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/*-------------------------------------------------------------------------
*
* nodeFuncs.c--
* All node routines more complicated than simple access/modification
*
* Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/nodes/nodeFuncs.c,v 1.7 1998/02/26 04:32:09 momjian Exp $
*
*-------------------------------------------------------------------------
*/
#include <sys/types.h>
#include "postgres.h"
#include "nodes/primnodes.h"
#include "nodes/plannodes.h"
#include "nodes/pg_list.h"
#include "nodes/relation.h"
#include "nodes/nodeFuncs.h"
#include "utils/lsyscache.h"
static bool var_is_inner(Var *var);
/*
* single_node -
* Returns t if node corresponds to a single-noded expression
*/
bool
single_node(Node *node)
{
if (IsA(node, Ident) ||IsA(node, Const) ||IsA(node, Var) ||IsA(node, Param))
return (true);
else
return (false);
}
/*****************************************************************************
* VAR nodes
*****************************************************************************/
/*
* var_is_outer
* var_is_inner
* var_is_mat
* var_is_rel
*
* Returns t iff the var node corresponds to (respectively):
* the outer relation in a join
* the inner relation of a join
* a materialized relation
* a base relation (i.e., not an attribute reference, a variable from
* some lower join level, or a sort result)
* var node is an array reference
*
*/
bool
var_is_outer(Var *var)
{
return ((bool) (var->varno == OUTER));
}
static bool
var_is_inner(Var *var)
{
return ((bool) (var->varno == INNER));
}
bool
var_is_rel(Var *var)
{
return (bool)
!(var_is_inner(var) || var_is_outer(var));
}
/*****************************************************************************
* OPER nodes
*****************************************************************************/
/*
* replace_opid -
*
* Given a oper node, resets the opfid field with the
* procedure OID (regproc id).
*
* Returns the modified oper node.
*
*/
Oper *
replace_opid(Oper *oper)
{
oper->opid = get_opcode(oper->opno);
oper->op_fcache = NULL;
return (oper);
}
/*****************************************************************************
* constant (CONST, PARAM) nodes
*****************************************************************************/
/*
* non_null -
* Returns t if the node is a non-null constant, e.g., if the node has a
* valid `constvalue' field.
*
*/
bool
non_null(Expr *c)
{
if (IsA(c, Const) &&!((Const *) c)->constisnull)
return (true);
else
return (false);
}
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