Update to Gren summer 2024.

Author: robinheghan

cat/gren.json

@@ -4,14 +4,14 @@
     "source-directories": [
         "src"
     ],
-    "gren-version": "0.3.0",
+    "gren-version": "0.4.0",
     "dependencies": {
         "direct": {
-            "gren-lang/core": "4.0.1",
-            "gren-lang/node": "3.0.1"
+            "gren-lang/core": "5.0.0",
+            "gren-lang/node": "4.0.0"
         },
         "indirect": {
-            "gren-lang/url": "3.0.0"
+            "gren-lang/url": "4.0.0"
         }
     }
 }

cat/src/Main.gren

@@ -3,77 +3,32 @@ module Main exposing (main)
 import Node
 import Bytes exposing (Bytes)
 import Stream exposing (Stream)
-import Node exposing (Program, Environment)
+import Node exposing (Environment)
 import FileSystem
+import FileSystem.Path as Path
 import Init
 import Task
 
 
-main : Program Model Msg
+main : Node.SimpleProgram a
 main =
-    Node.defineProgram
-        { init = init
-        , update = update
-        , subscriptions = \_ -> Sub.none
-        }
+    Node.defineSimpleProgram init
 
 
-type alias Model =
-    { stdout : Stream 
-    , stderr : Stream
-    }
-
-
-type Msg
-    = OpenResult (Result FileSystem.AccessError (FileSystem.ReadableFileHandle Never))
-    | ReadResult (Result FileSystem.UnknownFileSystemError Bytes)
-
-init : Environment -> Init.Task { model : Model, command : Cmd Msg }
+init : Environment -> Init.Task (Cmd a)
 init env =
     Init.await FileSystem.initialize <| \fsPermission ->
-        Node.startProgram
-            { model =
-                { stdout = env.stdout
-                , stderr = env.stderr
-                }
-            , command =
-                case env.args of
-                    [ _, _, file ] ->
-                        FileSystem.openForRead fsPermission file
-                            |> Task.attempt OpenResult
-
-                    _ ->
-                        Stream.sendLine env.stderr <|
-                            "Exactly one argument is required: the file name to read"
-            }
-
-update : Msg -> Model -> { model : Model, command : Cmd Msg }
-update msg model =
-    case msg of
-        OpenResult (Ok fh) ->
-            { model = model
-            , command =
-                FileSystem.read fh
-                    |> Task.attempt ReadResult
-            }
-
-        OpenResult (Err error) ->
-            { model = model
-            , command =
-                Stream.sendLine model.stderr <|
-                    "Failed to open file"
-            }
-
-        ReadResult (Ok bytes) ->
-            { model = model
-            , command = 
-                Stream.send model.stdout bytes
-            }
-
-        ReadResult (Err error) ->
-            { model = model
-            , command =
-                Stream.sendLine model.stderr <|
-                    "Failed to read file"
-            }
-
+        case env.args of
+            [ _, _, file ] ->
+                FileSystem.readFile fsPermission (Path.fromPosixString file)
+                    |> Task.map (Bytes.toString >> Maybe.withDefault "")
+                    |> Task.onError (Task.succeed << FileSystem.errorToString)
+                    |> Task.andThen (Stream.sendLine env.stdout)
+                    |> Task.execute
+                    |> Node.endWithCmd
+
+            _ ->
+                "Exactly one argument is required: the file name to read"
+                    |> Stream.sendLine env.stderr
+                    |> Task.execute
+                    |> Node.endWithCmd