ekmett/lens — pull request #438 by danidiaz (2014-05-02 18:55:06+00:00)
Title: Apply and ArrowApply instances for ReifiedMonadicFold

let showS = \x -> (putStrLn . show $ x) >> return x

*Main> (MonadicFold $ folded.act showS, [2,3,4])^!!runMonadicFold app.to (*3)
2
3
4
[6,9,12]

*Main> (MonadicFold $ folded.act showS, [2,3,4])^!!runMonadicFold app.to (*3).act showS
2
6
3
9
4
12
[6,9,12]