How to create a "new mode" for vim (i.e., loop and get user input, then execute the associated actions)

Question

I'm trying to create something of a "new mode" in vim. The details of the mode are unimportant, but there is one thing I need to be able to do.

I need to do something like the following pseudo-code:

get user input (movement keys like "j" or complex keys like "dd")
while user_input != <esc>
   execute the user input
endwhile

In other words, I need a loop that will read what the user is doing, then perform the associated action.

I've already got the following code:

let char = nr2char(getchar())
while char =~ '^\w$'
    execute "normal ". char
    let char = nr2char(getchar())
endwhile

This works fine for user movements (j, k, etc.), but fails for more complex multi-character commands like dd.

Also, this is a small annoyance, but the cursor disappears during getchar(), meaning you effectively can't see the cursor (this is of less importance because of what I'm trying to do, but hopefully has a solution as well).

Does anyone have any idea how I can get multi-character actions to work?

Answer 1

I think you might be interested in submode.vim, if not to use it, to at least see how they've implemented this feature.