exexpr.c

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/*************************************************************************
 * Copyright (c) 2011 AT&T Intellectual Property 
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors: Details at https://graphviz.org
 *************************************************************************/
 
/*
 * Glenn Fowler
 * AT&T Research
 *
 * expression library
 */
 
#include <expr/exlib.h>
#include <stddef.h>
 
/*
 * return the expression for name or sym coerced to type
 */
 
Exnode_t*
exexpr(Expr_t* ex, const char* name, Exid_t* sym, int type)
{
        if (ex)
        {
                if (!sym)
                        sym = name ? dtmatch(ex->symbols, name) : &ex->main;
                if (sym && sym->lex == PROCEDURE && sym->value)
                {
                        if (type != DELETE_T)
                                return excast(ex, sym->value->data.procedure.body, type, NULL, 0);
                        exfreenode(ex, sym->value);
                        sym->lex = NAME;
                        sym->value = 0;
                }
        }
        return 0;
}