srecord IVF1WithToString<A>(S toString, IVF1<A> f) is IVF1<A> {
  public void get(A a) {
    f.get(a);
  }
  
  toString { ret toString; }
}

static <A> IVF1<A> ivf1WithToString(S toString, IVF1<A> f) {
  ret f == null ?: new IVF1WithToString<A>(toString, f);
}