Key repeats and ranges in Vim mappings

Question

I want to define a mapping in my .gvimrc such that if the last key pressed is held, the triggered action is repeated. Specifically, I want to do something like

map <SPACE>t :set transparency-=1
map <SPACE>T :set transparency+=1

for MacVim, but I want the transparency to continue to be decreased/increased when t/T are held (don't want to have to keep pressing the spacebar).

If you have a suggestion for a nicer way to adjust the transparency, I would appreciate that also.

Separately, it would be nice to be able be able to type 20 SPACE t and have the transparency decreased by 20; however, when I try I get an

E481: No range allowed.

How do I enable range specification?

Thanks a lot.

Answer 1

I am not sure about the first part of your question, but to get 20 <Space> t to be able to do its job:

:map <space>t :<C-U>exe "set transparency-=".v:count1<CR>

• With <C-U> you remove the line range that is added to your ex command when you type 20 in Normal mode.
• With exe you execute 'dynamic' vimscript.
• v:count1 is the count given for the last Normal mode command (20 in this example). And if there is no count given it defaults to 1.

For additional information see

:h v:count
:h v:count1

Update:

You can omit exe using let form instead of set one:

:map <space>t :<C-U>let &transparency-=v:count1<CR>

See :h :let-&.