Question

Suppose I want to create a map in vim that will call an ex command as part of its work. And suppose that the ex command takes a register name as input.

Here is a toy example:

nmap <leader>p :put x

The problem there is that the ‘x’ register will always be used.
But when typing, I want to be able to write:

"a<leader>p

To use the ‘a’ register, or:

"b<leader>p

to use the ‘b’ register.

Is there a way that I can pass the ‘current normal-mode register’ along to the ‘ex’ command?

Answer 1

Ah, I figured it out.

The trick is to use <expr> in the mapping.

So, for my example, the answer is:

nnoremap <expr> <leader>p ':put ' . v:register . '<CR>'

Check :h map-expression and :h v:register for more info.