The Rust translation of this kata depends on having solved the Rust version of the Isomorphism kata, which no longer exists.

I'm currently learning functional programming and type theory and this has been a really great Kata to introduce me to the concept.

I took some time to add a Scala Translation. Please review.

A suggestion: would love to see an Isomorphism-style kata where you'd have to write a Category instance for ISO or something else -- and thanks to that, leverage some wicked cool machinery to achieve something useful.

What has really kicked me in this kata: the realization that I could code every ISO by hand, as explicit (ltr, rtl) pairs with convoluted messy definitions of ltr, rtl -- but I didn't have to, because Haskell could build those functions automatically, just by following my high-level proofs. Isn't this amazing!

So, perhaps this insight could be reached from another angle: by offering the choice to hand-code a huge monster term VS to derive that same term by type magic.

Fixed isoUnOptional. Please review the new Java translation

Java translation added!

Excited!

I am a little confused with one specific test in Haskell, but it's only a edge case, I didn't put it into the translation,
but it won't affect anything, because there're other tests that check the same thing.