gistfile1.m

static NSString *readToken (PushbackReader *rdr) {
  NSMutableString *sb = [NSMutableString string];
  unichar ch = [rdr read];
  for (;;) {
    if (!ch || isWhitespace(ch))
      return [NSString stringWithString:sb];
    [sb appendFormat:@"%C", ch];
    ch = [rdr read];
  }
  return nil;
}