How to use the result of a function in a Vim keymap?

Question

I have a function in Vim script that returns a string.

" Return first directory with ".git" folder, if none is found
" return the current directory
function! s:project_root()
      for vcs in ['.git']
          let dir = finddir(vcs.'/..', expand('%:p:h').';')
          if !empty(dir)
              return dir
          endif
      endfor
      " If there is no root dir use the current dir
      return expand('%:p:h')
  endfunction

I would like to use this function in a key mapping as the argument to a command called Files. So something like this

nnoremap <leader>f :Files<Space><insert result of function call here><CR>

I tried doing:

execute 'nnoremap <leader>f :Files<Space>'.s:project_root()

but I believe this only calls the function once (when the .vimrc is loaded), when I need the function to be called everytime the keybinding is pressed.

Answer 1

Do the :execute inside your mapping instead.

You don't need to use <Space> in mappings, you can just use an actual space instead.

You probably want to include a <cr> at the end, to actually execute the :Files command and not leave it pending on the command line waiting for you to press enter (but, again, maybe that's what you want?)

Putting it all together:

nnoremap <leader>f :execute 'Files '.<SID>project_root()<cr>