Wired-in type class

Joachim Breitner mail at joachim-breitner.de
Fri Aug 16 15:43:20 CEST 2013

Dear List,

I have some questions about the inner parts of GHC, where I need to
learn a lot. This is related to my attempts on newtype casting, but
should probably be kept separate from the conceptual discussions.

Say I need to create a wired-in type class, because it cannot be
represented in Haskell. The Core type constructor that will come out of
it will have one field of type ~R#, which is the reason why I cannot
write it in Haskell.

It seems that defining something wired-in is not a very local operation
that affects, at least primops.txt.pp and TysPrim.lhs. Does it affect

It seems that there is not precedent of a wired-in type class. Is that
possible without touching too many parts of the compiler? 

Or is it saner to just have "class NT a b" in a module in ghc-prim
without the constraint and use special magic when compiling that file to
add the required field to the data constructor representing the class?
(Similar to how the kind of ~ is adjusted during compilation?)


Joachim “nomeata” Breitner
  mail at joachim-breitner.dehttp://www.joachim-breitner.de/
  Jabber: nomeata at joachim-breitner.de  • GPG-Key: 0x4743206C
  Debian Developer: nomeata at debian.org
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