Hi, Am Montag, den 25.07.2016, 14:59 -0400 schrieb David Feuer:
Both `restrictKeys` and `withoutKeys` are special cases of `filterWithKey` (although they should be considerably more efficient than implementations using that function).
I’m risking to derailing this discussion, but how viable would it be to *not* add a new exported name for this, but recommend (e.g. in the docs) to use filter (`S.elem` set) map and then rely on rewrite rules to get the desired performance effect (by rewriting this expression to an non-exported restrictKeys)? I guess the answer is: Not viable enough, because rewrite rules are not applied reliably enough, and because you cannot easily have the effect of a partial "map `restrictKeys`". But nevertheless it is an interesting idea to imagine a programming language where APIs can be minimal, modular and composable without performance penalties. Greetings, Joachim -- Joachim “nomeata” Breitner mail@joachim-breitner.de • https://www.joachim-breitner.de/ XMPP: nomeata@joachim-breitner.de • OpenPGP-Key: 0xF0FBF51F Debian Developer: nomeata@debian.org