That's a nice approach for debugging! If the mapping is close enough, I don't mind reading the JS output. I'm curious about the general approach to compilation, though. It seems like a statically typed language could take advantage of the knowledge of types to generate an even more efficient version of the program that uses typed arrays and views (though, yes, it would require implementing a garbage collector unless relying on some kind of WeakMap in the JS engine). I've heard of garbage collected languages compiling to LLVM which would allow Emscripten to assist you, but I've also heard that LLVM has a really hard time with GC languages.