Highlight results of :grep while in quickfix window

Question

To my .vimrc I added a hook which automates entering the quickfix after :grep processing:

autocmd QuickFixCmdPost [^l]* nested cwindow 20

Another thing I care about but can't achieve is automation of applying highlight/color of all found occurrences while being in the quickfix. What I observed, it's really easy to do manually:

/pattern

by re-typing the same pattern which went to the :grep we will get all occurrences highlighted in all of the files referenced by the quickfix.

Is it possible to program it so that vim will know the grep's matches (or at least the pattern passed) and automatically perform the /pattern search command after :cwindow is executed - or perform any other method to apply that highlight?

---

UPDATE

Assuming we can deliver a custom command for :grep in .vimrc, like:

command! -nargs=+ G execute "grep -rIn <args> ."

now the pattern itself is provided by the means of a custom command which might be helpful(?).

I admit I'm not a good vim programmer. Can it all be somehow chained together (as another autocmd/function and preserving the effect of cwindow hook) to get that highlight to be applied?

Answer 1

Option 1 Hack

A hack... you could get the title of the quickfix window, and then strip off the parts that arent the search term:

    let pattern = getqflist({'title' : 0}).title
    let pattern = strip_off_not_search_parts(pattern)

And then add a match with:

    call clearmatches()
    silent call matchadd('Search', pattern) " Hi group / pattern

I have found it hard to get the search highlighting as if you typed it, you could try feedkeys() but I had little joy with it.

Option 2 Wrapper

You are going to want to improve it as time passes by :) I recommend vim the hardway, and :help input

function! GrepWithHighlight()
    let searchString = input("Input search string: ")
    if searchString == '' || searchString == '\n'
        echom "Aborted Search."
        return
    endif
    exe 'vimgrep /'.searchString.'/ **/*'
    " Open the quickfix window first so match applies to it
    copen
    call clearmatches()
    silent call matchadd('Search', searchString) " Hi group / pattern
endfunction
noremap <leader>v :call GrepWithHighlight()<Cr>

Answer 2

After experiments I have observed that matchadd() proposed by run_the_race highlights occurrences only in the quickfix window but not in the window with file buffers which would be even more desirable. We could apply matchadd() twice (before copen and after) but this method has side-effects while applying to files anyway (e.g. clearmatches() also clears existing custom matches).

For above reasons I tried to replace matchadd() with regular search highlight (managed by hlsearch and the search register) but this is impossible to achieve within a function, what :h function-search-undo clearly states. Therefore I figured out slightly different solution (seems even simpler by occasion):

autocmd QuickFixCmdPost * nested cwindow 20 | redraw!
command! -nargs=+ Grep execute "let @/ = '<args>' | set hlsearch | silent grep -rI <args> ."
noremap <leader>g :Grep<space>

redraw! prevents weird artifacts when drawing quickfix over quickfix or grep returns no results. let @/ = and hl search take care about populating the search register and triggering the highlight itself. silent avoids a need of pressing Enter after shell processing. Of course one can add custom "must be" options between grep and <args> strings, like:

--exclude=tags --exclude-dir=build --exclude-dir=.git

It's most ergonomic and robust highlighted grep I could reach (keeping in mind that some REGEX inconsistencies between grep and vim may diverge the highlight effect, for that one can use vimgrep which is unacceptably slow).

Answer 3

I wrote a wrapper for :grep. I'm using ripgrep as grep replacement. The wrapper automatically opens the quickfix window and highlights the matches. Whether it's a single word or a "string with spaces"

" :Grep "Peding Transaction"               " with fixed strings
" :Grep! "\sTransaction"                   " regex
" :Grep \$stateParam
" :Grep "Pending Transaction" -g "*.php"   " with rg parameters
" :Grep "Pending Transaction" vendor/      " with path
" :Grep "Pending Transaction" -g "*.php" vendor   " with rg parameters and path

" rg as :grep
set grepprg=rg\ --vimgrep\ --follow\ --hidden
set grepformat^=%f:%l:%c:%m

hi QuickFixMatch guifg=#839e00

function! s:Grep(isFixed, args) abort
    let fixedArg = a:isFixed ? '' : '-F'
    let argArray = split(a:args)
    let restArgs = ''

    let quotedStringPattern = '^\".\{-}\"'
    let pattern = matchstr(a:args, quotedStringPattern) " check for first pattern with space in quotes

    if !empty(pattern)
        let matchPattern = substitute(pattern, '"', '', 'g')
        let restArgs = substitute(a:args, quotedStringPattern, '', '')
    else
        let pattern = argArray[0]
        let matchPattern = pattern
        let restArgs = join(argArray[1:], ' ')
    endif

    execute 'silent! grep! '. fixedArg . ' ' . pattern . ' ' . restArgs . ' | cwindow 20 | redraw! | match QuickFixMatch /' . matchPattern . '/'
endfunction

command! -nargs=+ -complete=file -bang Grep silent! call s:Grep(<bang>0, <q-args>)

https://gist.github.com/dr0bz/2932b41ee57b8dfeca161e77b2572354