public static <A, B, C> List<C> map2(
Map2<A, B, C> fn, final Collection<A> as, final Collection<B> bs) {
assert as.size() == bs.size();
ArrayList<C> cs = new ArrayList<C>(as.size());
Iterator<A> aiter = as.iterator();
Iterator<B> biter = bs.iterator();
while (aiter.hasNext() && biter.hasNext()) cs.add(fn.apply(aiter.next(), biter.next()));
return cs;
}
public static <A, B> A foldl(final Map2<A, B, A> f, A a, final Collection<B> xs) {
for (B b : xs) a = f.apply(a, b);
return a;
}
public C apply(B b) {
return target.apply(a, b);
}
