Tagged: csharp

I've been working on something for a while now that I haven't really talked about here, so it's about time. It's called Stainless, and it's a programming language.

The short version is that it's C#'s syntax on top of C's memory model. It compiles to native code through LLVM, lays out its types exactly like C does, and can call into C (or be called from it) with no wrapper layer in between. Instead of a garbage collector it uses reference counting, so objects are cleaned up the moment nothing points at them anymore. And there are no header files: the compiler reads the whole program up front, so you declare something once and use it anywhere.

If you know C#, most of this should look familiar:

module Points;

import Standard.Console;

record Point(int X, int Y);

String Describe(Point p) => p switch
{
    (0, 0) => "the origin",
    { X: 0 } => "on the Y axis",
    (var x, var y) when x == y => "on the diagonal",
    _ => $"somewhere else ({p.X}, {p.Y})"
};

int Main()
{
    Point[] points = [new(0, 0), new(0, 5), new(3, 3), new(4, 1)];
    foreach (var p in points)
        Console.WriteLine(Describe(p));
    return 0;
}

Records, pattern matching, collection expressions, target-typed new, generics, lambdas and properties are all there. A few things are different on purpose: there are no exceptions (errors are Result values instead), there's no async/await (it has parallel and spawn), and lambdas capture by value.

The part I'm proudest of is that it's built out of itself. The standard library, a GUI framework with Win32 and GTK back ends, and an IDE with a form designer and a debugger are all written in Stainless. If the language couldn't handle a real program, I'd have found out pretty quickly.

It's still experimental, it's still changing, and it's just me working on it, so don't go shipping anything important with it yet. That said, there are builds for Windows and Linux on the releases page if you want to try it. You'll need clang installed, and the README walks you through the rest.

Everything's up on GitHub: github.com/xeons/stainless

If you give it a try, I'd love to hear what you think.

So I was attempting to make use of IO completion ports and build a high performance socket server in C# by making use of the *Async methods such as ReceiveAsync with SocketAsyncEventArgs. However I’ve encountered a problem which I cannot seem to find a solution for which involves a StackOverException being triggered by the execution of these methods. You see, at first glance everything appeared to be humming along nicely, until I decided to flood my server with about 12,000 randomly sized packets. That’s when the problem shows up.

I have a TryReceive method that makes the first call to ReceiveAsync, and if it returns FALSE, then I call the ProcessReceive directly, otherwise it gets called by the Completed event getting invoked on the SocketAsyncEventArgs. ProcessReceive then does some processing of the message and then calls TryReceive to start the process all over again. For whatever reason, the ReceiveAsync is always completing synchronously and creating a recursive loop with my two methods.

I’m not really sure what to try at this point, other than possibly trying to call it on another thread, but I’m worried that might cause some other recursive thread call issues. If anyone has any ideas feel free to hit up my contact form.

Here’s some extracted snippets of code to show how the calls are structured.

private void TryReceive()
{
...
    if (!Socket.ReceiveAsync(_receiveEventArg))
        ProcessReceive(_receiveEventArg);
...
}

private void OnAsyncCompleted(object sender, SocketAsyncEventArgs e)
{
    // Determine which type of operation just completed and call the associated handler
    switch (e.LastOperation)
    {
        case SocketAsyncOperation.Receive:
            ProcessReceive(e);
            break;
        case SocketAsyncOperation.Send:
            ProcessSend(e);
            break;
        default:
            throw new ArgumentException("The last operation completed on the socket was not a receive or send");
    }

}

private void ProcessReceive(SocketAsyncEventArgs e)
{
...
    if (e.SocketError == SocketError.Success)
    {
        // If zero is returned from a read operation, the remote end has closed the connection
        if (size > 0)
            TryReceive();
        else
            Disconnect();
        }
    }
...
}

I’ve added some new content to go along with the new host. I’m hoping I can keep adding new content over the next couple months, we’ll see how things go and how stressed out I get. I still plan on working on several projects including a forum script I had previously been fixing up. I’ll continue to get any of my old projects broken up into snippets and tutorials.

I also updated my contact form so that it actually goes to my primary email now, so if you had attempted to contact me in the past it probably got lost. The new form also includes more methods of contact.