dhall-1.14.0: Prelude/Natural/sum

{-
Add all the numbers in a `List`

Examples:

```
./sum [ 2, 3, 5 ] = 10

./sum ([] : List Natural) = 0
```
-}
    let sum
        : List Natural → Natural
        =   λ(xs : List Natural)
          → List/fold
            Natural
            xs
            Natural
            (λ(l : Natural) → λ(r : Natural) → l + r)
            0

in  sum