Can async-await be available in other .NET languages besides C#?

Question

The async-await pattern is one of the more powerful additions to .NET 4.5 and C# 5.0

It is currently only available in C# and VB as far as I know.

Is this API a feature of the .NET CLR or of the C# compiler itself?

What I'm really asking is this - should we expect async/await in the other .NET languages such as:

• C++ (via C++/CLI)
• Python (via IronPython)
• PHP (via Phalanger)
• JavaScript (via IronJS)

Please note I'm not asking about asynchronous programming in general, but about the specifics of the async-await pattern (asynchronous code which is written synchronously).

Answer 1

Is this API a feature of the .NET CLR or of the C# compiler itself?

This is a feature of the compiler. There were no CLR changes required to support async and await. Other languages would need to be extended to support it. There is nothing preventing a compiler from doing this, but it would have to be changed in the compiler and language itself.

C++ does support some asynchrony in Windows Store applications via task/then, though it's not as usable as the async/await keywords in C# and VB.

It is currently only available in C# and VB as far as I know

Note that F# also has async support (which predates the C# and VB.Net versions by quite a bit). It is different than the C# style async support, but similar (and inspired the C# and VB.Net teams).

Answer 2

The C# and VB.Net compilers implement the await pattern by transforming the original method into a state machine. This is very similar to say how the F# async / work flow pattern works. This type of transformation is possible in any language that targets the CLR.