[skrebbel]

SpiderMonkey is easily embeddable like I said. The Mozilla Public License is less liberal than BSD/MIT, but for most practical purposes it's the same.

It's not tiny though (for an underbelly feeling, I found an old binary Windows build online of about 800kb).

Looking at the current SpiderMonkey docs, things look like they've only improved. Back in the day, I just took SpiderMonkey from the "js" subdirectory of the Firefox repo. They split it off and documented build steps since then.

I'm not saying there's no space for contenders here, but don't underestimate the quality of what's out there already. SpiderMonkey really is remarkably easy to interface with.

[brassybadger]

After a quick glance it also seems that newer versions of SpiderMonkey only offer a C++ API, so you can't embed it anymore into C apps without some glue code. I checked out jsapi.h in SpiderMonkey24 - maybe some trick is needed to use SM from C?

[pcwalton]

New versions of SpiderMonkey only expose a C++ API (because of exact rooting), but we'll need to fix that at some point as part of Servo since this is a hazard for Rust. Currently we use an old version of SpiderMonkey for this reason.