From 83034116b02497576d97bffc9e91a5476cc60d41 Mon Sep 17 00:00:00 2001
From: Noah Loomans <noahloomans@gmail.com>
Date: Wed, 13 Sep 2017 21:36:32 +0200
Subject: decode union type

---
 src/client/elm/Main.elm | 58 ++++++++++++++++++++++++++++++++++++++-----------
 1 file changed, 45 insertions(+), 13 deletions(-)

(limited to 'src/client/elm')

diff --git a/src/client/elm/Main.elm b/src/client/elm/Main.elm
index 8e1e9c8..de1f1fe 100644
--- a/src/client/elm/Main.elm
+++ b/src/client/elm/Main.elm
@@ -1,8 +1,7 @@
 module Main exposing (..)
 
--- import Html.Attributes exposing (..)
 import Html exposing (..)
-import Json.Decode exposing (string, Decoder)
+import Json.Decode exposing (Decoder, andThen, fail, string, succeed)
 import Json.Decode.Pipeline exposing (decode, required)
 
 
@@ -15,7 +14,9 @@ main =
         , subscriptions = subscriptions
         }
 
-type alias Flags = Json.Decode.Value
+
+type alias Flags =
+    Json.Decode.Value
 
 
 type alias Model =
@@ -24,7 +25,7 @@ type alias Model =
 
 
 type alias User =
-    { type_ : String
+    { type_ : UserType
     , value : String
     }
 
@@ -35,31 +36,62 @@ type UserType
     | Room
     | Student
 
+
 init : Flags -> ( Model, Cmd msg )
 init flags =
     case Json.Decode.decodeValue decodeUsers flags of
         Ok user ->
-            (Model user, Cmd.none)
+            ( Model user, Cmd.none )
 
         Err err ->
             Debug.crash err
 
+
 decodeUsers : Decoder (List User)
-decodeUsers = Json.Decode.list decodeUser
+decodeUsers =
+    Json.Decode.list decodeUser
+
 
 decodeUser : Decoder User
 decodeUser =
-  decode User
-    |> required "type" string
-    |> required "value" string
+    decode User
+        |> required "type" decodeUserType
+        |> required "value" string
+
+
+decodeUserType : Json.Decode.Decoder UserType
+decodeUserType =
+    string
+        |> andThen
+            (\s ->
+                case s of
+                    "s" ->
+                        succeed Student
+
+                    "c" ->
+                        succeed Class
+
+                    "t" ->
+                        succeed Teacher
+
+                    "r" ->
+                        succeed Room
+
+                    _ ->
+                        fail ("What the f*ck is " ++ s ++ "?")
+            )
+
+
+update : msg -> Model -> ( Model, Cmd msg )
+update msg model =
+    ( model, Cmd.none )
 
-update : msg -> Model -> (Model, Cmd msg)
-update msg model = (model, Cmd.none)
 
 view : Model -> Html msg
 view model =
-  text <| toString model
+    text <| toString model
+
 
 subscriptions : Model -> Sub msg
 subscriptions model =
-  Sub.none
\ No newline at end of file
+    Sub.none
-- 
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