Let us all take a moment

to appreciate the underused an undervalued do-while. If I ever had a reason to use a while loop that executed before evaluating the predicate, the do-while loop is the loop I would choose.

loops

What's that and why do I need it? Loops are just a primitive special case of tail recursion, which is just a primitive special case of recursion. In a decent language you can write your own loops like this library:
http://hackage.haskell.org/package/monad-loops-0.4.2/docs/Control-Monad-Loops.html