{-
Tag each element of the list with its index
-}
let indexed
    : ∀(a : Type) → List a → List { index : Natural, value : a }
    = List/indexed

let example0 =
        assert
      :   indexed Bool [ True, False, True ]
        ≡ [ { index = 0, value = True }
          , { index = 1, value = False }
          , { index = 2, value = True }
          ]

let example1 =
        assert
      :   indexed Bool ([] : List Bool)
        ≡ ([] : List { index : Natural, value : Bool })

in  indexed