new language extensions

Duncan Coutts duncan.coutts at
Wed Nov 7 16:40:25 EST 2007

Last call for objections or comments.

We'd like to get this into Language.Haskell.Extension asap so we can
include it in the Cabal distributed with ghc-6.8.2. Currently there are
packages that compiled fine with Cabal and ghc-6.6.x but not with
ghc-6.8.x because we're missing these new more fine-grained language



On Mon, 2007-11-05 at 22:00 +0000, Duncan Coutts wrote:
> All,
> GHC 6.8 has a lot of new names for language extensions which are not yet
> listed in Language.Haskell.Extension:
> UnicodeSyntax
> PatternSignatures
> UnliftedFFITypes
> LiberalTypeSynonyms
> TypeOperators
> PArr
> RecordWildCards
> RecordPuns
> DisambiguateRecordFields
> OverloadedStrings
> MonoPatBinds
> RelaxedPolyRec
> ExtendedDefaultRules
> UnboxedTuples
> DeriveDataTypeable
> ConstrainedClassMethods
> These are the extension names you can list in the "extensions:" field in
> a .cabal file and are also in the {-# LANGUAGE #-} pragma.
> So I propose we add all of these to the Extension enumeration data type.
> I'd like to keep this addition separate from the proposal to make
> Extension a String or newtype String, since I expect even in that case
> we need a central list of extensions so different implementations can
> agree on names when they implement the same extensions, or to ensure
> they pick different names for different extensions.
> It'd also be nice if we could document all these extensions in the
> Language.Haskell.Extension module so we can refer to it from the cabal
> documentation about the extensions field.
> Duncan
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