Support Emscripten

[charto]

Support Emscripten

[jjrv]

Using gyp with Emscripten on Windows seems complicated. A Visual Studio plugin might help: https://github.com/james-allison/vs-tool/tree/VS2013-Support

[bsergeev]

Yes, gyp on Windows is often troublesome, there are some workarounds posted (although I haven't tried them myself):
https://www.robertkehoe.com/2015/03/fix-node-gyp-rebuild-error-on-windows/

But what this Visual Studio plugin has to do with gyp? Will you be able to replace gyp project with Visual Studio (or, perhaps, CMake) project to build node extensions and/or invoke Emscripten?

BTW, you don't need a VS extension to invoke Emscripten, as it can be easily invoked from a command line/script as a custom build step in Visual Studio.

[jjrv]

node-gyp can generate a Makefile that uses emcc on Windows but neither Microsoft's nmake nor GNU's gnumake was able to run it, so it would be better to configure node-gyp to generate a suitable .sln or patch it afterwards to use emcc. I didn't think that would be possible but will look into it. For Makefiles, it's easy to set CXX in make_global_settings in binding.gyp.

The goal is that nbind users could compile their project to a Node.js or Emscripten module by changing a single setting somewhere, in the same way on Windows, Linux and OS X.

The command npm run test-asm in the feature/emscripten-support branch already works on Linux and runs the same tests (using node-gyp) as the native Node.js addon, but through Emscripten.

[jjrv]

@bsergeev thanks for the hints, I got it working. Only problem is that it always re-compiles everything. I guess it will be up to the Visual Studio user to fix that manually somehow, but nbind is now able to create a basic Emscripten solution that compiles (I'll commit it to feature/emscripten-support soon and then npm run test-asm will also work on Windows).

Now I'll have to fix a bug with callbacks when using the -O2 option in Emscripten, improve documentation and then it's ready for release. Rest of the missing features will go to issue #8.

[jjrv]

Closing this now, the last missing things can be done later.