HaRe and incremental type checking / type inference

[AlanKim Zimmerman]

Basically I want to be able to make a few small changes to an already type
checked AST and then query the type system, similar to what is possible
with typed holes.

So in my example I would like to move baz to the top level, and then invoke
the type checker to get the required signature, without having to convert
the partial result back to source and re-run the entire compilation.

Alan





On Sun, Jul 13, 2014 at 10:21 PM, Richard Eisenberg <eir at cis.upenn.edu>
wrote:

> Hello Alan,
>
> It's not clear what you're asking for here. What's keeping you from
> "accessing the full power of the GHC type system"?
>
> Richard
>
> On Jul 9, 2014, at 4:35 PM, AlanKim Zimmerman <alan.zimm at gmail.com> wrote:
>
> > I have hit a problem in HaRe when lifting a declaration from e.g. a
> where clause of a function to the top level, where there is a type
> signature of any complexity.
> >
> > e.g lifting 'baz' from function 'foo' below
> >
> > --------------------------
> > foo a = baz
> >   where
> >     baz :: Int
> >     baz = xx 1 a
> >
> >     xx :: (Num t) => t -> t -> t
> >     xx p1 p2 = p1 + p2
> > --------------------------------------
> >
> > becomes
> >
> > ---------------------------------------------
> > foo a = (baz xx a)
> >   where
> >     xx :: (Num t) => t -> t -> t
> >     xx p1 p2 = p1 + p2
> >
> > -- baz:: (forall t. Num t => t -> t -> t) -> Int ->Int
> > baz :: Num a => (a -> t1 -> t) -> t1 -> t
> > baz xx a= xx 1 a
> > -----------------------------------------------
> >
> > For a very small subset this can be calculated easily, but for full
> generality it would be great to access the full power of the GHC type
> system.
> >
> > So before diving in too deeply, I thought I would test the waters as to
> the feasibility of doing something like this. I was hoping that perhaps the
> effort at an external constraint solver might be making the interfacing
> slightly simpler.
> >
> > Regards
> >  Alan
> >
> > _______________________________________________
> > ghc-devs mailing list
> > ghc-devs at haskell.org
> > http://www.haskell.org/mailman/listinfo/ghc-devs
>
>
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