[Haskell-cafe] Proposal: Shorter Import Syntax

Anthony Cowley acowley at seas.upenn.edu
Thu Jun 4 21:36:01 UTC 2015

> On Jun 4, 2015, at 5:22 PM, Herbert Valerio Riedel <hvr at gnu.org> wrote:
>> On 2015-06-04 at 23:05:42 +0200, Alexey Shmalko wrote:
>> If I understand correctly, the initial proposal was to enable the new
>> syntax by default and it mustn't break any code (full
>> backward-compatible).
> That would be a departure from how language extensions were handled in
> GHC in the past afaik, and if there's no language pragma to toggle this
> new syntax, Cabal has no way to know that a new language syntax is
> required and that thereby needs exclude (not implemented yet) the
> affected package versions from the install-plan configuration space.

I can't parse your last sentence. The proposed syntax is currently a parse error, so a package that used it could depend on a GHC new enough to support it (eg with a base version constraint). No older packages would cause any errors whatsoever.


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