Make main in to a stub, update tests for new code

exercises/concept/paulas-palindromes/.docs/hints.md

@@ -4,35 +4,33 @@
 
 - Check out the [Elm Guide][elm-guide], which has a nice worked example that is similar.
 
-## 1. Define the Model type for the application
+## 1. Define the Model and Msg types for the application
 
 - The `Model` contains the application's state - all the data that the application needs.
 - This application just needs a string to store the text in the Text Box.
 - It can be any type, but in any useful application it is always a [record][record].
 
-## 2. Define the Msg type for the application
-
 - The `Msg` type is a defines the messages that are passed to the `update` function, to trigger specific changes in the model.
 - This application only needs one change to the model - updating the model when the text in the Text Box changes.
 - It can be any type, but in any useful application it is always a [custom type][custom-type].
 
-## 3. Write the update function
+## 2. Write the update function
 
 - In any useful application the update function will use a `case` statement to pattern match on the `Msg` parameter.
 - IN each branch of the case statement it will extract information it needs from the `Msg` parameter and return an updated `Model`
 - The `Model` should be a record, and [record update syntax][record-update-syntax] is normally used.
 
-## 4. Write the view function
+## 3. Write the view function
 
 - The `view` function should probably return a `div` for the root element
 - The first child should be an `input`, with a `value` attribute for the current text, and an `nInput` attribute / event with the relevant variant of the `Msg`.
 - The second child should probably be another `div` with a `text`child stating whether the text is a palindrome or not.
 
-## 5. Write the init function
+## 4. Write the init function
 
 - This should simply return a `Model` with sensible default values (probably an empty string).
 
-## 6. Write the main function
+## 5. Write the main function
 
 - The main function should just called [`Browser.sandbox`][browser-sandbox]
 - `Browser.sandbox` requires a [record][record] argument with the `init`, `update` and `view` functions.

exercises/concept/paulas-palindromes/.docs/instructions.md

@@ -10,29 +10,29 @@ You decide to do this using an Elm [sandbox][browser-sandox] application.
 The application will have a Text Box, that Paula can type her guess into, and text stating whether or not the text in the box is a palindrome or not.
 The text will update whenever the text in the Text Box changes.
 
-## 1. Define the Model type for the application
+## 1. Define the Model and Msg types for the application
 
 The application `Model` needs the string to check.
 
-## 2. Define the Msg type for the application
+The application needs a `Msg` to indicate that the text in the Text Box has changed. The variant for this should be called `Change`
 
-The application needs a `Msg` to indicate that the text in the Text Box has changed.
-
-## 3. Write the update function
+## 2. Write the update function
 
 The update function should take a `Msg` and a `Model` parameter, and return a new `Model`.
 
-## 4. Write the view function
+## 3. Write the view function
 
 Elm requires that the view function has to return an `Html msg` type, which means that you need to return a single element from the view function (and not an  array of elements).
 
-Inside this root element, there should be an `input` element (the Text Box),and a `div` with `text` content to state whether the text in the `input` is a palindrome or not.
+Inside this root element, there should be an `input` element (the Text Box), and a `div` with `text` content to state whether the text in the `input` is a palindrome or not.
+
+The text should be "This is a palindrome" or "Not a palindrome".
 
-## 5. Write the init function
+## 4. Write the init function
 
 The `init` function should return a sensible initial `Model` value.
 
-## 6. Write the main function
+## 5. Write the main function
 
 The `main` function should call [`Browser.sandbox`][browser-sandbox], passing a record parameter with the `init`, `update` and `view` functions.
 

exercises/concept/paulas-palindromes/.docs/introduction.md.tpl

@@ -0,0 +1,3 @@
+# Introduction
+
+%{concept: web-applications-1}

exercises/concept/arlos-alphabetiser/.meta/Exemplar.elm → exercises/concept/paulas-palindromes/.meta/Exemplar.elm

@@ -46,10 +46,17 @@ update msg model =
 
 -- VIEW
 
+isPalindrome : String -> String
+isPalindrome content =
+    if content == (content |> String.toLower |> String.reverse)  then
+        "This is a palindrome"
+    else
+        "Not a palindrome"
+
 
 view : Model -> Html Msg
 view model =
     div []
-        [ input [ placeholder "Text to alphabetise", value model.content, onInput Change ] []
-        , div [] [ text (model.content |> String.toLower |> String.toList |> List.sort |> String.fromList) ]
+        [ input [ placeholder "Text to check for a palindrome", value model.content, onInput Change ] []
+        , div [] [ text (isPalindrome model.content) ]
         ]

exercises/concept/arlos-alphabetiser/src/Browser.elm → exercises/concept/paulas-palindromes/src/Browser.elm

@@ -10,8 +10,6 @@ type alias Sandbox msg model =
     }
 
 
-sandbox :
-    Sandbox msg model
-    -> Html msg --Sandbox msg model
+sandbox : Sandbox msg model -> Html msg
 sandbox { init, view } =
     view init

exercises/concept/arlos-alphabetiser/src/Main.elm → exercises/concept/paulas-palindromes/src/Main.elm

@@ -1,4 +1,4 @@
-module Main exposing (Msg(..), init, main, update, view)
+module Main exposing (..)
 
 import Browser
 import Html exposing (Html, div, input, text)
@@ -7,7 +7,6 @@ import Html.Events exposing (onInput)
 
 
 
--- MAIN
 -- When you have finished this exercise, this file will be an Elm program.
 --
 -- You can copy this file to Ellie (an online Elm sandbox - https://ellie-app.com/)
@@ -21,46 +20,35 @@ import Html.Events exposing (onInput)
 -- - Then go to the url in the output to view the application (localhost://53529 or similar)
 
 
+-- MAIN
+
+main: Html msg
 main =
-    Browser.sandbox { init = init, update = update, view = view }
+    Debug.todo "Implement main function"
 
 
 
 -- MODEL
 
+-- define the Model type
 
-type alias Model =
-    { content : String
-    }
 
-
-init : Model
 init =
-    { content = "" }
+    Debug.todo "Implement init function"
 
 
 
 -- UPDATE
 
 
-type Msg
-    = Change String
-
+-- define the Msg type, with a `Change` variant
 
-update : Msg -> Model -> Model
 update msg model =
-    case msg of
-        Change newContent ->
-            { model | content = newContent }
-
+    Debug.todo "Implement update function"
 
 
 -- VIEW
 
 
-view : Model -> Html Msg
 view model =
-    div []
-        [ input [ placeholder "Text to alphabetise", value model.content, onInput Change ] []
-        , div [] [ text (model.content |> String.toLower |> String.toList |> List.sort |> String.fromList) ]
-        ]
+    Debug.todo "Implement view function"

exercises/concept/arlos-alphabetiser/tests/Tests.elm → exercises/concept/paulas-palindromes/tests/Tests.elm

@@ -1,7 +1,7 @@
 module Tests exposing (tests)
 
 import Expect
-import Main exposing (Msg(..), init, main, update, view)
+import Main exposing (..)
 import Test exposing (..)
 import Test.Html.Event as Event
 import Test.Html.Query as Query
@@ -10,12 +10,24 @@ import Test.Html.Selector exposing (tag, text)
 
 tests : Test
 tests =
-    describe "ArlosAlphabetiser"
+    describe "Paulas Palindromes"
         [ describe "1"
-            [ test "init should return a model empty content" <|
+            [test "Model is exposed" <|
                 \_ ->
-                    init
-                        |> Expect.equal { content = "" }
+                    let
+                        identity : Model -> Model
+                        identity model =
+                            model
+                    in
+                    Expect.pass,
+            test "Msg is exposed" <|
+                \_ ->
+                    let
+                        identity : Msg -> msg
+                        identity msg =
+                            msg
+                    in
+                    Expect.pass
             ]
         , describe "2"
             [ test "update should change the model content" <|
@@ -24,20 +36,31 @@ tests =
                         |> Expect.equal { content = "new content" }
             ]
         , describe "3"
-            [ test "view should alphabetise content" <|
+            [ test "view should identify content as a palindrome" <|
+                \_ ->
+                    view { content = "tacocat" }
+                        |> Query.fromHtml
+                        |> Query.has [ text "This is a palindrome" ]
+            , test "view should identify content that is not a palindrome" <|
                 \_ ->
-                    view { content = "cats" }
+                    view { content = "wrapcat" }
                         |> Query.fromHtml
-                        |> Query.has [ text "acst" ]
-            , test "view should blah" <|
+                        |> Query.has [ text "Not a palindrome" ]                        
+            , test "view should create Msg.Change onChange" <|
                 \_ ->
                     view { content = "" }
                         |> Query.fromHtml
                         |> Query.find [ tag "input" ]
-                        |> Event.simulate (Event.input "cats")
-                        |> Event.expect (Change "cats")
+                        |> Event.simulate (Event.input "cat")
+                        |> Event.expect (Change "cat")
             ]
         , describe "4"
+            [ test "init should return a model empty content" <|
+                \_ ->
+                    init
+                        |> Expect.equal { content = "" }
+            ]
+        , describe "5"
             [ test "main should create the sandbox" <|
                 \_ ->
                     -- This is a bit of a hack, and doesn't test the update function is passed,