In my .vimrc file I have included the following line:
autocmd vimenter * botright term
This means that, whenever vim starts, it will open a terminal at the bottom-right.
I would like to create a key-mapping that makes vim run a given, dynamically-generated command at the terminal. For example, I have added the following to my .vimrc file:
nmap <leader><leader> <C-w><C-w>python my_python_file.py<CR><C-w><C-w>
So if I am editing a file called my_py_file.py, I can press <leader><leader> and vim will first change windows (changing to the embedded terminal), then enter the command
python my_python_file.py
so that the file will run in python, and finally change back to the other window so that I can continue editing. This works! But I would like it to work for arbitrary files, not just for files that are named my_python_file.py. How can this be accomplished?
I have thought about using expand('%:p') to get the full path of the current file, but I have not been able to pass this string to the embedded terminal window as input. I have tried writing a function to accomplish this, but with no success.
The key is to use map <expr> <leader><leader> ... so that <leader><leader> can be mapped to a dynamically-generated binding. The below code snippet from a .vimrc file works with Vim 8.0:
" open a terminal directly below current window
nnoremap <leader>t :split<cr><c-w><c-j>:terminal ++curwin<cr><c-w><c-k>
" save current file and run python on it in terminal window directly below
nnoremap <expr> <leader><leader> ':w<cr><c-w><c-j>python ' . expand('%:p') . '<cr><c-w><c-k>'
This maps <leader>t to open a new terminal buffer, and <leader><leader> to run python in that terminal buffer. Note that the terminal stays in Terminal-Job mode the whole time.
Slight modification will be needed for this to work with NeoVim:
" open a terminal directly below current window
nnoremap <leader>t :split<cr><c-w><c-j>:terminal<cr><c-w><c-k>
" save current file and run python on it in terminal window directly below
nnoremap <expr> <leader><leader> ':w<cr><c-w><c-j>ipython ' . expand('%:p') . '<cr><c-\><c-n><c-w><c-k>'
In the NeoVim version, we must change from Terminal-Normal mode to Terminal-Job mode before passing input to the terminal, and then return to Terminal-Normal mode.