我是Elm的新手,我刚遇到这个:
update : Msg -> Model -> (Model, Cmd Msg)
update msg model =
case msg of
UrlChange location ->
( { model | history = location :: model.history }
, Cmd.none
)
有人能告诉我第5行的双冒号是什么吗?
那是合作者。它会在列表的前面添加一个项目。
1 :: [2,3] == [1,2,3]
1 :: [] == [1]
文档:
https://package.elm-lang.org/packages/elm/core/latest/List# ::