[Haskell-cafe] Better names for
tonyzorman at mailbox.org
Wed Apr 22 09:50:56 UTC 2020
On Wed, Apr 22 2020 11:17, Marc Busqué wrote:
> For instance, a functor can be both covariant and contravariant
Judging from personal experience, "functor" in mathematics always (for a
sufficiently small definition of always) refers to a covariant functor.
If something is contravariant you usually declare it explicitly. These
concepts are rather related though; one may view any contravariant
functor F: C -> D as a covariant one, either by F: C^o -> D or by
F: C -> D^o.
> Would `Cofunctor` be a better name for it?
Cofunctor has some ambiguity around it. While it might refer to a
contravariant functor it may as well refer to the dual of a functor
(which is again a functor).
Tony Zorman | PGP: 0xc927de8c7dfd57b8
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