This blog post from one of the people working on Duetto explains: http://allievi.sssup.it/techblog/?p=798 http://allievi.sssup.it/techblog/?p=798 Basically, th

This blog post from one of the people working on Duetto explains: http://allievi.sssup.it/techblog/?p=798 http://allievi.sssup.it/techblog/?p=798 Basically, the idea seems to be to translate more C++ features directly into high-level JavaScript equivalents, rather than into code that primarily operates on byte arrays, as I believe emscripten does.