[Haskell-cafe] Template Haskell vs Rewrite Rules?
Ismael Figueroa Palet
ifigueroap at gmail.com
Thu Apr 19 14:40:05 CEST 2012
Thanks (again) for your answer.
I'm not quite confident using TH yet, but it seems in your code you must
define an 'app' function, and then use [overloadedApp|... |] as a
quasiquoteator to inject the overloaded app, right?
Thanks for the zeroth reference too, one question remains for me: what are
the constrasts/differences between TH and RewriteRules? :-)
2012/4/19 Michael Sloan <mgsloan at gmail.com>
> You're in luck! This is something I've wanted to implement before in
> the past, and your email reminded me. While pretty awful, it could be
> used for doing some interesting value-interception instrumentation in
> Haskell. Recently I've been messing with TH a lot, so this initial
> implementation was rather straightforward.
> Note: Relatively untested implementation, let me know if you find any
> It only does this transformation to direct function application,
> unfortunately. In order to properly overload apply for infix
> operators, you'll need to be able to resolve fixities at compile time.
> This could be done by using the code in
> and using the fixity information yielded by TH's "reify". Someone
> aught to have done this before, but I haven't seen it.
> Handling the applications involved in do-notation, comprehensions,
> enumerations, and anything else that's such direct syntax sugar would
> also be a bit of work (but could be very useful for other TH
> quasiquoting stuff!).
> You might also be interested in this:
> Hope that helps!
> -Michael Sloan
> On Wed, Apr 18, 2012 at 9:49 AM, Ismael Figueroa Palet
> <ifigueroap at gmail.com> wrote:
> > I'm working on getting annotated versions of all instances of a function
> > a typeclass, and was wondering what are the relation/differences between
> > Template Haskell and the Rewrite Rules section. Of course this is
> > to GHC.
> > Another question, in Racket, primitive function application is denoted
> > #%app. And using macros I can re-export #%app to be a different function
> > so a program:
> > (g a) is rewritten into (f g a)
> > is there a way to do the same thing using TH or Rewrite Rules?
> > Thanks
> > --
> > Ismael
> > _______________________________________________
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> > Haskell-Cafe at haskell.org
> > http://www.haskell.org/mailman/listinfo/haskell-cafe
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