How to add action before "gf"?

Question

I'm using NVIM 0.8.2

I'd like to replace the default gf command (goto file under the cursor) to do something before and after the action.

For example:

echo "do something before"
goto file/dir under cursor
echo "do something after"

I can't find what command gf is calling, how can I do this?

Answer 1

Try this:

function Beforegf()
    "do something here
endfunction
function Aftergf()
    "do something here
endfunction
nnoremap gf :<c-u>call Beforegf()<cr>gf:<c-u>call Aftergf()<cr>

if Beforegf() is something that will move your cursor, you'll need to adjust accordingly. Example:

function Beforegf()
    " yank the WORD under the cursor into the f register
    norm! "fyiW
    pu='This is the line after the filename'
endfunction
function Aftergf()
    "do something here
endfunction
" Use the :e command with the contents of the f register to get the filename we yanked
nnoremap gf :<c-u>call Beforegf()<cr>:<c-u>exe 'e '.@f<cr>:<c-u>call Aftergf()<cr>

At any rate, you can use the normal command yiW followed by the Ex command execute 'edit '.@" as a rough equivalent of gf. I would warn, however, that a WORD is not the exact same thing as a filepath. If you want a really robust solution, take another look at :help gf and possibly incorporate the contents of the isfname option into your method of determining what to yank.