榆木效果，壁虱函数显然永远不会被调用 [英] elm effects, the tick function apparently never get called

问题描述

我试图使我的模型对时钟滴答做出反应，以便进行一些动画，如榆木建筑教程的示例8（旋转立方体）。

I am trying to make my model react to the clock ticks in order to do some animation like the example 8 (spinning cube) of the elm architecture tutorial.

https://github.com/evancz/elm-architecture-tutorial

由于我的程序无法正常运行，所以我尝试举一个最简单的例子来说明我的问题。

Since my program is not working I tried to make the simplest example I could demonstrating my problem.

module Test where

import Html exposing (..)
import Html.Events exposing (..)
import StartApp as StartApp
import Effects exposing (..)
import Time exposing (..) 

type alias Model =
 {debug : String}

type Action = 
 Start | Tick Time

initialModel = Model "initial"

update : Action -> Model -> (Model, Effects Action)
update action model =
  case action of
    Start  -> ({model | debug = "started"}, Effects.tick Tick)
    Tick _ -> ({model | debug = "hasTicked"}, Effects.none)

view : Signal.Address Action -> Model -> Html
view address model =
  div []
      [ button [onClick address Start] [text "start"]
      , p [] [text (.debug model)]
      ]

app =
    StartApp.start
          { init = (initialModel, Effects.none)
          , view = view
          , update = update
          , inputs = []
          }

main =
    app.html

当我运行该按钮时，当我单击该按钮时，该模型已正确更新为已启动，但从未触发滴答操作。

when I run this the model is correctly updated to "started" when I click the button, but the Tick action is never triggered.

我可能在这里丢失了一些东西，但我不知道在哪里。

I am probably missing something here but I don't know where.

推荐答案

您缺少任务端口。将其添加进去，然后就应该准备好了：

You're missing the tasks port. Add this in and you should be all set:

port tasks : Signal (Task.Task Effects.Never ())
port tasks =
  app.tasks

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