A glimpse at how Infragistics uses a C# to JavaScript transcompiler, powered by "Roslyn" (.NET Compiler Platform)

Infragistics - Mike Dour's Blog - Client-Side Excel Library CTP

If you haven’t seen it already, we recently released a 100% JavaScript-only, client-side Excel library for Ignite UI and I’m super excited about it. It allows you to read, write, and manipulate Excel workbooks. You can even create and solve formulas, all from inside the browser!! It was released in 14.2 as a CTP so we could get your feedback on it, but we will be releasing a complete RTM version in 15.1. You can find information and a live sample of it here. Definitely check out the overview page, which is packed with important information for using this library.

But that’s not even the coolest part. Not only did we deliver a purely JavaScript library for Excel workbooks, but it has all the features of our existing .NET Excel libraries. Did we re-write the entire C# Excel library in JavaScript to provide this level of feature parity? We could have, but it would have taken a lot of effort getting there not to mention the ongoing challenge of maintaining feature parity between the versions and addressing bugs in both implementations. So we came up with something better. We built a C# to JavaScript source-to-source compiler, or transcompiler. We have actually been using this for a few releases now to deliver some of the Ignite UI controls, but it was missing support for some constructs being used in the C# Excel library. So we really beefed up its language support as well as changed its semantic analysis engine. Now based on Microsoft’s .NET Compiler Platform ("Roslyn") for C# semantic analysis, our transcompiler is able to read in our existing C# Excel library and generate semantically equivalent JavaScript code. There are still a few rough edges to smooth out, but we are currently addressing these issues to deliver the highest quality Excel library we can in the next release.

Unfortunately, one of those rough edges was in documentation. ...

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So hopefully this can help you get started with the Client-Side Excel library preview. There are a few things that don’t work properly yet (such as loading files with dates), but what we have provided should give you a good sense of what’s to come in 15.1. Please let us know what you think and if there are any pain points with the API or ways you think we can do better to make this library as easy as possible to use. Let us know at igniteui@infragistics.com. We look forward to your feedback. Thanks!

While you guys know I have something of a fanboy crush on Infragistics (come on, I've been using their stuff, in many forms since its VBX days... ;) that's not why I'm blogging about this. What I wanted to highlight is how they are using .NET Compiler Platform ("Roslyn") as their transcompiler to take the C# and generate JavaScript...

"...We built a C# to JavaScript source-to-source compiler, or transcompiler. We have actually been using this for a few releases now to deliver some of the Ignite UI controls, but it was missing support for some constructs being used in the C# Excel library. So we really beefed up its language support as well as changed its semantic analysis engine. Now based on Microsoft’s .NET Compiler Platform ("Roslyn") for C# semantic analysis, our transcompiler is able to read in our existing C# Excel library and generate semantically equivalent JavaScript code. ..."

That's just cool. And something I wonder if they will productize? (If so, that wouldn't be cheap as I bet that's some serious IP). Still the fact they even share that this is some of their secret sauce is nice (see, I'm not a fanboy for just any reason.... ;)