How does $ work? :: hpaste — Haskell Pastebin

How does $ work?

Paste:#57093
Author:Edwin
Language:Haskell
Channel:#haskell Context in IRC
Created:2012-01-28 05:42:52 UTC
Raw:View raw link

f ::  Int -> Int
f x = (sum [1..x])^2 - (sum . squares) x
			where
				squares x = map (\i -> i^2) [1..x]

f' ::  Int -> Int
f' x = (sum [1..x])^2 - sum $ squares x
			where
				squares x = map (\i -> i^2) [1..x]

2:7: Warning: Redundant bracket
Found:
  (sum [1 .. x]) ^ 2
Why not:
  sum [1 .. x] ^ 2

4:50: Warning: Avoid lambda
Found:
  \ i -> i ^ 2
Why not:
  (^ 2)

7:8: Warning: Redundant bracket
Found:
  (sum [1 .. x]) ^ 2
Why not:
  sum [1 .. x] ^ 2

9:50: Warning: Avoid lambda
Found:
  \ i -> i ^ 2
Why not:
  (^ 2)