Our shiny new "grep operator" is working great, but part of writing Vimscript is being considerate and making your users' lives easier. We can do two more things to make our operator play nicely in the Vim ecosystem.
By yanking the text into the unnamed register we destroy anything that was previously in there. Further, by using a visual selection to yank the text in the case that our operator is applied with a motion, we also destroy any record of the most recent visual selection.
This isn't very nice to our users, so let's avoid using a visual selection in that case and also save the contents of the unnamed register before we yank in all cases so that we can restore it after we're done. Change the code to look like this:
nnoremap <leader>g :set operatorfunc=GrepOperator<cr>g@ vnoremap <leader>g :<c-u>call GrepOperator(visualmode())<cr> function! GrepOperator(type) let saved_unnamed_register = @@ if a:type ==# 'v' normal! `<v`>y elseif a:type ==# 'char' normal! `[y`] else return endif silent execute "grep! -R " . shellescape(@@) . " ." copen let @@ = saved_unnamed_register endfunction
We've added two
let statements at the top and bottom of the function. The
first saves the contents of
@@ into a variable and the second restores it.
Additionally, we've applied yank with a motion rather than a visual selection in
the case that our operator is applied with a motion.
Write and source the file. Make sure it works by yanking some text, then
<leader>giw to run our operator, then pressing
p to paste the text
you yanked before.
When writing Vim plugins you should always strive to save and restore any settings or registers your code modifies so you don't surprise and confuse your users.
Our script created a function named
GrepOperator in the global namespace.
This probably isn't a big deal, but when you're writing Vimscript it's far
better to be safe than sorry.
We can avoid polluting the global namespace by tweaking a couple of lines in our code. Edit the file to look like this:
nnoremap <leader>g :set operatorfunc=<SID>GrepOperator<cr>g@ vnoremap <leader>g :<c-u>call <SID>GrepOperator(visualmode())<cr> function! s:GrepOperator(type) let saved_unnamed_register = @@ if a:type ==# 'v' normal! `<v`>y elseif a:type ==# 'char' normal! `[v`]y else return endif silent execute "grep! -R " . shellescape(@@) . " ." copen let @@ = saved_unnamed_register endfunction
The first three lines of the script have changed. First, we modified the
function name to start with
s: which places it in the current script's
We also modified the mappings and prepended the
GrepOperator function name
<SID> so they could find the function. If we hadn't done this they would
have tried to find the function in the global namespace, which wouldn't have
grep-operator.vim script is not only extremely useful,
but it's also a considerate Vimscript citizen!
Treat yourself to a snack. You deserve it!