Jack: Allow WIP pseudo code

You know how you sometimes mock up code with some keywords to represent the structure of the logic but then put in hand-wavy text for rest of it because you've not fleshed it out yet?

Jack should support that directly. Something like:
if --calamity happens--
    --dont panic--
    --call 911--
end

Just a hint of an idea at this time. I'm not sure if -- is the right sigil/delimiter to use. "<<" seems like a good one from personal experience, but it has bad web mojo :).