Shared data type for extension flags

[Michael Smith]

That sounds like a good approach. Are there other things that would go
nicely
in a shared package like this, in addition to the extension data type?

On Wed, Sep 2, 2015 at 1:00 AM, Matthew Pickering <
matthewtpickering at gmail.com> wrote:

> Surely the easiest way here (including for other tooling - ie
> haskell-src-exts) is to create a package which just provides this
> enumeration. GHC, cabal, th, haskell-src-exts and so on then all
> depend on this package rather than creating their own enumeration.
>
> On Wed, Sep 2, 2015 at 9:47 AM, Michael Smith <michael at diglumi.com> wrote:
> > #10820 on Trac [1] and D1200 on Phabricator [2] discuss adding the
> > capababilty
> > to Template Haskell to detect which language extensions enabled.
> > Unfortunately,
> > since template-haskell can't depend on ghc (as ghc depends on
> > template-haskell),
> > it can't simply re-export the ExtensionFlag type from DynFlags to the
> user.
> >
> > There is a second data type encoding the list of possible language
> > extensions in
> > the Cabal package, in Language.Haskell.Extension [3]. But
> template-haskell
> > doesn't already depend on Cabal, and doing so seems like it would cause
> > difficulties, as the two packages can be upgraded separately.
> >
> > So adding this new feature to Template Haskell requires introducing a
> > *third*
> > data type for language extensions. It also requires enumerating this full
> > list
> > in two more places, to convert back and forth between the TH Extension
> data
> > type
> > and GHC's internal ExtensionFlag data type.
> >
> > Is there another way here? Can there be one single shared data type for
> this
> > somehow?
> >
> > [1] https://ghc.haskell.org/trac/ghc/ticket/10820
> > [2] https://phabricator.haskell.org/D1200
> > [3]
> >
> https://hackage.haskell.org/package/Cabal-1.22.4.0/docs/Language-Haskell-Extension.html
> >
> > _______________________________________________
> > ghc-devs mailing list
> > ghc-devs at haskell.org
> > http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs
> >
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.haskell.org/pipermail/ghc-devs/attachments/20150902/b76ecb4f/attachment-0001.html>