It might be nice to actually replace `drop (length args `div` 2) args` with a function `dropLevityArgs = dropWhile (isLevityTy . typeKind)` (I did this in my branch). When I see a code that drops half of the type arguments it doesn't make sense right away, but `dropLevityArgs` is at least giving an idea of what's actually happening. 2016-01-28 20:30 GMT-05:00 Ömer Sinan Ağacan <omeragacan@gmail.com>:
Ahh, levity is type of kinds, right? For some reason I thought kinds are now levities (or whatever it's called). This makes sense. I just tried and I think it works, thanks.
2016-01-28 19:39 GMT-05:00 Richard Eisenberg <eir@cis.upenn.edu>:
On Jan 28, 2016, at 5:48 PM, Ömer Sinan Ağacan <omeragacan@gmail.com> wrote:
| Just (tc, args) <- splitTyConApp_maybe ty , isUnboxedTupleTyCon tc = pprTrace "elimUbxSumRepTypes" (text "orig args:" <+> ppr args $$ text "dropWhile isLevityTy args = " <+> ppr (dropWhile isLevityTy args)) $ concatMap go (drop (length args `div` 2) args)
You want (dropWhile (isLevityTy . typeKind) args). isLevityTy simply checks if its argument is exactly `Levity`.
Does that work?
Richard