ifparser.h

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/*
 * $XConsortium: ifparser.h,v 1.1 92/08/22 13:05:39 rws Exp $
 *
 * Copyright 1992 Network Computing Devices, Inc.
 * 
 * Permission to use, copy, modify, and distribute this software and its
 * documentation for any purpose and without fee is hereby granted, provided
 * that the above copyright notice appear in all copies and that both that
 * copyright notice and this permission notice appear in supporting
 * documentation, and that the name of Network Computing Devices may not be
 * used in advertising or publicity pertaining to distribution of the software
 * without specific, written prior permission.  Network Computing Devices makes
 * no representations about the suitability of this software for any purpose.
 * It is provided ``as is'' without express or implied warranty.
 * 
 * NETWORK COMPUTING DEVICES DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS
 * SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS,
 * IN NO EVENT SHALL NETWORK COMPUTING DEVICES BE LIABLE FOR ANY SPECIAL,
 * INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
 * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
 * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
 * PERFORMANCE OF THIS SOFTWARE.
 * 
 * Author:  Jim Fulton
 *          Network Computing Devices, Inc.
 * 
 * Simple if statement processor
 *
 * This module can be used to evaluate string representations of C language
 * if constructs.  It accepts the following grammar:
 * 
 *     EXPRESSION  :=  VALUE
 *        |  VALUE  BINOP  EXPRESSION
 * 
 *     VALUE    :=  '('  EXPRESSION  ')'
 *        |  '!'  VALUE
 *        |  '-'  VALUE
 *        |  'defined'  '('  variable  ')'
 *        |  variable
 *        |  number
 * 
 *     BINOP    :=  '*'  |  '/'  |  '%'
 *        |  '+'  |  '-'
 *        |  '<<'  |  '>>'
 *        |  '<'  |  '>'  |  '<='  |  '>='
 *        |  '=='  |  '!='
 *        |  '&'  |  '|'
 *        |  '&&'  |  '||'
 * 
 * The normal C order of precidence is supported.
 * 
 * 
 * External Entry Points:
 * 
 *     ParseIfExpression    parse a string for #if
 */
 
#include <stdio.h>
 
struct IfParser {
  struct {        /* functions */
    const char *(*handle_error) (IfParser *, const char *, const char *);
    int (*eval_variable) (IfParser *, const char *, int);
    int (*eval_defined) (IfParser *, const char *, int);
  } funcs;
  char *data;
};
 
const char *ParseIfExpression(IfParser *, const char *, int *);