[Proposal] Renaming (:=:) to (==)

[Shachaf Ben-Kiki]

On Sat, Sep 28, 2013 at 6:57 PM, Edward Kmett <ekmett at gmail.com> wrote:
> As part of the discussion about Typeable, GHC 7.8 is going to include a
> Data.Type.Equality module that provides a polykinded type equality data
> type.
>
> I'd like to propose that we rename this type to (==) rather than the (:=:)
> it was developed under.
>
> We are already using (+), (-), (*), etc. at the type level in type-nats, so
> it would seem to fit the surrounding convention.
>
> I've done the work of preparing a patch, visible here:
>
> https://github.com/ekmett/packages-base/commit/fb47f8368ad3d40fdd79bdeec334c0554fb17110
>
> Thoughts?
>
> Normally, I'd let this run the usual 2 week course, but we're getting down
> to the wire for 7.8's release. Once 7.8 ships, we'd basically be stuck with
> the current name forever.
>
> Discussion Period: 1 week
>
> -Edward Kmett
>

+1. For what it's worth, I suggested that name before, and Richard
Eisenberg suggested that == should be for type-level Boolean equality:
<http://markmail.org/message/3yifytgt2k3cfwws>. I'm not convinced,
though -- this seems fundamental enough to deserve the simplest name
possible.

(I'm using that link because the haskell.org mailing list archive
seems to be gone... Hopefully that comes back, eventually.)

    Shachaf