/*
 * STANDARD ML OF NEW JERSEY COPYRIGHT NOTICE, LICENSE AND DISCLAIMER.
 * 
 * Copyright (c) 1989-1998 by Lucent Technologies
 * 
 * Permission to use, copy, modify, and distribute this software and its
 * documentation for any purpose and without fee is hereby granted, provided
 * that the above copyright notice appear in all copies and that both the
 * copyright notice and this permission notice and warranty disclaimer appear
 * in supporting documentation, and that the name of Lucent Technologies, Bell
 * Labs or any Lucent entity not be used in advertising or publicity pertaining
 * to distribution of the software without specific, written prior permission.
 *
 * Lucent disclaims all warranties with regard to this software, including all
 * implied warranties of merchantability and fitness. In no event shall Lucent
 * be liable for any special, indirect or consequential damages or any damages
 * whatsoever resulting from loss of use, data or profits, whether in an action
 * of contract, negligence or other tortious action, arising out of or in
 * connection with the use or performance of this software. 
 *
 * Taken from this URL:
 * http://www.smlnj.org/license.html
 * 
 * This license is compatible with the GNU GPL (see section "Standard ML of New
 * Jersey Copyright License"):
 * http://www.gnu.org/licenses/license-list.html#StandardMLofNJ
 */

/*
 * Copyright 1996-1999 by Scott Hudson, Frank Flannery, C. Scott Ananian
 */

package weka.core.parser.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;
}