Comment Feed for Andrew Davey

Re: C9 Lectures: Dr. Erik Meijer - Functional Programming Fundamentals, Chapter 1 of 13

Andrew Davey — Thu, 01 Oct 2009 18:39:48 GMT

Re: Expressions everywhere

You should check out Nemerle if feels very much like C#, but with everything (within a method) being an expression.

posted by Andrew Davey

Re: Doug Hauger: Inside the Windows Azure Platform Business Model

Andrew Davey — Tue, 18 Aug 2009 10:39:06 GMT

Charges for "compute" are applied even when an instance is idle. So a website that does nothing will cost $86.40 per month!

There must be a fairer use model possible. Google App Engine seems to manage it.

posted by Andrew Davey

Re: Brian Beckman: Don't fear the Monad

Andrew Davey — Sat, 24 Nov 2007 08:45:14 GMT

Will we ever see a Microsoft backed version of Haskell for .NET?

posted by Andrew Davey

Re: Mobile Model in MVP web app

Andrew Davey — Thu, 01 Nov 2007 08:35:47 GMT

I keep asking Nikhil about open sourcing Script# and he keeps ignoring me
I'm going to keep using it for now. Nikhil does at least release new versions semi-regularly. Please contact him yourself as well to maintain community pressure to open source Script#!

posted by Andrew Davey

Re: Mobile Model in MVP web app

Andrew Davey — Thu, 18 Oct 2007 10:16:16 GMT

The code is now online here:

www.aboutcode.net/files/SplitModel.zip

You will also need to install my code generator tool. This is used to generate code from XML files.

www.aboutcode.net/files/Equin.CodeGenerator.zip

posted by Andrew Davey

Re: Client-side Model-View-Presenter

Andrew Davey — Sat, 29 Sep 2007 19:18:21 GMT

So I reckon phase two is to use my tier-splitting macro to enable certain model methods to be decorated with [RunAtServer] attributes.
The macro would do all the plumbing to call the server and execute the model there. This would allow a totally seemless Model class to be written. With the client part ending up in JavaScript and the server part being C#.

posted by Andrew Davey

Re: Client-side Model-View-Presenter

Andrew Davey — Sat, 29 Sep 2007 14:56:38 GMT

Seeing as client-side MVP is viable, the next step would be create a framework to reduce some of the boiler-plate coding required. For example, the View class that basically maps to and from DOM elements could probably be code generated.

Thanks for the link to ProMesh.NET, I like the use of attributes making the whole process much more declarative. I'll certainly be considering similar approachs when expanding my client-side MVP framework.

posted by Andrew Davey

Re: Functional ADO.NET

Andrew Davey — Mon, 03 Sep 2007 09:57:17 GMT

It depends on if you need the reader or not. Sometimes I need to know that no records were returned.

A good approach would be to have an overloaded method. One that passes the reader, another that passes each data record.

I hope people find this pattern useful and adapt it to meet their needs as you have done
Also, does anyone know if this pattern has a name?

posted by Andrew Davey

Re: HanselMinutes on 9 - #1 -

Andrew Davey — Wed, 28 Mar 2007 19:17:16 GMT

Quite simply, the best video I have seen for a while on Channel 9!
Quick, snappy, fun and interesting. I look forward to more in this style.
Keep hunting down the devs!

posted by Andrew Davey

Re: Lap around ASP.NET Ajax Demo from JAOO 2006 Conference, Denmark

Andrew Davey — Wed, 11 Oct 2006 16:01:03 GMT

It played fine for me (playing it embedded in C9 website).

posted by Andrew Davey

Re: Anders Hejlsberg - Lang.Net 2006 Compiler Symposium

Andrew Davey — Sat, 23 Sep 2006 00:30:59 GMT

I think you can replace "(sender, e)" with just "()" - or at least I hope it'll support that!

C#3.0 is looking sweeeet!

ktr wrote:

// to this (C# 3) ------------------------------------

button1.Click += (sender, e) => doSomething();
// i think you can do that ^ ... lol

posted by Andrew Davey

Re: Programming in the Age of Concurrency: Software Transactional Memory

Andrew Davey — Mon, 04 Sep 2006 21:24:53 GMT

Excellent video!
I downloaded the C# code and took a quick look.
Good work with the runtime proxy generation. Geez, it must have been painful writing all that emit IL code!

I'll take a look at writing some Nemerle macros to make the syntax nice. I'm thinking macros along the lines of:

foo = atomic(Foo(arg1, arg2))
<==>
foo = XAction.MakeFactory(typeof(Foo)).Create(arg1, arg2) : Foo;
-------------------------
atomic(foo.Bar(x,y,z))
<==>
XAction.Run(XStart(foo.Bar), x, y, z);
--------------------------
retry
<==>
XAction.Retry();
--------------------------
y = attempt { Get1, Get2 } (arg1, arg2)
<==>
y = XAction.Run(XAction.OrElse(new XStart(Get1), new XStart(Get2)), arg1, arg2) : int;

y = attempt {Get1, Get2, Get3} (arg1, arg2)
<==>
y = XAction.Run(XAction.OrElse(XAction.OrElse(new XStart(Get1), XAction.OrElse(new XStart(Get2), new XStart(Get3)))), arg1, arg2) : int;

posted by Andrew Davey

Re: Brian Beckman: Monads, Monoids, and Mort

Andrew Davey — Fri, 01 Sep 2006 07:39:20 GMT

John Melville, MD wrote:

In C# 3.0 I think you can build 95% of this with extension methods, like this:

namespace DoDynamic {
    public static class DoDynamic
    {
        public static object call (this object s, string name,
               param object[] parameters)
        {
            // find and call the function using reflection
        }
    }
}




Your sample becomes:
void Test()
{
  object foo = GetData(); // "late" is a new, psuedo-type, keyword.
  foo.Call("DoSomething");
}.



In adddition to being doable with the next c# as it is currently specified this syntax also makes the dynamic nature of each 
call plainly obvious, and it is possible to chose dynamic or static on a per call, rather than a per-object basis.

Not exactly what you asked for, but pretty close and already working (in beta builds.)

That's a good compromise for now I guess. I could also then add "Get" and "Set" extension methods for properties...

posted by Andrew Davey

Re: Brian Beckman: Monads, Monoids, and Mort

Andrew Davey — Thu, 31 Aug 2006 17:33:49 GMT

androidi wrote:

Andrew Davey wrote:
So in C# I'd love to see:
void Test()
{
late foo = GetData(); // "late" is a new, psuedo-type, keyword.
foo.DoSomething();
}

How is this different from how LINQ uses C# 3.x for example? It's not RTM yet which is too bad yeah.

Er.. LINQ stuff is statically typed. Here I'm talking about late binding (i.e. at runtime).

posted by Andrew Davey

Re: Brian Beckman: Monads, Monoids, and Mort

Andrew Davey — Thu, 31 Aug 2006 16:55:27 GMT

Do people see VB's inherent verbosity getting the in way of implementing features, like lambda expressions, in way that won't confuse Mort?

In C# 3.0:
list.Where(x => x == 42)
is nice and succint.

I've not been able to find a VB 9 version of that yet. The VB future's website still uses "AddressOf" to a seperate function.
Does anyone know what the anonymous method/closure/lambda expression syntax looks like in VB 9?

posted by Andrew Davey

Re: Brian Beckman: Monads, Monoids, and Mort

Andrew Davey — Thu, 31 Aug 2006 14:52:43 GMT

Adding late binding to C# could be done easily if they copied Boo. In Boo you can declare a variable "as duck". Then any references to members on that variable are late-bound. I like the approach because it makes the declaration explicit.

def Foo():
x as duck = GetSomething()
print x.Bar()

Note that it's duck as in "duck typing".

Where it gets more awesome is if you implement the IQuackFu interface on a class. This interface defines three methods: QuackInvoke, QuackGet and QuackSet. So when calling code invokes any member on your class, the compiler actually makes it call the dispatcher methods of the interface, passing the member name and arguments.
This basically means you can do funky stuff like add methods at runtime to a class. See http://docs.codehaus.org/pages/viewpage.action?pageId=13653 for a cool dynamic mixin example.

Adding this feature to C# would not in any way affect normal early-bound code. People are free to ignore the feature, but it's there if they really need it (e.g. with COM interop).
Adding support for something like IQuackFu (changing to a less silly name too I bet!) would actually surpass VB's dynamic abilities.

So in C# I'd love to see:
void Test()
{
late foo = GetData(); // "late" is a new, psuedo-type, keyword.
foo.DoSomething();
}

posted by Andrew Davey

Re: Windows Marketplace: Write a Windows app. We'll sell it for you.

Andrew Davey — Mon, 28 Aug 2006 22:36:25 GMT

I don't think they said that it is a requirement... Just that if you do have it, then it's flagged up. The idea being a user can tell if the app has been logo certified.

posted by Andrew Davey

Re: Programming in the Age of Concurrency: The Accelerator Project

Andrew Davey — Mon, 28 Aug 2006 15:59:57 GMT

Minh wrote:

I'm curious - why not implement this as a library on top of multi - core CPU's (which seems a much moreuseful Scenario) rather than a GPU ?

(or perhaps You find the limited Ps instruction set easier to start out with)

Parallel data and parallel instructions are two different beasts I guess. Trying to operate on a single dataset from multiple processors causes all kinds of memory/cache issues. When you can split the data up and work independently then its fine. However when you can't, the only performant way to operate is in one processor. In this case taking advantage of the data parallelism inside a single GPU.
Of course, I'm not an expert by any means in this area... hopefully the boffins at MSR are finding clever solutions to these tricky problems.

posted by Andrew Davey

Re: Programming in the Age of Concurrency: The Accelerator Project

Andrew Davey — Mon, 28 Aug 2006 13:41:03 GMT

They are using Managed DirectX. So that takes care of talking to the video card for them.

posted by Andrew Davey

Re: Programming in the Age of Concurrency: The Accelerator Project

Andrew Davey — Sun, 27 Aug 2006 18:56:13 GMT

What happens for those lucky people with dual video cards? Can Accelerator use both in parallel?

(No I don't have dual cards, I just like the idea!)

posted by Andrew Davey

Re: Programming in the Age of Concurrency: The Accelerator Project

Andrew Davey — Sat, 26 Aug 2006 19:30:19 GMT

I wonder if I can justify a shiny new graphics card under the guise of "research"

posted by Andrew Davey

Re: Programming in the Age of Concurrency: The Accelerator Project

Andrew Davey — Sat, 26 Aug 2006 19:29:11 GMT

Data parallelism for big numerical problems is kind of obvious. I think the next challenge is bringing parallelism to regular business apps. For example, if I have a list of business objects and want to validate them all, or maybe check for changes against a web service, doing a simple "foreach" loop is dumb when I have 2 or more CPUs. Maybe one day we will languages and compilers smart enough to just express "validate all these objects" and have it work out the most efficient way to do it...

posted by Andrew Davey

Re: Programming in the Age of Concurrency: The Accelerator Project

Andrew Davey — Sat, 26 Aug 2006 19:20:39 GMT

Even if the SDK has no source it's managed code, so you can get Reflector in there and have a snoop around

posted by Andrew Davey

Re: Programming in the Age of Concurrency: The Accelerator Project

Andrew Davey — Fri, 25 Aug 2006 22:12:12 GMT

Defered evalution is definately a very interesting subject. The work being done with LINQ is along the same lines. The compiler generates an expression tree that can then be passed around as data and transformed before evaluation.
I wonder if its possible to take expression trees generated by LINQ and transform them into parallelisable computations. I suppose it really comes down to "map" and "reduce" functions in the end. Whilst you are kind of limited to pure arithmetic operations in the GPU, the future of multi-cores certainly could widen the scope.

Of course, I can't talk about abstract syntax trees without once again mentioning syntactic macros It would be interesting to look at using syntactic macros to perform staged computation. I'm sure some of the parallelising of operations can be decided at compile time. That could make for even more performance increases since you can take some weight off the JIT compiler.

Anyway... Awesome work and great video Charles.
BTW: Charles, you need to get a secondary job at MSR being "social glue"! We need to get all these academics down to the bar to mix their ideas.

posted by Andrew Davey

Re: Erik Meijer: Democratizing the Cloud

Andrew Davey — Wed, 09 Aug 2006 17:36:12 GMT

I dislike weak typing, at least in the form that VB gives us. There are languages that allow types to change at runtime (adding methods, etc) but I never really found the need for that feature. For me type inference is the big winner. Both VB and C# are getting this in next version. It means much simpler code to read and write, whilst still having the safety of the compiler.
I always thought it strange to discard years of advanced compiler and type systems design!

I hope the next version of VB does have the "Dynamic Interface" feature. It provides the best way to program against weakly typed objects. It lets the all your code be strongly typed to the interface, however at runtime you can attempt to cast any object type you want to it. I believe the runtime will then check the validity of the object upfront - so you get fail fast, rather than fail half way through some nasty computation due to mis-spelling a function!

posted by Andrew Davey