Re: junk in *grep* buffers

[Juri Linkov]

[Resending to address@hidden due to bounce from fencepost.gnu.org]

> It would seem much safer to do the translation of escape sequences to
> text-properties in the process filter (maybe it could add a
> `font-lock-face' property, so that the displayed result would honor
> font-lock-mode).

When the process filter deletes escape sequences it is not possible
to use compile font-lock machinery to locate column positions
of grep matches in `grep-regexp-alist' and to use them while browsing
grep matches in source buffers with `next-error'.

Perhaps we should revert to the initial variant where escape sequences
were hidden under `invisible' and `intangible' properties because this
is a more reliable method.  There were two complaints about invisible
grep markers that can be fixed now:

1. Copied text preserves invisible grep markers.  This can be fixed
by removing invisible markers in a buffer-substring filter added
to the new variable `buffer-substring-filters'.

2. Search stumbles upon invisible markers.  Search can be fixed to
ignore invisible text.  This will be useful for other modes as well,
e.g. for Info to skip invisible `*Note' in cross references with
a search string overlapping the invisible text.

-- 
Juri Linkov
http://www.jurta.org/emacs/