How to remap `m` key correctly?

Question

I want to remap the m key for executing a function after a mark is set. I tried with this function but it doesn't work. The mark function is not running correctly, and hello world is never printed. How can I map this correctly? I am not sure how can I wait for m to complete its action before running other action.

vim.api.nvim_set_keymap("n", "m", "m<cmd>echo 'hello world'<cr>", {noremap = true})

Answer 1

You probably want to use :h getchar() to let the user input the name of the mark they want to set, otherwise your mapped m command will be executed without a mark name and that doesn't work.

Here is an example in vimscript using a function: You remap m to call the MarkAndDo function. This function reads the input of the user with getchar() and uses execute to run the command m + mark name then you can do whatever you want in the function.

function! MarkAndDo()
    execute "normal! m" . nr2char(getchar())
    echo "hello world"
endfunction

nnoremap <silent> m :call MarkAndDo()<CR>

Adapting this solution to the nvim_set_keymap() api is straight forwards:

vim.api.nvim_set_keymap("n", "m", ":call MarkAndDo()<CR>", {noremap= true})

If you want to keep it a one liner that should be possible too but I think that it's better to use a function to keep your code readable.