[kragen]

also edwin, in mit scheme: https://www.gnu.org/software/mit-scheme/documentation/stable...

more generally, though, even if you aren't using a gui library with a built-in text editor widget, gigahertz and gigaflops make it not especially challenging to write a usable text editor in a high-level language. http://canonical.org/~kragen/sw/dev3/edumb.py is 183 lines of fairly straightforward python and includes full-text search and infinite undo; it's not quite usable but pretty close. its really stupid buffer data structure might start to get unresponsive once you're editing a file in the neighborhood of 100k