Possibly

In short:

Never marks states as impossible
```
empty : Is Possibly Empty filling_
```

Possibly marks states as possible

top : Is Never Empty (StackFilled element) -> element

→ you can carry over non-emptiness-information

import Fillable exposing (Is(..), toFillingOrIfEmpty)


type Focus item possiblyOrNever hole
    = Item item
    | Hole possiblyOrNever


type Hole
    = HoleTag Never


toFocus :
    Is possiblyOrNever Empty value
    -> Focus value possiblyOrNever Hole
toFocus =
    \fillable ->
        case fillable of
            Empty possiblyOrNever ->
                Hole possiblyOrNever


            Filled value ->
                value |> Item

toFocus =
    \fillable ->
        fillable
            |> Fillable.map Item
            |> toFillingOrIfEmpty Hole

type Possibly

= Possible

Marks a state as possible to occur.

in results

fromMaybe : Maybe value -> Is value Possibly Empty


fromList : List element -> Is (StackFilled element) Possibly Empty

in type declarations

type alias Model =
    WithoutConstructorFunction
        { selected : Is Choice Possibly Empty
        , planets : Is (StackFilled Planet) Possibly Empty
        , searchKeyWords : Is (StackFilled String) Never Empty
        }


type alias WithoutConstructorFunction record =
    record

where WithoutConstructorFunction stops the compiler from creating a positional constructor function for Model.

Read more about the general idea in the module documentation. or readme.

If you still have questions, check out the readme.

Modules

Possibly

lue-bird/elm-allowable-state/1.0.0

Possibly

in results

in type declarations

Modules