/*

 * Copyright (c) 2003, 2005, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package com.sun.java_cup.internal.runtime;

/**

 * Defines the Symbol class, which is used to represent all terminals

 * and nonterminals while parsing.  The lexer should pass CUP Symbols

 * and CUP returns a Symbol.

 *

 * @author  Frank Flannery

 */

/* ****************************************************************

  Class Symbol

  what the parser expects to receive from the lexer.

  the token is identified as follows:

  sym:    the symbol type

  parse_state: the parse state.

  value:  is the lexical value of type Object

  left :  is the left position in the original input file

  right:  is the right position in the original input file

******************************************************************/

public class Symbol {

/*******************************

  Constructor for l,r values

 *******************************/

  public Symbol(int id, int l, int r, Object o) {

    this(id);

    left = l;

    right = r;

    value = o;

  }

/*******************************

  Constructor for no l,r values

********************************/

  public Symbol(int id, Object o) {

    this(id);

    left = -1;

    right = -1;

    value = o;

  }

/*****************************

  Constructor for no value

  ***************************/

  public Symbol(int sym_num, int l, int r) {

    sym = sym_num;

    left = l;

    right = r;

    value = null;

  }

/***********************************

  Constructor for no value or l,r

***********************************/

  public Symbol(int sym_num) {

    this(sym_num, -1);

    left = -1;

    right = -1;

    value = null;

  }

/***********************************

  Constructor to give a start state

***********************************/

  public Symbol(int sym_num, int state)

    {

      sym = sym_num;

      parse_state = state;

    }

/*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/

  /** The symbol number of the terminal or non terminal being represented */

  public int sym;

  /*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/

  /** The parse state to be recorded on the parse stack with this symbol.

   *  This field is for the convenience of the parser and shouldn't be

   *  modified except by the parser.

   */

  public int parse_state;

  /** This allows us to catch some errors caused by scanners recycling

   *  symbols.  For the use of the parser only. [CSA, 23-Jul-1999] */

  boolean used_by_parser = false;

/*******************************

  The data passed to parser

 *******************************/

  public int left, right;

  public Object value;

  /*****************************

    Printing this token out. (Override for pretty-print).

    ****************************/

  public String toString() { return "#"+sym; }

}