The partial operator allows you to partially apply a function.

For example, look at this implementation of an add function:

let add = (a, b) => a + b

In let add2 = partial add(2), add2 is a function that accepts a single argument and adds two to it.

Arguments may also be skipped and provided later:

let map123 = partial List.map(_, [1, 2, 3])

map123(a => a * 4) // [4, 8, 12]