dhall-1.24.0: dhall-lang/Prelude/Optional/unzip

{-
Unzip an `Optional` value into two separate `Optional` values

Examples:

```
./unzip Text Bool (Some { _1 = "ABC", _2 = True  })
= { _1 = Some "ABC", _2 = Some True }

./unzip Text Bool (None { _1 : Text, _2 : Bool })
= { _1 = None Text, _2 = None Bool }
```
-}
let unzip
    :   ∀(a : Type)
      → ∀(b : Type)
      → Optional { _1 : a, _2 : b }
      → { _1 : Optional a, _2 : Optional b }
    =   λ(a : Type)
      → λ(b : Type)
      → λ(xs : Optional { _1 : a, _2 : b })
      → { _1 =
            Optional/fold
            { _1 : a, _2 : b }
            xs
            (Optional a)
            (λ(x : { _1 : a, _2 : b }) → Some x._1)
            (None a)
        , _2 =
            Optional/fold
            { _1 : a, _2 : b }
            xs
            (Optional b)
            (λ(x : { _1 : a, _2 : b }) → Some x._2)
            (None b)
        }

in  unzip