[Emacs-diffs] fix/bug-2034 d22274b: Support mode line constructs for 'mode-name' in c-mode (bug#2034)

[Phil]

branch: fix/bug-2034
commit d22274b5c67fc82611354dc8079fd43eca574e92
Author: Phil Sainty <address@hidden>
Commit: Phil Sainty <address@hidden>

    Support mode line constructs for 'mode-name' in c-mode (bug#2034)
    
    Also make the inclusion of minor mode flags in 'mode-name' optional.
    
    * lisp/progmodes/cc-cmds.el (c-modeline-flags): New variable.
    (c-modeline-flags-major-modes-processed): New variable.
    (c-modeline-display-flags): New user option.
    (c-update-modeline): Use them.  Use mode line constructs, rather than
    string concatenation, to optionally include minor mode flags in
    'mode-name'.
    
    * lisp/progmodes/cc-mode.el (c-submit-bug-report): Format 'mode-name'.
    
    * lisp/progmodes/cc-styles.el (c-set-style): Format 'mode-name'.
    
    * etc/NEWS: Mention new user option and behaviors.
    
    * doc/misc/cc-mode.texi: Document 'c-modeline-display-flags'.
---
 doc/misc/cc-mode.texi       |  4 +++
 etc/NEWS                    | 13 +++++++++
 lisp/progmodes/cc-cmds.el   | 71 ++++++++++++++++++++++++++++++---------------
 lisp/progmodes/cc-mode.el   |  2 +-
 lisp/progmodes/cc-styles.el |  2 +-
 5 files changed, 66 insertions(+), 26 deletions(-)

diff --git a/doc/misc/cc-mode.texi b/doc/misc/cc-mode.texi
index 5a229c1..9b7ed69 100644
--- a/doc/misc/cc-mode.texi
+++ b/doc/misc/cc-mode.texi
@@ -1190,6 +1190,10 @@ you'd see @samp{C/address@hidden @samp{C} would be 
replaced with
 the name of the language in question for the other languages @ccmode{}
 supports.}.
 
address@hidden c-modeline-display-flags
+If you do not wish these minor mode states to be displayed, set the
+user option @code{c-modeline-display-flags} to @code{nil}.
+
 Here are the commands to toggle these modes:
 
 @table @asis
diff --git a/etc/NEWS b/etc/NEWS
index c92ee6e..7c64925 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -525,6 +525,19 @@ It was obsolete since Emacs 22.1, replaced by customize.
 Use of built-in libgnutls based functionality (described in the Emacs
 GnuTLS manual) is recommended instead.
 
+** CC mode
+
++++
+*** The user option 'c-modeline-display-flags' allows hiding the
+sequence of characters indicating the states of various minor modes,
+which by default are appended to 'mode-name' in the mode line (and
+elsewhere).
+
+---
+*** 'mode-name' is no longer required to be a string.  The function
+'c-update-modeline' now uses mode line constructs to append the minor
+mode flags to 'mode-name'.
+
 
 ** Message
 
diff --git a/lisp/progmodes/cc-cmds.el b/lisp/progmodes/cc-cmds.el
index 31cf0b1..4f21254 100644
--- a/lisp/progmodes/cc-cmds.el
+++ b/lisp/progmodes/cc-cmds.el
@@ -258,31 +258,54 @@ With universal argument, inserts the analysis as a 
comment on that line."
 (defvar c-block-comment-flag nil)
 (make-variable-buffer-local 'c-block-comment-flag)
 
+(defcustom c-modeline-display-flags t
+  "If non-nil, `mode-name' includes indicators for certain minor modes.
+
+See Info node `(ccmode) Minor Modes'.
+
+These flags are set by `c-update-modeline'."
+  :type 'boolean
+  :version "27.1"
+  :group 'c)
+
+(defvar-local c-modeline-flags nil
+  "Minor mode indicators to be appended to `mode-name'.
+
+See Info node `(ccmode) Minor Modes'.
+
+The flags are hidden when `c-modeline-display-flags' is nil.")
+
+(defvar-local c-modeline-flags-major-modes-processed nil
+  "Major modes for which `c-update-modeline' has processed `mode-name'.
+
+Needed to ensure that derived modes are processed.")
+
 (defun c-update-modeline ()
-  (let ((fmt (format "/%s%s%s%s%s"
-                    (if c-block-comment-flag "*" "/")
-                    (if c-electric-flag "l" "")
-                    (if (and c-electric-flag c-auto-newline)
-                        "a" "")
-                    (if c-hungry-delete-key "h" "")
-                    (if (and
-                         ;; (cc-)subword might not be loaded.
-                         (boundp 'c-subword-mode)
-                         (symbol-value 'c-subword-mode))
-                         ;; FIXME: subword-mode already comes with its
-                         ;; own lighter!
-                        "w"
-                      "")))
-        ;; FIXME: Derived modes might want to use something else
-        ;; than a string for `mode-name'.
-       (bare-mode-name (if (string-match "\\(^[^/]*\\)/" mode-name)
-                           (match-string 1 mode-name)
-                         mode-name)))
-    (setq mode-name
-         (if (> (length fmt) 1)
-             (concat bare-mode-name fmt)
-       bare-mode-name))
-    (force-mode-line-update)))
+  "Update `c-modeline-flags' and append to `mode-name'."
+  ;; Add additional mode line constructs to `mode-name'.
+  (unless (memq major-mode c-modeline-flags-major-modes-processed)
+    (setq mode-name (list mode-name (list 'c-modeline-display-flags
+                                         'c-modeline-flags)))
+    (unless (stringp (car mode-name))
+      (push "" mode-name))
+    (push major-mode c-modeline-flags-major-modes-processed))
+  ;; Generate the minor mode flags.
+  (setq c-modeline-flags
+       (format "/%s%s%s%s%s"
+               (if c-block-comment-flag "*" "/")
+               (if c-electric-flag "l" "")
+               (if (and c-electric-flag c-auto-newline)
+                   "a" "")
+               (if c-hungry-delete-key "h" "")
+               (if (and
+                    ;; (cc-)subword might not be loaded.
+                    (boundp 'c-subword-mode)
+                    (symbol-value 'c-subword-mode))
+                   ;; FIXME: subword-mode already comes with its
+                   ;; own lighter!
+                   "w"
+                 "")))
+  (force-mode-line-update))
 
 (defun c-toggle-syntactic-indentation (&optional arg)
   "Toggle syntactic indentation.
diff --git a/lisp/progmodes/cc-mode.el b/lisp/progmodes/cc-mode.el
index f09ca04..8a960f1 100644
--- a/lisp/progmodes/cc-mode.el
+++ b/lisp/progmodes/cc-mode.el
@@ -2521,7 +2521,7 @@ Key bindings:
         t (message "") nil)
      (reporter-submit-bug-report
       c-mode-help-address
-      (concat "CC Mode " c-version " (" mode-name ")")
+      (concat "CC Mode " c-version " (" (format-mode-line mode-name) ")")
       (let ((vars (append
                   c-style-variables
                   '(c-buffer-is-cc-mode
diff --git a/lisp/progmodes/cc-styles.el b/lisp/progmodes/cc-styles.el
index a1f3261..1f5258b 100644
--- a/lisp/progmodes/cc-styles.el
+++ b/lisp/progmodes/cc-styles.el
@@ -365,7 +365,7 @@ a null operation."
   (interactive
    (list (let ((completion-ignore-case t)
               (prompt (format "Which %s indentation style? "
-                              mode-name)))
+                              (format-mode-line mode-name))))
           (completing-read prompt c-style-alist nil t nil
                            'c-set-style-history
                            c-indentation-style))))