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  map (head &&& length) . sort . group
  filterM (const [True, False])
Can you show how you implement these in D?

If you want, I can explain these or give other examples of expressiveness I don't think you'll find in D.

Links explaining these Haskell code snippets:

http://stackoverflow.com/a/10410997/578288 – the `map` snippet converts a flat list into a multiset represented as a list of `(count, element)` tuples

http://stackoverflow.com/a/5378799/578288 – the `filterM` snippet returns the powerset of its list argument (http://en.wikipedia.org/wiki/Power_set)

That is one of the best implementations of powerset I've seen in a while. Thank you for that!

I think you mean group . sort

Oops, quick-typing on my phone can have problematic results :-)

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