creating sticky key mappings in vim

I have this in my vimrc file

nnoremap <leader>k <C-u>

I want to be able to continue to h开发者_运维百科old down the leader key, and just tap 'k' to scroll the screen as I like. But, at the moment, I have to release both keys first, and then press them again to get the desired action.

How do I implement it, so that I don't have to keep releasing the leader key to get the functionality to work?

Cheers.

TinyMode is a plugin that pretty much achieves what you're looking for. You could set it up so that you press <leader>k and then just tap k.