commit cfe000184696eec5de78b5bbf9390c0e205c0dcb
Author: Youwen Wu <youwenw@gmail.com>
Date:   Sun Feb 16 16:54:16 2025 -0800

    initial commit

diff --git a/.gitignore b/.gitignore
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+++ b/.gitignore
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+elm-stuff/
diff --git a/README.md b/README.md
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+++ b/README.md
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+# elm experiments
+
+a collection of various experiments to learn [Elm](https://elm-lang.org/)
diff --git a/elm.json b/elm.json
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+++ b/elm.json
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+{
+    "type": "application",
+    "source-directories": [
+        "src"
+    ],
+    "elm-version": "0.19.1",
+    "dependencies": {
+        "direct": {
+            "elm/browser": "1.0.2",
+            "elm/core": "1.0.5",
+            "elm/html": "1.0.0"
+        },
+        "indirect": {
+            "elm/json": "1.1.3",
+            "elm/time": "1.0.0",
+            "elm/url": "1.0.0",
+            "elm/virtual-dom": "1.0.3"
+        }
+    },
+    "test-dependencies": {
+        "direct": {},
+        "indirect": {}
+    }
+}
diff --git a/src/PasswordValidation.elm b/src/PasswordValidation.elm
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+++ b/src/PasswordValidation.elm
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+module PasswordValidation exposing (..)
+import Browser
+import Html exposing (..)
+import Html.Attributes exposing (..)
+import Html.Events exposing (onInput)
+
+
+
+-- MAIN
+
+
+main =
+  Browser.sandbox { init = init, update = update, view = view }
+
+
+
+-- MODEL
+
+
+type alias Model =
+  { name : String
+  , password : String
+  , passwordAgain : String
+  }
+
+
+init : Model
+init = Model "" "" ""
+
+
+
+-- UPDATE
+
+
+type Msg
+  = Name String
+  | Password String
+  | PasswordAgain String
+
+
+update : Msg -> Model -> Model
+update msg model =
+  case msg of
+    Name name ->
+      { model | name = name }
+    
+    Password password ->
+      { model | password = password }
+
+    PasswordAgain password ->
+      { model | passwordAgain = password }
+
+
+
+-- VIEW
+
+
+view : Model -> Html Msg
+view model =
+  div []
+    [ viewInput "text" "Name" model.name Name
+    , viewInput "password" "Password" model.password Password
+    , viewInput "password" "Re-enter Password" model.passwordAgain PasswordAgain
+    , viewValidation model
+    ]
+
+viewInput : String -> String -> String -> (String -> msg) -> Html msg
+viewInput t p v toMsg =
+  input [ type_ t, placeholder p, value v, onInput toMsg ] []
+
+viewValidation : Model -> Html msg
+viewValidation model =
+  if List.length (passwordHints model.password) > 0 then
+    div [ style "color" "red" ] (passwordHints model.password)
+  else if model.password /= model.passwordAgain  then
+    div [ style "color" "red" ] [ text "Passwords do not match!" ]
+  else
+    div [ style "color" "green" ] [ text "OK" ]
+
+passwordHints : String -> List (Html msg)
+passwordHints s =
+  (optional (String.length s <= 8) (text "Password must be at least 8 characters. "))
+  ++ (optional (String.toUpper s == s) (text "Password must contain an uppercase letter. "))
+  ++ (optional (String.toLower s == s) (text "Password must contain a lowercase letter. "))
+  ++ (optional (not (containsNumeric s)) (text "Password must contain a number. "))
+
+optional : Bool -> Html msg -> List (Html msg)
+optional b xs = if b then [xs] else []
+
+containsNumeric : String -> Bool
+containsNumeric s = List.any (\b -> b) (List.map (\x -> String.contains x s) ["1", "2", "3", "4", "5", "6", "7", "8", "9", "0"])