You may use incron [1] for this. incrond watches for file changes and can execute based on file actions.
[1] - http://incron.aiken.cz
This is yet another piece of the puzzle. At this point, I think the only missing ingredient is the ability to create temporary files without having to specify names (those can be created automatically based on time or whatnot). As long as the text box you're working with is addressable via some file descriptor, you can then start to create connections with something like this incron. And you could replicate the functionality that can be done in the current version of Conception.