How do I get an absolute value in Rust?

The docs are unhelpful: http://web.mit.edu/rust-lang_v0.9/doc/std/num/fn.abs.html

Obviously, I can see the function right there, but I haven't got the faintest idea how to call it.

Edit:

The problem is that it doesn't work. :)

use std::num;
let x = num::abs(value);

"Unresolved name: num::abs"

Edit 2: running the nightly from yesterday (11/26/2014); I don't know what version. I didn't realize those docs were so outdated. oO

Current docs seem to indicate there is no such function?

Nowadays, abs is a method on most number types.

let value = -42i32;
let x = value.abs();

Stack Overflow Q#27182808, score: 171