This idea isn't new. I used something just like this (but more ghetto) whenever I worked on Firefox extensions. It was called the Extension Developer Extension:
It's quite neat, but very easy to get confused: if you switch to a different tab to read documentation for example, then make an edit and save, it will try and load into the new tab (usually with strange results!)
7 comments
[ 4.0 ms ] story [ 15.2 ms ] threadhttp://ted.mielczarek.org/code/mozilla/extensiondev/
It had other features, but the REPL was the most important to me. This looks much nicer though.
In fact I would say it's a kind of a pattern: implementing REPLs for systems that weren't made with REPLs in mind.
(That doesn't say anything about the coolness of this hack though, one way or the other :)
Edit: Just realised that this is pure javascript, making it a lot easier to deploy than jssh, and also a lot more extensible. That is awesome.
On one hand, it's built on top of Firebug; this adds a lot of power (chrome inspection, javascript debugging/breakpoints in the chrome).
On the other, it's alpha, and not the focus of development (as far as I can tell)--it hasn't had a new release in some time.
It's quite neat, but very easy to get confused: if you switch to a different tab to read documentation for example, then make an edit and save, it will try and load into the new tab (usually with strange results!)