[Emacs-diffs] fix/bug-2034 ce79708 1/3: Support mode line constructs for 'mode-name' in c-mode (bug#2034)

[Phil]

branch: fix/bug-2034
commit ce797083c1b2ba0edffddc43fdcbc71b49f2f109
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-vars.el (c-modeline-display-flags): New user
    option.
    * lisp/progmodes/cc-cmds.el (c-modeline-flags): New variable.
    (c--modeline-major-mode): New internal buffer-local variable.
    (c-update-modeline): Use mode line constructs, rather than string
    concatenation, to optionally include minor mode flags in 'mode-name'.
    
    * lisp/progmodes/cc-cmds.el (c-toggle-auto-newline)
    (c-toggle-hungry-state, c-toggle-auto-hungry-state)
    (c-toggle-electric-state, c-toggle-comment-style):
    * lisp/progmodes/cc-mode.el (c-electric-indent-mode-hook)
    (c-electric-indent-local-mode-hook): Remove redundant calls to
    'c-update-modeline'.  It is no longer necessary to call this function
    every time one of the minor mode states changes.  The remaining calls
    are in 'c-basic-common-init' (which is called via 'c-common-init' by
    all the major modes defined in cc-mode.el), and in the :after-hook of
    those modes (which ensures that 'mode-name' is still processed for a
    derived mode that doesn't call 'c-common-init' itself).
    
    * lisp/progmodes/cc-mode.el (c-submit-bug-report):
    * lisp/progmodes/cc-styles.el (c-set-style): Format 'mode-name'.
    
    * doc/misc/cc-mode.texi: Document 'c-modeline-display-flags'.
    
    * etc/NEWS: Mention new user option and behaviors.
---
 doc/misc/cc-mode.texi       |  4 +++
 etc/NEWS                    | 12 +++++++++
 lisp/progmodes/cc-cmds.el   | 66 +++++++++++++++++++++++++--------------------
 lisp/progmodes/cc-mode.el   | 10 +++----
 lisp/progmodes/cc-styles.el |  2 +-
 lisp/progmodes/cc-vars.el   | 10 +++++++
 6 files changed, 69 insertions(+), 35 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..76f776d 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 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..d6f3503 100644
--- a/lisp/progmodes/cc-cmds.el
+++ b/lisp/progmodes/cc-cmds.el
@@ -258,31 +258,44 @@ 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)
 
+(defvar c-modeline-flags
+  '(c-modeline-display-flags
+    ("/"
+     (c-block-comment-flag "*" "/")
+     (c-electric-flag ("l" (c-auto-newline "a")))
+     (c-hungry-delete-key "h")
+     ;; FIXME: subword-mode already comes with its own lighter!
+     (c-subword-mode "w")))
+  "A mode line construct to indicate the enabled minor modes.
+
+See Info node `(ccmode) Minor Modes'.
+
+The flags are hidden when `c-modeline-display-flags' is nil.
+
+This construct is added to `mode-name' by `c-update-modeline'.")
+
+(defvar-local c--modeline-major-mode nil
+  "The last major mode processed by `c-update-modeline'.
+
+When the value of `major-mode' is not a match for this buffer-
+local value, we know that a new mode has been invoked (e.g. a
+derived mode of the previous value seen).  That in turn means
+that `mode-name' has been reset by the new major mode, and needs
+to be updated.")
+
 (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)))
+  "Add `c-modeline-flags' to `mode-name', if not already done.
+
+This is called from `c-basic-common-init' and should also be
+invoked via the :after-hook of the major mode.  The hook ensures
+that this function is still called for derived modes which don't
+call `c-basic-common-init'."
+  (unless (eq major-mode c--modeline-major-mode)
+    (setq mode-name (list mode-name 'c-modeline-flags))
+    (unless (stringp (car mode-name))
+      (push "" mode-name))
+    (setq c--modeline-major-mode major-mode))
+  (force-mode-line-update))
 
 (defun c-toggle-syntactic-indentation (&optional arg)
   "Toggle syntactic indentation.
@@ -322,7 +335,6 @@ after special characters such as brace, comma, semi-colon, 
and colon."
   (setq c-auto-newline
        (c-calculate-state arg (and c-auto-newline c-electric-flag)))
   (if c-auto-newline (setq c-electric-flag t))
-  (c-update-modeline)
   (c-keep-region-active))
 
 (defalias 'c-toggle-auto-state 'c-toggle-auto-newline)
@@ -339,7 +351,6 @@ the mode line after the mode name) the delete key gobbles 
all preceding
 whitespace in one fell swoop."
   (interactive "P")
   (setq c-hungry-delete-key (c-calculate-state arg c-hungry-delete-key))
-  (c-update-modeline)
   (c-keep-region-active))
 
 (defun c-toggle-auto-hungry-state (&optional arg)
@@ -352,7 +363,6 @@ See `c-toggle-auto-newline' and `c-toggle-hungry-state' for 
details."
   (interactive "P")
   (setq c-auto-newline (c-calculate-state arg c-auto-newline))
   (setq c-hungry-delete-key (c-calculate-state arg c-hungry-delete-key))
-  (c-update-modeline)
   (c-keep-region-active))
 
 (defun c-toggle-electric-state (&optional arg)
@@ -362,7 +372,6 @@ positive, turns it off when negative, and just toggles it 
when zero or
 left out."
   (interactive "P")
   (setq c-electric-flag (c-calculate-state arg c-electric-flag))
-  (c-update-modeline)
   (when (fboundp 'electric-indent-local-mode) ; Emacs 24.4 or later.
     (electric-indent-local-mode (if c-electric-flag 1 0)))
   (c-keep-region-active))
@@ -390,7 +399,6 @@ This action does nothing when the mode only has one comment 
style."
        (if c-block-comment-flag
            (concat " " c-block-comment-ender)
          ""))
-  (c-update-modeline)
   (c-keep-region-active))
 
 
diff --git a/lisp/progmodes/cc-mode.el b/lisp/progmodes/cc-mode.el
index f09ca04..456b826 100644
--- a/lisp/progmodes/cc-mode.el
+++ b/lisp/progmodes/cc-mode.el
@@ -642,6 +642,8 @@ that requires a literal mode spec at compile time."
 ;;       (setq minor-mode-alist
 ;;         (cons '(c-submode-indicators c-submode-indicators)
 ;;               minor-mode-alist)))
+
+  ;; Add minor mode flags to `mode-name'.
   (c-update-modeline)
 
   ;; Install the functions that ensure that various internal caches
@@ -2029,16 +2031,14 @@ This function is called from `c-common-init', once per 
mode initialization."
           (with-current-buffer buf
             (when c-buffer-is-cc-mode
               ;; Don't use `c-toggle-electric-state' here due to recursion.
-              (setq c-electric-flag electric-indent-mode)
-              (c-update-modeline))))
+              (setq c-electric-flag electric-indent-mode))))
         (buffer-list)))
 
 (defun c-electric-indent-local-mode-hook ()
   ;; Emacs has en/disabled `electric-indent-local-mode' for this buffer.
   ;; Propagate this through to this buffer's value of `c-electric-flag'
   (when c-buffer-is-cc-mode
-    (setq c-electric-flag electric-indent-mode)
-    (c-update-modeline)))
+    (setq c-electric-flag electric-indent-mode)))
 
 
 ;; Support for C
@@ -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))))
diff --git a/lisp/progmodes/cc-vars.el b/lisp/progmodes/cc-vars.el
index 0475114..8dee5e2 100644
--- a/lisp/progmodes/cc-vars.el
+++ b/lisp/progmodes/cc-vars.el
@@ -1695,6 +1695,16 @@ c-noise-macro-with-parens-names is invalid: %s" 
c-noise-macro-with-parens-names)
               (copy-sequence c-noise-macro-names))
              (t (error "c-make-noise-macro-regexps: \
 c-noise-macro-names is invalid: %s" c-noise-macro-names)))))
+
+(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 defined by `c-modeline-flags'."
+  :version "27.1"
+  :type 'boolean
+  :group 'c)
 
 ;; Non-customizable variables, still part of the interface to CC Mode
 (defvar c-macro-with-semi-re nil