Or

One or the other.

type Or first second

= First first

| Second second

One or the other.

When (not) to use this? → readme

observe

value : Or value value -> value

Treat the values from the First and Second case equally

[ Or.First 0, Or.Second 1 ] |> List.map Or.value
--> [ 0, 1 ]

onFirstMap : (first -> firstMapped) -> Or first second -> Or firstMapped second

In case it's the First, change it based on it's current value

Or.First "hello" |> Or.onFirstMap String.toUpper
--> Or.First "HELLO"


Or.Second "hello" |> Or.onFirstMap String.toUpper
--> Or.Second "hello"

Prefer a case..of if you handle both cases

onSecondMap : (second -> secondMapped) -> Or first second -> Or first secondMapped

In case it's the Second, change it based on it's current value

Or.First "hello" |> Or.onSecondMap String.toUpper
--> Or.First "hello"


Or.Second "hello" |> Or.onSecondMap String.toUpper
--> Or.Second "HELLO"

Prefer a case..of if you handle both cases

justOnFirst : Or first second_ -> Maybe first

Just if the first value is present, Nothing if the second is present

Or.First 0 |> Or.justOnFirst --> Just 0


Or.Second 1 |> Or.justOnFirst --> Nothing

Prefer a case..of if you handle both cases

justOnSecond : Or first_ second -> Maybe second

Just if the second value is present, Nothing if the first is present

Or.First 0 |> Or.justOnSecond --> Nothing


Or.Second 1 |> Or.justOnSecond --> Just 1

Prefer a case..of if you handle both cases