1 package java_cup.runtime; 2 3 /** 4 * Defines the Scanner interface, which CUP uses in the default 5 * implementation of <code>lr_parser.scan()</code>. Integration 6 * of scanners implementing <code>Scanner</code> is facilitated. 7 * 8 * @version last updated 23-Jul-1999 9 * @author David MacMahon <davidm@smartsc.com> 10 */ 11 12 /* ************************************************* 13 Interface Scanner 14 15 Declares the next_token() method that should be 16 implemented by scanners. This method is typically 17 called by lr_parser.scan(). End-of-file can be 18 indicated either by returning 19 <code>new Symbol(lr_parser.EOF_sym())</code> or 20 <code>null</code>. 21 ***************************************************/ 22 public interface Scanner { 23 /** Return the next token, or <code>null</code> on end-of-file. */ 24 public Symbol next_token() throws java.lang.Exception; 25 } 26