How can I bind the second argument in a function but not the first (in an elegant way)?
- by Frank Osterfeld
Is there a way in Haskell to bind the second argument but not the first of a function without using lambda functions or defining another "local" function?
Example. I have a binary function like:
sub :: Int -> Int -> Int
sub x y = x - y
Now if I want to bind the first argument, I can do so easily using (sub someExpression):
mapSubFrom5 x = map (sub 5) x
*Main> mapSubFrom5 [1,2,3,4,5]
[4,3,2,1,0]
That works fine if I want to bind the first n arguments without "gap".
If I want to bind the second argument but not the first, the two options I am aware of are more verbose:
Either via another, local, function:
mapSub5 x = map sub5 x
where sub5 x = sub x 5
*Main> mapSub5 [1,2,3,4,5]
[-4,-3,-2,-1,0]
Or using lambda:
mapSub5 x = map (\x -> sub x 5) x
While both are working fine, I like the elegance of "sub 5" and wonder if there is a similarly elegant way to bind the n-th (n 1) argument of a function?
