> Efficiency: Uses a lazy-loading piece tree to avoid loading huge files into RAM

I once started writing a text editor on Linux, and first went down a similar route: a piece table over a mmap()'d file. But I abandoned using mmap, because Linux file systems typically don't have mandatory locking enabled, so you can't be sure that the file data won't be modified by another program.

(Then I got bogged down in Unicode handling... so 95% of the code became just about that, and I tired of it)