[Haskell-cafe] GHC Extension Proposal: ArgumentBlock

Herbert Valerio Riedel hvr at gnu.org
Tue Sep 8 20:57:03 UTC 2015

On 2015-09-08 at 18:39:33 +0200, Silvio Frischknecht wrote:
>> That's still an extension (-XNondecreasingIndentation), just one enabled
>> by default.
> Interesting. Is there a list of extensions that are enabled by
> default?


> I'm sure whoever suggested it as default and not extension will be happy
> with this too.

Just to clarify, GHC has a "default" mode when you don't specify
-XHaskell2010 nor -XHaskell98, quoting the user's guide[1]

| By default, GHC mainly aims to behave (mostly) like a Haskell 2010
| compiler, although you can tell it to try to behave like a particular
| version of the language with the -XHaskell98 and -XHaskell2010
| flags. The known deviations from the standards are described
| below. Unless otherwise stated, the deviation applies in Haskell 98,
| Haskell 2010 and the default modes.

But as soon as you have a cabal project, you get reminded to set the
`default-language` property, which most of the time is then set to
Haskell2010, which in turn means not having `-XNondecreasingIndentation`
enabled implicitly.

 [1]: https://downloads.haskell.org/~ghc/latest/docs/html/users_guide/bugs-and-infelicities.html#vs-Haskell-defn

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