Re: Is it evil to add "deriving Typeable" to newtype Q?

Robert Greayer <[email protected]> Wed, 5 May 2010 11:22:13 -0400
Newsgroups gmane.comp.lang.haskell.template
Message-ID <[email protected]>
On Wed, May 5, 2010 at 4:13 AM, Leonel Fonseca <[email protected]> wrote:
> Hi everybody,
>
> Is it reasonable to add "deriving Typeable" to newtype Q?
>
> In case you wonder why I want to do that, it is because I've constructed =
a Q
> [Dec] inside a monad, I want to extract=A0 it from the monad (via runIO) =
and
> the monad has constraint "Typeable" over this parameter.
>
> I've also tried to write the Typeable instance in my own module (not
> Language.Haskell.TH.Syntax). But I've got no luck since the Q type
> constructor is exported but the data constructor is not.
>
> Thanks.
> --
>
> Leonel Fonseca.
>
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>

This question might be better asked at Haskell-Cafe --
template-haskell (the mailing list) is pretty quiet, and TH questions
are perfectly appropriate on -Cafe.  The separate template-haskell
mailing list is perhaps edging toward retirement.