@item
@cindex abbrev tables in modes
The mode may have its own abbrev table or may share one with other
-related modes. If it has its own abbrev table, it should store this in
-a variable named @code{@var{modename}-mode-abbrev-table}. @xref{Abbrev
-Tables}.
+related modes. If it has its own abbrev table, it should store this
+in a variable named @code{@var{modename}-mode-abbrev-table}. If the
+major mode command defines any abbrevs itself, it should pass @code{t}
+for the @var{system-flag} argument to @code{define-abbrev}.
+@xref{Abbrev Tables}.
@item
The mode should specify how to do highlighting for Font Lock mode, by
@end example
@noindent
-This tells Emacs that new buffers created while the current buffer is in
-Funny mode should not inherit Funny mode. Modes such as Dired, Rmail,
+This tells Emacs that new buffers created while the current buffer is
+in Funny mode should not inherit Funny mode, in case
+@code{default-major-mode} is @code{nil}. Modes such as Dired, Rmail,
and Buffer List use this feature.
@item
file that contains the mode definition. @xref{Auto Major Mode}.
@item
-In the documentation, you should provide a sample @code{autoload} form
-and an example of how to add to @code{auto-mode-alist}, that users can
-include in their init files (@pxref{Init File}).
+In the comments that document the file, you should provide a sample
+@code{autoload} form and an example of how to add to
+@code{auto-mode-alist}, that users can include in their init files
+(@pxref{Init File}).
@item
@cindex mode loading
@smallexample
@group
-;; @r{Create mode-specific tables.}
-(defvar text-mode-syntax-table nil
- "Syntax table used while in text mode.")
+;; @r{Create the syntax table for this mode.}
+(defvar text-mode-syntax-table
+ (let ((st (make-syntax-table)))
+ (modify-syntax-entry ?\" ". " st)
+ (modify-syntax-entry ?\\ ". " st)
+ ;; We add `p' so that M-c on 'hello' leads to 'Hello' rather than 'hello'.
+ (modify-syntax-entry ?' "w p" st)
+ st)
+ "Syntax table used while in `text-mode'.")
@end group
+;; @r{Create the keymap for this mode.}
@group
-(if text-mode-syntax-table
- () ; @r{Do not change the table if it is already set up.}
- (setq text-mode-syntax-table (make-syntax-table))
- (modify-syntax-entry ?\" ". " text-mode-syntax-table)
- (modify-syntax-entry ?\\ ". " text-mode-syntax-table)
- (modify-syntax-entry ?' "w " text-mode-syntax-table))
+(defvar text-mode-map
+ (let ((map (make-sparse-keymap)))
+ (define-key map "\e\t" 'ispell-complete-word)
+ (define-key map "\es" 'center-line)
+ (define-key map "\eS" 'center-paragraph)
+ map)
+ "Keymap for `text-mode'.
+Many other modes, such as `mail-mode', `outline-mode' and `indented-text-mode',
+inherit all the commands defined in this map.")
@end group
+@end smallexample
+ Here is how the actual mode command is defined now:
+
+@smallexample
@group
-(defvar text-mode-abbrev-table nil
- "Abbrev table used while in text mode.")
-(define-abbrev-table 'text-mode-abbrev-table ())
+(define-derived-mode text-mode nil "Text"
+ "Major mode for editing text written for humans to read.
+In this mode, paragraphs are delimited only by blank or white lines.
+You can thus get the full benefit of adaptive filling
+ (see the variable `adaptive-fill-mode').
+\\{text-mode-map}
+Turning on Text mode runs the normal hook `text-mode-hook'."
@end group
-
@group
-(defvar text-mode-map nil ; @r{Create a mode-specific keymap.}
- "Keymap for Text mode.
-Many other modes, such as Mail mode, Outline mode and Indented Text mode,
-inherit all the commands defined in this map.")
-
-(if text-mode-map
- () ; @r{Do not change the keymap if it is already set up.}
- (setq text-mode-map (make-sparse-keymap))
- (define-key text-mode-map "\e\t" 'ispell-complete-word)
- (define-key text-mode-map "\t" 'indent-relative)
- (define-key text-mode-map "\es" 'center-line)
- (define-key text-mode-map "\eS" 'center-paragraph))
+ (make-local-variable 'text-mode-variant)
+ (setq text-mode-variant t)
+ ;; @r{These two lines are a feature added recently.}
+ (set (make-local-variable 'require-final-newline)
+ mode-require-final-newline)
+ (set (make-local-variable 'indent-line-function) 'indent-relative))
@end group
@end smallexample
- This was formerly the complete major mode function definition for Text mode:
+ But here is how it was defined formerly, before
+@code{define-derived-mode} existed:
@smallexample
+@group
+;; @r{This isn't needed nowadays, since @code{define-derived-mode} does it.}
+(defvar text-mode-abbrev-table nil
+ "Abbrev table used while in text mode.")
+(define-abbrev-table 'text-mode-abbrev-table ())
+@end group
+
@group
(defun text-mode ()
"Major mode for editing text intended for humans to read...
(set-syntax-table text-mode-syntax-table)
@end group
@group
+ ;; @r{These four lines are absent from the current version}
+ ;; @r{not because this is done some other way, but rather}
+ ;; @r{because nowadays Text mode uses the normal definition of paragraphs.}
(make-local-variable 'paragraph-start)
(setq paragraph-start (concat "[ \t]*$\\|" page-delimiter))
(make-local-variable 'paragraph-separate)
@group
;; @r{Create mode-specific table variables.}
(defvar lisp-mode-syntax-table nil "")
-(defvar emacs-lisp-mode-syntax-table nil "")
(defvar lisp-mode-abbrev-table nil "")
@end group
@group
-(if (not emacs-lisp-mode-syntax-table) ; @r{Do not change the table}
- ; @r{if it is already set.}
+(defvar emacs-lisp-mode-syntax-table
+ (let ((table (make-syntax-table)))
(let ((i 0))
- (setq emacs-lisp-mode-syntax-table (make-syntax-table))
@end group
@group
- ;; @r{Set syntax of chars up to 0 to class of chars that are}
+ ;; @r{Set syntax of chars up to @samp{0} to say they are}
;; @r{part of symbol names but not words.}
- ;; @r{(The number 0 is @code{48} in the @acronym{ASCII} character set.)}
+ ;; @r{(The digit @samp{0} is @code{48} in the @acronym{ASCII} character set.)}
(while (< i ?0)
- (modify-syntax-entry i "_ " emacs-lisp-mode-syntax-table)
- (setq i (1+ i)))
- @dots{}
+ (modify-syntax-entry i "_ " table)
+ (setq i (1+ i)))
+ ;; @r{@dots{} similar code follows for other character ranges.}
@end group
@group
- ;; @r{Set the syntax for other characters.}
- (modify-syntax-entry ? " " emacs-lisp-mode-syntax-table)
- (modify-syntax-entry ?\t " " emacs-lisp-mode-syntax-table)
- @dots{}
+ ;; @r{Then set the syntax codes for characters that are special in Lisp.}
+ (modify-syntax-entry ? " " table)
+ (modify-syntax-entry ?\t " " table)
+ (modify-syntax-entry ?\f " " table)
+ (modify-syntax-entry ?\n "> " table)
@end group
@group
- (modify-syntax-entry ?\( "() " emacs-lisp-mode-syntax-table)
- (modify-syntax-entry ?\) ")( " emacs-lisp-mode-syntax-table)
- @dots{}))
+ ;; @r{Give CR the same syntax as newline, for selective-display.}
+ (modify-syntax-entry ?\^m "> " table)
+ (modify-syntax-entry ?\; "< " table)
+ (modify-syntax-entry ?` "' " table)
+ (modify-syntax-entry ?' "' " table)
+ (modify-syntax-entry ?, "' " table)
+@end group
+@end group
+@group
+ ;; @r{@dots{}likewise for many other characters@dots{}}
+ (modify-syntax-entry ?\( "() " table)
+ (modify-syntax-entry ?\) ")( " table)
+ (modify-syntax-entry ?\[ "(] " table)
+ (modify-syntax-entry ?\] ")[ " table))
+ table))
+@end group
;; @r{Create an abbrev table for lisp-mode.}
(define-abbrev-table 'lisp-mode-abbrev-table ())
@end group
@smallexample
@group
(defun lisp-mode-variables (lisp-syntax)
- (cond (lisp-syntax
- (set-syntax-table lisp-mode-syntax-table)))
+ (when lisp-syntax
+ (set-syntax-table lisp-mode-syntax-table))
(setq local-abbrev-table lisp-mode-abbrev-table)
@dots{}
@end group
(defvar shared-lisp-mode-map ()
"Keymap for commands shared by all sorts of Lisp modes.")
+;; @r{Putting this @code{if} after the @code{defvar} is an older style.}
(if shared-lisp-mode-map
()
(setq shared-lisp-mode-map (make-sparse-keymap))
; @r{finds out what to describe.}
(setq mode-name "Lisp") ; @r{This goes into the mode line.}
(lisp-mode-variables t) ; @r{This defines various variables.}
+ (make-local-variable 'comment-start-skip)
+ (setq comment-start-skip
+ "\\(\\(^\\|[^\\\\\n]\\)\\(\\\\\\\\\\)*\\)\\(;+\\|#|\\) *")
+ (make-local-variable 'font-lock-keywords-case-fold-search)
+ (setq font-lock-keywords-case-fold-search t)
@end group
@group
(setq imenu-case-fold-search t)
other tables.
In addition, there are several conventions that are specific to
-minor modes.
+minor modes. (The easiest way to follow all the conventions is to use
+the macro @code{define-minor-mode}; @ref{Defining Minor Modes}.)
@itemize @bullet
@item
If just setting the variable is not sufficient to enable the mode, you
should also specify a @code{:set} method which enables the mode by
-invoke the mode command. Note in the variable's documentation string that
+invoking the mode command. Note in the variable's documentation string that
setting the variable other than via Custom may not take effect.
Also mark the definition with an autoload cookie (@pxref{Autoload}),
;; The indicator for the mode line.
" Hungry"
;; The minor mode bindings.
- '(("\C-\^?" . hungry-electric-delete)
- ("\C-\M-\^?"
- . (lambda ()
- (interactive)
- (hungry-electric-delete t))))
+ '(("\C-\^?" . hungry-electric-delete))
:group 'hunger)
@end smallexample
@code{hungry-mode} to toggle it, a variable named @code{hungry-mode}
which indicates whether the mode is enabled, and a variable named
@code{hungry-mode-map} which holds the keymap that is active when the
-mode is enabled. It initializes the keymap with key bindings for
-@kbd{C-@key{DEL}} and @kbd{C-M-@key{DEL}}. It puts the variable
-@code{hungry-mode} into custom group @code{hunger}. There are no
-@var{body} forms---many minor modes don't need any.
+mode is enabled. It initializes the keymap with a key binding for
+@kbd{C-@key{DEL}}. It puts the variable @code{hungry-mode} into
+custom group @code{hunger}. There are no @var{body} forms---many
+minor modes don't need any.
Here's an equivalent way to write it:
and the frame title.
@end defun
- The mode line is usually displayed in inverse video; see
-@code{mode-line-inverse-video} in @ref{Inverse Video}.
+ The selected window's mode line is usually displayed in a different
+color using the face @code{mode-line}. Other windows' mode lines
+appear in the face @code{mode-line-inactive} instead. @xref{Faces}.
A window that is just one line tall does not display either a mode
line or a header line, even if the variables call for one. A window
effect, since it is impossible to move point into the mode line. This
keymap can only take real effect for mouse clicks.
+ When the mode line refers to a variable which does not have a
+non-@code{nil} @code{risky-local-variable} property, any text
+properties given or specified within that variable's values are
+ignored. This is because such properties could otherwise specify
+functions to be called, and those functions could come from file
+local variables.
+
@node Header Lines
@subsection Window Header Lines
@cindex header line (of a window)
directly to that location in the buffer. Imenu works by constructing
a buffer index which lists the names and buffer positions of the
definitions, or other named portions of the buffer; then the user can
-choose one of them and move point to it. The user-level commands for
-using Imenu are described in the Emacs Manual (@pxref{Imenu,, Imenu,
-emacs, the Emacs Manual}). This section explains how to customize
-Imenu's method of finding definitions or buffer portions for a
-particular major mode.
+choose one of them and move point to it. Major modes can add a menu
+bar item to use Imenu using @code{imenu-add-to-menubar}.
+
+@defun imenu-add-to-menubar name
+This function defines a local menu bar item named @var{name}
+to run Imenu.
+@end defun
+
+ The user-level commands for using Imenu are described in the Emacs
+Manual (@pxref{Imenu,, Imenu, emacs, the Emacs Manual}). This section
+explains how to customize Imenu's method of finding definitions or
+buffer portions for a particular major mode.
The usual and simplest way is to set the variable
@code{imenu-generic-expression}:
(@pxref{Faces for Font Lock}). Search-based fontification follows.
@menu
-* Font Lock Basics::
-* Search-based Fontification::
-* Other Font Lock Variables::
-* Levels of Font Lock::
-* Precalculated Fontification::
-* Faces for Font Lock::
-* Syntactic Font Lock::
+* Font Lock Basics:: Overview of customizing Font Lock.
+* Search-based Fontification:: Fontification based on regexps.
+* Other Font Lock Variables:: Additional customization facilities.
+* Levels of Font Lock:: Each mode can define alternative levels
+ so that the user can select more or less.
+* Precalculated Fontification:: How Lisp programs that produce the buffer
+ contents can also specify how to fontify it.
+* Faces for Font Lock:: Special faces specifically for Font Lock.
+* Syntactic Font Lock:: Defining character syntax based on context
+ using the Font Lock mechanism.
@end menu
@node Font Lock Basics
@node Precalculated Fontification
@subsection Precalculated Fontification
-In addition to using @code{font-lock-defaults} for search-based
+ In addition to using @code{font-lock-defaults} for search-based
fontification, you may use the special character property
@code{font-lock-face} (@pxref{Special Properties}). This property
acts just like the explicit @code{face} property, but its activation
@vindex font-lock-comment-face
Used (typically) for comments.
+@item font-lock-doc-face
+@vindex font-lock-doc-face
+Used (typically) for documentation strings in the code.
+
@item font-lock-string-face
@vindex font-lock-string-face
Used (typically) for string constants.
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