reverse-and-uppercase-every-other-char.elm

-- My first semi-complicated elm program after reading the first couple pages of the docs
-- I based this off of the text input example here (https://guide.elm-lang.org/architecture/text_fields.html) and used only the api documentation to figure the rest out 

import Browser
import Html exposing (Html, Attribute, div, input, text)
import Html.Attributes exposing (..)
import Html.Events exposing (onInput)



-- MAIN


main =
  Browser.sandbox { init = init, update = update, view = view }



-- MODEL


type alias Model =
  { content : String
  }


init : Model
init =
  { content = "" }



-- UPDATE


type Msg
  = Change String


update : Msg -> Model -> Model
update msg model =
  case msg of
    Change newContent ->
      { model | content = newContent }



-- VIEW

uppercaseEveryOtherChar content = 
  String.fromList (
    List.map
      (\(i, char) -> 
        if (Basics.modBy 2 i) == 1 then 
          Char.toUpper char 
        else
          Char.toLower char
      )
      (List.indexedMap Tuple.pair (String.toList content))
  )


view : Model -> Html Msg
view model =
  div []
    [ input [ placeholder "Text to reverse", value model.content, onInput Change ] []
    , div [] [ text (String.reverse (uppercaseEveryOtherChar model.content)) ]
    ]