Morph the N to a more narrow range

Morph from a Natural.

Inverse of Natural.Morph.n

Bit.O ↔ n0, Bit.I ↔ n1.

Inverse of Bit.Morph.n

Morph a digit in a given range

import Morph
import N exposing (n1, n2, n7, n9)


'5'
    |> Morph.toNarrow (N.Morph.inChar ( n1, n7 ))
    |> Result.map N.toInt
--> Ok 5


'1'
    |> Morph.toNarrow (N.Morph.inChar ( n2, n9 ))
    |> Result.toMaybe
--> Nothing