Entries for dcuccia

Thank god it's Monday! [Thank god it's Monday!]

dcuccia — Mon, 06 Oct 2008 06:28:55 GMT

Can't wait to work on the crap I couldn't finish all weekend...

Unconventional use of indexers [Unconventional use of indexers]

dcuccia — Thu, 11 Sep 2008 06:53:49 GMT

I'm playing around with trying to make array math in C# as easy and concise as in Matlab, and (besides array operators) the biggest language "mismatch" is in indexers, ranges, etc. In Matlab, I can easily get a subarray of A, such as A[0:5:255]

As a user of a fluent interface DSL in C#, would you ever put up with unconventional use of indexers? Like:

[code language="csharp"]A[Get.Range[0,5,255]][/code]

...where Range is actually a static readonly field holding an instance of class Range

[code language="csharp"]    public class Get
    {
        public static readonly Range Range = new Range();
        public static readonly Size Size = new Size();
    }

    public class Range
    {
        public Range this[int from, int to] { get { return new Range(from, 1, to); } }
        public Range this[int from, int every, int to] { get { return new Range(from, every, to); } }

        private Range(int start, int every, int stop) { Start = start; Every = every; Stop = stop; }
        private Range(int start, int stop) : this(start, 1, stop) { }
        internal Range() { } // for indexer use

        public int Start { get; private set; }
        public int Stop { get; private set; }
        public int Every { get; private set; }
        public int Count() { return (Stop - Start) / Every + 1; }
    }

    public class Size
    {
        public Size this[int d0] { get { return new Size(new int[] { d0 }); } }
        public Size this[int d0, int d1] { get { return new Size(new int[] { d0, d1 }); } }
        public Size this[int d0, int d1, int d2] { get { return new Size(new int[] { d0, d1, d2 }); } }
        public Size this[int d0, int d1, int d2, int d3] { get { return new Size(new int[] { d0, d1, d2, d3 }); } }

        private Size(int[] dimensions) { Dimensions = dimensions.ToArray(); }
        internal Size() { } // for indexer use

        public int[] Dimensions { get; private set; }
    }
[/code]

Obviously the following would be more C-sharpy:

[code language="csharp"]A[new Range(0,5,255)][/code]

But, isn't it OK to stray a bit as long as there's a consistent convention in the DSL?

in reply to Unconventional use of indexers

Zeep Mobile APIs - Free SMS! [Zeep Mobile APIs - Free SMS!]

dcuccia — Mon, 01 Sep 2008 00:29:45 GMT

This week on, um "This Week on C9" the guys pointed out Zeep Mobile, a free service for sending and receiving SMS messages (last 40 characters are reserved for targeted advertising).

They have both Ruby and Python APIs available on Google code.

Usage from "Getting Started" (Python example):

    import zeep.sms
    connection = zeep.sms.connect("<your api key>", "<your secret key>")
    connection.send_message("<user_id>", "Surfs up!")

Based on the source code, it looks like someone with even basic web authentication skills could whip up a .NET/Silverlight version...

in reply to Zeep Mobile APIs - Free SMS!

"Near C Performance" w/ TraceMonkey JavaScript Engine ["Near C Performance" w/ TraceMonkey JavaScript Engine]

dcuccia — Sun, 31 Aug 2008 00:56:08 GMT

Just saw this article on the TraceMonkey complier for FF 3.1, which allows Javascript language features to "achieve a speedup of 22x."

Knee-jerk reactions:

"Hey, no fair!"
JSC and Volta just got more relevant for cross-platform RIAs

Any thoughts?

in reply to "Near C Performance" w/ TraceMonkey JavaScript Engine

Extension Method for InvokeRequired? [Extension Method for InvokeRequired?]

dcuccia — Tue, 27 May 2008 08:03:43 GMT

Do you guys see any potential problems with the following InvokeRequired strategy for simple Actions?

public static class ControlInvokeRequiredExtensionMethods
{

    public static void ExecuteOnUIThread(this Control myControl, Action action)
    {
        if (myControl.InvokeRequired)
        {
            myControl.BeginInvoke(action);
        }
        else { action(); }
    }

    public static void ExecuteOnUIThread<T>(this Control myControl, Action<T> action, T parameter)
    {
        if (myControl.InvokeRequired)
        {
            myControl.BeginInvoke(action, new object[] { parameter });
        }
        else { action(parameter); }
    }

    // etc...
}

Sample usage:

RichTextBox textBox = new RichTextBox();
public void WriteMessage(string message)
{
     textBox.ExecuteOnUIThread(textBox.AppendText, message);
}

Found this alternative, but would prefer to avoid AOP. Seems to me like an Extension Method strikes a nice balance between simplicity and transparency.

in reply to Extension Method for InvokeRequired?

Pattern for initializable objects [Pattern for initializable objects]

dcuccia — Tue, 27 May 2008 05:37:49 GMT

Hi all,

I write a lot of code to control hardware (cameras, projectors, etc), and find myself frequently using the following pattern:

// Instantiate the class and the physical piece of hardware
Hardware h = new Hardware();

// Get settings from the user
HardwareSettings settings = GetSettingsFromGui();

// Set all parameters in an Initialize function
h.Initialize(settings);

The point of separating Initialize() is that I want to be able to change a piece of hardware's settings repeatedly w/o actually shutting it down.

Since this is a common pattern for me, I was just about to write an IInitializable interface, so that all my hardware could be spun up with the same code.

Is this a common pattern (eg. long-running db connections or something)? Is there a similar interface or pattern in the .NET BCL that already exists?

in reply to Pattern for initializable objects

Microsoft Acquires Springsource [Microsoft Acquires Springsource]

dcuccia — Tue, 01 Apr 2008 16:43:26 GMT

InfoQ Link

"a greater focus will be placed upon filling out the .Net-based side of the Spring Portfolio, with a .Net-based version of Spring Web Flow becoming the basis for the ASP.Net web development APIs."

"the Spring Framework would be integrated into the Windows operating system, with users having the ability to configure most settings and applications via associated Spring Beans"

"Mark Pollack, founder and lead of the Spring.Net project, added:

Anders Hejlsberg, Erik Meijer and I have had some excellent conversations around where Spring.Net can improve the development process for .Net applications, and we expect to add many of the existing Spring APIs in the .Net Framework 4.0 release. The AOP and Aspect namespaces will likely be added to the System namespace, and the DAO and Data namespaces will augment the existing ADO.Net APIs."

in reply to Microsoft Acquires Springsource

Silverlight on the iPhone [Silverlight on the iPhone]

dcuccia — Tue, 11 Mar 2008 06:45:29 GMT

Just saw this referencing this.

Confirms what ScottGu said w/o saying in his MIX keynote "anything with an SDK."

in reply to Silverlight on the iPhone

How do I apply generic constraints to: void MyFunction<T1, T2>() {}? [How do I apply generic constraints to: void MyFunction<T1, T2>() {}?]

dcuccia — Sat, 08 Mar 2008 23:25:18 GMT

I've tried the following...

void MyFunction<T1, T2>() where T1, T2 : struct {}

void MyFunction<T1, T2>() where T1: struct , T2 : struct {}

void MyFunction<T1, T2>() where T1: struct , where T2 : struct {}

...but alas, I'm stumped. Please help!

in reply to How do I apply generic constraints to: void MyFunction<T1, T2>() {}?

Dynamic Linq Expressions and GADTs...new approach to the expression problem in C#? [Dynamic Linq Expressions and GADTs...new approach to the expression problem in C#?]

dcuccia — Thu, 28 Feb 2008 17:50:08 GMT

Hi all,

I was watching the video of Anders Hejlsberg's talk at Lang.Net 2008. About 3/4 of the way through, he mentioned that you can actually compile Linq expressions at runtime, and this is part of the basis for dynamic C# features going forward. I had no idea that this sort of thing was enabled in 3.5...thought the only way to dynamic was through reflection or IL.

So, I've been playing around to understand the functionality, trying to address the expression problem for generalized algebraic data types (GADTs).

Let me know what you guys think of this kernel of an implementation:

namespace C9Question
{
    public class TestGADT
    {
        public static void Main()
        {
            Number<float> n1 = 5;
            Number<float> n2 = 4;
            Console.WriteLine(n1+n2);
            Console.Read();
        }
    }

    public struct Number<T> where T : struct
    {
        public T myNumber;

        public T Add(T a, T b)
        {
            Func<T, T, T> f = typeof(GADTHelper).GetFunc<T, T, T>("Add");
            return f(a, b);
        }

        public static Number<T> Add(Number<T> a, Number<T> b)
        {
            Func<T, T, T> f = typeof(GADTHelper).GetFunc<T, T, T>("Add");
            return new Number<T>() { myNumber = f(a.myNumber, b.myNumber) };
        }

        public static Number<T> operator +(Number<T> a, Number<T> b){ return Add(a, b); }
        public static implicit operator Number<T>(T value) { return new Number<T>() { myNumber = value }; }
        public override string ToString() { return myNumber.ToString(); }

        private static class GADTHelper
        {
            public static double Add(double myDouble, double addend) { return myDouble + addend; }
            public static float Add(float myFloat, float addend) { return myFloat+ addend; }
            public static int Add(int myInt, int addend) { return myInt+ addend; }
            public static long Add(long myLong, long addend) { return myLong+ addend; }
        }
    }

    public static class DynamicLinqExtensions
    {
        public static Func<T1, T2, TResult> GetFunc<T1, T2, TResult>(this Type t, string method)
        {
            Type[] types = new Type[] { typeof(T1), typeof(T2) };
            ParameterExpression p1 = Expression.Parameter(types[0], "p1");
            ParameterExpression p2 = Expression.Parameter(types[1], "p2");
            Expression body = Expression.Call(t.GetMethod(method, types), p1, p2);
            Expression<Func<T1, T2, TResult>> e = Expression.Lambda<Func<T1, T2, TResult>>(body, p1, p2);
            return e.Compile();
        }
    }
}

in reply to Dynamic Linq Expressions and GADTs...new approach to the expression problem in C#?

Windows Media Player 11 not installed?? [Windows Media Player 11 not installed??]

dcuccia — Thu, 14 Feb 2008 02:40:21 GMT

I'm using a clean install of Vista Business (x86), and Firefox 2.0.0.12 seems to think I don't have plugins for Windows Media Player installed. I discovered this trying to play music samples on Amazon, ala here. IE 7.0 works fine.

Anyone else have this problem?

in reply to Windows Media Player 11 not installed??

Extension Methods and LGPL? [Extension Methods and LGPL?]

dcuccia — Wed, 19 Sep 2007 07:22:00 GMT

Hi, I was reading