[c0nstantine]

Thank you for the detailed comment.

So Unicode is something on a top of my TODO list. Boundaries is a very interesting topic. Maybe I'll extend the doc to include the details.

> what's your driver? curiosity? or some itch?

It's an itch :). 8 years ago I explored automata theory and found finite transducers to be a handy and natural way to transform texts. And as regex corresponds to FSA (finite state acceptors) I wanted to create a language that corresponds to FST (finite state transducers). There is a lesser-known algorithm for FST determinization and I want to applied it to make the transformation fast and efficient. It turned out to be not that simple as I expected initially.