Are there GHC extensions we'd like to incorporate wholesale?

[Herbert Valerio Riedel]

On 2016-05-03 at 00:57:38 +0200, John Wiegley wrote:
> I wonder if there are GHC extensions we'd like to promote as features
> in the next report, as a starting point for discussing new additions.
>
> There are a few GHC features that have become part of the regular
> Haskell landscape, such that it's hard to imagine a modern Haskell
> without them.

Btw, last year I computed a frequency-list of used extensions over
Hackage packages[1]. I'm planning to recompute such a list over all of
Hackage as well as over a Stackage subset. That would give us empirical
popularity data besides the subjective data provided by the recent
reddit discussion.

> For example, MultiParamTypeClasses, OverloadedStrings, GADTs,
> TypeFamilies, etc.
>
> How much "work" is typically involved in promoting a feature to be in the
> Report, and how do we determine when it's a bad idea?

As a concrete example of the problems formalising an extension, I'd like
to point to the example of 'BangPatterns' which may appear to be also
such a candidate and were considered for Haskell2014 already.

Back then, Ian hit some roadblocks:

  https://mail.haskell.org/pipermail/haskell-prime/2013-February/003782.html

Of course, I'm sure it would have been possible to resolve the open
issues with a bit more persistence. :-)


 [1]: https://gist.github.com/hvr/fd4fa2f10d4a10c7ebcc


-- hvr