Looking for help writing some GHC RULES

[wren romano]

On Tue, Jul 22, 2014 at 6:42 PM, David Feuer <david.feuer at gmail.com> wrote:
> I'm looking for some help writing some translate/untranslate rules to
> implement fusion for a couple of basic functions (the ones I'm looking at
> right now are takeWhile and scanr, but there may be others). I have a
> translation for takeWhile that seems to be at least decent, and one for
> scanr that is completely untested. I've never mucked about with GHC RULES,
> however, so I don't even know where to begin.

Probably the best place to start is to take a look at the source for
GHC.Base and GHC.List, in particular the rules for map and filter
capture the overarching pattern of how to stage the different rules.

<http://hackage.haskell.org/package/base-4.7.0.1/docs/src/GHC-Base.html#map>
<http://hackage.haskell.org/package/base-4.7.0.1/docs/src/GHC-List.html#filter>

-- 
Live well,
~wren