djinn[1] can derive some glue functions for you. you tell it something like > glue :: (x -> y -> z -> (b,(c,a)) -> (c -> a -> d) -> x -> y -> z -> d and it tells you something like > glue f g x y z = let (b,(c,a)) = f x y z in g c a I changed the type of f slightly to avoid the trivial answer > glue _ g a _ c = g c a
[1] http://hackage.haskell.org/package/djinn 2010/10/9 André Batista Martins <andre...@netcabo.pt>: > > Might have not been clear, but i will try illustrate . > > > f:: a-> b -> c -> (b,(c,a)) > > f1 :: c -> a -> d > > > input type: > A B C > ---------- > | f | > | _____ | > > output (B,(C,A)) > > > C A > ---------- > | f1 | > | _____ | > > output D > > If i want compose f and f1, i need to do a correct input to f1 from the > output of f. > So i want one function to convert the output of "f" to input off "f!". > In this case, we do f1 fst (snd (t,(t1,t2))) snd (snd (t,(t1,t2))) > But i want do this automaticaly, for type of any two function. I search for > the "glue". > > I don't have any concern about what the function does, i only have interess > on input and output types. > > > Cheers, > André > > > > No dia 9 de Outubro de 2010 22:38, André Batista Martins > <andre...@netcabo.pt> escreveu: >> >> Hello, >> exists any algorithm to determine how terms can be changed to safisty >> the type of one function? >> >> >> example: >> >> f:: a-> b -> c -> (b,c,a) >> >> f1 :: c -> a -> d >> >> In my first function "f" i want assign the output "c" and "a" for to >> input of function "f1". >> I searched for any solution, but i didn't find any anything. >> >> One clue i have found is "minimal edit distance algorithm" for 2 strings. >> Perhaps if i convert de output type of "f" to one string, and de input of >> "f1" to another string and then use this algorithm , i will get one "dirty" >> solution... >> >> I'm open to any sugestion. > > > _______________________________________________ > Haskell-Cafe mailing list > Haskell-Cafe@haskell.org > http://www.haskell.org/mailman/listinfo/haskell-cafe > > _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
