And what's Reverse? I happen to know Reifies. But you'll also get a better (and more likely) answer if you reduce dependencies.
Richard
On Aug 1, 2015, at 8:05 PM, htebalaka
Alright. The first two examples show the issue and a fix for it; the last two have the same issue but existential quantification prevents the fix.
grad has type "(Num a, Traversable t) => (forall s. Reifies s Tape => t (Reverse s a) -> Reverse s a) -> t a -> t a", and I'm basically trying to supply a function to it, either by being polymorphic over all Num (of which Reverse s a is an instance), or by providing the specific 'Reifies s Tape => ...' type, neither of which are working.
amindfv wrote
You'll probably get more responses if you paste the code inline.
tom
El Aug 1, 2015, a las 11:25, htebalaka <
goodingm@
> escribió:
I'm curious if anyone can tell me why moving the pattern matching in these two examples makes it fail to compile, and what can be done to resolve the same issue in either of the latter two examples. As far as I can tell these should be equivalent. Unfortunately the solution used in the first examples won't work in the later ones due to the existential quantification. I've been asking on #haskell for a few days but haven't been able to find anyone who knows what the issue is.
Code is available here: http://lpaste.net/137586 <http://lpaste.net/137586>;
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