On Thu, Jul 10, 2014 at 1:12 PM, Silvan Jegen <s.je...@gmail.com> wrote: > On Thu, Jul 10, 2014 at 11:52 AM, Raphaël Proust <raphla...@gmail.com> wrote: >> On Thu, Jul 10, 2014 at 1:56 AM, Dimitris Zervas <dzer...@dzervas.gr> wrote: >> The trick that Yi uses is quite clever and not very complicated: >> keyboard input is passed to a lexer/parser which can be rewritten to >> provide alternative bindings. Treating keyboard events like that >> actually makes a lot of sense. It is not very specific to any >> programming paradigm and could be implemented in C (with a recursive >> descent parser if yacc is deemed to suck to much). > > Actually, I do not think you will need a "real" recursive parser. It > should be enough to use a finite state machine since you won't have > any recursively nested key bindings.
Yes, a state machine should be enough… > > I am not completely sure how to implement this but it sounds like a > very interesting problem. The states transition should probably look > something like this > > (count)? -> (operation)->(object) Operation is also optional and defaults to move (i.e., "5w" moves five words forward while "5dw" deletes five words forwards). And in vi[m] objects can have a count too. (e.g., "5dw" deletes one word five times, "d5w" deletes 5 words). And the object depends on the operation. And operation when repeated applies to the whole line (e.g., "dd", "yy"). Some operations also have optional qualifiers (e.g., yank/delete can take register). So the transition is a bit complicated. Well the vim one is, we can have something slightly saner. Also, mode changes can be integrated into this model. The keypress `v` gets into a different part of the state machine, &c. Cheers, -- ______________ Raphaël Proust
