Re: Permitting trailing commas for record syntax ADT declarations

On 2014-09-24 at 08:50:22 +0200, Edward Kmett wrote:

I'm personally of the "it should be a language extension like everything else" mindset.

Me too. Mostly for being able to have more useful error messages with older GHCs and other Haskell parsers. Because if it's a lang-ext pragma, you have to specify it somewhere explicitly ({-# LANGUAGE .. #-} and/or {other,default}-extenions in the cabal file), and if the parser used doesn't know that extension you get a more useful hint pointing you directly at your problem if you throw spurious-commas at a Haskell parser which doesn't support that extension (yet), or with Cabal involved, you'd even get a error message that the current compiler doesn't support that extension.