Re: Proposal: add `on` to the Prelude

One note: this does conflict with some other libraries, for instance GTK2HS On Tue, Sep 10, 2019 at 6:26 PM chessai . wrote:

+1

On Tue, Sep 10, 2019, 5:53 PM David Feuer wrote:

...

Every time I reach for Data.Function.on, I feel like a total dolt for having to import a module to get a function whose implementation is barely longer than the import. And it's a really good function too! Can we please add it to the Prelude?

on :: (b -> b -> c) -> (a -> b) -> a -> a -> c (.*.) `on` f = \x y -> f x .*. f y _______________________________________________ Libraries mailing list Libraries@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/libraries

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