	COMPARE_SCALAR_FIELD(direction);
	COMPARE_SCALAR_FIELD(howMany);
	COMPARE_STRING_FIELD(portalname);
	COMPARE_SCALAR_FIELD(ismove);

	return true;
}

static bool
_equalIndexStmt(IndexStmt *a, IndexStmt *b)
{
	COMPARE_STRING_FIELD(idxname);
	COMPARE_NODE_FIELD(relation);
	COMPARE_STRING_FIELD(accessMethod);
	COMPARE_NODE_FIELD(indexParams);
	COMPARE_NODE_FIELD(whereClause);
	COMPARE_NODE_FIELD(rangetable);
	COMPARE_SCALAR_FIELD(unique);
	COMPARE_SCALAR_FIELD(primary);
	COMPARE_SCALAR_FIELD(isconstraint);

	return true;
}

static bool
_equalCreateFunctionStmt(CreateFunctionStmt *a, CreateFunctionStmt *b)
{
	COMPARE_SCALAR_FIELD(replace);
	COMPARE_NODE_FIELD(funcname);
	COMPARE_NODE_FIELD(argTypes);
	COMPARE_NODE_FIELD(returnType);
	COMPARE_NODE_FIELD(options);
	COMPARE_NODE_FIELD(withClause);

	return true;
}

static bool
_equalRemoveAggrStmt(RemoveAggrStmt *a, RemoveAggrStmt *b)
{
	COMPARE_NODE_FIELD(aggname);
	COMPARE_NODE_FIELD(aggtype);
	COMPARE_SCALAR_FIELD(behavior);

	return true;
}

static bool
_equalRemoveFuncStmt(RemoveFuncStmt *a, RemoveFuncStmt *b)
{
	COMPARE_NODE_FIELD(funcname);
	COMPARE_NODE_FIELD(args);
	COMPARE_SCALAR_FIELD(behavior);

	return true;
}

static bool
_equalRemoveOperStmt(RemoveOperStmt *a, RemoveOperStmt *b)
{
	COMPARE_NODE_FIELD(opname);
	COMPARE_NODE_FIELD(args);
	COMPARE_SCALAR_FIELD(behavior);

	return true;
}

static bool
_equalRemoveOpClassStmt(RemoveOpClassStmt *a, RemoveOpClassStmt *b)
{
	COMPARE_NODE_FIELD(opclassname);
	COMPARE_STRING_FIELD(amname);
	COMPARE_SCALAR_FIELD(behavior);

	return true;
}

static bool
_equalRenameStmt(RenameStmt *a, RenameStmt *b)
{
	COMPARE_NODE_FIELD(relation);
	COMPARE_STRING_FIELD(oldname);
	COMPARE_STRING_FIELD(newname);
	COMPARE_SCALAR_FIELD(renameType);

	return true;
}

static bool
_equalRuleStmt(RuleStmt *a, RuleStmt *b)
{
	COMPARE_NODE_FIELD(relation);
	COMPARE_STRING_FIELD(rulename);
	COMPARE_NODE_FIELD(whereClause);
	COMPARE_SCALAR_FIELD(event);
	COMPARE_SCALAR_FIELD(instead);
	COMPARE_NODE_FIELD(actions);
	COMPARE_SCALAR_FIELD(replace);

	return true;
}

static bool
_equalNotifyStmt(NotifyStmt *a, NotifyStmt *b)
{
	COMPARE_NODE_FIELD(relation);

	return true;
}

static bool
_equalListenStmt(ListenStmt *a, ListenStmt *b)
{
	COMPARE_NODE_FIELD(relation);

	return true;
}

static bool
_equalUnlistenStmt(UnlistenStmt *a, UnlistenStmt *b)
{
	COMPARE_NODE_FIELD(relation);

	return true;
}

static bool
_equalTransactionStmt(TransactionStmt *a, TransactionStmt *b)
{
	COMPARE_SCALAR_FIELD(kind);
	COMPARE_NODE_FIELD(options);

	return true;
}

static bool
_equalCompositeTypeStmt(CompositeTypeStmt *a, CompositeTypeStmt *b)
{
	COMPARE_NODE_FIELD(typevar);
	COMPARE_NODE_FIELD(coldeflist);

	return true;
}

static bool
_equalViewStmt(ViewStmt *a, ViewStmt *b)
{
	COMPARE_NODE_FIELD(view);
	COMPARE_NODE_FIELD(aliases);
	COMPARE_NODE_FIELD(query);
	COMPARE_SCALAR_FIELD(replace);

	return true;
}

static bool
_equalLoadStmt(LoadStmt *a, LoadStmt *b)
{
	COMPARE_STRING_FIELD(filename);

	return true;
}

static bool
_equalCreateDomainStmt(CreateDomainStmt *a, CreateDomainStmt *b)
{
	COMPARE_NODE_FIELD(domainname);
	COMPARE_NODE_FIELD(typename);
	COMPARE_NODE_FIELD(constraints);

	return true;
}

static bool
_equalCreateOpClassStmt(CreateOpClassStmt *a, CreateOpClassStmt *b)
{
	COMPARE_NODE_FIELD(opclassname);
	COMPARE_STRING_FIELD(amname);
	COMPARE_NODE_FIELD(datatype);
	COMPARE_NODE_FIELD(items);
	COMPARE_SCALAR_FIELD(isDefault);

	return true;
}

static bool
_equalCreateOpClassItem(CreateOpClassItem *a, CreateOpClassItem *b)
{
	COMPARE_SCALAR_FIELD(itemtype);
	COMPARE_NODE_FIELD(name);
	COMPARE_NODE_FIELD(args);
	COMPARE_SCALAR_FIELD(number);
	COMPARE_SCALAR_FIELD(recheck);
	COMPARE_NODE_FIELD(storedtype);

	return true;
}

static bool
_equalCreatedbStmt(CreatedbStmt *a, CreatedbStmt *b)
{
	COMPARE_STRING_FIELD(dbname);
	COMPARE_NODE_FIELD(options);

	return true;
}

static bool
_equalAlterDatabaseSetStmt(AlterDatabaseSetStmt *a, AlterDatabaseSetStmt *b)
{
	COMPARE_STRING_FIELD(dbname);
	COMPARE_STRING_FIELD(variable);
	COMPARE_NODE_FIELD(value);

	return true;
}

static bool
_equalDropdbStmt(DropdbStmt *a, DropdbStmt *b)
{
	COMPARE_STRING_FIELD(dbname);

	return true;
}

static bool
_equalVacuumStmt(VacuumStmt *a, VacuumStmt *b)
{
	COMPARE_SCALAR_FIELD(vacuum);
	COMPARE_SCALAR_FIELD(full);
	COMPARE_SCALAR_FIELD(analyze);
	COMPARE_SCALAR_FIELD(freeze);
	COMPARE_SCALAR_FIELD(verbose);
	COMPARE_NODE_FIELD(relation);
	COMPARE_NODE_FIELD(va_cols);

	return true;
}

static bool
_equalExplainStmt(ExplainStmt *a, ExplainStmt *b)
{
	COMPARE_NODE_FIELD(query);
	COMPARE_SCALAR_FIELD(verbose);
	COMPARE_SCALAR_FIELD(analyze);

	return true;
}

static bool
_equalCreateSeqStmt(CreateSeqStmt *a, CreateSeqStmt *b)
{
	COMPARE_NODE_FIELD(sequence);
	COMPARE_NODE_FIELD(options);

	return true;
}

static bool
_equalAlterSeqStmt(AlterSeqStmt *a, AlterSeqStmt *b)
{
	COMPARE_NODE_FIELD(sequence);
	COMPARE_NODE_FIELD(options);

	return true;
}

static bool
_equalVariableSetStmt(VariableSetStmt *a, VariableSetStmt *b)
{
	COMPARE_STRING_FIELD(name);
	COMPARE_NODE_FIELD(args);
	COMPARE_SCALAR_FIELD(is_local);

	return true;
}

static bool
_equalVariableShowStmt(VariableShowStmt *a, VariableShowStmt *b)
{
	COMPARE_STRING_FIELD(name);

	return true;
}

static bool
_equalVariableResetStmt(VariableResetStmt *a, VariableResetStmt *b)
{
	COMPARE_STRING_FIELD(name);

	return true;
}

static bool
_equalCreateTrigStmt(CreateTrigStmt *a, CreateTrigStmt *b)
{
	COMPARE_STRING_FIELD(trigname);
	COMPARE_NODE_FIELD(relation);
	COMPARE_NODE_FIELD(funcname);
	COMPARE_NODE_FIELD(args);
	COMPARE_SCALAR_FIELD(before);
	COMPARE_SCALAR_FIELD(row);
	if (strcmp(a->actions, b->actions) != 0) /* in-line string field */
		return false;
	COMPARE_SCALAR_FIELD(isconstraint);
	COMPARE_SCALAR_FIELD(deferrable);
	COMPARE_SCALAR_FIELD(initdeferred);
	COMPARE_NODE_FIELD(constrrel);

	return true;
}

static bool
_equalDropPropertyStmt(DropPropertyStmt *a, DropPropertyStmt *b)
{
	COMPARE_NODE_FIELD(relation);
	COMPARE_STRING_FIELD(property);
	COMPARE_SCALAR_FIELD(removeType);
	COMPARE_SCALAR_FIELD(behavior);

	return true;
}

static bool
_equalCreatePLangStmt(CreatePLangStmt *a, CreatePLangStmt *b)
{
	COMPARE_STRING_FIELD(plname);
	COMPARE_NODE_FIELD(plhandler);
	COMPARE_NODE_FIELD(plvalidator);
	COMPARE_SCALAR_FIELD(pltrusted);

	return true;
}

static bool
_equalDropPLangStmt(DropPLangStmt *a, DropPLangStmt *b)
{
	COMPARE_STRING_FIELD(plname);
	COMPARE_SCALAR_FIELD(behavior);

	return true;
}

static bool
_equalCreateUserStmt(CreateUserStmt *a, CreateUserStmt *b)
{
	COMPARE_STRING_FIELD(user);
	COMPARE_NODE_FIELD(options);

	return true;
}

static bool
_equalAlterUserStmt(AlterUserStmt *a, AlterUserStmt *b)
{
	COMPARE_STRING_FIELD(user);
	COMPARE_NODE_FIELD(options);

	return true;
}

static bool
_equalAlterUserSetStmt(AlterUserSetStmt *a, AlterUserSetStmt *b)
{
	COMPARE_STRING_FIELD(user);
	COMPARE_STRING_FIELD(variable);
	COMPARE_NODE_FIELD(value);

	return true;
}

static bool
_equalDropUserStmt(DropUserStmt *a, DropUserStmt *b)
{
	COMPARE_NODE_FIELD(users);

	return true;
}

static bool
_equalLockStmt(LockStmt *a, LockStmt *b)
{
	COMPARE_NODE_FIELD(relations);
	COMPARE_SCALAR_FIELD(mode);

	return true;
}

static bool
_equalConstraintsSetStmt(ConstraintsSetStmt *a, ConstraintsSetStmt *b)
{
	COMPARE_NODE_FIELD(constraints);
	COMPARE_SCALAR_FIELD(deferred);

	return true;
}

static bool
_equalCreateGroupStmt(CreateGroupStmt *a, CreateGroupStmt *b)
{
	COMPARE_STRING_FIELD(name);
	COMPARE_NODE_FIELD(options);

	return true;
}

static bool
_equalAlterGroupStmt(AlterGroupStmt *a, AlterGroupStmt *b)
{
	COMPARE_STRING_FIELD(name);
	COMPARE_SCALAR_FIELD(action);
	COMPARE_NODE_FIELD(listUsers);

	return true;
}

static bool
_equalDropGroupStmt(DropGroupStmt *a, DropGroupStmt *b)
{
	COMPARE_STRING_FIELD(name);

	return true;
}

static bool
_equalReindexStmt(ReindexStmt *a, ReindexStmt *b)
{
	COMPARE_SCALAR_FIELD(kind);
	COMPARE_NODE_FIELD(relation);
	COMPARE_STRING_FIELD(name);
	COMPARE_SCALAR_FIELD(force);
	COMPARE_SCALAR_FIELD(all);

	return true;
}

static bool
_equalCreateSchemaStmt(CreateSchemaStmt *a, CreateSchemaStmt *b)
{
	COMPARE_STRING_FIELD(schemaname);
	COMPARE_STRING_FIELD(authid);
	COMPARE_NODE_FIELD(schemaElts);

	return true;
}

static bool
_equalCreateConversionStmt(CreateConversionStmt *a, CreateConversionStmt *b)
{
	COMPARE_NODE_FIELD(conversion_name);
	COMPARE_STRING_FIELD(for_encoding_name);
	COMPARE_STRING_FIELD(to_encoding_name);
	COMPARE_NODE_FIELD(func_name);
	COMPARE_SCALAR_FIELD(def);

	return true;
}

static bool
_equalCreateCastStmt(CreateCastStmt *a, CreateCastStmt *b)
{
	COMPARE_NODE_FIELD(sourcetype);
	COMPARE_NODE_FIELD(targettype);
	COMPARE_NODE_FIELD(func);
	COMPARE_SCALAR_FIELD(context);

	return true;
}

static bool
_equalDropCastStmt(DropCastStmt *a, DropCastStmt *b)
{
	COMPARE_NODE_FIELD(sourcetype);
	COMPARE_NODE_FIELD(targettype);
	COMPARE_SCALAR_FIELD(behavior);

	return true;
}

static bool
_equalPrepareStmt(PrepareStmt *a, PrepareStmt *b)
{
	COMPARE_STRING_FIELD(name);
	COMPARE_NODE_FIELD(argtypes);
	COMPARE_OIDLIST_FIELD(argtype_oids);
	COMPARE_NODE_FIELD(query);

	return true;
}

static bool
_equalExecuteStmt(ExecuteStmt *a, ExecuteStmt *b)
{
	COMPARE_STRING_FIELD(name);
	COMPARE_NODE_FIELD(into);
	COMPARE_NODE_FIELD(params);

	return true;
}

static bool
_equalDeallocateStmt(DeallocateStmt *a, DeallocateStmt *b)
{
	COMPARE_STRING_FIELD(name);

	return true;
}


/*
 * stuff from parsenodes.h
 */

static bool
_equalAExpr(A_Expr *a, A_Expr *b)
{
	COMPARE_SCALAR_FIELD(kind);
	COMPARE_NODE_FIELD(name);
	COMPARE_NODE_FIELD(lexpr);
	COMPARE_NODE_FIELD(rexpr);

	return true;
}

static bool
_equalColumnRef(ColumnRef *a, ColumnRef *b)
{
	COMPARE_NODE_FIELD(fields);
	COMPARE_NODE_FIELD(indirection);

	return true;
}

static bool
_equalParamRef(ParamRef *a, ParamRef *b)
{
	COMPARE_SCALAR_FIELD(number);
	COMPARE_NODE_FIELD(fields);
	COMPARE_NODE_FIELD(indirection);

	return true;
}

static bool
_equalAConst(A_Const *a, A_Const *b)
{
	if (!equal(&a->val, &b->val)) /* hack for in-line Value field */
		return false;
	COMPARE_NODE_FIELD(typename);

	return true;
}

static bool
_equalFuncCall(FuncCall *a, FuncCall *b)
{
	COMPARE_NODE_FIELD(funcname);
	COMPARE_NODE_FIELD(args);
	COMPARE_SCALAR_FIELD(agg_star);
	COMPARE_SCALAR_FIELD(agg_distinct);

	return true;
}

static bool
_equalAIndices(A_Indices *a, A_Indices *b)
{
	COMPARE_NODE_FIELD(lidx);
	COMPARE_NODE_FIELD(uidx);

	return true;
}

static bool
_equalExprFieldSelect(ExprFieldSelect *a, ExprFieldSelect *b)
{
	COMPARE_NODE_FIELD(arg);
	COMPARE_NODE_FIELD(fields);
	COMPARE_NODE_FIELD(indirection);

	return true;
}

static bool
_equalResTarget(ResTarget *a, ResTarget *b)
{
	COMPARE_STRING_FIELD(name);
	COMPARE_NODE_FIELD(indirection);
	COMPARE_NODE_FIELD(val);

	return true;
}

static bool
_equalTypeName(TypeName *a, TypeName *b)
{
	COMPARE_NODE_FIELD(names);
	COMPARE_SCALAR_FIELD(typeid);
	COMPARE_SCALAR_FIELD(timezone);
	COMPARE_SCALAR_FIELD(setof);
	COMPARE_SCALAR_FIELD(pct_type);
	COMPARE_SCALAR_FIELD(typmod);
	COMPARE_NODE_FIELD(arrayBounds);

	return true;
}

static bool
_equalTypeCast(TypeCast *a, TypeCast *b)
{
	COMPARE_NODE_FIELD(arg);
	COMPARE_NODE_FIELD(typename);

	return true;
}

static bool
_equalSortGroupBy(SortGroupBy *a, SortGroupBy *b)
{
	COMPARE_NODE_FIELD(useOp);
	COMPARE_NODE_FIELD(node);

	return true;
}

static bool
_equalRangeSubselect(RangeSubselect *a, RangeSubselect *b)
{
	COMPARE_NODE_FIELD(subquery);
	COMPARE_NODE_FIELD(alias);

	return true;
}

static bool
_equalRangeFunction(RangeFunction *a, RangeFunction *b)
{
	COMPARE_NODE_FIELD(funccallnode);
	COMPARE_NODE_FIELD(alias);
	COMPARE_NODE_FIELD(coldeflist);

	return true;
}

static bool
_equalIndexElem(IndexElem *a, IndexElem *b)
{
	COMPARE_STRING_FIELD(name);
	COMPARE_NODE_FIELD(expr);
	COMPARE_NODE_FIELD(opclass);

	return true;
}

static bool
_equalColumnDef(ColumnDef *a, ColumnDef *b)
{
	COMPARE_STRING_FIELD(colname);
	COMPARE_NODE_FIELD(typename);
	COMPARE_SCALAR_FIELD(inhcount);
	COMPARE_SCALAR_FIELD(is_local);
	COMPARE_SCALAR_FIELD(is_not_null);
	COMPARE_NODE_FIELD(raw_default);
	COMPARE_STRING_FIELD(cooked_default);
	COMPARE_NODE_FIELD(constraints);
	COMPARE_NODE_FIELD(support);

	return true;
}

static bool
_equalConstraint(Constraint *a, Constraint *b)
{
	COMPARE_SCALAR_FIELD(contype);
	COMPARE_STRING_FIELD(name);
	COMPARE_NODE_FIELD(raw_expr);
	COMPARE_STRING_FIELD(cooked_expr);
	COMPARE_NODE_FIELD(keys);

	return true;
}

static bool
_equalDefElem(DefElem *a, DefElem *b)
{
	COMPARE_STRING_FIELD(defname);
	COMPARE_NODE_FIELD(arg);

	return true;
}

static bool
_equalRangeTblEntry(RangeTblEntry *a, RangeTblEntry *b)
{
	COMPARE_SCALAR_FIELD(rtekind);
	COMPARE_SCALAR_FIELD(relid);
	COMPARE_NODE_FIELD(subquery);
	COMPARE_NODE_FIELD(funcexpr);
	COMPARE_NODE_FIELD(coldeflist);
	COMPARE_SCALAR_FIELD(jointype);
	COMPARE_NODE_FIELD(joinaliasvars);
	COMPARE_NODE_FIELD(alias);
	COMPARE_NODE_FIELD(eref);
	COMPARE_SCALAR_FIELD(inh);
	COMPARE_SCALAR_FIELD(inFromCl);
	COMPARE_SCALAR_FIELD(checkForRead);
	COMPARE_SCALAR_FIELD(checkForWrite);
	COMPARE_SCALAR_FIELD(checkAsUser);

	return true;
}

static bool
_equalSortClause(SortClause *a, SortClause *b)
{
	COMPARE_SCALAR_FIELD(tleSortGroupRef);
	COMPARE_SCALAR_FIELD(sortop);

	return true;
}

static bool
_equalFkConstraint(FkConstraint *a, FkConstraint *b)
{
	COMPARE_STRING_FIELD(constr_name);
	COMPARE_NODE_FIELD(pktable);
	COMPARE_NODE_FIELD(fk_attrs);
	COMPARE_NODE_FIELD(pk_attrs);
	COMPARE_SCALAR_FIELD(fk_matchtype);
	COMPARE_SCALAR_FIELD(fk_upd_action);
	COMPARE_SCALAR_FIELD(fk_del_action);
	COMPARE_SCALAR_FIELD(deferrable);
	COMPARE_SCALAR_FIELD(initdeferred);
	COMPARE_SCALAR_FIELD(skip_validation);

	return true;
}


/*
 * Stuff from pg_list.h
 */

static bool
_equalValue(Value *a, Value *b)
{
	COMPARE_SCALAR_FIELD(type);

	switch (a->type)
	{
		case T_Integer:
			COMPARE_SCALAR_FIELD(val.ival);
			break;
		case T_Float:
		case T_String:
		case T_BitString:
			COMPARE_STRING_FIELD(val.str);
			break;
		case T_Null:
			/* nothing to do */
			break;
		default:
			elog(ERROR, "_equalValue: unknown node type %d", a->type);
			break;
	}

	return true;
}

/*
 * equal
 *	  returns whether two nodes are equal
 */
bool
equal(void *a, void *b)
{
	bool		retval = false;

	if (a == b)
		return true;

	/*
	 * note that a!=b, so only one of them can be NULL
	 */
	if (a == NULL || b == NULL)
		return false;

	/*
	 * are they the same type of nodes?
	 */
	if (nodeTag(a) != nodeTag(b))
		return false;

	switch (nodeTag(a))
	{
		/*
		 * PRIMITIVE NODES
		 */
		case T_Resdom:
			retval = _equalResdom(a, b);
			break;
		case T_Alias:
			retval = _equalAlias(a, b);
			break;
		case T_RangeVar:
			retval = _equalRangeVar(a, b);
			break;
		case T_Var:
			retval = _equalVar(a, b);
			break;
		case T_Const:
			retval = _equalConst(a, b);
			break;
		case T_Param:
			retval = _equalParam(a, b);
			break;
		case T_Aggref:
			retval = _equalAggref(a, b);
			break;
		case T_ArrayRef:
			retval = _equalArrayRef(a, b);
			break;
		case T_FuncExpr:
			retval = _equalFuncExpr(a, b);
			break;
		case T_OpExpr:
			retval = _equalOpExpr(a, b);
			break;
		case T_DistinctExpr:
			retval = _equalDistinctExpr(a, b);
			break;
		case T_BoolExpr:
			retval = _equalBoolExpr(a, b);
			break;
		case T_SubLink:
			retval = _equalSubLink(a, b);
			break;
		case T_SubPlan:
			retval = _equalSubPlan(a, b);
			break;
		case T_FieldSelect:
			retval = _equalFieldSelect(a, b);
			break;
		case T_RelabelType:
			retval = _equalRelabelType(a, b);
			break;
		case T_CaseExpr:
			retval = _equalCaseExpr(a, b);
			break;
		case T_CaseWhen:
			retval = _equalCaseWhen(a, b);
			break;
		case T_ArrayExpr:
			retval = _equalArrayExpr(a, b);
			break;
		case T_CoalesceExpr:
			retval = _equalCoalesceExpr(a, b);
			break;
		case T_NullIfExpr:
			retval = _equalNullIfExpr(a, b);
			break;
		case T_NullTest:
			retval = _equalNullTest(a, b);
			break;
		case T_BooleanTest:
			retval = _equalBooleanTest(a, b);
			break;
		case T_CoerceToDomain:
			retval = _equalCoerceToDomain(a, b);
			break;
		case T_CoerceToDomainValue:
			retval = _equalCoerceToDomainValue(a, b);
			break;
		case T_TargetEntry:
			retval = _equalTargetEntry(a, b);
			break;
		case T_RangeTblRef:
			retval = _equalRangeTblRef(a, b);
			break;
		case T_FromExpr:
			retval = _equalFromExpr(a, b);
			break;
		case T_JoinExpr:
			retval = _equalJoinExpr(a, b);
			break;

			/*
			 * RELATION NODES
			 */
		case T_PathKeyItem:
			retval = _equalPathKeyItem(a, b);
			break;
		case T_RestrictInfo:
			retval = _equalRestrictInfo(a, b);
			break;
		case T_JoinInfo:
			retval = _equalJoinInfo(a, b);
			break;
		case T_InClauseInfo:
			retval = _equalInClauseInfo(a, b);
			break;

			/*
			 * LIST NODES
			 */
		case T_List:
			{
				List	   *la = (List *) a;
				List	   *lb = (List *) b;
				List	   *l;

				/*
				 * Try to reject by length check before we grovel through
				 * all the elements...
				 */
				if (length(la) != length(lb))
					return false;
				foreach(l, la)
				{
					if (!equal(lfirst(l), lfirst(lb)))
						return false;
					lb = lnext(lb);
				}
				retval = true;
			}
			break;

		case T_Integer:
		case T_Float:
		case T_String:
		case T_BitString:
		case T_Null:
			retval = _equalValue(a, b);
			break;

			/*
			 * PARSE NODES
			 */
		case T_Query:
			retval = _equalQuery(a, b);
			break;
		case T_InsertStmt:
			retval = _equalInsertStmt(a, b);
			break;
		case T_DeleteStmt:
			retval = _equalDeleteStmt(a, b);
			break;
		case T_UpdateStmt:
			retval = _equalUpdateStmt(a, b);
			break;
		case T_SelectStmt:
			retval = _equalSelectStmt(a, b);
			break;
		case T_SetOperationStmt:
			retval = _equalSetOperationStmt(a, b);
			break;
		case T_AlterTableStmt:
			retval = _equalAlterTableStmt(a, b);
			break;
		case T_AlterDomainStmt:
			retval = _equalAlterDomainStmt(a, b);
			break;
		case T_GrantStmt:
			retval = _equalGrantStmt(a, b);
			break;
		case T_DeclareCursorStmt:
			retval = _equalDeclareCursorStmt(a, b);
			break;
		case T_ClosePortalStmt:
			retval = _equalClosePortalStmt(a, b);
			break;
		case T_ClusterStmt:
			retval = _equalClusterStmt(a, b);
			break;
		case T_CopyStmt:
			retval = _equalCopyStmt(a, b);
			break;
		case T_CreateStmt:
			retval = _equalCreateStmt(a, b);
			break;
		case T_DefineStmt:
			retval = _equalDefineStmt(a, b);
			break;
		case T_DropStmt:
			retval = _equalDropStmt(a, b);
			break;
		case T_TruncateStmt:
			retval = _equalTruncateStmt(a, b);
			break;
		case T_CommentStmt:
			retval = _equalCommentStmt(a, b);
			break;
		case T_FetchStmt:
			retval = _equalFetchStmt(a, b);
			break;
		case T_IndexStmt:
			retval = _equalIndexStmt(a, b);
			break;
		case T_CreateFunctionStmt:
			retval = _equalCreateFunctionStmt(a, b);
			break;
		case T_RemoveAggrStmt:
			retval = _equalRemoveAggrStmt(a, b);
			break;
		case T_RemoveFuncStmt:
			retval = _equalRemoveFuncStmt(a, b);
			break;
		case T_RemoveOperStmt:
			retval = _equalRemoveOperStmt(a, b);
			break;
		case T_RemoveOpClassStmt:
			retval = _equalRemoveOpClassStmt(a, b);
			break;
		case T_RenameStmt:
			retval = _equalRenameStmt(a, b);
			break;
		case T_RuleStmt:
			retval = _equalRuleStmt(a, b);
			break;
		case T_NotifyStmt:
			retval = _equalNotifyStmt(a, b);
			break;
		case T_ListenStmt:
			retval = _equalListenStmt(a, b);
			break;
		case T_UnlistenStmt:
			retval = _equalUnlistenStmt(a, b);
			break;
		case T_TransactionStmt:
			retval = _equalTransactionStmt(a, b);
			break;
		case T_CompositeTypeStmt:
			retval = _equalCompositeTypeStmt(a, b);
			break;
		case T_ViewStmt:
			retval = _equalViewStmt(a, b);
			break;
		case T_LoadStmt:
			retval = _equalLoadStmt(a, b);
			break;
		case T_CreateDomainStmt:
			retval = _equalCreateDomainStmt(a, b);
			break;
		case T_CreateOpClassStmt:
			retval = _equalCreateOpClassStmt(a, b);
			break;
		case T_CreateOpClassItem:
			retval = _equalCreateOpClassItem(a, b);
			break;
		case T_CreatedbStmt:
			retval = _equalCreatedbStmt(a, b);
			break;
		case T_AlterDatabaseSetStmt:
			retval = _equalAlterDatabaseSetStmt(a, b);
			break;
		case T_DropdbStmt:
			retval = _equalDropdbStmt(a, b);
			break;
		case T_VacuumStmt:
			retval = _equalVacuumStmt(a, b);
			break;
		case T_ExplainStmt:
			retval = _equalExplainStmt(a, b);
			break;
		case T_CreateSeqStmt:
			retval = _equalCreateSeqStmt(a, b);
			break;
		case T_AlterSeqStmt:
			retval = _equalAlterSeqStmt(a, b);
			break;
		case T_VariableSetStmt:
			retval = _equalVariableSetStmt(a, b);
			break;
		case T_VariableShowStmt:
			retval = _equalVariableShowStmt(a, b);
			break;
		case T_VariableResetStmt:
			retval = _equalVariableResetStmt(a, b);
			break;
		case T_CreateTrigStmt:
			retval = _equalCreateTrigStmt(a, b);
			break;
		case T_DropPropertyStmt:
			retval = _equalDropPropertyStmt(a, b);
			break;
		case T_CreatePLangStmt:
			retval = _equalCreatePLangStmt(a, b);
			break;
		case T_DropPLangStmt:
			retval = _equalDropPLangStmt(a, b);
			break;
		case T_CreateUserStmt:
			retval = _equalCreateUserStmt(a, b);
			break;
		case T_AlterUserStmt:
			retval = _equalAlterUserStmt(a, b);
			break;
		case T_AlterUserSetStmt:
			retval = _equalAlterUserSetStmt(a, b);
			break;
		case T_DropUserStmt:
			retval = _equalDropUserStmt(a, b);
			break;
		case T_LockStmt:
			retval = _equalLockStmt(a, b);
			break;
		case T_ConstraintsSetStmt:
			retval = _equalConstraintsSetStmt(a, b);
			break;
		case T_CreateGroupStmt:
			retval = _equalCreateGroupStmt(a, b);
			break;
		case T_AlterGroupStmt:
			retval = _equalAlterGroupStmt(a, b);
			break;
		case T_DropGroupStmt:
			retval = _equalDropGroupStmt(a, b);
			break;
		case T_ReindexStmt:
			retval = _equalReindexStmt(a, b);
			break;
		case T_CheckPointStmt:
			retval = true;
			break;
		case T_CreateSchemaStmt:
			retval = _equalCreateSchemaStmt(a, b);
			break;
		case T_CreateConversionStmt:
			retval = _equalCreateConversionStmt(a, b);
			break;
		case T_CreateCastStmt:
			retval = _equalCreateCastStmt(a, b);
			break;
		case T_DropCastStmt:
			retval = _equalDropCastStmt(a, b);
			break;
		case T_PrepareStmt:
			retval = _equalPrepareStmt(a, b);
			break;
		case T_ExecuteStmt:
			retval = _equalExecuteStmt(a, b);
			break;
		case T_DeallocateStmt:
			retval = _equalDeallocateStmt(a, b);
			break;

		case T_A_Expr:
			retval = _equalAExpr(a, b);
			break;
		case T_ColumnRef:
			retval = _equalColumnRef(a, b);
			break;
		case T_ParamRef:
			retval = _equalParamRef(a, b);
			break;
		case T_A_Const:
			retval = _equalAConst(a, b);
			break;
		case T_FuncCall:
			retval = _equalFuncCall(a, b);
			break;
		case T_A_Indices:
			retval = _equalAIndices(a, b);
			break;
		case T_ExprFieldSelect:
			retval = _equalExprFieldSelect(a, b);
			break;
		case T_ResTarget:
			retval = _equalResTarget(a, b);
			break;
		case T_TypeCast:
			retval = _equalTypeCast(a, b);
			break;
		case T_SortGroupBy:
			retval = _equalSortGroupBy(a, b);
			break;
		case T_RangeSubselect:
			retval = _equalRangeSubselect(a, b);
			break;
		case T_RangeFunction:
			retval = _equalRangeFunction(a, b);
			break;
		case T_TypeName:
			retval = _equalTypeName(a, b);
			break;
		case T_IndexElem:
			retval = _equalIndexElem(a, b);
			break;
		case T_ColumnDef:
			retval = _equalColumnDef(a, b);
			break;
		case T_Constraint:
			retval = _equalConstraint(a, b);
			break;
		case T_DefElem:
			retval = _equalDefElem(a, b);
			break;
		case T_RangeTblEntry:
			retval = _equalRangeTblEntry(a, b);
			break;
		case T_SortClause:
			retval = _equalSortClause(a, b);
			break;
		case T_GroupClause:
			/* GroupClause is equivalent to SortClause */
			retval = _equalSortClause(a, b);
			break;
		case T_FkConstraint:
			retval = _equalFkConstraint(a, b);
			break;
		case T_PrivGrantee:
			retval = _equalPrivGrantee(a, b);
			break;
		case T_FuncWithArgs:
			retval = _equalFuncWithArgs(a, b);
			break;
		case T_InsertDefault:
			retval = _equalInsertDefault(a, b);
			break;

		default:
			elog(WARNING, "equal: don't know whether nodes of type %d are equal",
				 nodeTag(a));
			break;
	}

	return retval;
}
