/*-------------------------------------------------------------------------
 *
 * readfuncs.c
 *	  Reader functions for Postgres tree nodes.
 *
 * Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 *
 * IDENTIFICATION
 *	  $PostgreSQL: pgsql/src/backend/nodes/readfuncs.c,v 1.182 2005/10/15 02:49:19 momjian Exp $
 *
 * NOTES
 *	  Path and Plan nodes do not have any readfuncs support, because we
 *	  never have occasion to read them in.	(There was once code here that
 *	  claimed to read them, but it was broken as well as unused.)  We
 *	  never read executor state trees, either.
 *
 *-------------------------------------------------------------------------
 */
#include "postgres.h"

#include <math.h>

#include "nodes/parsenodes.h"
#include "nodes/readfuncs.h"


/*
 * Macros to simplify reading of different kinds of fields.  Use these
 * wherever possible to reduce the chance for silly typos.	Note that these
 * hard-wire conventions about the names of the local variables in a Read
 * routine.
 */

/* Macros for declaring appropriate local variables */

/* A few guys need only local_node */
#define READ_LOCALS_NO_FIELDS(nodeTypeName) \
	nodeTypeName *local_node = makeNode(nodeTypeName)

/* And a few guys need only the pg_strtok support fields */
#define READ_TEMP_LOCALS()	\
	char	   *token;		\
	int			length

/* ... but most need both */
#define READ_LOCALS(nodeTypeName)			\
	READ_LOCALS_NO_FIELDS(nodeTypeName);	\
	READ_TEMP_LOCALS()

/* Read an integer field (anything written as ":fldname %d") */
#define READ_INT_FIELD(fldname) \
	token = pg_strtok(&length);		/* skip :fldname */ \
	token = pg_strtok(&length);		/* get field value */ \
	local_node->fldname = atoi(token)

/* Read an unsigned integer field (anything written as ":fldname %u") */
#define READ_UINT_FIELD(fldname) \
	token = pg_strtok(&length);		/* skip :fldname */ \
	token = pg_strtok(&length);		/* get field value */ \
	local_node->fldname = atoui(token)

/* Read an OID field (don't hard-wire assumption that OID is same as uint) */
#define READ_OID_FIELD(fldname) \
	token = pg_strtok(&length);		/* skip :fldname */ \
	token = pg_strtok(&length);		/* get field value */ \
	local_node->fldname = atooid(token)

/* Read a char field (ie, one ascii character) */
#define READ_CHAR_FIELD(fldname) \
	token = pg_strtok(&length);		/* skip :fldname */ \
	token = pg_strtok(&length);		/* get field value */ \
	local_node->fldname = token[0]

/* Read an enumerated-type field that was written as an integer code */
#define READ_ENUM_FIELD(fldname, enumtype) \
	token = pg_strtok(&length);		/* skip :fldname */ \
	token = pg_strtok(&length);		/* get field value */ \
	local_node->fldname = (enumtype) atoi(token)

/* Read a float field */
#define READ_FLOAT_FIELD(fldname) \
	token = pg_strtok(&length);		/* skip :fldname */ \
	token = pg_strtok(&length);		/* get field value */ \
	local_node->fldname = atof(token)

/* Read a boolean field */
#define READ_BOOL_FIELD(fldname) \
	token = pg_strtok(&length);		/* skip :fldname */ \
	token = pg_strtok(&length);		/* get field value */ \
	local_node->fldname = strtobool(token)

/* Read a character-string field */
#define READ_STRING_FIELD(fldname) \
	token = pg_strtok(&length);		/* skip :fldname */ \
	token = pg_strtok(&length);		/* get field value */ \
	local_node->fldname = nullable_string(token, length)

/* Read a Node field */
#define READ_NODE_FIELD(fldname) \
	token = pg_strtok(&length);		/* skip :fldname */ \
	local_node->fldname = nodeRead(NULL, 0)

/* Routine exit */
#define READ_DONE() \
	return local_node


/*
 * NOTE: use atoi() to read values written with %d, or atoui() to read
 * values written with %u in outfuncs.c.  An exception is OID values,
 * for which use atooid().	(As of 7.1, outfuncs.c writes OIDs as %u,
 * but this will probably change in the future.)
 */
#define atoui(x)  ((unsigned int) strtoul((x), NULL, 10))

#define atooid(x)  ((Oid) strtoul((x), NULL, 10))

#define strtobool(x)  ((*(x) == 't') ? true : false)

#define nullable_string(token,length)  \
	((length) == 0 ? NULL : debackslash(token, length))


static Datum readDatum(bool typbyval);


/*
 * _readQuery
 */
static Query *
_readQuery(void)
{
	READ_LOCALS(Query);

	READ_ENUM_FIELD(commandType, CmdType);
	READ_ENUM_FIELD(querySource, QuerySource);
	READ_BOOL_FIELD(canSetTag);
	READ_NODE_FIELD(utilityStmt);
	READ_INT_FIELD(resultRelation);
	READ_NODE_FIELD(into);
	READ_BOOL_FIELD(hasAggs);
	READ_BOOL_FIELD(hasSubLinks);
	READ_NODE_FIELD(rtable);
	READ_NODE_FIELD(jointree);
	READ_NODE_FIELD(rowMarks);
	READ_BOOL_FIELD(forUpdate);
	READ_BOOL_FIELD(rowNoWait);
	READ_NODE_FIELD(targetList);
	READ_NODE_FIELD(groupClause);
	READ_NODE_FIELD(havingQual);
	READ_NODE_FIELD(distinctClause);
	READ_NODE_FIELD(sortClause);
	READ_NODE_FIELD(limitOffset);
	READ_NODE_FIELD(limitCount);
	READ_NODE_FIELD(setOperations);
	READ_NODE_FIELD(resultRelations);

	READ_DONE();
}

/*
 * _readNotifyStmt
 */
static NotifyStmt *
_readNotifyStmt(void)
{
	READ_LOCALS(NotifyStmt);

	READ_NODE_FIELD(relation);

	READ_DONE();
}

/*
 * _readDeclareCursorStmt
 */
static DeclareCursorStmt *
_readDeclareCursorStmt(void)
{
	READ_LOCALS(DeclareCursorStmt);

	READ_STRING_FIELD(portalname);
	READ_INT_FIELD(options);
	READ_NODE_FIELD(query);

	READ_DONE();
}

/*
 * _readSortClause
 */
static SortClause *
_readSortClause(void)
{
	READ_LOCALS(SortClause);

	READ_UINT_FIELD(tleSortGroupRef);
	READ_OID_FIELD(sortop);

	READ_DONE();
}

/*
 * _readGroupClause
 */
static GroupClause *
_readGroupClause(void)
{
	READ_LOCALS(GroupClause);

	READ_UINT_FIELD(tleSortGroupRef);
	READ_OID_FIELD(sortop);

	READ_DONE();
}

/*
 * _readSetOperationStmt
 */
static SetOperationStmt *
_readSetOperationStmt(void)
{
	READ_LOCALS(SetOperationStmt);

	READ_ENUM_FIELD(op, SetOperation);
	READ_BOOL_FIELD(all);
	READ_NODE_FIELD(larg);
	READ_NODE_FIELD(rarg);
	READ_NODE_FIELD(colTypes);

	READ_DONE();
}


/*
 *	Stuff from primnodes.h.
 */

static Alias *
_readAlias(void)
{
	READ_LOCALS(Alias);

	READ_STRING_FIELD(aliasname);
	READ_NODE_FIELD(colnames);

	READ_DONE();
}

static RangeVar *
_readRangeVar(void)
{
	READ_LOCALS(RangeVar);

	local_node->catalogname = NULL;		/* not currently saved in output
										 * format */

	READ_STRING_FIELD(schemaname);
	READ_STRING_FIELD(relname);
	READ_ENUM_FIELD(inhOpt, InhOption);
	READ_BOOL_FIELD(istemp);
	READ_NODE_FIELD(alias);

	READ_DONE();
}

/*
 * _readVar
 */
static Var *
_readVar(void)
{
	READ_LOCALS(Var);

	READ_UINT_FIELD(varno);
	READ_INT_FIELD(varattno);
	READ_OID_FIELD(vartype);
	READ_INT_FIELD(vartypmod);
	READ_UINT_FIELD(varlevelsup);
	READ_UINT_FIELD(varnoold);
	READ_INT_FIELD(varoattno);

	READ_DONE();
}

/*
 * _readConst
 */
static Const *
_readConst(void)
{
	READ_LOCALS(Const);

	READ_OID_FIELD(consttype);
	READ_INT_FIELD(constlen);
	READ_BOOL_FIELD(constbyval);
	READ_BOOL_FIELD(constisnull);

	token = pg_strtok(&length); /* skip :constvalue */
	if (local_node->constisnull)
		token = pg_strtok(&length);		/* skip "<>" */
	else
		local_node->constvalue = readDatum(local_node->constbyval);

	READ_DONE();
}

/*
 * _readParam
 */
static Param *
_readParam(void)
{
	READ_LOCALS(Param);

	READ_INT_FIELD(paramkind);
	READ_INT_FIELD(paramid);
	READ_STRING_FIELD(paramname);
	READ_OID_FIELD(paramtype);

	READ_DONE();
}

/*
 * _readAggref
 */
static Aggref *
_readAggref(void)
{
	READ_LOCALS(Aggref);

	READ_OID_FIELD(aggfnoid);
	READ_OID_FIELD(aggtype);
	READ_NODE_FIELD(target);
	READ_UINT_FIELD(agglevelsup);
	READ_BOOL_FIELD(aggstar);
	READ_BOOL_FIELD(aggdistinct);

	READ_DONE();
}

/*
 * _readArrayRef
 */
static ArrayRef *
_readArrayRef(void)
{
	READ_LOCALS(ArrayRef);

	READ_OID_FIELD(refrestype);
	READ_OID_FIELD(refarraytype);
	READ_OID_FIELD(refelemtype);
	READ_NODE_FIELD(refupperindexpr);
	READ_NODE_FIELD(reflowerindexpr);
	READ_NODE_FIELD(refexpr);
	READ_NODE_FIELD(refassgnexpr);

	READ_DONE();
}

/*
 * _readFuncExpr
 */
static FuncExpr *
_readFuncExpr(void)
{
	READ_LOCALS(FuncExpr);

	READ_OID_FIELD(funcid);
	READ_OID_FIELD(funcresulttype);
	READ_BOOL_FIELD(funcretset);
	READ_ENUM_FIELD(funcformat, CoercionForm);
	READ_NODE_FIELD(args);

	READ_DONE();
}

/*
 * _readOpExpr
 */
static OpExpr *
_readOpExpr(void)
{
	READ_LOCALS(OpExpr);

	READ_OID_FIELD(opno);
	READ_OID_FIELD(opfuncid);

	/*
	 * The opfuncid is stored in the textual format primarily for debugging
	 * and documentation reasons.  We want to always read it as zero to force
	 * it to be re-looked-up in the pg_operator entry.	This ensures that
	 * stored rules don't have hidden dependencies on operators' functions.
	 * (We don't currently support an ALTER OPERATOR command, but might
	 * someday.)
	 */
	local_node->opfuncid = InvalidOid;

	READ_OID_FIELD(opresulttype);
	READ_BOOL_FIELD(opretset);
	READ_NODE_FIELD(args);

	READ_DONE();
}

/*
 * _readDistinctExpr
 */
static DistinctExpr *
_readDistinctExpr(void)
{
	READ_LOCALS(DistinctExpr);

	READ_OID_FIELD(opno);
	READ_OID_FIELD(opfuncid);

	/*
	 * The opfuncid is stored in the textual format primarily for debugging
	 * and documentation reasons.  We want to always read it as zero to force
	 * it to be re-looked-up in the pg_operator entry.	This ensures that
	 * stored rules don't have hidden dependencies on operators' functions.
	 * (We don't currently support an ALTER OPERATOR command, but might
	 * someday.)
	 */
	local_node->opfuncid = InvalidOid;

	READ_OID_FIELD(opresulttype);
	READ_BOOL_FIELD(opretset);
	READ_NODE_FIELD(args);

	READ_DONE();
}

/*
 * _readScalarArrayOpExpr
 */
static ScalarArrayOpExpr *
_readScalarArrayOpExpr(void)
{
	READ_LOCALS(ScalarArrayOpExpr);

	READ_OID_FIELD(opno);
	READ_OID_FIELD(opfuncid);

	/*
	 * The opfuncid is stored in the textual format primarily for debugging
	 * and documentation reasons.  We want to always read it as zero to force
	 * it to be re-looked-up in the pg_operator entry.	This ensures that
	 * stored rules don't have hidden dependencies on operators' functions.
	 * (We don't currently support an ALTER OPERATOR command, but might
	 * someday.)
	 */
	local_node->opfuncid = InvalidOid;

	READ_BOOL_FIELD(useOr);
	READ_NODE_FIELD(args);

	READ_DONE();
}

/*
 * _readBoolExpr
 */
static BoolExpr *
_readBoolExpr(void)
{
	READ_LOCALS(BoolExpr);

	/* do-it-yourself enum representation */
	token = pg_strtok(&length); /* skip :boolop */
	token = pg_strtok(&length); /* get field value */
	if (strncmp(token, "and", 3) == 0)
		local_node->boolop = AND_EXPR;
	else if (strncmp(token, "or", 2) == 0)
		local_node->boolop = OR_EXPR;
	else if (strncmp(token, "not", 3) == 0)
		local_node->boolop = NOT_EXPR;
	else
		elog(ERROR, "unrecognized boolop \"%.*s\"", length, token);

	READ_NODE_FIELD(args);

	READ_DONE();
}

/*
 * _readSubLink
 */
static SubLink *
_readSubLink(void)
{
	READ_LOCALS(SubLink);

	READ_ENUM_FIELD(subLinkType, SubLinkType);
	READ_BOOL_FIELD(useOr);
	READ_NODE_FIELD(lefthand);
	READ_NODE_FIELD(operName);
	READ_NODE_FIELD(operOids);
	READ_NODE_FIELD(subselect);

	READ_DONE();
}

/*
 * _readSubPlan is not needed since it doesn't appear in stored rules.
 */

/*
 * _readFieldSelect
 */
static FieldSelect *
_readFieldSelect(void)
{
	READ_LOCALS(FieldSelect);

	READ_NODE_FIELD(arg);
	READ_INT_FIELD(fieldnum);
	READ_OID_FIELD(resulttype);
	READ_INT_FIELD(resulttypmod);

	READ_DONE();
}

/*
 * _readFieldStore
 */
static FieldStore *
_readFieldStore(void)
{
	READ_LOCALS(FieldStore);

	READ_NODE_FIELD(arg);
	READ_NODE_FIELD(newvals);
	READ_NODE_FIELD(fieldnums);
	READ_OID_FIELD(resulttype);

	READ_DONE();
}

/*
 * _readRelabelType
 */
static RelabelType *
_readRelabelType(void)
{
	READ_LOCALS(RelabelType);

	READ_NODE_FIELD(arg);
	READ_OID_FIELD(resulttype);
	READ_INT_FIELD(resulttypmod);
	READ_ENUM_FIELD(relabelformat, CoercionForm);

	READ_DONE();
}

/*
 * _readConvertRowtypeExpr
 */
static ConvertRowtypeExpr *
_readConvertRowtypeExpr(void)
{
	READ_LOCALS(ConvertRowtypeExpr);

	READ_NODE_FIELD(arg);
	READ_OID_FIELD(resulttype);
	READ_ENUM_FIELD(convertformat, CoercionForm);

	READ_DONE();
}

/*
 * _readCaseExpr
 */
static CaseExpr *
_readCaseExpr(void)
{
	READ_LOCALS(CaseExpr);

	READ_OID_FIELD(casetype);
	READ_NODE_FIELD(arg);
	READ_NODE_FIELD(args);
	READ_NODE_FIELD(defresult);

	READ_DONE();
}

/*
 * _readCaseWhen
 */
static CaseWhen *
_readCaseWhen(void)
{
	READ_LOCALS(CaseWhen);

	READ_NODE_FIELD(expr);
	READ_NODE_FIELD(result);

	READ_DONE();
}

/*
 * _readCaseTestExpr
 */
static CaseTestExpr *
_readCaseTestExpr(void)
{
	READ_LOCALS(CaseTestExpr);

	READ_OID_FIELD(typeId);
	READ_INT_FIELD(typeMod);

	READ_DONE();
}

/*
 * _readArrayExpr
 */
static ArrayExpr *
_readArrayExpr(void)
{
	READ_LOCALS(ArrayExpr);

	READ_OID_FIELD(array_typeid);
	READ_OID_FIELD(element_typeid);
	READ_NODE_FIELD(elements);
	READ_BOOL_FIELD(multidims);

	READ_DONE();
}

/*
 * _readRowExpr
 */
static RowExpr *
_readRowExpr(void)
{
	READ_LOCALS(RowExpr);

	READ_NODE_FIELD(args);
	READ_OID_FIELD(row_typeid);
	READ_ENUM_FIELD(row_format, CoercionForm);

	READ_DONE();
}

/*
 * _readCoalesceExpr
 */
static CoalesceExpr *
_readCoalesceExpr(void)
{
	READ_LOCALS(CoalesceExpr);

	READ_OID_FIELD(coalescetype);
	READ_NODE_FIELD(args);

	READ_DONE();
}

/*
 * _readMinMaxExpr
 */
static MinMaxExpr *
_readMinMaxExpr(void)
{
	READ_LOCALS(MinMaxExpr);

	READ_OID_FIELD(minmaxtype);
	READ_ENUM_FIELD(op, MinMaxOp);
	READ_NODE_FIELD(args);

	READ_DONE();
}

/*
 * _readNullIfExpr
 */
static NullIfExpr *
_readNullIfExpr(void)
{
	READ_LOCALS(NullIfExpr);

	READ_OID_FIELD(opno);
	READ_OID_FIELD(opfuncid);

	/*
	 * The opfuncid is stored in the textual format primarily for debugging
	 * and documentation reasons.  We want to always read it as zero to force
	 * it to be re-looked-up in the pg_operator entry.	This ensures that
	 * stored rules don't have hidden dependencies on operators' functions.
	 * (We don't currently support an ALTER OPERATOR command, but might
	 * someday.)
	 */
	local_node->opfuncid = InvalidOid;

	READ_OID_FIELD(opresulttype);
	READ_BOOL_FIELD(opretset);
	READ_NODE_FIELD(args);

	READ_DONE();
}

/*
 * _readNullTest
 */
static NullTest *
_readNullTest(void)
{
	READ_LOCALS(NullTest);

	READ_NODE_FIELD(arg);
	READ_ENUM_FIELD(nulltesttype, NullTestType);

	READ_DONE();
}

/*
 * _readBooleanTest
 */
static BooleanTest *
_readBooleanTest(void)
{
	READ_LOCALS(BooleanTest);

	READ_NODE_FIELD(arg);
	READ_ENUM_FIELD(booltesttype, BoolTestType);

	READ_DONE();
}

/*
 * _readCoerceToDomain
 */
static CoerceToDomain *
_readCoerceToDomain(void)
{
	READ_LOCALS(CoerceToDomain);

	READ_NODE_FIELD(arg);
	READ_OID_FIELD(resulttype);
	READ_INT_FIELD(resulttypmod);
	READ_ENUM_FIELD(coercionformat, CoercionForm);

	READ_DONE();
}

/*
 * _readCoerceToDomainValue
 */
static CoerceToDomainValue *
_readCoerceToDomainValue(void)
{
	READ_LOCALS(CoerceToDomainValue);

	READ_OID_FIELD(typeId);
	READ_INT_FIELD(typeMod);

	READ_DONE();
}

/*
 * _readSetToDefault
 */
static SetToDefault *
_readSetToDefault(void)
{
	READ_LOCALS(SetToDefault);

	READ_OID_FIELD(typeId);
	READ_INT_FIELD(typeMod);

	READ_DONE();
}

/*
 * _readTargetEntry
 */
static TargetEntry *
_readTargetEntry(void)
{
	READ_LOCALS(TargetEntry);

	READ_NODE_FIELD(expr);
	READ_INT_FIELD(resno);
	READ_STRING_FIELD(resname);
	READ_UINT_FIELD(ressortgroupref);
	READ_OID_FIELD(resorigtbl);
	READ_INT_FIELD(resorigcol);
	READ_BOOL_FIELD(resjunk);

	READ_DONE();
}

/*
 * _readRangeTblRef
 */
static RangeTblRef *
_readRangeTblRef(void)
{
	READ_LOCALS(RangeTblRef);

	READ_INT_FIELD(rtindex);

	READ_DONE();
}

/*
 * _readJoinExpr
 */
static JoinExpr *
_readJoinExpr(void)
{
	READ_LOCALS(JoinExpr);

	READ_ENUM_FIELD(jointype, JoinType);
	READ_BOOL_FIELD(isNatural);
	READ_NODE_FIELD(larg);
	READ_NODE_FIELD(rarg);
	READ_NODE_FIELD(using);
	READ_NODE_FIELD(quals);
	READ_NODE_FIELD(alias);
	READ_INT_FIELD(rtindex);

	READ_DONE();
}

/*
 * _readFromExpr
 */
static FromExpr *
_readFromExpr(void)
{
	READ_LOCALS(FromExpr);

	READ_NODE_FIELD(fromlist);
	READ_NODE_FIELD(quals);

	READ_DONE();
}


/*
 *	Stuff from parsenodes.h.
 */

static ColumnDef *
_readColumnDef(void)
{
	READ_LOCALS(ColumnDef);

	READ_STRING_FIELD(colname);
	READ_NODE_FIELD(typename);
	READ_INT_FIELD(inhcount);
	READ_BOOL_FIELD(is_local);
	READ_BOOL_FIELD(is_not_null);
	READ_NODE_FIELD(raw_default);
	READ_STRING_FIELD(cooked_default);
	READ_NODE_FIELD(constraints);
	READ_NODE_FIELD(support);

	READ_DONE();
}

static TypeName *
_readTypeName(void)
{
	READ_LOCALS(TypeName);

	READ_NODE_FIELD(names);
	READ_OID_FIELD(typeid);
	READ_BOOL_FIELD(timezone);
	READ_BOOL_FIELD(setof);
	READ_BOOL_FIELD(pct_type);
	READ_INT_FIELD(typmod);
	READ_NODE_FIELD(arrayBounds);

	READ_DONE();
}

/*
 * _readRangeTblEntry
 */
static RangeTblEntry *
_readRangeTblEntry(void)
{
	READ_LOCALS(RangeTblEntry);

	/* put alias + eref first to make dump more legible */
	READ_NODE_FIELD(alias);
	READ_NODE_FIELD(eref);
	READ_ENUM_FIELD(rtekind, RTEKind);

	switch (local_node->rtekind)
	{
		case RTE_RELATION:
		case RTE_SPECIAL:
			READ_OID_FIELD(relid);
			break;
		case RTE_SUBQUERY:
			READ_NODE_FIELD(subquery);
			break;
		case RTE_FUNCTION:
			READ_NODE_FIELD(funcexpr);
			READ_NODE_FIELD(coldeflist);
			break;
		case RTE_JOIN:
			READ_ENUM_FIELD(jointype, JoinType);
			READ_NODE_FIELD(joinaliasvars);
			break;
		default:
			elog(ERROR, "unrecognized RTE kind: %d",
				 (int) local_node->rtekind);
			break;
	}

	READ_BOOL_FIELD(inh);
	READ_BOOL_FIELD(inFromCl);
	READ_UINT_FIELD(requiredPerms);
	READ_OID_FIELD(checkAsUser);

	READ_DONE();
}


/*
 * parseNodeString
 *
 * Given a character string representing a node tree, parseNodeString creates
 * the internal node structure.
 *
 * The string to be read must already have been loaded into pg_strtok().
 */
Node *
parseNodeString(void)
{
	void	   *return_value;

	READ_TEMP_LOCALS();

	token = pg_strtok(&length);

#define MATCH(tokname, namelen) \
	(length == namelen && strncmp(token, tokname, namelen) == 0)

	if (MATCH("QUERY", 5))
		return_value = _readQuery();
	else if (MATCH("SORTCLAUSE", 10))
		return_value = _readSortClause();
	else if (MATCH("GROUPCLAUSE", 11))
		return_value = _readGroupClause();
	else if (MATCH("SETOPERATIONSTMT", 16))
		return_value = _readSetOperationStmt();
	else if (MATCH("ALIAS", 5))
		return_value = _readAlias();
	else if (MATCH("RANGEVAR", 8))
		return_value = _readRangeVar();
	else if (MATCH("VAR", 3))
		return_value = _readVar();
	else if (MATCH("CONST", 5))
		return_value = _readConst();
	else if (MATCH("PARAM", 5))
		return_value = _readParam();
	else if (MATCH("AGGREF", 6))
		return_value = _readAggref();
	else if (MATCH("ARRAYREF", 8))
		return_value = _readArrayRef();
	else if (MATCH("FUNCEXPR", 8))
		return_value = _readFuncExpr();
	else if (MATCH("OPEXPR", 6))
		return_value = _readOpExpr();
	else if (MATCH("DISTINCTEXPR", 12))
		return_value = _readDistinctExpr();
	else if (MATCH("SCALARARRAYOPEXPR", 17))
		return_value = _readScalarArrayOpExpr();
	else if (MATCH("BOOLEXPR", 8))
		return_value = _readBoolExpr();
	else if (MATCH("SUBLINK", 7))
		return_value = _readSubLink();
	else if (MATCH("FIELDSELECT", 11))
		return_value = _readFieldSelect();
	else if (MATCH("FIELDSTORE", 10))
		return_value = _readFieldStore();
	else if (MATCH("RELABELTYPE", 11))
		return_value = _readRelabelType();
	else if (MATCH("CONVERTROWTYPEEXPR", 18))
		return_value = _readConvertRowtypeExpr();
	else if (MATCH("CASE", 4))
		return_value = _readCaseExpr();
	else if (MATCH("WHEN", 4))
		return_value = _readCaseWhen();
	else if (MATCH("CASETESTEXPR", 12))
		return_value = _readCaseTestExpr();
	else if (MATCH("ARRAY", 5))
		return_value = _readArrayExpr();
	else if (MATCH("ROW", 3))
		return_value = _readRowExpr();
	else if (MATCH("COALESCE", 8))
		return_value = _readCoalesceExpr();
	else if (MATCH("MINMAX", 6))
		return_value = _readMinMaxExpr();
	else if (MATCH("NULLIFEXPR", 10))
		return_value = _readNullIfExpr();
	else if (MATCH("NULLTEST", 8))
		return_value = _readNullTest();
	else if (MATCH("BOOLEANTEST", 11))
		return_value = _readBooleanTest();
	else if (MATCH("COERCETODOMAIN", 14))
		return_value = _readCoerceToDomain();
	else if (MATCH("COERCETODOMAINVALUE", 19))
		return_value = _readCoerceToDomainValue();
	else if (MATCH("SETTODEFAULT", 12))
		return_value = _readSetToDefault();
	else if (MATCH("TARGETENTRY", 11))
		return_value = _readTargetEntry();
	else if (MATCH("RANGETBLREF", 11))
		return_value = _readRangeTblRef();
	else if (MATCH("JOINEXPR", 8))
		return_value = _readJoinExpr();
	else if (MATCH("FROMEXPR", 8))
		return_value = _readFromExpr();
	else if (MATCH("COLUMNDEF", 9))
		return_value = _readColumnDef();
	else if (MATCH("TYPENAME", 8))
		return_value = _readTypeName();
	else if (MATCH("RTE", 3))
		return_value = _readRangeTblEntry();
	else if (MATCH("NOTIFY", 6))
		return_value = _readNotifyStmt();
	else if (MATCH("DECLARECURSOR", 13))
		return_value = _readDeclareCursorStmt();
	else
	{
		elog(ERROR, "badly formatted node string \"%.32s\"...", token);
		return_value = NULL;	/* keep compiler quiet */
	}

	return (Node *) return_value;
}


/*
 * readDatum
 *
 * Given a string representation of a constant, recreate the appropriate
 * Datum.  The string representation embeds length info, but not byValue,
 * so we must be told that.
 */
static Datum
readDatum(bool typbyval)
{
	Size		length,
				i;
	int			tokenLength;
	char	   *token;
	Datum		res;
	char	   *s;

	/*
	 * read the actual length of the value
	 */
	token = pg_strtok(&tokenLength);
	length = atoui(token);

	token = pg_strtok(&tokenLength);	/* read the '[' */
	if (token == NULL || token[0] != '[')
		elog(ERROR, "expected \"[\" to start datum, but got \"%s\"; length = %lu",
			 token ? (const char *) token : "[NULL]",
			 (unsigned long) length);

	if (typbyval)
	{
		if (length > (Size) sizeof(Datum))
			elog(ERROR, "byval datum but length = %lu",
				 (unsigned long) length);
		res = (Datum) 0;
		s = (char *) (&res);
		for (i = 0; i < (Size) sizeof(Datum); i++)
		{
			token = pg_strtok(&tokenLength);
			s[i] = (char) atoi(token);
		}
	}
	else if (length <= 0)
		res = (Datum) NULL;
	else
	{
		s = (char *) palloc(length);
		for (i = 0; i < length; i++)
		{
			token = pg_strtok(&tokenLength);
			s[i] = (char) atoi(token);
		}
		res = PointerGetDatum(s);
	}

	token = pg_strtok(&tokenLength);	/* read the ']' */
	if (token == NULL || token[0] != ']')
		elog(ERROR, "expected \"]\" to end datum, but got \"%s\"; length = %lu",
			 token ? (const char *) token : "[NULL]",
			 (unsigned long) length);

	return res;
}
