Dump output using execute() in neovim

Question

Currently, I am using nnoremap <leader>d :vnew +pu=execute('')<left><left> to dump output in both vim and neovim. I tried it with verbose imap <tab> but it didn't work

nnoremap <leader>d :vnew +pu=execute('verbose imap <tab>')<left><left>

Answer 1

This is failing because when you use the +cmd argument to :vnew, you need to escape spaces with backslashes. As :help +cmd points out:

To include a white space in the {pat} or {command}, precede it with a backslash.

So, in your case, using the following would work:

:vnew +pu=execute('verbose\ imap\ <tab>')

Perhaps a better approach is to define a new user-command that would encapsulate the implementation. In that case, you can also modify the opened buffer to become a scratch-buffer, since you probably don't want to save its contents when quitting.

For example:

function! Dump(cmd)
  vnew
  setlocal buftype=nowrite bufhidden=delete noswapfile
  let result = trim(execute(a:cmd))
  put! =result
  1
endfunction
command! -nargs=* -complete=command Dump call Dump(<q-args>)

Which you can then use with:

:Dump verbose imap <tab>

Defining a user-command is also useful in that you can set up tab completion. In this case, to complete Vim commands, which is what you want to pass execute().