On Thu, 13/May/2010 at 18:57 +0100, Maciej Piechotka wrote:
Hmm. What GDAT/existential do you use (for lazy people who do not want to read paper)?
The GADT that I refered was from my faileds attempts.
How is it programmed in Lisp?
The paper don't give much details, but by what I undertood, if a random generated program don't compile it's discarted.
[...]
Both compiles but I'm not sure if they are what you want.
What I want is to can create trees like: U (a -> b) (U (c -> a) V) Or: B (a -> b -> c) (U (c -> a) V) (U (c -> b) V) And convert this to a function c -> b. I think I have achieved this now, but really don't understand exactly how it works. Look at this: data Tree a b c where B :: (a -> d -> b) -> Tree e a c -> Tree g d c -> Tree a b c U :: (a -> b) -> Tree d a c -> Tree a b c V :: (c -> d) -> Tree c d c treeToFunc :: Tree a b c -> c -> b treeToFunc (B f l r) = f <$> (treeToFunc l) <*> (treeToFunc r) treeToFunc (U f u) = f.(treeToFunc u) treeToFunc (V f) = f The only problem is that I need to create (V id) in the last leaf everytime: *Main> let r = B (\x y -> (fromInteger x) + y) (U floor (V id)) (U (**2) (V id)) *Main> (treeToFunc r) 3 12.0 Do you see any way to simplify this solution? Thanks, Edgar
Regards
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