Add new user option compilation-hidden-output

* doc/emacs/building.texi (Compilation Mode): Document it.
* lisp/progmodes/compile.el (compilation-hidden-output): New user
option.
(compilation-filter): Use it.
(compilation--hide-output): New function.

doc/emacs/building.texi

@@ -289,6 +289,19 @@ window so that the current error message is @var{n} lines from the
 top, whether or not there is a fringe; the default value, @code{nil},
 gives the behavior described above.
 
+@vindex compilation-hidden-output
+  Compilation output can sometimes be very verbose, and much of it isn't
+of particular interest to a user.  The
+@code{compilation-hidden-output} user option should either be a regexp
+or a list of regexps, and output that matches will be made invisible.
+For instance, to hide the verbose output from recursive makefiles, you
+can say something like:
+
+@lisp
+(setq compilation-hidden-output
+      '("^make[^\n]+\n"))
+@end lisp
+
 @vindex compilation-error-regexp-alist
 @vindex grep-regexp-alist
   To parse messages from the compiler, Compilation mode uses the

etc/NEWS

@@ -898,6 +898,11 @@ which is a change in behaviour from previous Emacs versions.
 
 ** Compile
 
++++
+*** New user option 'compilation-hidden-output'.
+This can be used to make specific parts of compilation output
+invisible.
+
 +++
 *** The 'compilation-auto-jump-to-first-error' has been extended.
 It can now have the additional values 'if-location-known' (which will

lisp/progmodes/compile.el

@@ -82,6 +82,25 @@ after `call-process' inserts the grep output into the buffer.")
   "Position of the start of the text inserted by `compilation-filter'.
 This is bound before running `compilation-filter-hook'.")
 
+(defcustom compilation-hidden-output nil
+  "Regexp to match output from the compilation that should be hidden.
+This can also be a list of regexps.
+
+The text matched by this variable will be made invisible, which
+means that it'll still be present in the buffer, so that
+navigation commands (for instance, `next-error') can still make
+use of the hidden text to determine the current directory and the
+like.
+
+For instance, to hide the verbose output from recursive
+makefiles, you can say something like:
+
+  (setq compilation-hidden-output
+        \\='(\"^make[^\n]+\n\"))"
+  :type '(choice regexp
+                 (repeat regexp))
+  :version "29.1")
+
 (defvar compilation-first-column 1
   "This is how compilers number the first column, usually 1 or 0.
 If this is buffer-local in the destination buffer, Emacs obeys
@@ -2441,8 +2460,8 @@ commands of Compilation major mode are available.  See
 
 (defun compilation-filter (proc string)
   "Process filter for compilation buffers.
-Just inserts the text,
-handles carriage motion (see `comint-inhibit-carriage-motion'),
+Just inserts the text, handles carriage motion (see
+`comint-inhibit-carriage-motion'), `compilation-hidden-output',
 and runs `compilation-filter-hook'."
   (when (buffer-live-p (process-buffer proc))
     (with-current-buffer (process-buffer proc)
@@ -2467,6 +2486,8 @@ and runs `compilation-filter-hook'."
                 (dolist (line (string-lines string nil t))
                   (compilation--insert-abbreviated-line
                    line compilation-max-output-line-length)))
+              (when compilation-hidden-output
+                (compilation--hide-output compilation-filter-start))
               (unless comint-inhibit-carriage-motion
                 (comint-carriage-motion (process-mark proc) (point)))
               (set-marker (process-mark proc) (point))
@@ -2479,6 +2500,24 @@ and runs `compilation-filter-hook'."
 	  (set-marker min nil)
 	  (set-marker max nil))))))
 
+(defun compilation--hide-output (start)
+  (save-excursion
+    (goto-char start)
+    (beginning-of-line)
+    ;; Apply the match to each line, but wait until we have a complete
+    ;; line.
+    (let ((start (point)))
+      (while (search-forward "\n" nil t)
+        (save-restriction
+          (narrow-to-region start (point))
+          (dolist (regexp (ensure-list compilation-hidden-output))
+            (goto-char start)
+            (while (re-search-forward regexp nil t)
+              (add-text-properties (match-beginning 0) (match-end 0)
+                                   '( invisible t
+                                      rear-nonsticky t))))
+          (goto-char (point-max)))))))
+
 (defun compilation--insert-abbreviated-line (string width)
   (if (and (> (current-column) 0)
            (get-text-property (1- (point)) 'button))