I've just watched "Philip Laureano - I Can't Believe It's Not Roslyn" video
(http://vimeo.com/43612919) and I am thrilled. Really!! Meta programming in
.NET is what I needed since I started using WPF. So after watching the move
I was so excited.

But I didn't want to learn new language as I'm using C# at work. And I
started investigating Roslyn. But I was using VS 2012 RC and liked new
await/async language features. Roslyn doesn't implement them yet. Nemerle
too (not that await/async like .NET's 4.5 feature - *Nemerle's
concurrency.n uses Threads which is very different - and in my opinion less
flexible/efficient* - correct me if I'm wrong). But Nemerle is ready too
use. But not in VS 2012. So I thought maybe use Roslyn and I won't have to
learn new language. Or maybe I will use any existing C# parser and do C#
compile-time transformations myself. But after trying to use syntax unknown
for VS and I saw that it would work well without integration with editor
and intellisense - too much trouble. I was torn - none of the solutions was
ideal. I wanted to give a try to Roslyn, but then it refused installing :)
Grrrr....

So here I am. Maybe that's better. Maybe I will appreciate another
Nemerle's features. I will give it a try at least. Do I have any choice? :)
It's the first not mainstream language that attracted my attention. As you
see it can give me the fastest access to metaprogramming in .NET. I hope
that the integration with VS 2012 is planned in a near future....

As I said one reason of my indecision was async/await functionality. I
wanted it all :) And hey! Roslyn couldn't give me it now. But Nemerle - why
not? It's true it is targetting only .NET 4.0 now. But there is Microsoft's
AsyncTargettingPack for .NET 4.0. It requires VS2012 compiler, true. But
Nemerle is an extensible compiler. And compiled async code uses standard
.NET 4.0 features. There is state-machine struct underneath. Rest is
included in AsyncTargettingPack dll.

And now my question is:

         Is anyone working on this async/await featue compatible with .NET
4.5 async/await for Nemerle?

Because if not, I would like to try myself. It sounds so interesting that I
cannot resist. To make it clear - I'm not saying that I will accomplish
anything!! I even don't know the basics of the language, yet. First I need
to learn it. And I can do it only in my free time (which is very short).
And it is not a trivial macro to write. Especially when it takes loops and
try/catch statements into account. Maybe I will give up in a middle. Who
knows. But I know that if its done it will not need any change when
migrating to .NET 4.5. And it can be compatible with other .NET's async
code.

         Is there any interest for that kind of functionality?

         Can I count on your help in difficult situations? :)

         I think the macro possible. But I don't know the language yet. Do
you know any obstacles? For example - will I have any troubles with
generating private structs nested in classes, attributes for methods,
goto's and labels for state machine?

         I don't know Nemerle design goals. Is it the preffered way to
implement it as macro? How the future versions of Nemerle and Nemerle's C#
compiler (that is a big question for me) will handle this async/await
functionality? Will the code be shared or different for both compilers?
Will it be a macro or what?

Ok. But before anything else I'm going to start learning the basics :))

Best Regards,
Marek Gibek

You need more recent macro library named "Computation Expressions" (github<https://github.com/rsdn/nemerle/tree/master/snippets/ComputationExpre...>,
wiki <https://github.com/rsdn/nemerle/wiki/Computation-Expression-macro>,
samples<https://github.com/rsdn/nemerle/blob/master/snippets/ComputationExpre...>).
But even in this library implementation of "async" feature is different
with C# (author say's it's closer to F# async).

About a year ago in russian forum one man asked: "Do you plan implement
async/await from future versions of C#?" and answer was: "No, we are
already have Computation Expressions".

If you still want to start learn Nemerle here<https://github.com/IlyaGerasimets/Sandbox/wiki>is english version of Vladislav Chistyakov articles for beginners
(translation currently in progress).

Thank you!! It is a very helpful answer.

I didn't know about new "Computation Expressions". It's much better than
"concurrency.n" macro. First of all it is now not only about threads but
also introduces ExecutionContext. It looks very similar to C#'s approach (I
don't know F# but I did a quick test and F#'s async is not compatible with
C#'s await out of a box too). So similar that this will be a very good
start point for me.

I don't agree with a statement from forum that if we already have
Computation Expressions we don't want to be compatible with C#. I need that
compatibility :) I cannot cheat myself that I will use only Nemerle's
assemblies even in my own solutions. Many 3rd party libraries will be
created (C#'s async/await isn't in production yet). And I want to integrate
with them easily. And with my own code. And vice versa. It's unavoidable in
the near future, I think.

So here I am :). And I see now that the integration may be easier than I
initially thought.  It's because "Computation Expressions" looks powerful
enough. Maybe I don't need to generate exactly the same state machine at IL
level as C#'s compiler does *). Maybe all AST transformations are already
written :) Maybe the only thing I need to do is to introduce IAwaitable
support. It would be great!

And I am very grateful for the link to translation of Vladislav articles.
Yes, I still want to learn Nemerle! I would missed them otherwise (as they
are in sandbox yet) and they look very promising.

Thanks again,
Marek Gibek

*) Maybe it would be a little bit faster. Microsoft has rewritten this
state machine code at least for three times. But it's not my priority.

http://nemerle.org/wiki/index.php?title=ComputationExpression_macro

Vlad Chistyakov
www.rsdn.ru

19.06.2012 14:48 пользователь "Marek Gibek" <gib...@gmail.com> написал:у

First version of .NET's Task-based Asynchronous Pattern for Nemerle 1.1 is
ready and can be downloaded from here:
https://sites.google.com/site/gibekm/downloads/nemerle/asyncawait

Marek