On 06.12.2020 23:00, Juri Linkov wrote:
>>> dired-do-find-regexp uses 'ignores' to filter out ignored files.
>>> You could add another filter to filter out files without matches
>>> using 'grep -PzL'.
>> Right. This is sorta a backup plan. Although, when the number of files to
>> search can be counted on one hand, there's nothing too bad in doing the
>> search in Emacs.
> Another backup plan is to use ripgrep.  Its multiline handling with -U
> also allows to search words ignoring any whitespace, even newlines.
> This is like isearch-lax-whitespace using search-whitespace-regexp
> when it contains a newline, e.g. "[ \t\r\n]+".

Right. It has a problem of its own, though: it still outputs a file name 
per line, even when a match is spread across several lines (unlike 
pcregrep). So we're left guessing where a given multiline match ends.

Also, 'sort' doesn't seem to be able to treat both : and \0 as 
separators at the same time.

Here's a rough patch, for illustration. It's kind of working, but I'm 
not loving it.