{-
Returns the absolute value of an `Integer`, i.e. its non-negative value.
-}
let abs
    : Integer → Natural
    =   λ(n : Integer)
      →       if Natural/isZero (Integer/clamp n)

        then  Integer/clamp (Integer/negate n)

        else  Integer/clamp n

let example0 = assert : abs +7 ≡ 7

let example2 = assert : abs +0 ≡ 0

let example3 = assert : abs -3 ≡ 3

in  abs