I want to remap Ctrl-A (normal mode) to do something similar
with other data, e.g.
:nmap <c-a> ciw<c-r>=IncRoman(@-)<cr><esc>
Now if a count is provided this will mess up the text, e.g.
10<c-a> does 10ciw...
What is a good way to catch the count and make it available to
the function call?
Well, after hacking at it on and off for the last day or two,
trying various ideas, this is one of my uglier hacks and abuses
of vim's conventions.
function! IncRoman(initial, howmuch)
" do your own IncRoman stuff here...this
" just a generic increment
try
let l:result = a:initial + a:howmuch
catch
let l:result = a:howmuch
endtry
return l:result
endfunction
:noremap <c-a> :<home><right><right><right><right><c-u>let
howmuch=<end>+1<cr>ciw<c-r>=IncRoman(@-,howmuch)<cr><esc>
This one-liner mapping (in case mailers on either end of things
ended up breaking that mapping line) seems to work correctly on
various values that I threw at it. If you try to increment a
non-number, it will replace it with the increment quantity, which
seemed reasonable to me. If you don't like the behavior, you can
change the "catch" clause to return what you prefer (either the
initial contents, or an empty string would be other good candidates).
It should even be swappable if you have a companion DecRoman
function with the same sort of call-signature.
It's a horrible abuse of the fact that vim, when you start typing
a count and press the colon, defaults to the range ".,.+x" where
"x" is one less than the count given. But it works :)
Funny behaviors may occur is you specify a register as well, such as
"_5^A
(where ^A is the control+A at hand), though it seems to be pretty
smart about matters.
You can't just use <home> followed by 4x <del> statements, but
rather you have to go <home> followed by 4x <right> statements
and then use <c-u> because otherwise, you end up cancelling the
command line. Crazy stuff.
Happy hacking,
-tim
