This is a really tough problem. I worked on something like this extensively in 2005. Ultimately, the hardest part was syntax highlighting on the current line,

This is a really tough problem. I worked on something like this extensively in 2005. Ultimately, the hardest part was syntax highlighting on the current line, because you had to monitor input to figure out when a "token" had been completed, and then do the corresponding magic. Dealing with the idiosyncrasies of changing colors and maintaining cursor position makes this a real bitch. Turning off syntax coloring on the active line definitely makes the problem easier. Wish I would have thought of that. Strange how you can spend days on a problem but never think of the "easy" solution.