package java_cup.runtime;

/**
 * Defines the Scanner interface, which CUP uses in the default implementation
 * of <code>lr_parser.scan()</code>. Integration of scanners implementing
 * <code>Scanner</code> is facilitated.
 *
 * @version last updated 23-Jul-1999
 * @author David MacMahon <davidm@smartsc.com>
 */

/*
 * ************************************************* Interface Scanner
 * 
 * Declares the next_token() method that should be implemented by scanners. This
 * method is typically called by lr_parser.scan(). End-of-file can be indicated
 * either by returning <code>new Symbol(lr_parser.EOF_sym())</code> or
 * <code>null</code>.
 ***************************************************/
public interface Scanner {
  /** Return the next token, or <code>null</code> on end-of-file. */
  public Symbol next_token() throws java.lang.Exception;
}
