ValidationExtra.elm

import Html exposing (..)
import Html.App as Html
import Html.Attributes exposing (..)
import Html.Events exposing (onInput)
import String exposing (length)

main =
  Html.beginnerProgram
    { model = model
    , view = view
    , update = update
    }



-- MODEL


type alias Model =
  { name : String
  , password : String
  , passwordAgain : String
  }


model : Model
model =
  Model "" "" ""



-- UPDATE


type Msg
    = Name String
    | Password String
    | PasswordAgain String


update : Msg -> Model -> Model
update action model =
  case action of
    Name name ->
      { model | name = name }

    Password password ->
      { model | password = password }

    PasswordAgain password ->
      { model | passwordAgain = password }



-- VIEW


view : Model -> Html Msg
view model =
  div []
    [ input [ type' "text", placeholder "Name", onInput Name ] []
    , input [ type' "password", placeholder "Password", onInput Password ] []
    , input [ type' "password", placeholder "Re-enter Password", onInput PasswordAgain ] []
    , viewValidation model
    ]


viewValidation : Model -> Html msg
viewValidation model =
  let
    renderReq : (String, String) -> Html msg
    renderReq (colour, message) =
      p [style [("color", colour)]] [text message]

    checkForRequisites : String -> String -> List (String -> String -> (String, String)) -> List (String, String)
    checkForRequisites pass matchpass reqs =
      List.map (\req -> req pass matchpass) reqs

    matchReq : String -> String -> (String, String)
    matchReq pass matchpass = 
      if pass == matchpass then
        ("green", "Passwords match: OK")
      else
        ("red", "Passwords do not match!")

    lengthReq : String -> String -> (String, String)    
    lengthReq pass matchpass =
      if length( pass ) >= 10 then
        ("green", "Password length: OK")
      else
        ("red", "Password too short!")

    reqs : List (String -> String -> (String, String))
    reqs = [matchReq, lengthReq]

    checked : List (String, String)
    checked = checkForRequisites model.password model.passwordAgain reqs
  in
    div [ ] (List.map renderReq checked)