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Comment by _old_dude_ | Hacker News Reader

Monad to the rescue

  Optional.of(op)
    .filter(v -> !v.cond)
    .map(v -> op2(v))
    .filter(v2 -> !v2.cond)
    .map(/* do more stuff */)
    .orElseGet(() -> my_else)

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Yep, in an expression language that's how you'd do it. However, we're an imperative language, and the advantage of `else` is that we can use an imperative construct, `if()`, to locate the else case in the code - so we don't need to handle it in the typesystem. That's an inversion from monadic languages, where types contain/emulate statements - in C-likes, statements contain expressions/types! So `breakelse` effectively is glue that lets us turn part of the type into a control flow, which is deliberately not represented in the typesystem. `Optional.case(:else: breakelse).X` and now in X, we're no longer dealing with an `Optional` at all. We're not "inside" the Optional as we would be with `map`; we've effectively everted the entire `Optional` using non-local flow from the `else` case.

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