ekmett/semigroupoids — pull request #15 by exergasia (2014-07-30 23:35:46+00:00)
Title: Foldable1/Traversable1 instance for 2-tuples.

Higher tuples not included because apparently they lack Foldable/Traversable and I don't want to mess around with orphans. I don't think I've ever seen a 4-tuple in the wild anyway, but 3-tuples pop up sometimes.