D => asm.js for the web?

[bearophile]

Maybe you remember the NaCl or PNaCl plug-in from Google, that 
allows to safely run code at near native speed on the browser 
(only 10-30% speed loss, in a probably safe sandbox). This 
plug-in seems interesting, but so far I think it's not getting a 
lot of traction, and it seems Mozilla is not interested in it.

Now on Reddit they have linked "asm.js". It's an easy to compile 
subset of JavaScript, that contains type annotations (inside 
comments, so it's still valid standard JavaScript). Mozilla has 
created a modified version of its JIT that recognizes asm.js code 
and compiles it ahead of time to give, they say, about half the 
speed of native code (if it's not recognized, it's seen as normal 
JS). Even if this speed will increase a little with time, I think 
it will keep being a little slower than NaCl code, but maybe for 
lot of people the speed of asm.js will be enough (and the safety 
of NaCl is not so certain).

A modified version of Emscripten (a LLVM bytecode to JavaScript 
compiler) outputs asm.js. So if you have C/C++ code, with 
Emscripten and some parts of LLVM you compile it to asm.js, and 
then Firefox Nightly recognizes it (there is an annotation).

So given the LDC2 project, maybe with LDC+Emscripten+asm.js there 
is a chance to see D on the web. I think someone will be happy to 
use D instead of C/C++ on the web for performance-sensitive code, 
like games. This is a small window of opportunity for D.

Bye,
bearophile