static <A> A mapMethodLike optPar_func(S name, O[] opt, IF0<A> defaultValue) {
  int n = l(opt);
  if (n == 1 && opt[0] instanceof Map) {
    Map map = cast opt[0];
    ret map.containsKey(name) ? (A) map.get(name) : callF(defaultValue);
  }
  if (!even(l(opt))) fail("Odd parameter length");
  for (int i = 0; i < l(opt); i += 2)
    if (eq(opt[i], name))
      ret (A) opt[i+1];
  ret callF(defaultValue);
}

Began life as a copy of #1006679