It’s time to start thinking reactively!  What have you been waiting for?

Maybe you were waiting for this:
Yesterday, Microsoft announced that Reactive Extensions (Rx) is now an open source project.  The complete source code for Rx 2.0 is being hosted at http://rx.codeplex.com under the Apache License 2.0.  After an extensive prerelease period and two “officially” released versions, Rx is finally being opened up to the community for a look inside the monadic machinery that helps developers to compose asynchronous queries with ease.  Not only that, but now you can submit bug fixes and implement features yourself.*

Maybe you were waiting for this:
Interactive Extensions (Ix) for .NET and JavaScript are open as well.  They are included under the same source control root as Rx.  I’ve decided to form a habit:  Whenever I create a new project, before I even write a single line of code, I’ll add references to the Rx Package and Ix Package from NuGet.  (Note:  I just started a discussion about the future of distribution, so those links may change.)

Maybe you were waiting for this:
The Rx Team has included brand new libraries to support C/C++.  They are aptly named Rx++ and Ix++.

Or maybe this:
The Rx Team has included new “Rx binding” examples, which are basically just specialized examples illustrating how to apply Rx and LINQ to specific domains.  They’ve included Tx, which is a set of code samples showing how to use LINQ to Events; e.g., real-time queries from trace logs for ETW, Windows Events and SQL Server Extended Events.  Another Rx binding example they’ve included is LINQ2Charts, which “allows developers to use LINQ to create/change/update charts in an easy way and avoid having to deal with XML or other underneath data structures”.

They’re also looking for new examples of Rx bindings, so let them know if you’ve got any.

Or this?
Rx already has an open source community building libraries and tools around it.  And now that Rx itself is open source, that should help to strengthen the existing open source Rx community by exposing it to more developers.  So even if you can’t/won’t contribute code directly to Rx, either due to complexity or legal constraints or whatever, then at least consider contributing code and/or feedback to one of the existing open source projects that enhance Rx.

Seriously, are you still considering how to develop asynchronous applications without Rx?  Are you also considering how to simplify data extraction from a SQL Server table without using SQL?  Or concurrently poke your eyes out with the pointy ends of a Metro-style button?

My (Additional) Impressions

A primary key to success for any open source library is to be extremely useful.  Another key to success is to be unique.  Rx is both, so I have no doubt that it will flourish in the open source world.

Rx goes a long way to make asynchronous programming easy.  It’s a solid library built around core principles that hides much of the complexity of controlling and coordinating asynchrony within any kind of application.  Opening it will help to lower the learning curve and increase the adoption rate of this amazing library, enabling developers to create complex asynchronous queries with relative ease and without any spaghetti code left over.  If asynchronous spaghetti code were a disease, Rx is the cure.

The more functionality a library offers, the more it becomes imperative to be able to peruse the source code.  Understanding user error and library bugs can be very difficult without source code, especially given the inherent complexity of asynchronous programming and the many factors of Rx’s public contracts, which must be considered while developing and debugging.  Capturing every last detail about Rx operators in documentation may be overly cumbersome or even impossible.  Opening Rx can help to make building and debugging complex asynchronous queries much easier.

Opening Rx allows the community to be less entitled and more empowered.  Developers using Rx already identify bugs and request features by posting them in the Rx forum, so it makes perfect sense to allow them to fix bugs and implement features themselves in a timely manner and share their work directly with the community.

Opening Rx to the community will help to tighten their relationship.  It will help to focus the flow of feedback to Microsoft, enabling more informed decisions about the shape of features and the future of Rx.

I’ve noticed the trend at Microsoft to move very useful products into open source projects on CodePlex.  I’ve been wondering whether Rx would take this route as well.  There are many great uses for Rx and its reach will certainly grow even more as an open source project.  The communities around Microsoft’s many open source projects are continuously growing and Rx certainly deserves to benefit from community involvement as much as any other product.

*After jumping through a legal hoop or two.  Read the Rx project home page for details.