package java_cup.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.
 * 
 * @version last updated: 7/3/96
 * @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
 * xleft: is the left position Object in the original input file xright: is the
 * left position Object in the original input file
 ******************************************************************************/
@SuppressWarnings (
{ "all" } )
public class Symbol
{

  // TUM 20060327: Added new Constructor to provide more flexible way
  // for location handling
  /*******************************
   *******************************/
  public Symbol ( int id, Symbol left, Symbol right, Object o )
  {
    this ( id, left.left, right.right, o );
  }


  public Symbol ( int id, Symbol left, Symbol right )
  {
    this ( id, left.left, right.right );
  }


  /*****************************************************************************
   * 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, -1, -1, o );
  }


  /*****************************************************************************
   * Constructor for no value
   ****************************************************************************/
  public Symbol ( int id, int l, int r )
  {
    this ( id, l, r, null );
  }


  /*****************************************************************************
   * Constructor for no value or l,r
   ****************************************************************************/
  public Symbol ( int sym_num )
  {
    this ( sym_num, -1 );
    left = -1;
    right = -1;
  }


  /*****************************************************************************
   * Constructor to give a start state
   ****************************************************************************/
  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;
  }
}