Override a mapping with leader key

Question

I am trying to create a mapping that has 2 functions:

On 1st use: redefine itself to be used

After: execute the newly saved mapping

The workflow could be :

<leader>r -> map <leader>r dd

<leader>r -> dd

<leader>r -> dd

...

So I came up with this mapping :

map <Leader>r :nnoremap <Leader>r

And I get :

<leader>r -> :nnoremap r

My leader key is \<Space> and so a space is inserted and now I can trigger the mapping but with only pressing r.

Do you know a method to "escape" the leader key in a mapping ?

Answer 1

Inside a mapping, escape < with <lt> (and | with <Bar>). The following example shows a working demo of your idea:

:nnoremap <Leader>r :nnoremap <lt>Leader>r :echo "hi"<lt>CR><CR>

PS: You should use :noremap for the initial mapping, too.

Answer 2

From reading the Vim source, it would seem that all occurrences of <Leader> in a mapping are replaced by the leader character, you can't escape this. From term.c replace_keycodes() (abbreviated):

if (strncmp(src, "<Leader>", 8) == 0) {
    p = get_var_value("g:mapleader");
}

I only did a quick reading, so perhaps I missed something.

---

The easiest workaround I can figure out is using a character code to "hide" the <Leader> part from this piece of code, which seems to run before the code that replaces the character codes:

map <Leader>r :nnoremap <Char-0x3c>Leader>r

<Char-0x3c> is the hex code for the < character.

---

Note I didn't know about the <Char- syntax either by the way, I found it by typing :help key-mapping; at the top of the page there's an index and the "Mapping special keys" and "Special characters" sections looked interesting enough to skim, which is where I found this ;-)