ekmett/mtl — pull request #13 by kantp (2014-06-05 11:34:39+00:00)
Title: Ensure strictness in the state in modify'.

The old implementation of modify' used state f with a function f that was strict in the new state. However, in state itself, f is applied to the state in a non-strict way, so the strictness is lost.

The implementation suggested here should ensure that the state is evaluated.