Re: Proposal: Num instance for (a -> b)

-1, per the very confusing errors that would ensue. If this behavior is desired, you can use a newtype wrapper. As it happens, this fits the pattern of ANum http://hackage.haskell.org/package/ANum. (Any Applicative can be made an instance of Num in this way.) -- Dan Burton On Sun, Nov 11, 2018 at 12:28 AM Tom Murphy wrote:

On 11/11/18, Henning Thielemann wrote:

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On Sun, 11 Nov 2018, Henning Thielemann wrote:

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On Sat, 10 Nov 2018, Daniel Cartwright wrote:

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relevant reddit comment thread:

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urce=reddit-android

https://wiki.haskell.org/index.php?title=Num_instance_for_functions&oldid=36632

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In short: It would make 2(x+y) no longer a type error but equivalent to

https://www.reddit.com/r/haskell/comments/9vtis5/the_universe_of_discourse_i... 2.

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We would lose a lot of type safety for little syntactic gain.

Btw. before adding more Wat instances please implement the GHC warning about such instances: https://ghc.haskell.org/trac/ghc/ticket/11796

This is my feeling as well.

Tom _______________________________________________ Libraries mailing list Libraries@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/libraries