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Re: Data instances in ghc 6.2.1?: msg#00043

lang.haskell.glasgow.bugs

Subject: Re: Data instances in ghc 6.2.1?

Hi Claus,
the tuple instances did not make it into GHC 6.2 because of CVS branching policy.
GHC CVS HEAD compiles the example.
And yes, SPJ approved recently that Language.Haskell.Syntax should derive Data and Typeable.
But, I can't access cvs.haskell.org.
Already for a while, it asks for my password, which I never got handed out.
Ralf

Claus Reinke wrote:

Shouldn't there be more instances of Data and friends?

I thought that tuples beyond size 2 were mentioned
here before ghc 6.2, but this silly example doesn't work
because of missing Data instance (it does work with d instead of d3):

import Data.Generics

-- file = "Tst.hs"

d = (["hi","head"],("ho",(True,"head")))
d3 = (["hi","head"],"ho",(True,"head"))

main = print $ everywhere (id `extT` worker) d3
where
worker "head" = "tail"
worker s = s

Since these instances claim to be derivable: shouldn't
that be done for the stuff in Language.Haskell.Syntax?

cheers,
claus

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