@ref{Keymaps}, and @ref{Syntax Tables}.
@menu
-* Hooks:: How to use hooks; how to write code that provides hooks.
-* Major Modes:: Defining major modes.
-* Minor Modes:: Defining minor modes.
-* Mode Line Format:: Customizing the text that appears in the mode line.
+* Hooks:: How to use hooks; how to write code that provides hooks.
+* Major Modes:: Defining major modes.
+* Minor Modes:: Defining minor modes.
+* Mode Line Format:: Customizing the text that appears in the mode line.
* Imenu:: How a mode can provide a menu
of definitions in the buffer.
* Font Lock Mode:: How modes can highlight text according to syntax.
its value is just a single function, not a list of functions.
@menu
-* Running Hooks:: How to run a hook.
-* Setting Hooks:: How to put functions on a hook, or remove them.
+* Running Hooks:: How to run a hook.
+* Setting Hooks:: How to put functions on a hook, or remove them.
@end menu
@node Running Hooks
to another major mode in the same buffer.
@menu
-* Major Mode Basics::
-* Major Mode Conventions:: Coding conventions for keymaps, etc.
-* Auto Major Mode:: How Emacs chooses the major mode automatically.
-* Mode Help:: Finding out how to use a mode.
-* Derived Modes:: Defining a new major mode based on another major
+* Major Mode Basics::
+* Major Mode Conventions:: Coding conventions for keymaps, etc.
+* Auto Major Mode:: How Emacs chooses the major mode automatically.
+* Mode Help:: Finding out how to use a mode.
+* Derived Modes:: Defining a new major mode based on another major
mode.
-* Generic Modes:: Defining a simple major mode that supports
+* Generic Modes:: Defining a simple major mode that supports
comment syntax and Font Lock mode.
-* Mode Hooks:: Hooks run at the end of major mode functions.
-* Example Major Modes:: Text mode and Lisp modes.
+* Mode Hooks:: Hooks run at the end of major mode functions.
+* Example Major Modes:: Text mode and Lisp modes.
@end menu
@node Major Mode Basics
is distinct from that of Text mode, but uses that of Text mode.
Even if the new mode is not an obvious derivative of any other mode,
-it is convenient to use @code{define-derived-mode} with a @code{nil}
-parent argument, since it automatically enforces the most important
-coding conventions for you.
+we recommend to use @code{define-derived-mode}, since it automatically
+enforces the most important coding conventions for you.
For a very simple programming language major mode that handles
comments and fontification, you can use @code{define-generic-mode}.
@code{eldoc-documentation-function} to tell ElDoc mode how to handle
this mode.
+@item
+The mode can specify how to complete various keywords by adding
+to the special hook @code{completion-at-point-functions}.
+
@item
Use @code{defvar} or @code{defcustom} to set mode-related variables, so
that they are not reinitialized if they already have a value. (Such
mode as special if the parent mode is special. The special mode
@code{special-mode} provides a convenient parent for other special
modes to inherit from; it sets @code{buffer-read-only} to @code{t},
-and does nothing else.
+and does little else.
@item
If you want to make the new mode the default for files with certain
@subsection Defining Derived Modes
@cindex derived mode
- It's often useful to define a new major mode in terms of an existing
-one. An easy way to do this is to use @code{define-derived-mode}.
+ The recommended way to define a new major mode is to derive it
+from an existing one using @code{define-derived-mode}. If there is no
+closely related mode, you can inherit from @code{text-mode},
+@code{special-mode}, or in the worst case @code{fundamental-mode}.
@defmac define-derived-mode variant parent name docstring keyword-args@dots{} body@dots{}
This macro defines @var{variant} as a major mode command, using
Turning on Text mode runs the normal hook `text-mode-hook'."
@end group
@group
- (make-local-variable 'text-mode-variant)
- (setq text-mode-variant t)
+ (set (make-local-variable 'text-mode-variant) t)
;; @r{These two lines are a feature added recently.}
(set (make-local-variable 'require-final-newline)
mode-require-final-newline)
@smallexample
@group
;; @r{This isn't needed nowadays, since @code{define-derived-mode} does it.}
-(defvar text-mode-abbrev-table nil
+(define-abbrev-table 'text-mode-abbrev-table ()
"Abbrev table used while in text mode.")
-(define-abbrev-table 'text-mode-abbrev-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]*$\\|" page-delimiter))
- (make-local-variable 'paragraph-separate)
- (setq paragraph-separate paragraph-start)
- (make-local-variable 'indent-line-function)
- (setq indent-line-function 'indent-relative-maybe)
+ (set (make-local-variable 'paragraph-start)
+ (concat "[ \t]*$\\|" page-delimiter))
+ (set (make-local-variable 'paragraph-separate) paragraph-start)
+ (set (make-local-variable 'indent-line-function) 'indent-relative-maybe)
@end group
@group
(setq mode-name "Text")
@smallexample
@group
- (make-local-variable 'paragraph-start)
- (setq paragraph-start (concat page-delimiter "\\|$" ))
- (make-local-variable 'paragraph-separate)
- (setq paragraph-separate paragraph-start)
+ (set (make-local-variable 'paragraph-start) (concat page-delimiter "\\|$" ))
+ (set (make-local-variable 'paragraph-separate) paragraph-start)
@dots{}
@end group
@group
- (make-local-variable 'comment-indent-function)
- (setq comment-indent-function 'lisp-comment-indent))
+ (set (make-local-variable 'comment-indent-function) 'lisp-comment-indent))
@dots{}
@end group
@end smallexample
@smallexample
@group
-(defvar shared-lisp-mode-map ()
+(defvar shared-lisp-mode-map
+ (let ((map (make-sparse-keymap)))
+ (define-key shared-lisp-mode-map "\e\C-q" 'indent-sexp)
+ (define-key shared-lisp-mode-map "\177"
+ 'backward-delete-char-untabify)
+ 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))
- (define-key shared-lisp-mode-map "\e\C-q" 'indent-sexp)
- (define-key shared-lisp-mode-map "\177"
- 'backward-delete-char-untabify))
@end group
@end smallexample
@smallexample
@group
-(defvar lisp-mode-map ()
+(defvar lisp-mode-map
+ (let ((map (make-sparse-keymap)))
+ (set-keymap-parent map shared-lisp-mode-map)
+ (define-key map "\e\C-x" 'lisp-eval-defun)
+ (define-key map "\C-c\C-z" 'run-lisp)
+ map)
"Keymap for ordinary Lisp mode...")
-
-(if lisp-mode-map
- ()
- (setq lisp-mode-map (make-sparse-keymap))
- (set-keymap-parent lisp-mode-map shared-lisp-mode-map)
- (define-key lisp-mode-map "\e\C-x" 'lisp-eval-defun)
- (define-key lisp-mode-map "\C-c\C-z" 'run-lisp))
@end group
@end smallexample
; @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)
+ (set (make-local-variable 'comment-start-skip)
+ "\\(\\(^\\|[^\\\\\n]\\)\\(\\\\\\\\\\)*\\)\\(;+\\|#|\\) *")
+ (set (make-local-variable 'font-lock-keywords-case-fold-search) t)
@end group
@group
(setq imenu-case-fold-search t)
minor modes.
@menu
-* Base: Mode Line Basics. Basic ideas of mode line control.
-* Data: Mode Line Data. The data structure that controls the mode line.
-* Top: Mode Line Top. The top level variable, mode-line-format.
-* Mode Line Variables:: Variables used in that data structure.
-* %-Constructs:: Putting information into a mode line.
-* Properties in Mode:: Using text properties in the mode line.
-* Header Lines:: Like a mode line, but at the top.
-* Emulating Mode Line:: Formatting text as the mode line would.
+* Base: Mode Line Basics. Basic ideas of mode line control.
+* Data: Mode Line Data. The data structure that controls the mode line.
+* Top: Mode Line Top. The top level variable, mode-line-format.
+* Mode Line Variables:: Variables used in that data structure.
+* %-Constructs:: Putting information into a mode line.
+* Properties in Mode:: Using text properties in the mode line.
+* Header Lines:: Like a mode line, but at the top.
+* Emulating Mode Line:: Formatting text as the mode line would.
@end menu
@node Mode Line Basics
* 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
+* 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:: Fontification based on syntax tables.
@end defvar
@ignore
- arch-tag: 4c7bff41-36e6-4da6-9e7f-9b9289e27c8e
+ Local Variables:
+ fill-column: 72
+ End:
@end ignore
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