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F# Interactive Windows Application and Some Questions

First of all best regards to the F# team for producing CTP! This is a great event! Thanks a million!

I have implemented a windows application in F# which is a wrapper for fsi.exe (F# REPL or Interactive Console). You can load a fsx or save your working text to a file and it works like F# console in Visual Studio. You select your code and press Alt+Enter and your code will be sent to fsi.exe and the result can be seen in the output window. Of course it is far from being comparable to the Visual Studio Interactive Console (We have intellisense there and much more utilities which are indeed very hard work to accomplish). Yet it is good enough for quick tests. It works well out of visual studio. Here the code and then questions:
(do not forget to add the necessary refrences if you are going to run this in REPL)

#light

open System
open System.Collections.Generic
open System.ComponentModel
open System.Data
open System.Drawing
open System.Linq
open System.Text
open System.Windows.Forms

open System.IO
open System.Diagnostics
open System.Threading

type MainForm =
    inherit Form
    
    val mutable components : System.ComponentModel.IContainer
    val mutable rtbInput : System.Windows.Forms.RichTextBox
    val mutable rtbOutput : System.Windows.Forms.RichTextBox
    val mutable ofdOpen : System.Windows.Forms.OpenFileDialog
    val mutable sfdSave : System.Windows.Forms.SaveFileDialog
    val mutable cmsMenu : System.Windows.Forms.ContextMenuStrip
    val mutable saveToolStripMenuItem : System.Windows.Forms.ToolStripMenuItem
    val mutable openToolStripMenuItem : System.Windows.Forms.ToolStripMenuItem
    val mutable exitToolStripMenuItem : System.Windows.Forms.ToolStripMenuItem
    
    val mutable proc : Process
    val mutable appPath : string
    val mutable reader : Thread
    val mutable errReader : Thread
    val mutable stop : ManualResetEvent
    
    override this.Dispose (disposing) =
        if disposing && (this.components <> null) then
            this.components.Dispose ()
        base.Dispose (disposing)
    
    member this.InitializeComponent () =
        this.components <- new System.ComponentModel.Container ()
        this.rtbInput <- new System.Windows.Forms.RichTextBox ()
        this.rtbOutput <- new System.Windows.Forms.RichTextBox ()
        this.ofdOpen <- new System.Windows.Forms.OpenFileDialog ()
        this.sfdSave <- new System.Windows.Forms.SaveFileDialog ()
        this.cmsMenu <- new System.Windows.Forms.ContextMenuStrip (this.components)
        this.saveToolStripMenuItem <- new System.Windows.Forms.ToolStripMenuItem ()
        this.openToolStripMenuItem <- new System.Windows.Forms.ToolStripMenuItem ()
        this.exitToolStripMenuItem <- new System.Windows.Forms.ToolStripMenuItem ()
        this.cmsMenu.SuspendLayout ()
        this.SuspendLayout ()
        // 
        // rtbInput
        // 
        this.rtbInput.AcceptsTab <- true
        this.rtbInput.ContextMenuStrip <- this.cmsMenu
        this.rtbInput.Dock <- System.Windows.Forms.DockStyle.Top
        this.rtbInput.Font <- new System.Drawing.Font ("Consolas", 11.75F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((byte) (0)))
        this.rtbInput.Location <- new System.Drawing.Point (0, 0)
        this.rtbInput.Name <- "rtbInput"
        this.rtbInput.Size <- new System.Drawing.Size (757, 312)
        this.rtbInput.TabIndex <- 0
        this.rtbInput.Text <- ""
        this.rtbInput.KeyDown.AddHandler(new System.Windows.Forms.KeyEventHandler (fun s e -> this.rtbInput_KeyDown (s, e)))
        this.rtbInput.KeyUp.AddHandler(new System.Windows.Forms.KeyEventHandler (fun s e -> this.rtbInput_KeyUp (s, e)))
        // 
        // rtbOutput
        // 
        this.rtbOutput.Location <- new System.Drawing.Point (0, 318)
        this.rtbOutput.Name <- "rtbOutput"
        this.rtbOutput.Size <- new System.Drawing.Size (757, 190)
        this.rtbOutput.TabIndex <- 1
        this.rtbOutput.Text <- ""
        this.rtbOutput.TextChanged.AddHandler(new System.EventHandler (fun s e -> this.rtbOutput_TextChanged (s, e)))
        // 
        // ofdOpen
        // 
        this.ofdOpen.Filter <- "F# script files (*.fsx)|*.fsx|All Files (*.*)|*.*"
        this.ofdOpen.FileOk.AddHandler(new System.ComponentModel.CancelEventHandler (fun s e -> this.ofdOpen_FileOk (s, e)))
        // 
        // sfdSave
        // 
        this.sfdSave.Filter <- "F# script files (*.fsx)|*.fsx|All Files (*.*)|*.*"
        this.sfdSave.FileOk.AddHandler(new System.ComponentModel.CancelEventHandler (fun s e -> this.sfdSave_FileOk (s, e)))
        // 
        // cmsMenu
        // 
        this.cmsMenu.Items.AddRange ([| (this.saveToolStripMenuItem :> System.Windows.Forms.ToolStripItem); 
                                        (this.openToolStripMenuItem :> System.Windows.Forms.ToolStripItem); 
                                        (this.exitToolStripMenuItem :> System.Windows.Forms.ToolStripItem) |])
        this.cmsMenu.Name <- "cmsMenu"
        this.cmsMenu.Size <- new System.Drawing.Size (153, 92)
        // 
        // saveToolStripMenuItem
        // 
        this.saveToolStripMenuItem.Name <- "saveToolStripMenuItem"
        this.saveToolStripMenuItem.ShortcutKeys <- System.Windows.Forms.Keys.Control ||| System.Windows.Forms.Keys.S
        this.saveToolStripMenuItem.Size <- new System.Drawing.Size (152, 22)
        this.saveToolStripMenuItem.Text <- "Save"
        this.saveToolStripMenuItem.Click.AddHandler(new System.EventHandler (fun s e -> this.saveToolStripMenuItem_Click(s, e)))
        // 
        // openToolStripMenuItem
        // 
        this.openToolStripMenuItem.Name <- "openToolStripMenuItem"
        this.openToolStripMenuItem.ShortcutKeys <- System.Windows.Forms.Keys.Control ||| System.Windows.Forms.Keys.O
        this.openToolStripMenuItem.Size <- new System.Drawing.Size (152, 22)
        this.openToolStripMenuItem.Text <- "Open"
        this.openToolStripMenuItem.Click.AddHandler(new System.EventHandler (fun s e -> this.openToolStripMenuItem_Click(s, e)))
        // 
        // exitToolStripMenuItem
        // 
        this.exitToolStripMenuItem.Name <- "exitToolStripMenuItem"
        this.exitToolStripMenuItem.ShortcutKeys <- System.Windows.Forms.Keys.Control ||| System.Windows.Forms.Keys.X
        this.exitToolStripMenuItem.Size <- new System.Drawing.Size (152, 22)
        this.exitToolStripMenuItem.Text <- "Exit"
        this.exitToolStripMenuItem.Click.AddHandler(new System.EventHandler (fun s e -> this.exitToolStripMenuItem_Click(s, e)))
        // 
        // MainForm
        // 
        this.AutoScaleDimensions <- new System.Drawing.SizeF (6.0f, 13.0f)
        this.AutoScaleMode <- System.Windows.Forms.AutoScaleMode.Font
        this.ClientSize <- new System.Drawing.Size (757, 508)
        this.ContextMenuStrip <- this.cmsMenu
        this.Controls.Add (this.rtbOutput)
        this.Controls.Add (this.rtbInput)
        this.Name <- "MainForm"
        this.Text <- "MainForm"
        this.FormClosing.AddHandler(new System.Windows.Forms.FormClosingEventHandler (fun s e -> this.MainForm_FormClosing(s, e)))
        this.ResizeEnd.AddHandler(new System.EventHandler (fun s e -> this.MainForm_ResizeEnd(s, e)))
        this.cmsMenu.ResumeLayout (false)
        this.ResumeLayout (false)
    
    member this.ErrReaderTrd () =
        let MAX_BUF = 4096
        let mutable buffer = Array.create MAX_BUF '0'
        let mutable bread = 0
        while not (this.stop.WaitOne (1, true)) do
            try
                bread <- this.proc.StandardError.Read (buffer, 0, MAX_BUF)
                while (bread > 0) do
                    this.rtbOutput.AppendText (new string (buffer, 0, bread))
                    bread <- this.proc.StandardError.Read (buffer, 0, MAX_BUF)
            with
            | _ -> ()
    
    member this.ReaderTrd () =
        let MAX_BUF = 4096
        let mutable buffer = Array.create MAX_BUF '0'
        let mutable bread = 0
        while not (this.stop.WaitOne (1, true)) do
            try
                bread <- this.proc.StandardOutput.Read (buffer, 0, MAX_BUF)
                while (bread > 0) do
                    this.rtbOutput.AppendText (new string (buffer, 0, bread))
                    bread <- this.proc.StandardOutput.Read (buffer, 0, MAX_BUF)
            with
            | _ -> ()
    
    member this.InitializeREPL () =
        let mutable psi = new ProcessStartInfo ()

        psi.FileName <- this.appPath
        psi.CreateNoWindow <- true
        psi.RedirectStandardInput <- true
        psi.RedirectStandardOutput <- true
        psi.RedirectStandardError <- true
        psi.UseShellExecute <- false
        psi.ErrorDialog <- true

        this.proc <- new Process ()
        this.proc.StartInfo <- psi
        this.proc.SynchronizingObject <- this
        this.proc.EnableRaisingEvents <- true
        this.proc.Start () |> ignore

        this.stop <- new ManualResetEvent (false)
        this.reader <- new Thread (new ThreadStart (this.ReaderTrd))
        this.errReader <- new Thread (new ThreadStart (this.ErrReaderTrd))

        this.reader.Start ()
        this.errReader.Start ()
    
    member this.MainForm_FormClosing (sender : System.Object, e : FormClosingEventArgs) =
        this.stop.Set () |> ignore
        Thread.Sleep (200)

        if not (this.reader.Join (200)) then
            this.reader.Abort ()

        if not (this.errReader.Join (200)) then
            this.errReader.Abort ()
        try
            this.proc.Kill ();
        with
        | _ -> ()
    
    member this.rtbOutput_TextChanged (sender : System.Object, e : EventArgs) =
        // still there is no good way to do this
        // I mean to make a RichTextBox auto scroll to bottom
        this.rtbOutput.SelectionStart <- this.rtbOutput.Text.Length + 10;
        this.rtbOutput.SelectionLength <- 0
        this.rtbOutput.ScrollToCaret ()
    
    member this.MainForm_ResizeEnd (sender : System.Object, e : EventArgs) =
        let src = this.Height - 32
        let top = src * 60 / 100
        let bottom = src - top

        this.rtbInput.Height <- top
        this.rtbOutput.Height <- bottom
    
    member this.rtbInput_KeyDown (sender : System.Object, e : KeyEventArgs) =
        if (e.KeyData = Keys.Tab) then
            e.Handled <- true
            this.rtbInput.AppendText ("    ")
    
    member this.rtbInput_KeyUp (sender : System.Object, e : KeyEventArgs) =
        if (e.KeyData = (Keys.Enter ||| Keys.Alt)) then
            this.rtbOutput.AppendText ("\r\n")
            this.proc.StandardInput.Write (this.rtbInput.SelectedText + "\r\n;;\r\n")

    member this.ofdOpen_FileOk (sender : System.Object, e : CancelEventArgs) =
        use sr = new StreamReader (this.ofdOpen.FileName)
        this.rtbInput.AppendText (sr.ReadToEnd ())
        sr.Close ()

    member this.sfdSave_FileOk (sender : System.Object, e : CancelEventArgs) =
        use sw = new StreamWriter (this.sfdSave.FileName)
        sw.Write (this.rtbInput.Text)
        sw.Flush ()
        sw.Close ()
    
    member this.saveToolStripMenuItem_Click (sender : System.Object, e : EventArgs) =
        this.sfdSave.ShowDialog () |> ignore
    
    member this.openToolStripMenuItem_Click (sender : System.Object, e : EventArgs) =
        this.ofdOpen.ShowDialog () |> ignore
    
    member this.exitToolStripMenuItem_Click (sender : System.Object, e : EventArgs) =
        this.Close () |> ignore
    
    new () as this = 
        { components = null;
          rtbInput = null;
          rtbOutput = null;
          ofdOpen = null;
          sfdSave = null;
          cmsMenu = null;
          saveToolStripMenuItem = null;
          openToolStripMenuItem = null;
          exitToolStripMenuItem = null;
          proc = null;
          appPath = null;
          reader = null;
          errReader = null;
          stop = null; }
        then
          this.appPath <- @"C:\Program Files\FSharp-1.9.6.0\bin\fsi.exe"
          this.InitializeComponent()
          this.InitializeREPL()

[<STAThread>]
let main() = 
    Application.EnableVisualStyles()
    Application.SetCompatibleTextRenderingDefault(false)
    Thread.Sleep(400)
    Application.Run(new MainForm())

[<STAThread>]
main()

Now the questions:
1 - When I am developing in Visual Studio, this code does not work from within VS. Is this something about fsi.exe and if not can anyone spot the problem?
2 - Debugging in reader threads almost does not work. It hits the line and when I press next step it continues to run.

I had some other problems that I don't remember yet I have enjoyed CTP indeed!
(There is another F# try of mine from old days at [link:cs.hubfs.net] that feelings came to life again!)

Best Regards

Thanks for the sample application, I have done something similar using WPF.

#light

open Microsoft.Win32
open System
open System.Diagnostics
open System.IO
open System.Windows
open System.Windows.Controls
open System.Windows.Data
open System.Windows.Input
open System.Windows.Media
open System.Windows.Threading

let inline add_list (collection: ^c) (items: ^i list) =
List.iter (fun i -> (^c : (member Add: ^i -> 'a) (collection, i)) |> ignore) items

let add_row_definitions (grid: Grid) heights =
add_list (grid.RowDefinitions) (List.map (FSGridLength.CreateRowDefinition) heights)

[<STAThread; EntryPointAttribute>]
let main args =
let app = Application ()

use fsi_proc =
new Process (
StartInfo = ProcessStartInfo (
FileName = @"C:\Program Files\FSharp-1.9.6.2\bin\fsi.exe",
CreateNoWindow = true,
RedirectStandardInput = true,
RedirectStandardOutput = true,
RedirectStandardError = true,
UseShellExecute = false,
ErrorDialog = false
),
EnableRaisingEvents = true
)

let inputTextBox =
TextBox (
AcceptsReturn = true,
FontFamily = FontFamily("Courier New")
)
ScrollViewer.SetHorizontalScrollBarVisibility (inputTextBox, ScrollBarVisibility.Auto)
ScrollViewer.SetVerticalScrollBarVisibility (inputTextBox, ScrollBarVisibility.Auto)

let outputTextBox =
TextBox (
AcceptsReturn = true,
IsReadOnly = true,
FontFamily = FontFamily("Courier New")
)
ScrollViewer.SetHorizontalScrollBarVisibility (outputTextBox, ScrollBarVisibility.Auto)
ScrollViewer.SetVerticalScrollBarVisibility (outputTextBox, ScrollBarVisibility.Auto)

fsi_proc.Start () |> ignore

let newl = Environment.NewLine

fsi_proc.OutputDataReceived.AddHandler (fun s e ->
app.Dispatcher.Invoke(DispatcherPriority.Input, Action (fun () ->
outputTextBox.AppendText (e.Data + newl))
) |> ignore
)
fsi_proc.BeginOutputReadLine ()

fsi_proc.ErrorDataReceived.AddHandler (fun s e ->
app.Dispatcher.Invoke(DispatcherPriority.Input, Action (fun () ->
outputTextBox.AppendText (e.Data + newl))
) |> ignore
)
fsi_proc.BeginErrorReadLine ()

let runInteractiveCommand = RoutedUICommand ()

let win =
Window (
Content =
let grid = Grid () in
add_row_definitions grid [Auto; Star 1.0; Pixel 5.0; Star 1.0];
add_list (grid.Children) [
(let menu = Menu () in
add_list (menu.Items) [
MenuItem (Header = "Open", Command = ApplicationCommands.Open);
MenuItem (Header = "Save", Command = ApplicationCommands.Save);
MenuItem (Header = "Execute", Command = runInteractiveCommand);
MenuItem (Header = "Exit", Command = ApplicationCommands.Close)
];
menu :> UIElement);
(Grid.SetRow (inputTextBox, 1);
inputTextBox :> UIElement);
(let gridSplitter =
GridSplitter (
HorizontalAlignment = HorizontalAlignment.Stretch,
Background = Brushes.LightGray
) in
Grid.SetRow (gridSplitter, 2);
gridSplitter :> UIElement)
(Grid.SetRow (outputTextBox, 3);
outputTextBox :> UIElement)
];
grid
)

let openFileDialog = OpenFileDialog (Filter = "F# script files (*.fsx)|*.fsx|All Files (*.*)|*.*")
openFileDialog.FileOk.AddHandler (fun s e ->
use sr = new StreamReader (openFileDialog.FileName)
sr.ReadToEnd () |> inputTextBox.AppendText
sr.Close ()
);

let saveFileDialog = SaveFileDialog (Filter = "F# script files (*.fsx)|*.fsx|All Files (*.*)|*.*")
saveFileDialog.FileOk.AddHandler (fun e s ->
use sw = new StreamWriter (saveFileDialog.FileName)
sw.Write (inputTextBox.Text)
sw.Close ()
);

add_list (win.InputBindings) [
KeyBinding(ApplicationCommands.Open, Key.S, ModifierKeys.Control)
KeyBinding(ApplicationCommands.Save, Key.O, ModifierKeys.Control)
KeyBinding(ApplicationCommands.Close, Key.X, ModifierKeys.Control)
KeyBinding(runInteractiveCommand, Key.Enter, ModifierKeys.Alt)
]

add_list (win.CommandBindings) [
CommandBinding(ApplicationCommands.Open, fun s e -> openFileDialog.ShowDialog() |> ignore)
CommandBinding(ApplicationCommands.Save, fun s e -> saveFileDialog.ShowDialog() |> ignore)
CommandBinding(ApplicationCommands.Close, fun s e -> win.Close())
CommandBinding(runInteractiveCommand, fun s e ->
inputTextBox.SelectedText + ";;" + newl |> fsi_proc.StandardInput.Write
)
]

app.Run win

By András Jankó on 12/22/2008 9:31 AM (permalink)

Thanks to you! In fact it is for some time that I have not look into F# and I do not know WPF well enough to work with fluently. It is good to see more F# code on .NET!

By Kaveh Shahbazian on 1/29/2009 10:27 AM (permalink)

Just for the record this implementation is much better to study. It has two implementations in F# and C# using WPF one can compare those languages.

By Kaveh Shahbazian on 12/14/2010 2:43 AM (permalink)

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