question: public void eat ( String s ) { String pn = peekN ( s . length ( ) ) ; if ( ! pn . equals ( s ) ) throw new RuntimeException ( "Parser expected '" + s + "' but got '" + pn + "'." ) ; seekN ( s . length ( ) ) ; }
target:  If the next characters are the same as those in s, seek over them. Otherwise throw RuntimeException.