OpenStep 4.2/Openstep-4.2-Intel-User.iso/usr/lib/emacs/info/emacs-9

GNU Info File | 1992-10-30 | 50KB | 872 lines

This is Info file ../info/emacs, produced by Makeinfo-1.49 from the
input file emacs.texi.
   This file documents the GNU Emacs editor.
   Copyright (C) 1985, 1986, 1988, 1992 Richard M. Stallman.
   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 "The GNU Manifesto", "Distribution" 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 the sections entitled "The GNU Manifesto",
"Distribution" and "GNU General Public License" may be included in a
translation approved by the author instead of in the original English.
File: emacs,  Node: Lisp Eval,  Next: Lisp Debug,  Prev: Lisp Libraries,  Up: Compiling/Testing
Evaluating Emacs-Lisp Expressions
=================================
   Lisp programs intended to be run in Emacs should be edited in
Emacs-Lisp mode; this will happen automatically for file names ending
in `.el'. By contrast, Lisp mode itself is used for editing Lisp
programs intended for other Lisp systems.  Emacs-Lisp mode can be
selected with the command `M-x emacs-lisp-mode'.
   For testing of Lisp programs to run in Emacs, it is useful to be
able to evaluate part of the program as it is found in the Emacs
buffer.  For example, after changing the text of a Lisp function
definition, evaluating the definition installs the change for future
calls to the function. Evaluation of Lisp expressions is also useful in
any kind of editing task for invoking noninteractive functions
(functions that are not commands).
`M-ESC'
     Read a Lisp expression in the minibuffer, evaluate it, and print
     the value in the minibuffer (`eval-expression').
`C-x C-e'
     Evaluate the Lisp expression before point, and print the value in
     the minibuffer (`eval-last-sexp').
`C-M-x'
     Evaluate the defun containing or after point, and print the value
     in the minibuffer (`eval-defun').
`M-x eval-region'
     Evaluate all the Lisp expressions in the region.
`M-x eval-current-buffer'
     Evaluate all the Lisp expressions in the buffer.
   `M-ESC' (`eval-expression') is the most basic command for evaluating
a Lisp expression interactively.  It reads the expression using the
minibuffer, so you can execute any expression on a buffer regardless of
what the buffer contains.  When the expression is evaluated, the current
buffer is once again the buffer that was current when `M-ESC' was typed.
   `M-ESC' can easily confuse users who do not understand it,
especially on keyboards with autorepeat where it can result from holding
down the ESC key for too long.  Therefore, `eval-expression' is
normally a disabled command.  Attempting to use this command asks for
confirmation and gives you the option of enabling it; once you enable
the command, confirmation will no longer be required for it. *Note
Disabling::.
   In Emacs-Lisp mode, the key `C-M-x' is bound to the function
`eval-defun', which parses the defun containing or following point as a
Lisp expression and evaluates it.  The value is printed in the echo
area.  This command is convenient for installing in the Lisp
environment changes that you have just made in the text of a function
definition.
   The command `C-x C-e' (`eval-last-sexp') performs a similar job but
is available in all major modes, not just Emacs-Lisp mode.  It finds
the sexp before point, reads it as a Lisp expression, evaluates it, and
prints the value in the echo area.  It is sometimes useful to type in an
expression and then, with point still after it, type `C-x C-e'.
   If `C-M-x' or `C-x C-e' is given a numeric argument, it prints the
value by insertion into the current buffer at point, rather than in the
echo area.  The argument value does not matter.
   The most general command for evaluating Lisp expressions from a
buffer is `eval-region'.  `M-x eval-region' parses the text of the
region as one or more Lisp expressions, evaluating them one by one.
`M-x eval-current-buffer' is similar but evaluates the entire buffer.
This is a reasonable way to install the contents of a file of Lisp code
that you are just ready to test.  After finding and fixing a bug, use
`C-M-x' on each function that you change, to keep the Lisp world in
step with the source file.
File: emacs,  Node: Lisp Debug,  Next: Lisp Interaction,  Prev: Lisp Eval,  Up: Compiling/Testing
The Emacs-Lisp Debugger
=======================
   GNU Emacs contains a debugger for Lisp programs executing inside it.
This debugger is normally not used; many commands frequently get Lisp
errors when invoked in inappropriate contexts (such as `C-f' at the end
of the buffer) and it would be very unpleasant for that to enter a
special debugging mode.  When you want to make Lisp errors invoke the
debugger, you must set the variable `debug-on-error' to non-`nil'.
Quitting with `C-g' is not considered an error, and `debug-on-error'
has no effect on the handling of `C-g'.  However, if you set
`debug-on-quit' non-`nil', `C-g' will invoke the debugger. This can be
useful for debugging an infinite loop; type `C-g' once the loop has had
time to reach its steady state.  `debug-on-quit' has no effect on
errors.
   You can also cause the debugger to be entered when a specified
function is called, or at a particular place in Lisp code.  Use `M-x
debug-on-entry' with argument FUN-NAME to cause function FUN-NAME to
enter the debugger as soon as it is called.  Use `M-x
cancel-debug-on-entry' to make the function stop entering the debugger
when called.  (Redefining the function also does this.)  To enter the
debugger from some other place in Lisp code, you must insert the
expression `(debug)' there and install the changed code with `C-M-x'.
*Note Lisp Eval::.
   When the debugger is entered, it displays the previously selected
buffer in one window and a buffer named `*Backtrace*' in another
window.  The backtrace buffer contains one line for each level of Lisp
function execution currently going on.  At the beginning of this buffer
is a message describing the reason that the debugger was invoked (such
as, what error message if it was invoked due to an error).
   The backtrace buffer is read-only, and is in a special major mode,
Backtrace mode, in which letters are defined as debugger commands.  The
usual Emacs editing commands are available; you can switch windows to
examine the buffer that was being edited at the time of the error, and
you can also switch buffers, visit files, and do any other sort of
editing. However, the debugger is a recursive editing level (*note
Recursive Edit::.) and it is wise to go back to the backtrace buffer
and exit the debugger officially when you don't want to use it any
more.  Exiting the debugger kills the backtrace buffer.
   The contents of the backtrace buffer show you the functions that are
executing and the arguments that were given to them.  It has the
additional purpose of allowing you to specify a stack frame by moving
point to the line describing that frame.  The frame whose line point is
on is considered the "current frame".  Some of the debugger commands
operate on the current frame.  Debugger commands are mainly used for
stepping through code an expression at a time.  Here is a list of them.
     Exit the debugger and continue execution.  In most cases,
     execution of the program continues as if the debugger had never
     been entered (aside from the effect of any variables or data
     structures you may have changed while inside the debugger).  This
     includes entry to the debugger due to function entry or exit,
     explicit invocation, quitting or certain errors.  Most errors
     cannot be continued; trying to continue one of them causes the
     same error to occur again.
     Continue execution, but enter the debugger the next time a Lisp
     function is called.  This allows you to step through the
     subexpressions of an expression, seeing what values the
     subexpressions compute and what else they do.
     The stack frame made for the function call which enters the
     debugger in this way will be flagged automatically for the
     debugger to be called when the frame is exited.  You can use the
     `u' command to cancel this flag.
     Set up to enter the debugger when the current frame is exited.
     Frames that will invoke the debugger on exit are flagged with
     stars.
     Don't enter the debugger when the current frame is exited.  This
     cancels a `b' command on that frame.
     Read a Lisp expression in the minibuffer, evaluate it, and print
     the value in the echo area.  This is the same as the command
     `M-ESC', except that `e' is not normally disabled like `M-ESC'.
     Terminate the program being debugged; return to top-level Emacs
     command execution.
     If the debugger was entered due to a `C-g' but you really want to
     quit, not to debug, use the `q' command.
     Return a value from the debugger.  The value is computed by
     reading an expression with the minibuffer and evaluating it.
     The value returned by the debugger makes a difference when the
     debugger was invoked due to exit from a Lisp call frame (as
     requested with `b'); then the value specified in the `r' command
     is used as the value of that frame.
     The debugger's return value also matters with many errors.  For
     example, `wrong-type-argument' errors will use the debugger's
     return value instead of the invalid argument; `no-catch' errors
     will use the debugger value as a throw tag instead of the tag that
     was not found. If an error was signaled by calling the Lisp
     function `signal', the debugger's return value is returned as the
     value of `signal'.
File: emacs,  Node: Lisp Interaction,  Next: External Lisp,  Prev: Lisp Debug,  Up: Compiling/Testing
Lisp Interaction Buffers
========================
   The buffer `*scratch*' which is selected when Emacs starts up is
provided for evaluating Lisp expressions interactively inside Emacs.
Both the expressions you evaluate and their output goes in the buffer.
   The `*scratch*' buffer's major mode is Lisp Interaction mode, which
is the same as Emacs-Lisp mode except for one command, LFD.  In
Emacs-Lisp mode, LFD is an indentation command, as usual.  In Lisp
Interaction mode, LFD is bound to `eval-print-last-sexp'.  This
function reads the Lisp expression before point, evaluates it, and
inserts the value in printed representation before point.
   Thus, the way to use the `*scratch*' buffer is to insert Lisp
expressions at the end, ending each one with LFD so that it will be
evaluated. The result is a complete typescript of the expressions you
have evaluated and their values.
   The rationale for this feature is that Emacs must have a buffer when
it starts up, but that buffer is not useful for editing files since a
new buffer is made for every file that you visit.  The Lisp interpreter
typescript is the most useful thing I can think of for the initial
buffer to do.  `M-x lisp-interaction-mode' will put any buffer in Lisp
Interaction mode.
File: emacs,  Node: External Lisp,  Prev: Lisp Interaction,  Up: Compiling/Testing
Running an External Lisp
========================
   Emacs has facilities for running programs in other Lisp systems.
You can run a Lisp process as an inferior of Emacs, and pass
expressions to it to be evaluated.  You can also pass changed function
definitions directly from the Emacs buffers in which you edit the Lisp
programs to the inferior Lisp process.
   To run an inferior Lisp process, type `M-x run-lisp'.  This runs the
program named `lisp', the same program you would run by typing `lisp'
as a shell command, with both input and output going through an Emacs
buffer named `*lisp*'.  That is to say, any "terminal output" from Lisp
will go into the buffer, advancing point, and any "terminal input" for
Lisp comes from text in the buffer.  To give input to Lisp, go to the
end of the buffer and type the input, terminated by RET.  The `*lisp*'
buffer is in Inferior Lisp mode, a mode which has all the special
characteristics of Lisp mode and Shell mode (*note Shell Mode::.).
   For the source files of programs to run in external Lisps, use Lisp
mode. This mode can be selected with `M-x lisp-mode', and is used
automatically for files whose names end in `.l' or `.lisp', as most Lisp
systems usually expect.
   When you edit a function in a Lisp program you are running, the
easiest way to send the changed definition to the inferior Lisp process
is the key `C-M-x'.  In Lisp mode, this runs the function
`lisp-send-defun', which finds the defun around or following point and
sends it as input to the Lisp process.  (Emacs can send input to any
inferior process regardless of what buffer is current.)
   Contrast the meanings of `C-M-x' in Lisp mode (for editing programs
to be run in another Lisp system) and Emacs-Lisp mode (for editing Lisp
programs to be run in Emacs): in both modes it has the effect of
installing the function definition that point is in, but the way of
doing so is different according to where the relevant Lisp environment
is found. *Note Lisp Modes::.
File: emacs,  Node: Abbrevs,  Next: Picture,  Prev: Compiling/Testing,  Up: Top
Abbrevs
*******
   An "abbrev" is a word which "expands", if you insert it, into some
different text.  Abbrevs are defined by the user to expand in specific
ways.  For example, you might define `foo' as an abbrev expanding to
`find outer otter'.  With this abbrev defined, you would be able to get
`find outer otter ' into the buffer by typing `f o o SPC'.
   Abbrevs expand only when Abbrev mode (a minor mode) is enabled.
Disabling Abbrev mode does not cause abbrev definitions to be forgotten,
but they do not expand until Abbrev mode is enabled again.  The command
`M-x abbrev-mode' toggles Abbrev mode; with a numeric argument, it
turns Abbrev mode on if the argument is positive, off otherwise. *Note
Minor Modes::.  `abbrev-mode' is also a variable; Abbrev mode is on
when the variable is non-`nil'.  The variable `abbrev-mode'
automatically becomes local to the current buffer when it is set.
   Abbrev definitions can be "mode-specific"--active only in one major
mode.  Abbrevs can also have "global" definitions that are active in
all major modes.  The same abbrev can have a global definition and
various mode-specific definitions for different major modes.  A mode
specific definition for the current major mode overrides a global
definition.
   Abbrevs can be defined interactively during the editing session.
Lists of abbrev definitions can also be saved in files and reloaded in
later sessions.  Some users keep extensive lists of abbrevs that they
load in every session.
   A second kind of abbreviation facility is called the "dynamic
expansion".  Dynamic abbrev expansion happens only when you give an
explicit command and the result of the expansion depends only on the
current contents of the buffer.  *Note Dynamic Abbrevs::.
* Menu:
* Defining Abbrevs::  Defining an abbrev, so it will expand when typed.
* Expanding Abbrevs:: Controlling expansion: prefixes, canceling expansion.
* Editing Abbrevs::   Viewing or editing the entire list of defined abbrevs.
* Saving Abbrevs::    Saving the entire list of abbrevs for another session.
* Dynamic Abbrevs::   Abbreviations for words already in the buffer.
File: emacs,  Node: Defining Abbrevs,  Next: Expanding Abbrevs,  Prev: Abbrevs,  Up: Abbrevs
Defining Abbrevs
================
`C-x +'
     Define an abbrev to expand into some text before point
     (`add-global-abbrev').
`C-x C-a'
     Similar, but define an abbrev available only in the current major
     mode (`add-mode-abbrev').
`C-x -'
     Define a word in the buffer as an abbrev
     (`inverse-add-global-abbrev').
`C-x C-h'
     Define a word in the buffer as a mode-specific abbrev
     (`inverse-add-mode-abbrev').
`M-x kill-all-abbrevs'
     After this command, there are no abbrev definitions in effect.
   The usual way to define an abbrev is to enter the text you want the
abbrev to expand to, position point after it, and type `C-x +'
(`add-global-abbrev').  This reads the abbrev itself using the
minibuffer, and then defines it as an abbrev for one or more words
before point.  Use a numeric argument to say how many words before
point should be taken as the expansion.  For example, to define the
abbrev `foo' as mentioned above, insert the text `find outer otter' and
then type `C-u 3 C-x + f o o RET'.
   An argument of zero to `C-x +' means to use the contents of the
region as the expansion of the abbrev being defined.
   The command `C-x C-a' (`add-mode-abbrev') is similar, but defines a
mode-specific abbrev.  Mode specific abbrevs are active only in a
particular major mode.  `C-x C-a' defines an abbrev for the major mode
in effect at the time `C-x C-a' is typed.  The arguments work the same
as for `C-x +'.
   If the text of the abbrev you want is already in the buffer instead
of the expansion, use command `C-x -' (`inverse-add-global-abbrev')
instead of `C-x +', or use `C-x C-h' (`inverse-add-mode-abbrev')
instead of `C-x C-a'.  These commands are called "inverse" because they
invert the meaning of the argument found in the buffer and the argument
read using the minibuffer.
   To change the definition of an abbrev, just add the new definition.
You will be asked to confirm if the abbrev has a prior definition.  To
remove an abbrev definition, give a negative argument to `C-x +' or `C-x
C-a'.  You must choose the command to specify whether to kill a global
definition or a mode-specific definition for the current mode, since
those two definitions are independent for one abbrev.
   `M-x kill-all-abbrevs' removes all the abbrev definitions there are.
File: emacs,  Node: Expanding Abbrevs,  Next: Editing Abbrevs,  Prev: Defining Abbrevs,  Up: Abbrevs
Controlling Abbrev Expansion
============================
   An abbrev expands whenever it is present in the buffer just before
point and a self-inserting punctuation character (SPC, comma, etc.) is
typed.  Most often the way an abbrev is used is to insert the abbrev
followed by punctuation.
   Abbrev expansion preserves case; thus, `foo' expands into `find
outer otter'; `Foo' into `Find outer otter', and `FOO' into `FIND OUTER
OTTER' or `Find Outer Otter' according to the variable
`abbrev-all-caps' (a non-`nil' value chooses the first of the two
expansions).
   These two commands are used to control abbrev expansion:
`M-''
     Separate a prefix from a following abbrev to be expanded
     (`abbrev-prefix-mark').
`C-x ''
     Expand the abbrev before point (`expand-abbrev'). This is
     effective even when Abbrev mode is not enabled.
`M-x unexpand-abbrev'
     Undo last abbrev expansion.
`M-x expand-region-abbrevs'
     Expand some or all abbrevs found in the region.
   You may wish to expand an abbrev with a prefix attached; for
example, if `cnst' expands into `construction', you might want to use
it to enter `reconstruction'.  It does not work to type `recnst',
because that is not necessarily a defined abbrev.  What does work is to
use the command `M-'' (`abbrev-prefix-mark') in between the prefix `re'
and the abbrev `cnst'.  First, insert `re'.  Then type `M-''; this
inserts a minus sign in the buffer to indicate that it has done its
work.  Then insert the abbrev `cnst'; the buffer now contains
`re-cnst'.  Now insert a punctuation character to expand the abbrev
`cnst' into `construction'.  The minus sign is deleted at this point,
because `M-'' left word for this to be done.  The resulting text is the
desired `reconstruction'.
   If you actually want the text of the abbrev in the buffer, rather
than its expansion, you can accomplish this by inserting the following
punctuation with `C-q'.  Thus, `foo C-q -' leaves `foo-' in the buffer.
   If you expand an abbrev by mistake, you can undo the expansion
(replace the expansion by the original abbrev text) with `M-x
unexpand-abbrev'. `C-_' (`undo') can also be used to undo the
expansion; but first it will undo the insertion of the following
punctuation character!
   `M-x expand-region-abbrevs' searches through the region for defined
abbrevs, and for each one found offers to replace it with its expansion.
This command is useful if you have typed in text using abbrevs but
forgot to turn on Abbrev mode first.  It may also be useful together
with a special set of abbrev definitions for making several global
replacements at once.  This command is effective even if Abbrev mode is
not enabled.
File: emacs,  Node: Editing Abbrevs,  Next: Saving Abbrevs,  Prev: Expanding Abbrevs,  Up: Abbrevs
Examining and Editing Abbrevs
=============================
`M-x list-abbrevs'
     Print a list of all abbrev definitions.
`M-x edit-abbrevs'
     Edit a list of abbrevs; you can add, alter or remove definitions.
   The output from `M-x list-abbrevs' looks like this:
     (lisp-mode-abbrev-table)
     "dk"           0    "define-key"
     (global-abbrev-table)
     "dfn"           0    "definition"
(Some blank lines of no semantic significance, and some other abbrev
tables, have been omitted.)
   A line containing a name in parentheses is the header for abbrevs in
a particular abbrev table; `global-abbrev-table' contains all the global
abbrevs, and the other abbrev tables that are named after major modes
contain the mode-specific abbrevs.
   Within each abbrev table, each nonblank line defines one abbrev.  The
word at the beginning is the abbrev.  The number that appears is the
number of times the abbrev has been expanded.  Emacs keeps track of
this to help you see which abbrevs you actually use, in case you decide
to eliminate those that you don't use often.  The string at the end of
the line is the expansion.
   `M-x edit-abbrevs' allows you to add, change or kill abbrev
definitions by editing a list of them in an Emacs buffer.  The list has
the same format described above.  The buffer of abbrevs is called
`*Abbrevs*', and is in Edit-Abbrevs mode.  This mode redefines the key
`C-c C-c' to install the abbrev definitions as specified in the buffer.
 The command that does this is `edit-abbrevs-redefine'.  Any abbrevs
not described in the buffer are eliminated when this is done.
   `edit-abbrevs' is actually the same as `list-abbrevs' except that it
selects the buffer `*Abbrevs*' whereas `list-abbrevs' merely displays
it in another window.
File: emacs,  Node: Saving Abbrevs,  Next: Dynamic Abbrevs,  Prev: Editing Abbrevs,  Up: Abbrevs
Saving Abbrevs
==============
   These commands allow you to keep abbrev definitions between editing
sessions.
`M-x write-abbrev-file'
     Write a file describing all defined abbrevs.
`M-x read-abbrev-file'
     Read such a file and define abbrevs as specified there.
`M-x quietly-read-abbrev-file'
     Similar but do not display a message about what is going on.
`M-x define-abbrevs'
     Define abbrevs from buffer.
`M-x insert-abbrevs'
     Insert all abbrevs and their expansions into the buffer.
   `M-x write-abbrev-file' reads a file name using the minibuffer and
writes a description of all current abbrev definitions into that file.
The text stored in the file looks like the output of `M-x list-abbrevs'.
This is used to save abbrev definitions for use in a later session.
   `M-x read-abbrev-file' reads a file name using the minibuffer and
reads the file, defining abbrevs according to the contents of the file.
`M-x quietly-read-abbrev-file' is the same except that it does not
display a message in the echo area saying that it is doing its work; it
is actually useful primarily in the `.emacs' file.  If an empty
argument is given to either of these functions, the file name used is
the value of the variable `abbrev-file-name', which is by default
`"~/.abbrev_defs"'.
   Emacs will offer to save abbrevs automatically if you have changed
any of them, whenever it offers to save all files (for `C-x s' or `C-x
C-c').  This feature can be inhibited by setting the variable
`save-abbrevs' to `nil'.
   The commands `M-x insert-abbrevs' and `M-x define-abbrevs' are
similar to the previous commands but work on text in an Emacs buffer.
`M-x insert-abbrevs' inserts text into the current buffer before point,
describing all current abbrev definitions; `M-x define-abbrevs' parses
the entire current buffer and defines abbrevs accordingly.
File: emacs,  Node: Dynamic Abbrevs,  Prev: Saving Abbrevs,  Up: Abbrevs
Dynamic Abbrev Expansion
========================
   The abbrev facility described above operates automatically as you
insert text, but all abbrevs must be defined explicitly.  By contrast,
"dynamic abbrevs" allow the meanings of abbrevs to be determined
automatically from the contents of the buffer, but dynamic abbrev
expansion happens only when you request it explicitly.
`M-/'
     Expand the word in the buffer before point as a "dynamic abbrev",
     by searching in the buffer for words starting with that
     abbreviation (`dabbrev-expand').
   For example, if the buffer contains `does this follow ' and you type
`f o M-/', the effect is to insert `follow' because that is the last
word in the buffer that starts with `fo'.  A numeric argument to `M-/'
says to take the second, third, etc. distinct expansion found looking
backward from point.  Repeating `M-/' searches for an alternative
expansion by looking farther back.  After the part of the buffer
preceding point has been considered, the part of the buffer after point
is searched.
   Dynamic abbrev expansion is completely independent of Abbrev mode;
the expansion of a word with `M-/' is completely independent of whether
it has a definition as an ordinary abbrev.
File: emacs,  Node: Picture,  Next: Sending Mail,  Prev: Abbrevs,  Up: Top
Editing Pictures
****************
   If you want to create a picture made out of text characters (for
example, a picture of the division of a register into fields, as a
comment in a program), use the command `edit-picture' to enter Picture
mode.
   In Picture mode, editing is based on the "quarter-plane" model of
text, according to which the text characters lie studded on an area that
stretches infinitely far to the right and downward.  The concept of the
end of a line does not exist in this model; the most you can say is
where the last nonblank character on the line is found.
   Of course, Emacs really always considers text as a sequence of
characters, and lines really do have ends.  But in Picture mode most
frequently-used keys are rebound to commands that simulate the
quarter-plane model of text.  They do this by inserting spaces or by
converting tabs to spaces.
   Most of the basic editing commands of Emacs are redefined by Picture
mode to do essentially the same thing but in a quarter-plane way.  In
addition, Picture mode defines various keys starting with the `C-c'
prefix to run special picture editing commands.
   One of these keys, `C-c C-c', is pretty important.  Often a picture
is part of a larger file that is usually edited in some other major
mode. `M-x edit-picture' records the name of the previous major mode,
and then you can use the `C-c C-c' command (`picture-mode-exit') to
restore that mode.  `C-c C-c' also deletes spaces from the ends of
lines, unless given a numeric argument.
   The commands used in Picture mode all work in other modes (provided
the `picture' library is loaded), but are not bound to keys except in
Picture mode.  Note that the descriptions below talk of moving "one
column" and so on, but all the picture mode commands handle numeric
arguments as their normal equivalents do.
   Turning on Picture mode calls the value of the variable
`picture-mode-hook' as a function, with no arguments, if that value
exists and is non-`nil'.
* Menu:
* Basic Picture::         Basic concepts and simple commands of Picture Mode.
* Insert in Picture::     Controlling direction of cursor motion
                           after "self-inserting" characters.
* Tabs in Picture::       Various features for tab stops and indentation.
* Rectangles in Picture:: Clearing and superimposing rectangles.
File: emacs,  Node: Basic Picture,  Next: Insert in Picture,  Prev: Picture,  Up: Picture
Basic Editing in Picture Mode
=============================
   Most keys do the same thing in Picture mode that they usually do,
but do it in a quarter-plane style.  For example, `C-f' is rebound to
run `picture-forward-column', which is defined to move point one column
to the right, by inserting a space if necessary, so that the actual end
of the line makes no difference.  `C-b' is rebound to run
`picture-backward-column', which always moves point left one column,
converting a tab to multiple spaces if necessary.  `C-n' and `C-p' are
rebound to run `picture-move-down' and `picture-move-up', which can
either insert spaces or convert tabs as necessary to make sure that
point stays in exactly the same column.  `C-e' runs
`picture-end-of-line', which moves to after the last nonblank character
on the line.  There is no need to change `C-a', as the choice of screen
model does not affect beginnings of lines.
   Insertion of text is adapted to the quarter-plane screen model
through the use of Overwrite mode (*note Minor Modes::.).
Self-inserting characters replace existing text, column by column,
rather than pushing existing text to the right.  RET runs
`picture-newline', which just moves to the beginning of the following
line so that new text will replace that line.
   Deletion and killing of text are replaced with erasure.  DEL
(`picture-backward-clear-column') replaces the preceding character with
a space rather than removing it.  `C-d' (`picture-clear-column') does
the same thing in a forward direction. `C-k' (`picture-clear-line')
really kills the contents of lines, but does not ever remove the
newlines from the buffer.
   To do actual insertion, you must use special commands.  `C-o'
(`picture-open-line') still creates a blank line, but does so after the
current line; it never splits a line.  `C-M-o', `split-line', makes
sense in Picture mode, so it is not changed.  LFD
(`picture-duplicate-line') inserts below the current line another line
with the same contents.
   Real deletion can be done with `C-w', or with `C-c C-d' (which is
defined as `delete-char', as `C-d' is in other modes), or with one of
the picture rectangle commands (*note Rectangles in Picture::.).
File: emacs,  Node: Insert in Picture,  Next: Tabs in Picture,  Prev: Basic Picture,  Up: Picture
Controlling Motion after Insert
===============================
   Since "self-inserting" characters in Picture mode just overwrite and
move point, there is no essential restriction on how point should be
moved. Normally point moves right, but you can specify any of the eight
orthogonal or diagonal directions for motion after a "self-inserting"
character. This is useful for drawing lines in the buffer.
`C-c <'
     Move left after insertion (`picture-movement-left').
`C-c >'
     Move right after insertion (`picture-movement-right').
`C-c ^'
     Move up after insertion (`picture-movement-up').
`C-c .'
     Move down after insertion (`picture-movement-down').
`C-c `'
     Move up and left ("northwest") after insertion
     (`picture-movement-nw').
`C-c ''
     Move up and right ("northeast") after insertion
     (`picture-movement-ne').
`C-c /'
     Move down and left ("southwest") after insertion
     (`picture-movement-sw').
`C-c \'
     Move down and right ("southeast") after insertion
     (`picture-movement-se').
   Two motion commands move based on the current Picture insertion
direction.  The command `C-c C-f' (`picture-motion') moves in the same
direction as motion after "insertion" currently does, while `C-c C-b'
(`picture-motion-reverse') moves in the opposite direction.
File: emacs,  Node: Tabs in Picture,  Next: Rectangles in Picture,  Prev: Insert in Picture,  Up: Picture
Picture Mode Tabs
=================
   Two kinds of tab-like action are provided in Picture mode.
Context-based tabbing is done with `M-TAB' (`picture-tab-search').
With no argument, it moves to a point underneath the next "interesting"
character that follows whitespace in the previous nonblank line.
"Next" here means "appearing at a horizontal position greater than the
one point starts out at".  With an argument, as in `C-u M-TAB', this
command moves to the next such interesting character in the current
line.  `M-TAB' does not change the text; it only moves point.
"Interesting" characters are defined by the variable
`picture-tab-chars', which contains a string whose characters are all
considered interesting.  Its default value is `"!-~"'.
   TAB itself runs `picture-tab', which operates based on the current
tab stop settings; it is the Picture mode equivalent of
`tab-to-tab-stop'.  Normally it just moves point, but with a numeric
argument it clears the text that it moves over.
   The context-based and tab-stop-based forms of tabbing are brought
together by the command `C-c TAB', `picture-set-tab-stops'. This
command sets the tab stops to the positions which `M-TAB' would
consider significant in the current line.  The use of this command,
together with TAB, can get the effect of context-based tabbing.  But
`M-TAB' is more convenient in the cases where it is sufficient.
File: emacs,  Node: Rectangles in Picture,  Prev: Tabs in Picture,  Up: Picture
Picture Mode Rectangle Commands
===============================
   Picture mode defines commands for working on rectangular pieces of
the text in ways that fit with the quarter-plane model.  The standard
rectangle commands may also be useful (*note Rectangles::.).
`C-c C-k'
     Clear out the region-rectangle (`picture-clear-rectangle').  With
     argument, kill it.
`C-c C-w R'
     Similar but save rectangle contents in register R first
     (`picture-clear-rectangle-to-register').
`C-c C-y'
     Copy last killed rectangle into the buffer by overwriting, with
     upper left corner at point (`picture-yank-rectangle').  With
     argument, insert instead.
`C-c C-x R'
     Similar, but use the rectangle in register R
     (`picture-yank-rectangle-from-register').
   The picture rectangle commands `C-c C-k' (`picture-clear-rectangle')
and `C-c C-w' (`picture-clear-rectangle-to-register') differ from the
standard rectangle commands in that they normally clear the rectangle
instead of deleting it; this is analogous with the way `C-d' is changed
in Picture mode.
   However, deletion of rectangles can be useful in Picture mode, so
these commands delete the rectangle if given a numeric argument.
   The Picture mode commands for yanking rectangles differ from the
standard ones in overwriting instead of inserting.  This is the same
way that Picture mode insertion of other text is different from other
modes. `C-c C-y' (`picture-yank-rectangle') inserts (by overwriting) the
rectangle that was most recently killed, while `C-c C-x'
(`picture-yank-rectangle-from-register') does likewise for the
rectangle found in a specified register.
File: emacs,  Node: Sending Mail,  Next: Rmail,  Prev: Picture,  Up: Top
Sending Mail
************
   To send a message in Emacs, you start by typing a command (`C-x m')
to select and initialize the `*mail*' buffer.  Then you edit the text
and headers of the message in this buffer, and type another command
(`C-c C-c') to send the message.
`C-x m'
     Begin composing a message to send (`mail').
`C-x 4 m'
     Likewise, but display the message in another window
     (`mail-other-window').
`C-c C-c'
     In Mail mode, send the message and switch to another buffer
     (`mail-send-and-exit').
   The command `C-x m' (`mail') selects a buffer named `*mail*' and
initializes it with the skeleton of an outgoing message. `C-x 4 m'
(`mail-other-window') selects the `*mail*' buffer in a different
window, leaving the previous current buffer visible.
   Because the mail composition buffer is an ordinary Emacs buffer, you
can switch to other buffers while in the middle of composing mail, and
switch back later (or never).  If you use the `C-x m' command again
when you have been composing another message but have not sent it, you
are asked to confirm before the old message is erased.  If you answer
`n', the `*mail*' buffer is left selected with its old contents, so you
can finish the old message and send it.  `C-u C-x m' is another way to
do this.  Sending the message marks the `*mail*' buffer "unmodified",
which avoids the need for confirmation when `C-x m' is next used.
   If you are composing a message in the `*mail*' buffer and want to
send another message before finishing the first, rename the `*mail*'
buffer using `M-x rename-buffer' (*note Misc Buffer::.).
* Menu:
* Format: Mail Format.    Format of the mail being composed.
* Headers: Mail Headers.  Details of allowed mail header fields.
* Mode: Mail Mode.        Special commands for editing mail being composed.
File: emacs,  Node: Mail Format,  Next: Mail Headers,  Prev: Sending Mail,  Up: Sending Mail
The Format of the Mail Buffer
=============================
   In addition to the "text" or contents, a message has "header fields"
which say who sent it, when, to whom, why, and so on.  Some header
fields such as the date and sender are created automatically after the
message is sent.  Others, such as the recipient names, must be
specified by you in order to send the message properly.
   Mail mode provides a few commands to help you edit some header
fields, and some are preinitialized in the buffer automatically at
times.  You can insert or edit any header fields using ordinary editing
commands.
   The line in the buffer that says
     --text follows this line--
is a special delimiter that separates the headers you have specified
from the text.  Whatever follows this line is the text of the message;
the headers precede it.  The delimiter line itself does not appear in
the message actually sent.  The text used for the delimiter line is
controlled by the variable `mail-header-separator'.
   Here is an example of what the headers and text in the `*mail*'
buffer might look like.
     To: rms@mc
     CC: mly@mc, rg@oz
     Subject: The Emacs Manual
     --Text follows this line--
     Please ignore this message.
File: emacs,  Node: Mail Headers,  Next: Mail Mode,  Prev: Mail Format,  Up: Sending Mail
Mail Header Fields
==================
   There are several header fields you can use in the `*mail*' buffer.
Each header field starts with a field name at the beginning of a line,
terminated by a colon.  It does not matter whether you use upper or
lower case in the field name.  After the colon and optional whitespace
comes the contents of the field.
     This field contains the mailing addresses to which the message is
     addressed.
`Subject'
     The contents of the `Subject' field should be a piece of text that
     says what the message is about.  The reason `Subject' fields are
     useful is that most mail-reading programs can provide a summary of
     messages, listing the subject of each message but not its text.
     This field contains additional mailing addresses to send the
     message to, but whose readers should not regard the message as
     addressed to them.
`BCC'
     This field contains additional mailing addresses to send the
     message to, but which should not appear in the header of the
     message actually sent.
`FCC'
     This field contains the name of one file (in Unix mail file
     format) to which a copy of the message should be appended when the
     message is sent.
`From'
     Use the `From' field to say who you are, when the account you are
     using to send the mail is not your own.  The contents of the
     `From' field should be a valid mailing address, since replies will
     normally go there.
`Reply-To'
     Use the `Reply-to' field to direct replies to a different address,
     not your own.  There is no difference between `From' and
     `Reply-to' in their effect on where replies go, but they convey a
     different meaning to the human who reads the message.
     If you set the variable `mail-default-reply-to' to a non-`nil'
     value, then every message you begin to edit will have a `Reply-to'
     field whose contents are the value of the variable.
`In-Reply-To'
     This field contains a piece of text describing a message you are
     replying to.  Some mail systems can use this information to
     correlate related pieces of mail.  Normally this field is filled
     in by Rmail when you are replying to a message in Rmail, and you
     never need to think about it (*note Rmail::.).
   The `To', `CC', `BCC' and `FCC' fields can appear any number of
times, to specify many places to send the message.
   The `To', `CC', and `BCC' fields can have continuation lines.  All
the lines starting with whitespace, following the line on which the
field starts, are considered part of the field.  For example,
     To: foo@here, this@there,
       [e-mail]3281
   If you have a `~/.mailrc' file, Emacs will scan it for mail aliases
the first time you try to send mail in an Emacs session.  Aliases found
in the `To', `CC', and `BCC' fields will be expanded where appropriate.
   If the variable `mail-archive-file-name' is non-`nil', it should be a
string naming a file; every time you start to edit a message to send,
an `FCC' field will be put in for that file.  Unless you remove the
`FCC' field, every message will be written into that file when it is
sent.
File: emacs,  Node: Mail Mode,  Prev: Mail Headers,  Up: Sending Mail
Mail Mode
=========
   The major mode used in the `*mail*' buffer is Mail mode, which is
much like Text mode except that various special commands are provided on
the `C-c' prefix.  These commands all have to do specifically with
editing or sending the message.
`C-c C-s'
     Send the message, and leave the `*mail*' buffer selected
     (`mail-send').
`C-c C-c'
     Send the message, and select some other buffer
     (`mail-send-and-exit').
`C-c C-f C-t'
     Move to the `To' header field, creating one if there is none
     (`mail-to').
`C-c C-f C-s'
     Move to the `Subject' header field, creating one if there is none
     (`mail-subject').
`C-c C-f C-c'
     Move to the `CC' header field, creating one if there is none
     (`mail-cc').
`C-c C-w'
     Insert the file `~/.signature' at the end of the message text
     (`mail-signature').
`C-c C-y'
     Yank the selected message from Rmail (`mail-yank-original'). This
     command does nothing unless your command to start sending a
     message was issued with Rmail.
`C-c C-q'
     Fill all paragraphs of yanked old messages, each individually
     (`mail-fill-yanked-message').
   There are two ways to send the message.  `C-c C-s' (`mail-send')
sends the message and marks the `*mail*' buffer unmodified, but leaves
that buffer selected so that you can modify the message (perhaps with
new recipients) and send it again.  `C-c C-c' (`mail-send-and-exit')
sends and then deletes the window (if there is another window) or
switches to another buffer.  It puts the `*mail*' buffer at the lowest
priority for automatic reselection, since you are finished with using
it.  This is the usual way to send the message.
   Mail mode provides some other special commands that are useful for
editing the headers and text of the message before you send it.  There
are three commands defined to move point to particular header fields,
all based on the prefix `C-c C-f' (`C-f' is for "field").  They are
`C-c C-f C-t' (`mail-to') to move to the `To' field, `C-c C-f C-s'
(`mail-subject') for the `Subject' field, and `C-c C-f C-c' (`mail-cc')
for the `CC' field.  These fields have special motion commands because
they are the most common fields for the user to want to edit.
   `C-c C-w' (`mail-signature') adds a standard piece text at the end
of the message to say more about who you are.  The text comes from the
file `.signature' in your home directory.
   When mail sending is invoked from the Rmail mail reader using an
Rmail command, `C-c C-y' can be used inside the `*mail*' buffer to
insert the text of the message you are replying to.  Normally it
indents each line of that message four spaces and eliminates most
header fields.  A numeric argument specifies the number of spaces to
indent.  An argument of just `C-u' says not to indent at all and not to
eliminate anything. `C-c C-y' always uses the current message from the
`RMAIL' buffer, so you can insert several old messages by selecting one
in `RMAIL', switching to `*mail*' and yanking it, then switching back to
`RMAIL' to select another.
   After using `C-c C-y', you can type the command `C-c C-q'
(`mail-fill-yanked-message') to fill the paragraphs of the yanked old
message or messages.  One use of `C-c C-q' fills all such paragraphs,
each one separately.
   Turning on Mail mode (which `C-x m' does automatically) calls the
value of `text-mode-hook', if it is not void or `nil', and then calls
the value of `mail-mode-hook' if that is not void or `nil'.  Aside from
these, the `mail' command runs `mail-setup-hook' whenever it
initializes the `*mail*' buffer for editing a message.
File: emacs,  Node: Rmail,  Next: Recursive Edit,  Prev: Sending Mail,  Up: Top
Reading Mail with Rmail
***********************
   Rmail is an Emacs subsystem for reading and disposing of mail that
you receive.  Rmail stores mail messages in files called "Rmail files".
 Reading the message in an Rmail file is done in a special major mode,
Rmail mode, which redefines most letters to run commands for managing
mail.  To enter Rmail, type `M-x rmail'.  This reads your primary mail
file, merges new mail in from your inboxes, displays the first new
message, and lets you begin reading.
   Using Rmail in the simplest fashion, you have one Rmail file,
`~/RMAIL', in which all of your mail is saved.  It is called your
"primary mail file".  In more sophisticated usage, you can copy
messages into other Rmail files and then edit those files with Rmail.
   Rmail displays only one message at a time.  It is called the "current
message".  Rmail mode's special commands can do such things as move to
another message, delete the message, copy the message into another
file, or send a reply.
   Within the Rmail file, messages are arranged sequentially in order
of receipt.  They are also assigned consecutive integers as their
"message numbers".  The number of the current message is displayed in
Rmail's mode line, followed by the total number of messages in the
file.  You can move to a message by specifying its message number using
the `j' key (*note Rmail Motion::.).
   Following the usual conventions of Emacs, changes in an Rmail file
become permanent only when the file is saved.  You can do this with `s'
(`rmail-save'), which also expunges deleted messages from the file
first (*note Rmail Deletion::.).  To save the file without expunging,
use `C-x C-s'.  Rmail saves the Rmail file spontaneously when moving new
mail from an inbox file (*note Rmail Inbox::.).
   You can exit Rmail with `q' (`rmail-quit'); this expunges and saves
the Rmail file and then switches to another buffer.  But there is no
need to `exit' formally.  If you switch from Rmail to editing in other
buffers, and never happen to switch back, you have exited.  Just make
sure to save the Rmail file eventually (like any other file you have
changed).  `C-x s' is a good enough way to do this (*note Saving::.).
* Menu:
* Scroll: Rmail Scrolling.   Scrolling through a message.
* Motion: Rmail Motion.      Moving to another message.
* Deletion: Rmail Deletion.  Deleting and expunging messages.
* Inbox: Rmail Inbox.        How mail gets into the Rmail file.
* Files: Rmail Files.        Using multiple Rmail files.
* Output: Rmail Output.         Copying message out to files.
* Labels: Rmail Labels.      Classifying messages by labeling them.
* Summary: Rmail Summary.    Summaries show brief info on many messages.
* Reply: Rmail Reply.        Sending replies to messages you are viewing.
* Editing: Rmail Editing.    Editing message text and headers in Rmail.
* Digest: Rmail Digest.      Extracting the messages from a digest message.
File: emacs,  Node: Rmail Scrolling,  Next: Rmail Motion,  Prev: Rmail,  Up: Rmail
Scrolling Within a Message
==========================
   When Rmail displays a message that does not fit on the screen, it is
necessary to scroll through it.  This could be done with `C-v', `M-v'
and `M-<', but in Rmail scrolling is so frequent that it deserves to be
easier to type.
`SPC'
     Scroll forward (`scroll-up').
`DEL'
     Scroll backward (`scroll-down').
     Scroll to start of message (`rmail-beginning-of-message').
   Since the most common thing to do while reading a message is to
scroll through it by screenfuls, Rmail makes SPC and DEL synonyms of
`C-v' (`scroll-up') and `M-v' (`scroll-down').
   The command `.' (`rmail-beginning-of-message') scrolls back to the
beginning of the selected message.  This is not quite the same as `M-<':
for one thing, it does not set the mark; for another, it resets the
buffer boundaries to the current message if you have changed them.