[Haskell-cafe] Non-derivable Typeable

[Roman Cheplyaka]

Thanks, looking forward to it!

Roman

* José Pedro Magalhães <jpm at cs.uu.nl> [2013-01-22 14:41:25+0000]
> Yes, that will work. But soon we'll have poly-kinded Typeable in HEAD,
> which will be able to derive that instance.
> 
> 
> Cheers,
> Pedro
> 
> On Tue, Jan 22, 2013 at 2:34 PM, Roman Cheplyaka <roma at ro-che.info> wrote:
> 
> > I just found mkTyCon3 which generates the fingerprint automatically.
> > (I was looking at Data.Typeable.Internal.mkTyCon before.)
> > That answers my question.
> >
> > (Of course, a way to derive the instance would be even better...)
> >
> > Roman
> >
> > * Roman Cheplyaka <roma at ro-che.info> [2013-01-22 15:28:55+0200]
> > > I need to declare a Typeable instance for a type which has an argument
> > > of kind * -> *. GHC refuses to derive it.
> > >
> > > What is a recommended way to go about it?
> > >
> > > In particular, if I write the instance by hand, how important is the
> > > fingerprint, and how could I generate it?
> > >
> > > Roman
> >
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