/*
 * AnaGram, A System for Syntax Directed Programming
 * Copyright 1993-2002 Parsifal Software. All Rights Reserved.
 * See the file COPYING for license and usage terms.
 *
 * mrule.h - marked rules
 */

#ifndef MRULE_H
#define MRULE_H

#include "rule.h"

class MarkedRule {
public:
  Rule rule;
  int index;

  MarkedRule() : rule(0), index(0) {}
  MarkedRule(const Rule &r, int x) : rule(r), index(x) {}
  MarkedRule(const Rule &r) : rule(r), index(r->length()) {}

  int operator < (const MarkedRule &r) const {
    if ((int) rule < (int) r.rule) return 1;
    if ((int) r.rule < (int) rule) return 0;
    return index < r.index;
  }

  Token leftToken()  { return rule.token(index - 1); }
  Token rightToken() { return rule.token(index); }
  int positionLeft()  { return index == 0; }
  int positionRight() { return (unsigned) index == rule->length(); }
  MarkedRule nextLeft()  { return MarkedRule(rule, index - 1); }
  MarkedRule nextRight() { return MarkedRule(rule, index + 1); }
};


#endif /* MRULE_H */