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());
}

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 ( ) ) ; }
if the next characters are the same as those in s , seek over them . otherwise throw runtimeexception .
