The Infix Operator

This is a good time to introduce the infix operator that helps us make code a bit more readable. Normally, we apply a function by writing `<FUNCTION> <ARGUMENT1> <ARGUMENT2>`, but we could also write it using the infix operator as `<ARGUMENT1> `<FUNCTION>` <ARGUMENT2>`. This way, we make the code more readable – for example, in the case of`res = mod sum 2`, we can instead write:
res = sum `mod` 2 -- using the infix operator ``
Which then reads as "`res` is equal to `sum modulo 2`". Note that the infix operator can be used this way for functions that take in two arguments. For functions with more than two arguments, we would need to add parentheses to explicitly create expressions (which return another function – currying):
ghci> multiply x y z = x * y * z
ghci> (1 `multiply` 2) 3
6