use Set and not List to model tags

elm/src/Logged.elm

@@ -6,6 +6,9 @@ import LoggedModel exposing (..)
 import Style exposing (..)
 import Tags exposing (..)
 
+-- elm/core
+import Set exposing (..)
+
 -- elm/http
 import Http exposing (..)
 
@@ -65,7 +68,7 @@ viewTag tag = Element.el
   [ normalPadding
   , normalSpacing
   ]
-  ( Element.text tag.name )
+  ( Element.text tag )
 
 view : Model -> Element Msg
 view model = Component.mainRow
@@ -87,7 +90,7 @@ view model = Component.mainRow
           , width = fill
           , view = \content -> Element.el
             tableRowStyle
-            ( row [] ( List.map viewTag content.tags ) ) }
+            ( row [] ( List.map viewTag ( toList content.tags ) ) ) }
         ]
       }
     ]
@@ -106,17 +109,17 @@ view model = Component.mainRow
 
 -- HTTP
 
-retrieveUrl : List Tag -> String
+retrieveUrl : Set Tag -> String
 retrieveUrl tags = Url.Builder.custom
   ( CrossOrigin "http://localhost:8080" )
   [ "get-contents" ]
-  ( List.map ( \tag -> Url.Builder.string "tag" tag.name ) tags )
+  ( List.map ( \tag -> Url.Builder.string "tag" tag ) ( toList tags ) )
   Nothing
 
 authorization : Token -> Header
 authorization token = Http.header "Authorization" ( String.append "Bearer " token )
 
-retrieveContents : Token -> List Tag -> Cmd Msg
+retrieveContents : Token -> Set Tag -> Cmd Msg
 retrieveContents token tags = Http.request
   { method  = "GET"
   , headers = [ authorization token ]
@@ -133,13 +136,12 @@ handleContentsResponse result = case result of
   Err error -> FetchFailed error
 
 tagDecoder : Decoder Tag
-tagDecoder = Json.Decode.map Tag
-  ( field "name" Json.Decode.string )
+tagDecoder = field "name" Json.Decode.string
 
 contentDecoder : Decoder Content
 contentDecoder = map2 Content
   ( field "message" Json.Decode.string )
-  ( field "tags"    ( Json.Decode.list ( Json.Decode.map Tag Json.Decode.string )))
+  ( field "tags"    ( Json.Decode.map fromList ( Json.Decode.list ( Json.Decode.string ) ) ) )
 
 wrappedContentDecoder : Decoder Content
 wrappedContentDecoder = Json.Decode.map identity
@@ -162,10 +164,10 @@ handleNewContentResponse content result = case result of
   Ok () -> SubmitSuccessful content
 
 tagEncoder : Tag -> Json.Encode.Value
-tagEncoder tag = Json.Encode.string tag.name
+tagEncoder tag = Json.Encode.string tag
 
 contentEncoder : Content -> Json.Encode.Value
 contentEncoder content = Json.Encode.object
   [ ( "message", Json.Encode.string content.message )
-  , ( "tags", Json.Encode.list tagEncoder content.tags)
+  , ( "tags", Json.Encode.list tagEncoder ( toList content.tags ) )
   ]

elm/src/LoggedModel.elm

@@ -1,10 +1,11 @@
 module LoggedModel exposing (..)
 
-type alias Tag =
-  { name : String
-  }
+-- elm/core
+import Set exposing (..)
+
+type alias Tag = String
 
 type alias Content =
   { message : String
-  , tags    : List Tag
+  , tags    : Set Tag
   }

elm/src/Main.elm

@@ -10,6 +10,7 @@ import Style exposing (..)
 import Browser exposing (..)
 
 -- elm/core
+import Set exposing (..)
 import Tuple exposing (mapBoth)
 
 -- mdgriffith/elm-ui
@@ -42,7 +43,7 @@ type Msg
 
 updateAnonymous : Anonymous.Msg -> Anonymous.Model -> ( Model, Cmd Msg )
 updateAnonymous msg anonymousModel = case msg of
-  Login ( Succeeded token ) -> ( LoggedIn ( Logged.init token ), Cmd.map LoggedInMsg ( retrieveContents token [] ) )
+  Login ( Succeeded token ) -> ( LoggedIn ( Logged.init token ), Cmd.map LoggedInMsg ( retrieveContents token empty ) )
   _                         -> Tuple.mapBoth Anonymous ( Cmd.map AnonymousMsg ) (Anonymous.update msg anonymousModel)
 
 update : Msg -> Model -> ( Model, Cmd Msg )

elm/src/Tags.elm

@@ -4,6 +4,9 @@ import Component exposing (..)
 import LoggedModel exposing (..)
 import Style exposing (..)
 
+-- elm/core
+import Set exposing (..)
+
 -- mdgriffith/elm-ui
 import Element exposing (..)
 import Element.Background exposing (..)
@@ -16,11 +19,11 @@ import Element.Input exposing (labelAbove)
 
 type alias Model =
   { newTag : String
-  , tags : List Tag
+  , tags : Set Tag
   }
 
 init : Model
-init = Model "" []
+init = Model "" empty
 
 -- UPDATE
 
@@ -29,31 +32,20 @@ type Msg
   | Submit
   | Remove String
 
-update : ( List Tag -> Cmd msg ) -> Msg -> Model -> ( Model, Cmd msg )
+update : ( Set Tag -> Cmd msg ) -> Msg -> Model -> ( Model, Cmd msg )
 update onSubmit msg model = case msg of
   NewTag newTag -> ( { model | newTag = newTag }, Cmd.none )
   Submit        ->
     let
-      tags = ( Tag model.newTag ) :: model.tags
+      tags = insert model.newTag model.tags
     in
       ( { model | newTag = "", tags = tags }, onSubmit tags )
   Remove id     ->
     let
-      tags = removeTag id model.tags
+      tags = remove id model.tags
     in
       ( { model | tags = tags }, onSubmit tags )
 
-removeTag : String -> List Tag -> List Tag
-removeTag id tags = remove ( Tag id ) tags
-
-remove : a -> List a -> List a
-remove value list = case list of
-  []               -> []
-  ( head :: tail ) ->
-    if   head == value
-    then remove value tail
-    else head :: remove value tail
-
 -- VIEW
 
 removable : String -> Element Msg -> Element Msg
@@ -66,7 +58,7 @@ removable id element = row
   ]
 
 viewRemovableTag : ( Tag -> Element Msg ) -> Tag -> Element Msg
-viewRemovableTag viewTag tag = removable tag.name ( viewTag tag )
+viewRemovableTag viewTag tag = removable tag ( viewTag tag )
 
 view : ( Tag -> Element Msg ) -> String -> String -> Model -> Element Msg
 view viewTag label submitText model = column
@@ -80,5 +72,5 @@ view viewTag label submitText model = column
     , label       = labelAbove [] ( Element.text label )
     } )
   , Component.button Submit submitText
-  , Element.row [ normalSpacing ] ( List.map (viewRemovableTag viewTag) model.tags )
+  , Element.row [ normalSpacing ] ( List.map (viewRemovableTag viewTag) ( toList model.tags ) )
   ]