Practical use of curried functions?

Question

There are tons of tutorials on how to curry functions, and as many questions here at stackoverflow. However, after reading The Little Schemer, several books, tutorials, blog

Answer 1

They can make code easier to read. Consider the following two Haskell snippets:

lengths :: [[a]] -> [Int]
lengths xs = map length xs

lengths' :: [[a]] -> [Int]
lengths' = map length

Why give a name to a variable you're not going to use?

Curried functions also help in situations like this:

doubleAndSum ys = map (\xs -> sum (map (*2) xs) ys

doubleAndSum' = map (sum . map (*2))

Removing those extra variables makes the code easier to read and there's no need for you to mentally keep clear what xs is and what ys is.

HTH.