[Haskell-cafe] Better names for

Tony Zorman tonyzorman at mailbox.org
Wed Apr 22 09:50:56 UTC 2020

Hi Marc,

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
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 865 bytes
Desc: not available
URL: <http://mail.haskell.org/pipermail/haskell-cafe/attachments/20200422/95ec1ad1/attachment.sig>

More information about the Haskell-Cafe mailing list