[Emacs-diffs] fix/bug-2034 d604e33: Support mode line constructs for 'mode-name' in c-mode (bug#2034)

[Phil]

branch: fix/bug-2034
commit d604e331abfaf523f4421b68182784aab718954b
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.
    
    * cc-cmds.el (c-modeline-flags): 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'.
    
    * 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                  | 12 +++++++++
 lisp/progmodes/cc-cmds.el | 65 ++++++++++++++++++++++++++++++-----------------
 3 files changed, 57 insertions(+), 24 deletions(-)

diff --git a/doc/misc/cc-mode.texi b/doc/misc/cc-mode.texi
index 5a229c1..4dc33cb 100644
--- a/doc/misc/cc-mode.texi
+++ b/doc/misc/cc-mode.texi
@@ -1179,6 +1179,7 @@ you initialize a buffer, the comment style is set to the 
default for
 the major mode, electric mode and syntactic-indentation mode are
 enabled, but the other three modes are disabled.
 
address@hidden c-modeline-display-flags
 @ccmode{} displays the current state of the first five of these minor
 modes on the mode line by appending characters to the major mode's
 name: @samp{/} or @samp{*} to indicate the comment style (respectively
@@ -1190,6 +1191,9 @@ 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.}.
 
+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..e2ae500 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -525,6 +525,18 @@ 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 minor mode indicator characters which are otherwise
+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..10e7440 100644
--- a/lisp/progmodes/cc-cmds.el
+++ b/lisp/progmodes/cc-cmds.el
@@ -258,31 +258,48 @@ 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.
+
+If the default value of `c-modeline-flags' is made non-nil,
+`c-update-modeline' will not add the constructs to `mode-name'
+necessary for displaying the flags.")
+
 (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'."
+  (unless c-modeline-flags
+    (setq mode-name (list "" mode-name (list 'c-modeline-display-flags
+                                            'c-modeline-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.