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mmm.texi
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\input texinfo
@c %**start of header
@documentencoding UTF-8
@setfilename mmm.info
@settitle MMM Mode Manual
@c %**end of header
@syncodeindex vr fn
@set MASON_VERSION 0.896
@dircategory GNU Emacs Lisp
@direntry
* MMM-Mode: (mmm). Multiple Major Modes for Emacs
@end direntry
@ifinfo
Copyright 2000 Michael Abraham Shulman.
Permission is granted to make and distribute verbatim copies of this
manual provided the copyright notice and this permission notice are
preserved on all copies.
@ignore
Permission is granted to process this file through TeX and print the
results, provided the printed document carries a copying permission
notice identical to this one except for the removal of this paragraph
(this paragraph not being relevant to the printed manual).
@end ignore
Permission is granted to copy and distribute modified versions of this
manual under the conditions for verbatim copying, provided also that the
sections entitled ``Copying'' and ``GNU General Public License'' are
included exactly as in the original, and provided that the entire
resulting derived work is distributed under the terms of a permission
notice identical to this one.
Permission is granted to copy and distribute translations of this manual
into another language, under the above conditions for modified versions,
except that this permission notice may be stated in a translation
approved by the Free Software Foundation.
@end ifinfo
@titlepage
@title MMM Mode Manual
@subtitle Multiple Major Modes for Emacs
@author Michael Abraham Shulman
@page
@vskip 0pt plus 1filll
Copyright @copyright{} 2000 Michael Abraham Shulman.
Permission is granted to make and distribute verbatim copies of this
manual provided the copyright notice and this permission notice are
preserved on all copies.
Permission is granted to copy and distribute modified versions of this
manual under the conditions for verbatim copying, provided also that the
sections entitled ``Copying'' and ``GNU General Public License'' are
included exactly as in the original, and provided that the entire
resulting derived work is distributed under the terms of a permission
notice identical to this one.
Permission is granted to copy and distribute translations of this manual
into another language, under the above conditions for modified versions,
except that this permission notice may be stated in a translation
approved by the Free Software Foundation.
@end titlepage
@ifnottex
@node Top
@top MMM Mode
MMM Mode is a minor mode for Emacs which allows Multiple Major Modes to
coexist in a single buffer.
@end ifnottex
@menu
* Overview:: An overview and introduction to MMM Mode.
* Basics:: The basics of how to use it.
* Customizing:: Customizing how it works to your needs.
* Supplied Classes:: The supplied submode classes.
* Writing Classes:: Writing your own submode classes.
* Indices:: Just that.
@detailmenu
--- The Detailed Node Listing ---
Overview of MMM Mode
* Basic Concepts:: A simple explanation of how it works.
* Installation:: How to install MMM Mode.
* Quick Start:: Getting started using MMM Mode quickly.
MMM Mode Basics
* MMM Minor Mode:: The Emacs minor mode that manages it all.
* Submode Classes:: What they are and how to use them.
* Selecting Classes:: How MMM Mode knows what classes to use.
* Insertion:: Inserting new submode regions automatically.
* Re-parsing:: Re-scanning for submode regions.
* Interactive:: Adding submode regions manually.
* Global Mode:: Turning MMM Mode on automatically.
The MMM Minor Mode
* Enabling MMM Mode:: Turning MMM Mode on and off.
* MMM Mode Keys:: Default key bindings in MMM Mode.
How MMM Mode selects submode classes
* File Classes:: Classes for a single file.
* Mode-Ext Classes:: Classes for a given mode or extension.
* Global Classes:: Classes for all MMM Mode buffers.
MMM Global Mode
* Major Mode Hook:: Using MMM's Major Mode Hook
Customizing MMM Mode
* Region Coloring:: Changing or removing background colors.
* Preferred Modes:: Choosing which major modes to use.
* Mode Line:: What is displayed in the mode line.
* Key Bindings:: Customizing the MMM Mode key bindings.
* Local Variables:: What local variables are saved for submodes.
* Changing Classes:: Changing the supplied submode classes.
* Hooks:: How to make MMM Mode run your code.
Supplied Submode Classes
* Mason:: Mason server-side Perl in HTML.
* File Variables:: Elisp code in File Variables.
* Here-documents:: Code in shell and Perl here-documents.
* Javascript:: Javascript embedded in HTML.
* Embedded CSS:: CSS Styles embedded in HTML.
* Embperl:: Another syntax for Perl in HTML.
* ePerl:: A general Perl-embedding syntax.
* JSP:: Java code embedded in HTML.
* RPM:: Shell scripts in RPM Spec Files.
* Noweb:: Noweb literate programs.
Writing Submode Classes
* Basic Classes:: Writing a simple submode class.
* Paired Delimiters:: Matching paired delimiters.
* Region Placement:: Placing the region more accurately.
* Submode Groups:: Grouping several classes together.
* Calculated Submodes:: Deciding the submode at run-time.
* Calculated Faces:: Deciding the display face at run-time.
* Insertion Commands:: Inserting regions automatically.
* Region Names:: Naming regions for syntax grouping.
* Other Hooks:: Running code at arbitrary points.
* Delimiters:: Controlling delimiter overlays.
* Misc Keywords:: Other miscellaneous options.
Indices
* Concept Index:: Index of MMM Mode Concepts.
* Function Index:: Index of functions and variables.
* Keystroke Index:: Index of key bindings in MMM Mode.
@end detailmenu
@end menu
@node Overview
@chapter Overview of MMM Mode
@cindex overview of mmm-mode
@cindex mmm-mode, overview of
MMM Mode is a minor mode for Emacs which allows Multiple Major Modes to
coexist in a single buffer. The name is an abbreviation of `Multiple
Major Modes'@footnote{The name is derived from @file{mmm.el} for XEmacs
by Gongquan Chen <chen@@posc.org>, from which MMM Mode was adapted.}. A
major mode is a customization of Emacs for editing a certain type of
text, such as code for a specific programming language. @xref{Major
Modes, , , emacs, The Emacs Manual}, for details.
MMM Mode is a general extension to Emacs which is useful whenever one
file contains text in two or more programming languages, or that
should be in two or more different modes. For example:
@itemize @bullet
@item
CGI scripts written in any language, from Perl to PL/SQL, may want to
output verbatim HTML, and the writer of such scripts may want to use
Emacs' html-mode or sgml-mode to edit this HTML code, while remaining
in the appropriate programming language mode for the rest of the
file. @xref{Here-documents}, for example.
@item
There are now many ``content delivery systems'' which turn the CGI
script idea around and simply add extra commands to an HTML file,
often in some programming language, which are interpreted on the
server. @xref{Mason}, @xref{Embperl}, @xref{ePerl}, @xref{JSP}.
@item
HTML itself can also contain embedded languages such as Javascript and
CSS styles, for which Emacs has different major modes.
@xref{Javascript}, and @xref{Embedded CSS}, for example.
@item
The idea of ``literate programming'' requires the same file to contain
documentation (written as text, html, latex, etc.) and code (in an
appropriate programming language). @xref{Noweb}, for example.
@item
Emacs allows files of any type to contain `local variables', which can
include Emacs Lisp code to be evaluated. @xref{File Variables, , ,
emacs, The Emacs Manual}. It may be easier to edit this code in Emacs
Lisp mode than in whatever mode is used for the rest of the file.
@xref{File Variables}.
@item
There are many more possible uses for MMM Mode. RPM spec files can
contain shell scripts (@pxref{RPM}). Email or newsgroup messages may
contain sample code. And so on. We encourage you to experiment.
@end itemize
@menu
* Basic Concepts:: A simple explanation of how it works.
* Installation:: How to install MMM Mode.
* Quick Start:: Getting started using MMM Mode quickly.
@end menu
@node Basic Concepts
@section Basic Concepts
@cindex dominant major mode
@cindex major mode, dominant
@cindex default major mode
@cindex major mode, default
@cindex submode regions
@cindex regions, submode
@cindex overlays, submode
@cindex submode overlays
@cindex mmm-ification
The way MMM Mode works is as follows. Each buffer has a @dfn{dominant}
or @dfn{default} major mode, which is chosen as major modes normally
are: the user can set it interactively, or it can be chosen
automatically with @code{auto-mode-alist} (@pxref{Choosing Modes, , , emacs,
The Emacs Manual}). Within the file, MMM Mode creates @dfn{submode
regions} within which other major modes are in effect. While the point
is in a submode region, the following changes occur:
@enumerate
@item
The local keymap is that of the submode. This means the key bindings for
the submode are available, while those of the dominant mode are not.
@item
The mode line (@pxref{Mode Line, , , emacs, The Emacs Manual}) changes
to show which submode region is active. This can be configured; see
@ref{Mode Line}.
@item
The major mode menu, both on the menu bar and the mouse popup, are that
of the submode.
@item
Some local variables of the submode shadow those of the default mode
(@pxref{Local Variables}). For the user, this serves to help make Emacs
behave as if the submode were the major mode.
@item
The syntax table and indentation are those of the submode.
@item
Font-lock (@pxref{Font Lock, , , emacs, The Emacs Manual}) fontifies
correctly for the submode.
@item
The submode regions are highlighted by a background color; see
@ref{Region Coloring}.
@end enumerate
The submode regions are represented internally by Emacs Lisp objects
known as @dfn{overlays}. Some of the above are implemented by overlay
properties, and others are updated by an MMM Mode function in
@code{post-command-hook}. You don't need to know this to use MMM
Mode, but it
may make any error messages you come across more understandable.
@xref{Overlays, , , elisp, The GNU Emacs Lisp Reference Manual}, for
more information on overlays.
Because overlays are not saved with a file, every time a file is opened,
they must be created. Creating submode regions is occasionally referred
to as @dfn{mmm-ification}. (I've never had occasion to pronounce this,
but if I did I would probably say `mummification'. Like what they did in
ancient Egypt.) You can mmm-ify a buffer interactively, but most often
MMM Mode will find and create submode regions automatically based on a
buffer's file extension, dominant mode, or local variables.
@node Installation
@section Installing MMM Mode
The recommended way to install MMM Mode is from GNU ELPA.
@lisp
(package-install 'mmm-mode)
@end lisp
@noindent
You can also add the MMM Mode directory to your @code{load-path}.
@lisp
(add-to-list 'load-path "/path/to/mmm-mode/")
@end lisp
@noindent
The Makefile distributed with MMM Mode can be used to byte compile the
code and build the Info documentation with a simple @code{make}
command. Don't forget to add the MMM mode directory to your
@code{Info-directory-list}.
@lisp
(add-to-list 'Info-directory-list pkg-dir)
@end lisp
Once the package is installed or @code{load-path} configured, MMM Mode
must be loaded. You can
load all of MMM Mode with the line
@lisp
(require 'mmm-mode)
@end lisp
@noindent
but if you use MMM Mode only rarely, it may not be desirable to load all
of it at the beginning of every editing session. You can load just
enough of MMM Mode so it will turn itself on when necessary and load the
rest of itself, by using instead the line
@lisp
(require 'mmm-auto)
@end lisp
@noindent
in your initialization file.
One more thing you may want to do right now is to set the variable
@code{mmm-global-mode}. If this variable is @code{nil} (the default),
MMM Mode will never turn itself on. If it is @code{t}, MMM Mode will
turn itself on in every buffer. Probably the most useful value for it,
however, is the symbol @code{maybe} (actually, anything that is not
@code{nil} and not @code{t}), which causes MMM Mode to turn itself on in
precisely those buffers where it would be useful. You can do this with
a line such as:
@lisp
(setq mmm-global-mode 'maybe)
@end lisp
@noindent
in your initialization file. @xref{Global Mode}, for more detailed
information.
@node Quick Start
@section Getting Started Quickly
Perhaps the simplest way to create submode regions is to do it
interactively by specifying a region. First you must turn MMM Mode
on---say, with @kbd{M-x mmm-mode}---then place point and mark around the
area you want to make into a submode region, type @kbd{C-c % C-r}, and
enter the desired major mode. @xref{Interactive}, for more details.
A better way to add submode regions is by using submode classes, which
store a lot of useful information for MMM Mode about how to add and
manipulate the regions created. @xref{Submode Classes}, for more
details. There are several sample submode classes that come with MMM
Mode, which are documented later in this manual. Look through these and
determine if one of them fits your needs. If so, I suggest reading the
comments on that mode. Then come back here to find out how to use it.
To apply a submode class to a buffer interactively, turn MMM Mode on as
above, then type @kbd{C-c % C-c} and enter the name of the class.
Submode regions should be added automatically, if there are any regions
in the buffer appropriate to the submode class.
If you want a given file to always use a given submode class, you can
express this in a file variable: add a line containing the string
@samp{-*- mmm-classes: @var{class} -*-} at the top of the file.
@var{class} can also be a list of submode classes.
@xref{File Variables, , , emacs, The Emacs Manual}, for more information
and other methods. Now whenever MMM Mode is turned on in that file, it
will be mmm-ified according to @var{class}. If @code{mmm-global-mode} is
non-nil, then MMM Mode will turn itself on whenever a file with a
@code{mmm-classes} local variable is opened. @xref{Global Mode}, for more
information.
If you want a submode class to apply to @emph{all} files in a certain
major mode or with a certain extension, add a line such as this to your
initialization file:
@lisp
(mmm-add-mode-ext-class @var{mode} @var{extension} @var{class})
@end lisp
@noindent
After this call, any file opened whose name matches the regular
expression @var{extension} @emph{and} whose default mode is @var{mode}
will be automatically mmm-ified according to @var{class} (assuming
@code{mmm-global-mode} is non-nil). If one of @var{extension} or
@var{mode} is @code{nil}, a file need only satisfy the other one to be
mmm-ified.
You can now read the rest of this manual to learn more about how MMM
Mode works and how to configure it to your preferences. If none of the
supplied submode classes fit your needs, then you can try to write your
own. @xref{Writing Classes}, for more information.
@node Basics
@chapter MMM Mode Basics
This chapter explains the most important parts of how to use MMM Mode.
@menu
* MMM Minor Mode:: The Emacs minor mode that manages it all.
* Submode Classes:: What they are and how to use them.
* Selecting Classes:: How MMM Mode knows what classes to use.
* Insertion:: Inserting new submode regions automatically.
* Re-parsing:: Re-scanning for submode regions.
* Interactive:: Adding submode regions manually.
* Global Mode:: Turning MMM Mode on automatically.
@end menu
@node MMM Minor Mode
@section The MMM Minor Mode
@cindex mode, mmm minor
@cindex minor mode, mmm
@cindex mmm minor mode
An Emacs minor mode is an optional feature which can be turned on or off
in a given buffer, independently of the major mode. @xref{Minor Modes, ,
, emacs, The Emacs Manual}. MMM Mode is implemented as a minor mode
@code{mmm-mode} which manages the submode regions. @code{mmm-mode}
must be turned on in a buffer for submode regions to be
effective. When activated, @code{mmm-mode} is denoted by @samp{MMM} in
the mode line (@pxref{Mode Line}).
@menu
* Enabling MMM Mode:: Turning MMM Mode on and off.
* MMM Mode Keys:: Default key bindings in MMM Mode.
@end menu
@node Enabling MMM Mode
@subsection Enabling MMM Mode
@cindex mmm mode, turning on
@cindex mmm mode, turning off
@cindex turning on mmm mode
@cindex turning off mmm mode
@cindex mmm mode, enabling
@cindex mmm mode, disabling
@cindex enabling mmm mode
@cindex disabling mmm mode
If @code{mmm-global-mode} is non-@code{nil} (@pxref{Global Mode}),
@code{mmm-mode} will be enabled automatically whenever a file
with associated submode classes is opened (@pxref{Selecting Classes}).
It is also turned on by interactive mmm-ification (@pxref{Interactive}),
although the interactive commands do not have key bindings when it is
not on and must be invoked via @kbd{M-x}. You can also turn it on (or
off) manually with @kbd{M-x mmm-mode}, in which case it applies all
submode classes associated with the buffer. Turning MMM Mode off
automatically removes all submode regions from the buffer.
@deffn Command mmm-mode @var{arg}
Toggle the state of MMM Mode in the current buffer. If @var{arg} is
supplied, turn MMM Mode on if and only if @var{arg} is positive.
@end deffn
@defun mmm-mode-on
Turn MMM Mode on unconditionally in the current buffer.
@end defun
@defun mmm-mode-off
Turn MMM Mode off unconditionally in the current buffer.
@end defun
@defvar mmm-mode
This variable represents whether MMM Mode is on in the current buffer.
Do not set this variable directly; use one of the above functions.
@end defvar
@node MMM Mode Keys
@subsection Key Bindings in MMM Mode
@cindex mmm mode key bindings
@cindex key bindings in mmm mode
@findex mmm-insertion-help
@kindex C-c % h
When MMM Mode is on, it defines a number of key bindings. By default,
these are bound after the prefix sequence @kbd{C-c %}. Minor mode
keymaps are supposed to use @kbd{C-c @var{punctuation}} sequences, and I
find this one to be a good mnemonic because @samp{%} is used by Mason to
denote special tags. This prefix key can be customized; @ref{Key
Bindings}.
There are two types of key bindings in MMM Mode: @dfn{commands} and
@dfn{insertions}. Command bindings run MMM Mode interactive functions to
do things like re-parse the buffer or end the current submode region,
and are defined statically as normal Emacs key-bindings. Insertion
bindings insert submode region skeletons with delimiters into the
buffer, and are defined dynamically, according to which submode classes
(@pxref{Submode Classes}) are in effect, via a keymap default binding.
To distinguish between the two, MMM Mode uses distinct modifier keys for
each. By default, command bindings use the control key (e.g. @kbd{C-c %
C-b} re-parses the buffer), and insertion bindings do not (e.g. @kbd{C-c
% p}, when the Mason class is in effect, inserts a
@samp{<%perl>...</%perl>} region). This makes the command bindings
different from in previous versions, however, so the variable
@code{mmm-use-old-bindings} is provided. If this variable is set to `t'
before MMM Mode is loaded, the bindings will be reversed: insertion
bindings will use the control key and command bindings will not.
Normally, Emacs gives help on a prefix command if you type @kbd{C-h}
after that command (e.g. @kbd{C-x C-h} displays all key bindings
starting with @kbd{C-x}). Because of how insertion bindings are
implemented dynamically with a default binding, they do not show up when
you hit @kbd{C-c % C-h}. For this reason, MMM Mode defines the command
@kbd{C-c % h} which displays a list of all currently valid insertion key
sequences. If you use the defaults for command and insertion bindings,
the @kbd{C-h} and @kbd{h} should be mnemonic.
In the rest of this manual, I will assume you are using the defaults for
the mode prefix (@kbd{C-c %}) and the command and insertion modifiers.
You can customize them, however; @ref{Key Bindings}.
@node Submode Classes
@section Understanding Submode Classes
@cindex submode classes
@cindex classes, submode
A submode class represents a ``type'' of submode region. It specifies
how to find the regions, what their delimiters look like, what submode
they should be, how to insert them, and how they behave in other ways.
It is represented by a symbol, such as @code{mason} or
@code{eval-elisp}.
For example, in the Mason set of classes, there is one class
representing all @samp{<%...%>} inline Perl regions, and one
representing regions such as @samp{<%perl>...</%perl>},
@samp{<%init>...</%init>}, and so on. These are different to Mason, but
to Emacs they are all just Perl sections, so they are covered by the
same submode class.
But it would be tedious if whenever we wanted to use the Mason classes,
we had to specify both of these. (Actually, this is a simplification:
there are some half a dozen Mason submode classes.) So submode classes
can also ``group'' others together, and we can refer to the @code{mason}
class and mean all of them.
The way a submode class is used is to @dfn{apply} it to a buffer. This
scans the buffer for regions which should be submode regions according
to that class, and also remembers the class for later, so that new
submode regions can be inserted and scanned for later.
@node Selecting Classes
@section How MMM Mode selects submode classes
Submode classes that apply to a buffer come from three sources:
mode/extension-associated classes, file-local classes, and interactive
MMM-ification (@pxref{Interactive}). Whenever MMM Mode is turned on in a
buffer (@pxref{MMM Minor Mode}, and @ref{Global Mode}), it inspects the
value of two variables to determine which classes to automatically apply
to the buffer. This covers the first two sources; the latter is covered
in a later chapter.
@menu
* File Classes:: Classes for a single file.
* Mode-Ext Classes:: Classes for a given mode or extension.
* Global Classes:: Classes for all MMM Mode buffers.
@end menu
@node File Classes
@subsection File-Local Submode Classes
@defvar mmm-classes
This variable is always buffer-local when set. Its value should be
either a single symbol or a list of symbols. Each symbol represents a
submode class that is applied to the buffer.
@end defvar
@code{mmm-classes} is usually set in a file local variables list.
@xref{File Variables, , , emacs, The Emacs Manual}. The easiest way to
do this is for the first line of the file to contain the string
@samp{-*- mmm-classes: @var{classes} -*-}, where @var{classes} is the
desired value of @code{mmm-classes} for the file in question. It can
also be done with a local variables list at the end of the file.
@node Mode-Ext Classes
@subsection Submode Classes Associated with Modes and Extensions
@defopt mmm-mode-ext-classes-alist
This global variable associates certain submode classes with major modes
and/or file extensions. Its value is a list of elements of the form
@code{(@var{mode} @var{ext} @var{class})}. Any buffer whose major mode
is @var{mode} (a symbol) @emph{and} whose file name matches @var{ext} (a
regular expression) will automatically have the submode class
@var{class} applied to it.
If @var{mode} is @code{nil}, then only @var{ext} is considered to
determine if a buffer fits the criteria, and vice versa. Thus if both
@var{mode} and @var{ext} are nil, then @var{class} is applied to
@emph{all} buffers in which MMM Mode is on. Note that @var{ext} can be
any regular expression, although its name indicates that it most often
refers to the file extension.
If @var{class} is the symbol @code{t}, then no submode class is actually
applied for this association. However, if @code{mmm-global-mode} is
non-@code{nil} and non-@code{t}, MMM Mode will be turned on in matching
buffers even if there are no actual submode classes being applied.
@xref{Global Mode}.
@end defopt
@defun mmm-add-mode-ext-class @var{mode} @var{ext} @var{class}
This function adds an element to @code{mmm-mode-ext-classes-alist},
associating the submode class @var{class} with the major mode @var{mode}
and extension @var{ext}.
Older versions of MMM Mode required this function to be used to control
the value of @code{mmm-mode-ext-classes-alist}, rather than setting it
directly. In this version it is provided purely for convenience and
backward compatibility.
@end defun
@node Global Classes
@subsection Globally Applied Classes and the Universal Class
In addition to file-local and mode-ext-associated submode classes, MMM
Mode also allows you to specify that certain submode classes apply to
@emph{all} buffers in which MMM Mode is enabled.
@defopt mmm-global-classes
This variable's value should be a list of submode classes that apply to
all buffers with MMM Mode on. It can be overriden in a file local
variables list, such as to disable global class for a specific file.
Its default value is @code{(universal)}.
@end defopt
The default global class is the ``universal class'', which is defined in
the file @file{mmm-univ.el} (loaded automatically), and allows the
author of text to specify that a certain section of it be in a specific
major mode. Thus, for example, when writing an email message that
includes sample code, the author can allow readers of the message (who
use emacs and MMM) to view the code in the appropriate major mode. The
syntax used is @samp{@{%@var{mode}%@} ... @{%/@var{mode}%@}}, where
@var{mode} should be the name of the major mode, with or without the
customary @samp{-mode} suffix: for example, both @samp{cperl} and
@samp{cperl-mode} are acceptable.
The universal class also defines an insertion key, @samp{/}, which
prompts for the submode to use. @xref{Insertion}. The universal class
is most useful when @code{mmm-global-mode} is set to @code{t};
@ref{Global Mode}.
@node Insertion
@section Inserting new submode regions
So much for noticing submode regions already present when you open a
file. When editing a file with MMM Mode on, you will often want to add a
new submode region. MMM Mode provides several facilities to help you.
The simplest is to just hit a few keys and have the region and its
delimiters inserted for you.
Each submode class can define an association of keystrokes with
``skeletons'' to insert a submode region. If there are several submode
classes enabled in a buffer, it is conceivable that the keys they use
for insertion might conflict, but unlikely as most buffers will not use
more than one or two submode classes groups.
As an example of how insertion works, consider the Mason classes. In a
buffer with MMM Mode enabled and Mason associated, the key sequence
@kbd{C-c % p} inserts the following perl section (the semicolon is to
prevent CPerl Mode from getting confused---@pxref{Mason}):
@example
<%perl>-<-;
-!-
->-</%perl>
@end example
In this schematic representation, the string @samp{-!-} represents the
position of point (the cursor), @samp{-<-} represents the beginning of
the submode region, and @samp{->-} its end.
All insertion keys come after the MMM Mode prefix keys (by default
@kbd{C-c %}; @pxref{Key Bindings}) and are by default single characters
such as @kbd{p}, @kbd{%}, and @kbd{i}. To avoid confusion, all the MMM
Mode commands are bound by default to control characters (after the same
prefix keys), such as @kbd{C-b}, @kbd{C-%} and @kbd{C-r}. This is a
change from earlier versions of MMM Mode, and can be customized; see
@ref{Key Bindings}.
To find out what insertion keys are available, consult the documentation
for the submode class you are using. If it is one of the classes
supplied with MMM Mode, you can find it in this Info file.
Because insertion keys are implemented with a ``default binding'' for
flexibility, they do not show up in the output of @kbd{C-h m} and cannot
be found with @kbd{C-h k}. For this reason, MMM Mode supplies the
command @kbd{C-c % h} (@code{mmm-insertion-help} to view the available
insertion keys.
@node Re-parsing
@section Re-Parsing Submode Regions
@cindex re-parsing submode regions
@cindex parsing submode regions
@cindex submode regions, re-parsing
@cindex regions, submode, re-parsing
@cindex submode regions, clearing
@cindex clearing submode regions
@cindex regions, submode, clearing
@kindex C-c % C-b
@kindex C-c % C-g
@kindex C-c % C-%
@kindex C-c % C-5
@kindex C-c % C-k
Describe @code{mmm-parse-buffer}, @code{mmm-parse-region},
@code{mmm-parse-block}, and @code{mmm-clear-current-region}.
@node Interactive
@section Interactive MMM-ification Functions
@cindex interactive mmm-ification
@cindex mmm-ification, interactive
@cindex mmm-ification by region
@cindex mmm-ification by regexp
@cindex mmm-ification by class
@cindex region, mmm-ification by
@cindex regexp, mmm-ification by
@cindex class, mmm-ification by
@kindex C-c % C-r
@kindex C-c % C-c
@kindex C-c % C-x
@cindex mmm-ification, interactive history
@cindex history of interactive mmm-ification
@cindex interactive mmm-ification, history of
There are several commands you can use to create submode regions
interactively, rather than by applying a submode class to a buffer.
These commands (in particular, @code{mmm-ify-region}), can be useful
when editing a file or email message containing a snippet of code in
some other language. Also see @ref{Global Classes}, for an alternate
approach to the same problem.
@table @kbd
@item C-c % C-r
Creates a submode region between point and mark. Prompts for the submode
to use, which must be a valid Emacs major mode name, such as
@code{emacs-lisp-mode} or @code{cperl-mode}. Adds markers to the
interactive history. (@code{mmm-ify-region})
@item C-c % C-c
Applies an already-defined submode class to the buffer, which it prompts
for. Adds this class to the interactive history.
(@code{mmm-ify-by-class})
@item C-c % C-x
Scans the buffer for submode regions (prompts for the submode) using
front and back regular expressions that it also prompts for. Briefly, it
starts at the beginning of the buffer and searches for the front regexp.
If it finds a match, it searches for the back regexp. If it finds a
match for that as well, it makes a submode region between the two
matches and continues searching until no more matches are found. Adds
the regexps to the interactive history. (@code{mmm-ify-by-regexp})
@end table
These commands are also useful when designing a new submode class
(@pxref{Submode Classes}). Working with the regexps interactively can
make it easier to debug and tune the class before starting to use it on
automatic. All these commands also add to value of the following
variable.
@defvar mmm-interactive-history
Stores a history of all interactive mmm-ification that has been
performed in the current buffer. This way, for example, the re-parsing
functions (@pxref{Re-parsing}) will respect interactively added regions,
and the insertion keys for classes that were added interactively are
available.
@end defvar
If for any reason you want to ``wipe the slate clean'', this command
should help you. By default, it has no key binding, so you must invoke
it with @kbd{M-x mmm-clear-history @key{RET}}.
@deffn Command mmm-clear-history
Clears all history of interactive mmm-ification in the current buffer.
This command does not affect existing submode regions; to remove them,
you may want to re-parse the buffer with @kbd{C-c % C-b}
(@code{mmm-parse-buffer}).
@end deffn
@node Global Mode
@section MMM Global Mode
@cindex mode, mmm global
@cindex global mmm mode
@cindex mmm global mode
@vindex mmm-never-modes
When a file has associated submode classes (@pxref{Selecting Classes}),
you may want MMM Mode to turn itself on and parse that file for submode
regions automatically whenever it is opened in an Emacs buffer. The
value of the following variable controls when MMM Mode turns itself on
automatically.
@defopt mmm-global-mode
Do not be misled by the fact that this variable's name ends in
@samp{-mode}: it is not a simple on/off switch. There are three possible
(meanings of) values for it: @code{t}, @code{nil}, and anything else.
When this variable is @code{nil}, MMM Mode is never enabled
automatically. If it is enabled manually, such as by typing @kbd{M-x
mmm-mode}, any submode classes associated with the buffer will still be
used, however.
When this variable is @code{t}, MMM Mode is enabled automatically in
@emph{all} buffers, including those not visiting files, except those
whose major mode is an element of @code{mmm-never-modes}. The default
value of this variable contains modes such as @code{help-mode} and
@code{dired-mode} in which most users would never want MMM Mode, and
in which MMM might cause problems.
When this variable is neither @code{nil} nor @code{t}, MMM Mode is
enabled automatically in all buffers that would have associated submode
classes; i.e. only if there would be something for it to do. The value
of @code{mmm-never-modes} is still respected, however. Note that this
can include buffers not visiting files, if that buffer's major mode is
present in @code{mmm-mode-ext-classes-alist} with a @code{nil} value for
@var{ext} (@pxref{Mode-Ext Classes}). Submode class values of @code{t}
in @code{mmm-mode-ext-classes-alist} cause MMM Mode to be enabled in
matching buffers, but supply no submode classes to be applied.
@end defopt
@menu
* Major Mode Hook:: Using MMM's Major Mode Hook
@end menu
@node Major Mode Hook
@subsection The Major Mode Hook
@cindex hook, major mode
@cindex major mode hook
@vindex mmm-major-mode-hook
This section is intended for users who understand Emacs Lisp and want to
know how MMM Global Mode is implemented, and perhaps use the same
technique. In fact, MMM Mode exports a hook variable that you can use
easily, without understanding any of the details---see below.
In order to enable itself in @emph{all} buffers, however, MMM Mode has
to hook itself into all major modes. Global Font Lock Mode from the
standard Emacs distribution (@pxref{Font Lock, , , emacs, The Emacs
Manual}) has a similar problem, and solves it by adding a function to
@code{change-major-mode-hook}, which is run by
@code{kill-all-local-variables}, which is run in turn by all major mode
functions at the @emph{beginning}. This function stores a list of which
buffers need fontification. It then adds a different function to
@code{post-command-hook}, which checks if the current buffer needs
fontification, and if so performs it. MMM Global Mode uses the same
technique.
In the interests of generality, and for your use, the function that MMM
Mode runs in @code{post-command-hook} (@code{mmm-run-major-mode-hook})
is not specific to MMM Mode, but rather runs the hook variable
@code{mmm-major-mode-hook}, which by default contains a function
(@code{mmm-mode-on-maybe}) which possibly turns MMM Mode on, depending
on the value of @code{mmm-global-mode}. Thus, to run another function
in all major modes, all you need to do is add it to this hook. For
example, the following line in an initialization file will turn on Auto
Fill Mode (@pxref{Auto Fill, , , emacs, The Emacs Manual}) in all
buffers:
@lisp
(add-hook 'mmm-major-mode-hook 'turn-on-auto-fill)
@end lisp
@node Customizing
@chapter Customizing MMM Mode
This chapter explains how to customize the appearance and functioning of
MMM Mode however you want.
@menu
* Region Coloring:: Changing or removing background colors.
* Preferred Modes:: Choosing which major modes to use.
* Mode Line:: What is displayed in the mode line.
* Key Bindings:: Customizing the MMM Mode key bindings.
* Local Variables:: What local variables are saved for submodes.
* Changing Classes:: Changing the supplied submode classes.
* Hooks:: How to make MMM Mode run your code.
@end menu
@node Region Coloring
@section Customizing Region Coloring
@cindex faces, submode
@cindex submode faces
@cindex customizing submode faces
@cindex default submode face
By default, MMM Mode highlights all submode regions with a background
color. There are three levels of this decoration, controlled by the
following variable:
@defopt mmm-submode-decoration-level
This variable controls the level of coloring of submode regions. It
should be one of the integers 0, 1, or 2, representing (respectively)
none, low, and high coloring.
@end defopt
No coloring means exactly that. Submode regions have the same
background as the rest of the text. This produces the minimal
interference with font-lock coloration. In particular, if you want to
use background colors for font-lock, this may be a good idea, because
the submode highlight, if present, overrides any font-lock background
coloring.
Low coloring uses the same background color for all submode regions.
This color is specified with the face @code{mmm-default-submode-face}
(@pxref{Faces, , , emacs, The Emacs Manual}) which can be customized,
either through the Emacs ``customize'' interface or using direct Lisp
commands such as @code{set-face-background}. Of course, other aspects
of the face can also be set, such as the foreground color, bold,
underline, etc. These are more likely to conflict with font-lock,
however, so only a background color is recommended.
High coloring uses multiple background colors, depending on the function
of the submode region. The recognized functions and their meanings are
as follows:
@table @samp
@item init
Code that is executed at the beginning of (something), as initialization
of some sort.
@item cleanup
Code that is executed at the end of (something), as some sort of clean
up facility.
@item declaration
Code that provides declarations of some sort, perhaps global or local
arguments, variables, or methods.
@item comment
Text that is not executed as code, but instead serves to document the
code around it. Submode regions of this function often use a mode such
as Text Mode rather than a programming language mode.
@item output
An expression that is evaluated and its value interpolated into the
output produced.
@item code
Executed code not falling under any other category.
@item special
Submode regions not falling under any other category, such as component
calls.
@end table
The different background colors are provided by the faces
@code{mmm-@var{function}-submode-face}, which can be customized in the
same way as @code{mmm-default-submode-face}.
@node Preferred Modes
@section Preferred Major Modes
Certain of the supplied submode classes know only the language that
certain sections are written in, but not what major mode you prefer to
use to edit such code. For example, many people prefer CPerl mode over
Perl mode; you may have a special mode for Javascript or just use C++
mode. This variable allows you to tell submodes such as Mason
(@pxref{Mason}) and Embedded Javascript (@pxref{Javascript}) what major
mode to use for the submodes:
@defopt mmm-major-mode-preferences
The elements of this list are cons cells of the form
@code{(@var{language} . @var{mode})}. @var{language} should be a symbol
such as @code{perl}, @code{html-js}, or @code{java}, while @var{mode}
should be the name of a major mode such as @code{perl-mode},
@code{cperl-mode}, @code{javascript-mode}, or @code{c++-mode}.
You probably won't have to set this variable at all; MMM tries to make
intelligent guesses about what modes you prefer. For example, if a
function called @code{javascript-mode} exists, it is chosen, otherwise
@code{c++-mode} is used. Similarly for @code{jde-mode} and
@code{java-mode}.
@end defopt