Asynchronous composition using LINQ/Extension methods

[Alex Shtof]

Hi all developers. Lately I started working on a library that allows to compose complex asynchronous operations from simple ones using LINQ syntax and extension methods. It can be found here. The idea itself was taken from F# asynchronous workflows, so I don't take any credit for the idea, just for the implementation. The need occurred when I was working for a company that had an existing server that provided a known set of operations and we needed to write a UI client that the operations it wanted to perform were composition (sequential or parallel) of the server's operations. So instead of writing the ugly code with callbacks and exception handling we came up with this idea. Here is a simple example for the library's usage:

// compose an operation that runs two async operations sequentially. Note that the parameters of
// the second operation depend on the result from the first operation, and so does the final result.
Async operation =
from dataItems1 in provider1.AsyncGetDataItems("data items id")
from dataItems2 in provider2.AsyncGetDataItems(dataItems1)
select dataItems1.Concat(dataItems2).ToArray();

// execute the above composed operation. The callback will receive the result.
operation.Execute(CompletionCallback);

I would like you to try and and send me any feedback about the design/implementation and of course bug reports. Thanks! Alex. P.S. I Googled it and found out that something already blogged about it. So other people came up with this idea too. I just didn't find a ready-to-use library that people can download and start using, so I decided to write one.