Re: [Haskell-cafe] Proposal: Shorter Import Syntax

On Jun 4, 2015, at 5:22 PM, Herbert Valerio Riedel wrote:

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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. Anthony