Re: [Haskell-cafe] ANNOUNCE: Generic Haskell 1.80 (Emerald)

On Apr 12, 2008, at 13:33 , Thomas van Noort wrote:

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On 12/04/2008, Thomas van Noort wrote:

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That's a good question. Unfortunately, only Haskell98 types are currently supported by the Generic Haskell compiler.

I thought constrained types were Haskell 98, but now I'm in doubt...

language. Generic Haskell is fully reflexive with respect to the types that are definable in Haskell 98, except for constraints in data-type definitions. So a data type of the form

data Eq a => Set a = NilSet | ConsSet a (Set a)

is not dealt with correctly. However, constrained data types are a corner case in Haskell and can easily be simulated using other means.

I was under the impression "corner case" here means that H98 lets you write it but doesn't handle it very sanely (a GHC-specific extension being needed to achieve that). -- brandon s. allbery [solaris,freebsd,perl,pugs,haskell] allbery@kf8nh.com system administrator [openafs,heimdal,too many hats] allbery@ece.cmu.edu electrical and computer engineering, carnegie mellon university KF8NH