Wired-in type class

[Joachim Breitner]

Hi,

thanks for your pointers, they are very helpful. The problem is that one
way of implementing NT involves a class declaration (not just instances)
that I cannot write in Haskell. I tried to completely generate the the
class in GHC.Prim, without corresponding source, but that failed (e.g.
that module has mi_decl = []; I took that as a sign that I’m not on the
right track).

So I am back at generating a TypeCon in GHC.Prim which (to Haskell
abstractly) contains the non-Haskell-fields and then have a simple class
with one member of that type. Semantically all the same, and easier
implementation.


Am Freitag, den 16.08.2013, 10:25 -0700 schrieb Iavor Diatchki:

> The exact shape of the evidence depends on the class method, but
> `makeDict` in the same function may give you an idea of what to do in
> your particular case.  If the evidence needs to be more complex (i.e.,
> you need to generate an implementation in Core, Simon showed me
> another trick involving rules, which is a bit of a hack, but does seem
> to work, so I could show you what I did there too, so just ask).

In my case, I’d like to generate instances when the users asks for it
via derving clauses; but there as well I have the issue that deriving
stuff happens before desugaring, but the implementation will have to be
in Core. So I’m very much interested in the trick.

Greetings,
Joachim

-- 
Joachim “nomeata” Breitner
  mail at joachim-breitner.de • http://www.joachim-breitner.de/
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  Debian Developer: nomeata at debian.org
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