Statechart

A pure Elm implementation of statecharts designed to hook directy into The Elm Architecture update function.

type alias Statechart msg model =

Tree (StateConfig msg model)

type alias StateModel =

{ currentStateName : String

, targetStateName : String

, history : Dict String String

}

decoder : Decoder StateModel

Decode a stored StateModel.

encode : StateModel -> Value

Encode the StateModel into a value ready to be stored in the main model.

Statechart msg model

-> List (Statechart msg model)

-> Statechart msg model

Make the top level statechart

BranchStateConfig msg model

-> List (Statechart msg model)

-> Statechart msg model

Make a compound state from a StateConfig

mkState : LeafStateConfig msg model -> Statechart msg model

Make a state from a StateConfig

noAction : Maybe model -> msg -> ( msg, List model )

The identity action that does nothing

empty : StateModel

An empty StateModel; this is the initial value in the model.

Config msg model

-> ( model, Cmd msg )

-> Result String ( model, Cmd msg )

Start the statechart in its starting state. This can fail in the case of a badly configured statechart.

Config msg model

-> msg

-> ( model, Cmd msg )

-> Result String ( model, Cmd msg )

Step through the statechart in response to an incoming message. This can fail in the case of non-existant state names.

Modules