bug#30503: 27.0.50; allow hiding M-x grep command line

[Juri Linkov]

retitle 30503 allow hiding M-x rgrep/lgrep/zrgrep command line
thanks

> The first thing you see after M-x grep is a 1382-character line like
> this:
>
> find . -type d \( -path \*/SCCS -o -path \*/RCS -o -path \*/CVS -o -path
> \*/MCVS -o -path \*/.src -o -path \*/.svn -o -path \*/.git -o -path
> \*/.hg -o -path \*/.bzr -o -path \*/_MTN -o -path \*/_darcs -o -path
> \*/\{arch\} \) -prune -o \! -type d \( -name .\#\* -o -name \*.o -o -name
> \*\~ -o -name \*.bin -o -name \*.lbin -o -name \*.so -o -name \*.a -o -name
> \*.ln -o -name \*.blg -o -name \*.bbl -o -name \*.elc -o -name
> \*.lof -o -name \*.glo -o -name \*.idx -o -name \*.lot -o -name
> \*.fmt -o -name \*.tfm -o -name \*.class -o -name \*.fas -o -name
> \*.lib -o -name \*.mem -o -name \*.x86f -o -name \*.sparcf -o -name
> \*.dfsl -o -name \*.pfsl -o -name \*.d64fsl -o -name \*.p64fsl -o -name
> \*.lx64fsl -o -name \*.lx32fsl -o -name \*.dx64fsl -o -name
> \*.dx32fsl -o -name \*.fx64fsl -o -name \*.fx32fsl -o -name
> \*.sx64fsl -o -name \*.sx32fsl -o -name \*.wx64fsl -o -name
> \*.wx32fsl -o -name \*.fasl -o -name \*.ufsl -o -name \*.fsl -o -name
> \*.dxl -o -name \*.lo -o -name \*.la -o -name \*.gmo -o
>   -name \*.mo -o -name \*.toc -o -name \*.aux -o -name \*.cp -o -name
> \*.fn -o -name \*.ky -o -name \*.pg -o -name \*.tp -o -name \*.vr -o -name
> \*.cps -o -name \*.fns -o -name \*.kys -o -name \*.pgs -o -name
> \*.tps -o -name \*.vrs -o -name \*.pyc -o -name \*.pyo \) -prune -o -type
> f \( -iname \* -o -iname .\[\!.\]\* -o -iname ..\?\* \) -exec
> grep --color -nH --null -e Emacs \{\} +
>
> Could we provide an option to hide the barrage of ignored directories
> and files?  It might also be worth adding a text button or keybinding
> to toggle their visibility interactively.

Yes, this is a real problem.  Even though I set truncate-lines to t,
often there is a need to see grep switches at the end of the
command line.  So there is a patch to hide uninteresting parts
under a button like is used to hide part of output by
elisp-last-sexp-toggle-display.  It supports rgrep, lgrep and zrgrep.

diff --git a/lisp/progmodes/grep.el b/lisp/progmodes/grep.el
index 14e251e..34a9b2f 100644
--- a/lisp/progmodes/grep.el
+++ b/lisp/progmodes/grep.el
@@ -452,7 +452,13 @@ grep-mode-font-lock-keywords
      ;; "filename=linenumber=" for lines with function names in "git grep -p".
      ("^.+?\\([-=\0]\\)[0-9]+\\([-=]\\).*\n" (0 grep-context-face)
       (1 (if (eq (char-after (match-beginning 1)) ?\0)
-             `(face nil display ,(match-string 2))))))
+             `(face nil display ,(match-string 2)))))
+     ;; Hide excessive part of the command from rgrep
+     ("^find \\(\\. -type d .*\\\\)\\)"
+      (1 (rgrep-command-hide)))
+     ;; Hide excessive part of the command from lgrep
+     ("^grep \\( *--exclude.*--exclude[^ ]+\\)"
+      (1 (rgrep-command-hide))))
    "Additional things to highlight in grep output.
 This gets tacked on the end of the generated expressions.")
 
@@ -1166,6 +1173,32 @@ rgrep-default-command
                  (shell-quote-argument ")")
                  " -prune -o ")))))
 
+(defun rgrep-command-hide ()
+  (let ((map (make-sparse-keymap)))
+    (define-key map [down-mouse-2] 'mouse-set-point)
+    (define-key map [mouse-2] 'rgrep-command-show)
+    (define-key map "\C-m" 'rgrep-command-show)
+    `(face nil display "[...]" mouse-face highlight
+          help-echo "RET, mouse-2: toggle truncated command"
+          keymap ,map)))
+
+(defun rgrep-command-show ()
+  (interactive)
+  (when (get-text-property (point) 'display)
+    (let ((beg (or (previous-single-property-change
+                    (min (point-max) (1+ (point))) 'display)
+                   (point)))
+          (end (or (next-single-property-change
+                    (point) 'display)
+                   (point)))
+          (inhibit-modification-hooks t)
+          (inhibit-read-only t)
+         (buffer-undo-list t)
+         (modified (buffer-modified-p)))
+      (remove-list-of-text-properties
+       beg end '(display help-echo mouse-face help-echo keymap))
+      (set-buffer-modified-p modified))))
+
 ;;;###autoload
 (defun zrgrep (regexp &optional files dir confirm template)
   "Recursively grep for REGEXP in gzipped FILES in tree rooted at DIR.