More explicitly, the expression there seems to rely on knowing the arity of the function and the number of lists at compile time. Basically, I was asking for a function cl_map such that:
cl_map foo [xs:[ys:[zs:...]]] = foo <$> xs <*> ys <*> zs <*> ...
> traverse_ print (sequenceA [ZipList [1,2], ZipList [3,4]])
[1,3]
[2,4]Basically, instead of your example I would like to do something like this:
> cl_map (+) [ZipList [1,2,3], ZipList [4,5,6]]
[5,7,9]
> cl_map (+ 3) [ZipList [1,2,3]]
[4,5,6]
> cl_map max3 [ZipList [1,2], ZipList [3,4], ZipList [5,6]] where max3 x y z = max x (max y z)
[5, 6]
Note: If this doesn't work with ZipList, that's ok - the important part is being able to supply the function at runtime. Also, please don't assume that the function is associative or anything like that - it's an arbitrary function of N parameters.