assert(parser != NULL);
assert(id != NULL);
const Value* alternativeParser(AttributeParser parser[],			       unsigned n,			       StringTokenizer& st){  assert(parser != NULL);  const Value* res = NULL;  unsigned i = 0;  while (res == NULL && i < n) {    res = (parser[i])(st);    if (res == NULL) i++;  }  return res;}