[gavinpc]

This kind of as-you-type evaluator is extremely valuable to me. I've written a few tools to support this in emacs, and I use the JS one all the time.[0]

I also wrote one for Graphviz (which outputs to an SVG buffer), and sometimes I'll put the output from the JS playground in `play-graphviz` mode so I can see real-time graph output from JS (by writing code to print dot graphs). ATM I don't know any other tools that can do that sort of thing, let alone compose independent ones to that end. Long live Emacs!

[0] https://bitbucket.org/gavinpc/play-modes/src/default/js-play... (There is an odd bug in OSX where the first character of the input is eaten, so I always begin these "playgrounds" with "/// playing with <whatever>". There are some other oddities which I should document.)