If I'll ever resolve this I will give it a negative review. After all I am here for programming not guessing. Good the fact I decided to read here. Now I know that it is not about the solution but about the question. The difficulty must be in programming not in guessing what funny someone wants.

I'll tell my powerful friends to try them :D

Thanks! Your Kata is really welcomed. You never know.

And I've made an extreme performance version of this kata, maybe you could try? :D

Open the link given, and find the green button on the right top side :D

Scala

Here it is, the Groovy one

Wait, don't go, I need you. I'm modifying my translation (code style issue) and I need you to approve the forks :D

What is dan? Have a look at the Katas I authored, they still need reviews, and some of them should be at least a bit challenging (but not too hard).

Я не уверен что смогу решить Ваши каты. Я никогда не был силён в таких задачах - чисто математических, а сейчас уже нахожусь во второй половине рассказа "Цветы для Элджернона". :(
Это я для того что бы Вы не думали что я игнорирую из снобизма или типа того.
Успехов.

ps: название функции в тесте всё таки лучше исправить на height.

Wow, how annoying. Test cases suck, I now have that too, and it runs through. :P

Только что решил My smallest code interpreter (aka Brainf**k) - это просто смешно. Остальные каты 2-го уровня просто требуют много писанины и всё. А Folding through a fixed point я уже даже и не пытаюсь, такая теория категория мне не по мозгам. Ох, валенок я!
(строго: ) Утешать не надо!

Well done Ivana - we need people like you to continue creating kata. Though there also needs to be challengers worthy of taking them in the community, feel free to share your newly created kata with any friends to get more action on them!

added. Both directions: Random strings and Random RegExps. Btw. I found that if you use === -as opposed to == - in the quickcheck code the validation dies with an empty red text box as a response. :(. So don't use ===

ok, I think I will add some random (Arbitrary) examples to this, some Arbitrary String that - parsed - matches my implementation, and an Arbitrary instance (behind the scenes) to Regexp that I map back to String, so I can check for let a = arbitrary in parseRegexp (show a) == Just a. This will take some time though....

I've added some invalid tests, one question is what to do with ""? Is it Nothing or is it Just (Str [])? Now I test for Nothing (as that's what my solution does :D) But I can change that.. What do you think?