question: protected static token do_id ( ) throws java . io . IOException { StringBuffer result = new StringBuffer ( ) ; String result_str ; Integer keyword_num ; char buffer [ ] = new char [ 1 ] ; buffer [ 0 ] = ( char ) next_char ; result . append ( buffer , 0 , 1 ) ; advance ( ) ; while ( id_char ( next_char ) ) { buffer [ 0 ] = ( char ) next_char ; result . append ( buffer , 0 , 1 ) ; advance ( ) ; } result_str = result . toString ( ) ; keyword_num = ( Integer ) keywords . get ( result_str ) ; if ( keyword_num != null ) return new token ( keyword_num . intValue ( ) ) ; return new str_token ( sym . ID , result_str ) ; }
target:  Process an identifier.  Identifiers begin with a letter, underscore, or dollar sign, which is followed by zero or more letters, numbers, underscores or dollar signs.  This routine returns an str_token suitable for return by the scanner.