Failable Monad
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public sealed interface Failable<A> extends CoProduct2<List<String>, A, Failable<A>>, Monad<A, Failable<?>> { | |
@Override | |
default <B> Failable<B> flatMap(Fn1<? super A, ? extends Monad<B, Failable<?>>> fn1) { | |
return match(Failed::new, fn1.fmap(Monad::coerce)); | |
} | |
@Override | |
default <B> Failable<B> pure(B b) { | |
return new Success<>(b); | |
} | |
@Override | |
default <B> Failable<B> zip(Applicative<Fn1<? super A, ? extends B>, Failable<?>> appFn) { | |
Failable<Fn1<? super A, ? extends B>> coerce = appFn.coerce(); | |
return match(failures -> coerce.match(otherFailures -> new Failed<>(addAll(ArrayList::new, | |
failures, | |
otherFailures)), | |
constantly(new Failed<>(failures))), | |
a -> coerce.match(Failed::new, | |
fn -> new Success<>(fn.apply(a)))); | |
} | |
record Failed<A>(List<String> failures) implements Failable<A> { | |
@Override | |
public <R> R match(Fn1<? super List<String>, ? extends R> fn1, Fn1<? super A, ? extends R> fn11) { | |
return fn1.apply(failures); | |
} | |
} | |
record Success<A>(A value) implements Failable<A> { | |
@Override | |
public <R> R match(Fn1<? super List<String>, ? extends R> fn1, Fn1<? super A, ? extends R> fn11) { | |
return fn11.apply(value); | |
} | |
} | |
} |
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