Signal.toggle for Elm

toggle.elm

import Signal
import Html
import Html (div, text, button)
import Html.Events (onClick)

toggle s1 s2 s =
  Signal.foldp 
    (\prev curr -> 
      if prev == s1 then s2 else s1) s1 s

toggler = Signal.channel "blah"

main = Signal.map scene
  <| toggle "blah" "diddy"
  <| Signal.subscribe toggler

scene s =
  Html.toElement 500 500
    <| div
        [] 
        [ text s
        , button 
            [onClick <| Signal.send toggler s] 
            [text "Toggle That"]
        ]