Publish state to a port

Interop.elm

module Interop where

import Signal
import String
import Html exposing (..)
import Html.Attributes exposing (value)
import Html.Events exposing (on, targetValue)

type Field = Name
           | Age

type Action = NoOp
            | Change Field String

type alias Model = {
  name : String,
  age  : Int
}

main =
  Signal.map (view actions.address) model

initialModel : Model
initialModel =
  {
    name = "",
    age  = 0
  }

update : Action -> Model -> Model
update action model =
  case action of
    NoOp ->
      model
    Change field value ->
      case field of
        Name ->
          { model | name = value }
        Age ->
          { model | age = Maybe.withDefault 0 <| Result.toMaybe <| String.toInt value }

view : Signal.Address Action -> Model -> Html
view address model =
  div
    []
    [ div
        []
        [ label [] [text "Name"]
        , input
            [ value model.name
            , on "change" targetValue (\value -> Signal.message address (Change Name value))
            ]
            []
        ]
    , div
        []
        [ label [] [text "Age"]
        , input
            [ value <| toString model.age
            , on "change" targetValue (\value -> Signal.message address (Change Age value))
            ]
            []
        ]
    ]


actions : Signal.Mailbox Action
actions =
  Signal.mailbox NoOp


model : Signal Model
model =
  Signal.foldp update initialModel actions.signal


port save : Signal (Maybe Int)

port onSave : Signal Model
port onSave =
  Signal.map (\_ -> initialModel) save