static <A> ISetAndGet<A> iSetAndGet(ISetter<A> setter, IF0<A> getter) {
  ret new ISetAndGet<A> {
    public void set(A a) { setter?.set(a); }
    public A get() { ret getter?!; }
  };
}

static <A, B> ISetAndGet<A> iSetAndGet(B target, IVF2<B, A> setter, IF1<B, A> getter) {
  ret new ISetAndGet<A> {
    public void set(A a) { if (target != null && setter != null) setter.get(target, a); }
    public A get() { ret target == null || getter == null ? null : getter.get(target); }
  };
}

Began life as a copy of #1031577