用没有括号的$重写`map（fgh）x`？

Question

I would like check whether we can't rewrite map (fgh) x with $ without parentheses as I didn't find a way.

Here are my trials:

map (f.g.h) x
-> map (f.g.h) $ x  -- OK, no benefit
-> map $ f.g.h $ x  -- wrong as map doesn't take one parameter
-> (map $ f.g.h) x  -- Ok, no benefit, ugly :-)

Only elegant option I found was to use

negate . sum . tail <$> [[1..5], [3..6]]]

but I would like to be sure that I didn't skip some options above. Thank you

Answer 1

how about?

let u = f.g.h in map u x

no parenthesis, no $

Answer 2

If you define the function

map (f.g.h) x

You thus process each element of x with f . g . h f . g . h f . g . h , this means that we first apply h on it, then g on the result, and finally f on that result.

But we can also work with three separate map s, like:

map f $ map g $ map h x