Proxy and new-typeable

[Edward Kmett]

If you insist on adding Proxy to Data.Typeable, I'd like to strongly
suggest that we might want to look at promoting Data.Proxy from the tagged
package to base.

It offers a lot of instances that I currently rely upon in production code
and is already in use in a large portion of the ~42 reverse dependencies of
that package:

http://packdeps.haskellers.com/reverse/tagged

Of course we could invert the dependencies from packages outside of base at
that time.

Exporting a crippled Proxy from Data.Typeable *without* those instances
will basically just ensure that I need to somehow support both, fight
needlessly with orphans and/or deal with qualified imports everywhere, and
it will break about 3 dozen modules of mine, and impact others.

All in all this makes me personally rather strongly opposed to the idea of
just randomly throwing a Proxy type in the module without ensuring we don't
lose existing functionality along the way.

-Edward

On Wed, Mar 20, 2013 at 4:04 AM, José Pedro Magalhães <jpm at cs.uu.nl> wrote:

> Data.Typeable no longer uses Proxy, yet I think it is convenient to have a
> Proxy datatype
> defined somewhere in base, and re-export it from Data.Typeable, as you
> might often often
> want to use it.
>
>
> Cheers,
> Pedro
>
>
> On Wed, Mar 20, 2013 at 12:35 AM, Edward Kmett <ekmett at gmail.com> wrote:
>
>> +1 for finding a resolution. The idea of another Proxy floating around
>> fills me with unease.
>>
>> -Edward
>>
>> On Tue, Mar 19, 2013 at 7:48 PM, Ben Gamari <bgamari.foss at gmail.com>wrote:
>>
>>> José Pedro Magalhães <jpm at cs.uu.nl> writes:
>>>
>>> > Yes, it's entirely unproblematic, and a good suggestion.
>>> >
>>> What happened to this proposal? As far as I can tell the new-typeable
>>> work is in (or rather, the branch has been deleted) yet Data.Typeable
>>> still seems to have its own Proxy. Given that there has been talk of a
>>> 7.8 release, this should probably be resolved quickly (although it's not
>>> clear to me from the massive thread where that discussion concluded).
>>>
>>> Cheers,
>>>
>>> - Ben
>>>
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>>
>>
>
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