package java_cup.runtime;/** This class represents a (terminal or non-terminal) symbol that, among *  other things can be placed on the parse stack.  Symbols are used to  *  keep track of state on the parse stack.  The symbol currently on top *  of the stack contains the current state in the parse_state field. *  In addition to the parse_state field, symbols also maintain a record *  of the symbol number that they represent in the sym field.  Finally,  *  symbols are used contain to any attributes used by semantic action (this *  is done via fields added in subclasses -- see for example, int_token and *  str_token). * * @see java_cup.runtime.token * @see java_cup.runtime.int_token * @see java_cup.runtime.str_token * @version last updated: 11/25/95 * @author  Scott Hudson */public class symbol {  /** Full constructor. */  public symbol(int sym_num, int state)    {      sym = sym_num;      parse_state = state;    }  /*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/  /** Constructor without a known state. */  public symbol(int sym_num)    {      this(sym_num, -1);    }  /*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/  /** 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;};