Debugger Integration

[guybedford]

Brought up at CTW - Spidermonkey has a debugger API that we should figure out the right integration for.

Unfortunately it does not include a debugging protocol itself, so one would need to be implemented on top of WASI sockets or otherwise. Apparently VSCode solved this for Python using a character device on preview1 to handle the V8 debugging protocol.

The debugging that needs to be handled is stepping through the JS code, when yielding through to external component model import calls, I suppose this would suspend the entire debugging interface while the external call is made, then reinitiate the debugging interface after that. This seems fine as far as I can tell.

We could possibly even have a first-class world import for debugging support, by exposing the world for debug builds only, and then relying on hosts that support the debugger protocol imports and exports, as an alternative to implementing it on top of wasi sockets.

Should be a really interesting project!