[Haskell-beginners] Question about precedence

[Michael Orlitzky]

On 07/01/2013 12:14 PM, Marc Gorenstein wrote:
> What sort of beast is ( / 8) in Haskell? It looks like it is a function
> that divides a number by 8.
> 

Yep. This is probably easier to think about with addition rather than
division.

So, (+) is a function. It takes two arguments, and adds them. You need
the parenthesis to prevent it from being an infix operator (used in
*between* the numbers), but that's just a detail. Try it in ghci:

  ghci> (+) 1 2
  3

Thanks to currying, you can construct a function called "plus_one" by
leaving off the last argument:

  ghci> let plus_one = (+) 1
  ghci> let plus_one = (+ 1)

Either notation will work, but they do subtly different things: in the
first case, you get 1 + x, and in the second, you get x + 1. Nevertheless.

  ghci> plus_one 2
  3

Division works the same way.