Annotation of 43BSDReno/contrib/emacs-18.55/info/emacs-8, revision 1.1.1.1

1.1       root        1: Info file emacs, produced by texinfo-format-buffer   -*-Text-*-
                      2: from file emacs.tex
                      3: 
                      4: This file documents the GNU Emacs editor.
                      5: 
                      6: Copyright (C) 1985, 1986 Richard M. Stallman.
                      7: 
                      8: Permission is granted to make and distribute verbatim copies of
                      9: this manual provided the copyright notice and this permission notice
                     10: are preserved on all copies.
                     11: 
                     12: Permission is granted to copy and distribute modified versions of this
                     13: manual under the conditions for verbatim copying, provided also that the
                     14: sections entitled "The GNU Manifesto", "Distribution" and "GNU Emacs
                     15: General Public License" are included exactly as in the original, and
                     16: provided that the entire resulting derived work is distributed under the
                     17: terms of a permission notice identical to this one.
                     18: 
                     19: Permission is granted to copy and distribute translations of this manual
                     20: into another language, under the above conditions for modified versions,
                     21: except that the sections entitled "The GNU Manifesto", "Distribution"
                     22: and "GNU Emacs General Public License" may be included in a translation
                     23: approved by the author instead of in the original English.
                     24: 
                     25: 
                     26: File: emacs  Node: Fortran Columns, Prev: Fortran Comments, Up: Fortran, Next: Fortran Abbrev
                     27: 
                     28: Columns
                     29: -------
                     30: 
                     31: `C-c C-r'     
                     32:      Displays a "column ruler" momentarily above the current line
                     33:      (`fortran-column-ruler').
                     34: `C-c C-w'     
                     35:      Splits the current window horizontally so that it is 72 columns wide.
                     36:      This may help you avoid going over that limit (`fortran-window-create').
                     37: 
                     38:   The command `C-c C-r' (`fortran-column-ruler') shows a column
                     39: ruler momentarily above the current line.  The comment ruler is two lines
                     40: of text that show you the locations of columns with special significance
                     41: in Fortran programs.  Square brackets show the limits of the columns for
                     42: line numbers, and curly brackets show the limits of the columns for the
                     43: statement body.  Column numbers appear above them.
                     44: 
                     45:   Note that the column numbers count from zero, as always in GNU Emacs.  As
                     46: a result, the numbers may not be those you are familiar with; but the
                     47: actual positions in the line are standard Fortran.
                     48: 
                     49:   The text used to display the column ruler is the value of the variable
                     50: `fortran-comment-ruler'.  By changing this variable, you can change
                     51: the display.
                     52: 
                     53:   For even more help, use `C-c C-w' (`fortran-create-window'), a
                     54: command which splits the current window horizontally, making a window 72
                     55: columns wide.  By editing in this window you can immediately see when you
                     56: make a line too wide to be correct Fortran.
                     57: 
                     58: 
                     59: File: emacs  Node: Fortran Abbrev, Prev: Fortran Columns, Up: Fortran
                     60: 
                     61: Fortran Keyword Abbrevs
                     62: -----------------------
                     63: 
                     64:   Fortran mode provides many built-in abbrevs for common keywords and
                     65: declarations.  These are the same sort of abbrev that you can define
                     66: yourself.  To use them, you must turn on Abbrev mode.  *Note Abbrevs::.
                     67: 
                     68:   The built-in abbrevs are unusual in one way: they all start with a
                     69: semicolon.  You cannot normally use semicolon in an abbrev, but Fortran
                     70: mode makes this possible by changing the syntax of semicolon to "word
                     71: constituent".
                     72: 
                     73:   For example, one built-in Fortran abbrev is `;c' for `continue'.  If you
                     74: insert `;c' and then insert a punctuation character such as a space or a
                     75: newline, the `;c' will change automatically to `continue', provided Abbrev
                     76: mode is enabled.
                     77: 
                     78:   Type `;?' or `;C-h' to display a list of all the built-in
                     79: Fortran abbrevs and what they stand for.
                     80: 
                     81: 
                     82: File: emacs  Node: Running, Prev: Programs, Up: Top, Next: Abbrevs
                     83: 
                     84: Compiling and Testing Programs
                     85: ******************************
                     86: 
                     87:   The previous chapter discusses the Emacs commands that are useful for
                     88: making changes in programs.  This chapter deals with commands that assist
                     89: in the larger process of developing and maintaining programs.
                     90: 
                     91: * Menu:
                     92: 
                     93: * Compilation::        Compiling programs in languages other than Lisp
                     94:                         (C, Pascal, etc.)
                     95: * Modes: Lisp Modes.   Various modes for editing Lisp programs, with
                     96:                        different facilities for running the Lisp programs.
                     97: * Libraries: Lisp Libraries.      Creating Lisp programs to run in Emacs.
                     98: * Interaction: Lisp Interaction.  Executing Lisp in an Emacs buffer.
                     99: * Eval: Lisp Eval.     Executing a single Lisp expression in Emacs.
                    100: * Debug: Lisp Debug.   Debugging Lisp programs running in Emacs.
                    101: * External Lisp::      Communicating through Emacs with a separate Lisp.
                    102: 
                    103: 
                    104: File: emacs  Node: Compilation, Prev: Running, Up: Running, Next: Lisp Modes
                    105: 
                    106: Running `make', or Compilers Generally
                    107: ======================================
                    108: 
                    109:   Emacs can run compilers for noninteractive languages such as C and
                    110: Fortran as inferior processes, feeding the error log into an Emacs buffer.
                    111: It can also parse the error messages and visit the files in which errors
                    112: are found, moving point right to the line where the error occurred.
                    113: 
                    114: `M-x compile'     
                    115:      Run a compiler asynchronously under Emacs, with error messages to
                    116:      `*compilation*' buffer.
                    117: `M-x grep'     
                    118:      Run `grep' asynchronously under Emacs, with matching lines
                    119:      listed in the buffer named `*compilation*'.
                    120: `M-x kill-compiler'     
                    121: `M-x kill-grep'     
                    122:      Kill the running compilation or `grep' subprocess.
                    123: `C-x `'     
                    124:      Visit the locus of the next compiler error message or `grep' match.
                    125: 
                    126:   To run `make' or another compiler, do `M-x compile'.  This command
                    127: reads a shell command line using the minibuffer, and then executes the
                    128: specified command line in an inferior shell with output going to the buffer
                    129: named `*compilation*'.  The current buffer's default directory is used
                    130: as the working directory for the execution of the command; normally,
                    131: therefore, the makefile comes from this directory.
                    132: 
                    133:   When the shell command line is read, the minibuffer appears containing a
                    134: default command line, which is the command you used the last time you did
                    135: `M-x compile'.  If you type just RET, the same command line is used
                    136: again.  The first `M-x compile' provides `make -k' as the default.
                    137: The default is taken from the variable `compile-command'; if the
                    138: appropriate compilation command for a file is something other than
                    139: `make -k', it can be useful to have the file specify a local value for
                    140: `compile-command' (*Note File Variables::).
                    141: 
                    142:   Starting a compilation causes the buffer `*compilation*' to be
                    143: displayed in another window but not selected.  Its mode line tells you
                    144: whether compilation is finished, with the word `run' or `exit' inside
                    145: the parentheses.  You do not have to keep this buffer visible; compilation
                    146: continues in any case.
                    147: 
                    148:   To kill the compilation process, do `M-x kill-compilation'.  You will see
                    149: that the mode line of the `*compilation*' buffer changes to say `signal'
                    150: instead of `run'.  Starting a new compilation also kills any running
                    151: compilation, as only one can exist at any time.  However, this requires
                    152: confirmation before actually killing a compilation that is running.
                    153: 
                    154:   To parse the compiler error messages, type `C-x `' (`next-error').  The
                    155: character following the `C-x' is the grave accent, not the single
                    156: quote.  This command displays the buffer `*compilation*' in one window
                    157: and the buffer in which the next error occurred in another window.  Point
                    158: in that buffer is moved to the line where the error was found.  The
                    159: corresponding error message is scrolled to the top of the window in which
                    160: `*compilation*' is displayed.
                    161: 
                    162:   The first time `C-x `' is used after the start of a compilation, it
                    163: parses all the error messages, visits all the files that have error
                    164: messages, and makes markers pointing at the lines that the error messages
                    165: refer to.  Then it moves to the first error message location.  Subsequent
                    166: uses of `C-x `' advance down the data set up by the first use.  When
                    167: the preparsed error messages are exhausted, the next `C-x `' checks for
                    168: any more error messages that have come in; this is useful if you start
                    169: editing the compiler errors while the compilation is still going on.  If no
                    170: more error messages have come in, `C-x `' reports an error.
                    171: 
                    172:   `C-u C-x `' discards the preparsed error message data and parses the
                    173: `*compilation*' buffer over again, then displaying the first error.
                    174: This way, you can process the same set of errors again.
                    175: 
                    176:   Instead of running a compiler, you can run `grep' and see the lines
                    177: on which matches were found.  To do this, type `M-x grep' with an argument
                    178: line that contains the same arguments you would give `grep' when running
                    179: it normally: a `grep'-style regexp (usually in singlequotes to quote
                    180: the shell's special characters) followed by filenames which may use wildcards.
                    181: The output from `grep' goes in the `*compilation*' buffer and the
                    182: lines that matched can be found with `C-x `' as if they were compilation
                    183: errors.
                    184: 
                    185:   Note: a shell is used to run the compile command, but the shell is told
                    186: that it should be noninteractive.  This means in particular that the shell
                    187: starts up with no prompt.  If you find your usual shell prompt making an
                    188: unsightly appearance in the `*compilation*' buffer, it means you have
                    189: made a mistake in your shell's init file (`.cshrc' or `.shrc' or
                    190: ...) by setting the prompt unconditionally.  The shell init file should
                    191: set the prompt only if there already is a prompt.  In `csh', here is
                    192: how to do it:
                    193: 
                    194:      if ($?prompt) set prompt = ... 
                    195: 
                    196: 
                    197: File: emacs  Node: Lisp Modes, Prev: Compilation, Up: Running, Next: Lisp Libraries
                    198: 
                    199: Major Modes for Lisp
                    200: ====================
                    201: 
                    202:   Emacs has four different major modes for Lisp.  They are the same in
                    203: terms of editing commands, but differ in the commands for executing Lisp
                    204: expressions.
                    205: 
                    206: Emacs-Lisp mode     
                    207:      The mode for editing source files of programs to run in Emacs Lisp.
                    208:      This mode defines `C-M-x' to evaluate the current defun.
                    209:      *Note Lisp Libraries::.
                    210: Lisp Interaction mode     
                    211:      The mode for an interactive session with Emacs Lisp.  It defines
                    212:      LFD to evaluate the sexp before point and insert its value in the
                    213:      buffer.  *Note Lisp Interaction::.
                    214: Lisp mode     
                    215:      The mode for editing source files of programs that run in Lisps other
                    216:      than Emacs Lisp.  This mode defines `C-M-x' to send the current defun
                    217:      to an inferior Lisp process.  *Note External Lisp::.
                    218: Inferior Lisp mode     
                    219:      The mode for an interactive session with an inferior Lisp process.
                    220:      This mode combines the special features of Lisp mode and Shell mode
                    221:      (*Note Shell Mode::).
                    222: Scheme mode     
                    223:      Like Lisp mode but for Scheme programs.
                    224: Inferior Scheme mode     
                    225:      The mode for an interactive session with an inferior Scheme process.
                    226: 
                    227: 
                    228: File: emacs  Node: Lisp Libraries, Prev: Lisp Modes, Up: Running, Next: Lisp Eval
                    229: 
                    230: Libraries of Lisp Code for Emacs
                    231: ================================
                    232: 
                    233:   Lisp code for Emacs editing commands is stored in files whose names
                    234: conventionally end in `.el'.  This ending tells Emacs to edit them in
                    235: Emacs-Lisp mode (*Note Lisp Modes::).
                    236: 
                    237: * Menu:
                    238: 
                    239: * Loading::            Loading libraries of Lisp code into Emacs for use.
                    240: * Compiling Libraries:: Compiling a library makes it load and run faster.
                    241: * Mocklisp::           Converting Mocklisp to Lisp so GNU Emacs can run it.
                    242: 
                    243: 
                    244: File: emacs  Node: Loading, Prev: Lisp Libraries, Up: Lisp Libraries, Next: Compiling Libraries
                    245: 
                    246: Loading Libraries
                    247: -----------------
                    248: 
                    249:   To execute a file of Emacs Lisp, use `M-x load-file'.  This command
                    250: reads a file name using the minibuffer and then executes the contents of
                    251: that file as Lisp code.  It is not necessary to visit the file first;
                    252: in any case, this command reads the file as found on disk, not text in
                    253: an Emacs buffer.
                    254: 
                    255:   Once a file of Lisp code is installed in the Emacs Lisp library
                    256: directories, users can load it using `M-x load-library'.  Programs can
                    257: load it by calling `load-library', or with `load', a more primitive
                    258: function that is similar but accepts some additional arguments.
                    259: 
                    260:   `M-x load-library' differs from `M-x load-file' in that it
                    261: searches a sequence of directories and tries three file names in each
                    262: directory.  The three names are, first, the specified name with `.elc'
                    263: appended; second, with `.el' appended; third, the specified
                    264: name alone.  A `.elc' file would be the result of compiling the Lisp
                    265: file into byte code; it is loaded if possible in preference to the Lisp
                    266: file itself because the compiled file will load and run faster.
                    267: 
                    268:   Because the argument to `load-library' is usually not in itself
                    269: a valid file name, file name completion is not available.  Indeed, when
                    270: using this command, you usually do not know exactly what file name
                    271: will be used.
                    272: 
                    273:   The sequence of directories searched by `M-x load-library' is
                    274: specified by the variable `load-path', a list of strings that are
                    275: directory names.  The default value of the list contains the directory where
                    276: the Lisp code for Emacs itself is stored.  If you have libraries of
                    277: your own, put them in a single directory and add that directory
                    278: to `load-path'.  `nil' in this list stands for the current default
                    279: directory, but it is probably not a good idea to put `nil' in the
                    280: list.  If you find yourself wishing that `nil' were in the list,
                    281: most likely what you really want to do is use `M-x load-file'
                    282: this once.
                    283: 
                    284:   Often you do not have to give any command to load a library, because the
                    285: commands defined in the library are set up to "autoload" that library.
                    286: Running any of those commands causes `load' to be called to load the
                    287: library; this replaces the autoload definitions with the real ones from the
                    288: library.
                    289: 
                    290:   If autoloading a file does not finish, either because of an error or
                    291: because of a `C-g' quit, all function definitions made by the file are
                    292: undone automatically.  So are any calls to `provide'.  As a consequence,
                    293: if you use one of the autoloadable commands again, the entire file will be
                    294: loaded a second time.  This prevents problems where the command is no
                    295: longer autoloading but it works wrong because not all the file was loaded.
                    296: Function definitions are undone only for autoloading; explicit calls to
                    297: `load' do not undo anything if loading is not completed.
                    298: 
                    299: 
                    300: File: emacs  Node: Compiling Libraries, Prev: Loading, Up: Lisp Libraries, Next: Mocklisp
                    301: 
                    302: Compiling Libraries
                    303: -------------------
                    304: 
                    305:   Emacs Lisp code can be compiled into byte-code which loads faster,
                    306: takes up less space when loaded, and executes faster.
                    307: 
                    308:   The way to make a byte-code compiled file from an Emacs-Lisp source file
                    309: is with `M-x byte-compile-file'.  The default argument for this
                    310: function is the file visited in the current buffer.  It reads the specified
                    311: file, compiles it into byte code, and writes an output file whose name is
                    312: made by appending `c' to the input file name.  Thus, the file
                    313: `rmail.el' would be compiled into `rmail.elc'.
                    314: 
                    315:   To recompile the changed Lisp files in a directory, use `M-x
                    316: byte-recompile-directory'.  Specify just the directory name as an argument.
                    317: Each `.el' file that has been byte-compiled before is byte-compiled
                    318: again if it has changed since the previous compilation.  A numeric argument
                    319: to this command tells it to offer to compile each `.el' file that has
                    320: not already been compiled.  You must answer `y' or `n' to each
                    321: offer.
                    322: 
                    323:   Emacs can be invoked noninteractively from the shell to do byte compilation
                    324: with the aid of the function `batch-byte-compile'.  In this case,
                    325: the files to be compiled are specified with command-line arguments.
                    326: Use a shell command of the form
                    327: 
                    328:      emacs -batch -f batch-byte-compile FILES...
                    329: 
                    330:   Directory names may also be given as arguments;
                    331: `byte-recompile-directory' is invoked (in effect) on each such directory.
                    332: `batch-byte-compile' uses all the remaining command-line arguments as
                    333: file or directory names, then kills the Emacs process.
                    334: 
                    335:   `M-x disassemble' explains the result of byte compilation.  Its
                    336: argument is a function name.  It displays the byte-compiled code in a help
                    337: window in symbolic form, one instruction per line.  If the instruction
                    338: refers to a variable or constant, that is shown too.
                    339: 
                    340: 
                    341: File: emacs  Node: Mocklisp, Prev: Compiling Libraries, Up: Lisp Libraries
                    342: 
                    343: Converting Mocklisp to Lisp
                    344: ---------------------------
                    345: 
                    346:   GNU Emacs can run Mocklisp files by converting them to Emacs Lisp first.
                    347: To convert a Mocklisp file, visit it and then type `M-x
                    348: convert-mocklisp-buffer'.  Then save the resulting buffer of Lisp file in a
                    349: file whose name ends in `.el' and use the new file as a Lisp library.
                    350: 
                    351:   It does not currently work to byte-compile converted Mocklisp code.
                    352: This is because converted Mocklisp code uses some special Lisp features
                    353: to deal with Mocklisp's incompatible ideas of how arguments are evaluated
                    354: and which values signify "true" or "false".
                    355: 
                    356: 
                    357: File: emacs  Node: Lisp Eval, Prev: Lisp Libraries, Up: Running, Next: Lisp Debug
                    358: 
                    359: Evaluating Emacs-Lisp Expressions
                    360: =================================
                    361: 
                    362:   Lisp programs intended to be run in Emacs should be edited in Emacs-Lisp
                    363: mode; this will happen automatically for file names ending in `.el'.
                    364: By contrast, Lisp mode itself is used for editing Lisp programs intended
                    365: for other Lisp systems.  Emacs-Lisp mode can be selected with the command
                    366: `M-x emacs-lisp-mode'.
                    367: 
                    368:   For testing of Lisp programs to run in Emacs, it is useful to be able to
                    369: evaluate part of the program as it is found in the Emacs buffer.  For
                    370: example, after changing the text of a Lisp function definition, evaluating
                    371: the definition installs the change for future calls to the function.
                    372: Evaluation of Lisp expressions is also useful in any kind of editing task
                    373: for invoking noninteractive functions (functions that are not commands).
                    374: 
                    375: `M-ESC'     
                    376:      Read a Lisp expression in the minibuffer, evaluate it, and print the
                    377:      value in the minibuffer (`eval-expression').
                    378: `C-x C-e'     
                    379:      Evaluate the Lisp expression before point, and print the value in the
                    380:      minibuffer (`eval-last-sexp').
                    381: `C-M-x'     
                    382:      Evaluate the defun containing or after point, and print the value in
                    383:      the minibuffer (`eval-defun').
                    384: `M-x eval-region'     
                    385:      Evaluate all the Lisp expressions in the region.
                    386: `M-x eval-current-buffer'     
                    387:      Evaluate all the Lisp expressions in the buffer.
                    388: 
                    389:   `M-ESC' (`eval-expression') is the most basic command for evaluating
                    390: a Lisp expression interactively.  It reads the expression using the
                    391: minibuffer, so you can execute any expression on a buffer regardless of
                    392: what the buffer contains.  When the expression is evaluated, the current
                    393: buffer is once again the buffer that was current when `M-ESC' was
                    394: typed.
                    395: 
                    396:   `M-ESC' can easily confuse users who do not understand it, especially on
                    397: keyboards with autorepeat where it can result from holding down the ESC key
                    398: for too long.  Therefore, `eval-expression' is normally a disabled command.
                    399: Attempting to use this command asks for confirmation and gives you the
                    400: option of enabling it; once you enable the command, confirmation will no
                    401: longer be required for it.  *Note Disabling::.
                    402: 
                    403:   In Emacs-Lisp mode, the key `C-M-x' is bound to the function `eval-defun',
                    404: which parses the defun containing or following point as a Lisp expression
                    405: and evaluates it.  The value is printed in the echo area.  This command is
                    406: convenient for installing in the Lisp environment changes that you have
                    407: just made in the text of a function definition.
                    408: 
                    409:   The command `C-x C-e' (`eval-last-sexp') performs a similar job
                    410: but is available in all major modes, not just Emacs-Lisp mode.  It finds
                    411: the sexp before point, reads it as a Lisp expression, evaluates it, and
                    412: prints the value in the echo area.  It is sometimes useful to type in an
                    413: expression and then, with point still after it, type `C-x C-e'.
                    414: 
                    415:   If `C-M-x' or `C-x C-e' is given a numeric argument, it prints the value
                    416: by insertion into the current buffer at point, rather than in the echo
                    417: area.  The argument value does not matter.
                    418: 
                    419:   The most general command for evaluating Lisp expressions from a buffer is
                    420: `eval-region'.  `M-x eval-region' parses the text of the region as one or
                    421: more Lisp expressions, evaluating them one by one.  `M-x eval-current-buffer'
                    422: is similar but evaluates the entire buffer.  This is a reasonable way to
                    423: install the contents of a file of Lisp code that you are just ready to
                    424: test.  After finding and fixing a bug, use `C-M-x' on each function
                    425: that you change, to keep the Lisp world in step with the source file.
                    426: 
                    427: 
                    428: File: emacs  Node: Lisp Debug, Prev: Lisp Eval, Up: Running, Next: Lisp Interaction
                    429: 
                    430: The Emacs-Lisp Debugger
                    431: =======================
                    432: 
                    433:   GNU Emacs contains a debugger for Lisp programs executing inside it.
                    434: This debugger is normally not used; many commands frequently get Lisp
                    435: errors when invoked in inappropriate contexts (such as `C-f' at the end of
                    436: the buffer) and it would be very unpleasant for that to enter a special
                    437: debugging mode.  When you want to make Lisp errors invoke the debugger, you
                    438: must set the variable `debug-on-error' to non-`nil'.  Quitting with `C-g'
                    439: is not considered an error, and `debug-on-error' has no effect on the
                    440: handling of `C-g'.  However, if you set `debug-on-quit' non-`nil', `C-g'
                    441: will invoke the debugger.  This can be useful for debugging an infinite
                    442: loop; type `C-g' once the loop has had time to reach its steady state.
                    443: `debug-on-quit' has no effect on errors.
                    444: 
                    445:   You can also cause the debugger to be entered when a specified function
                    446: is called, or at a particular place in Lisp code.  Use `M-x debug-on-entry'
                    447: with argument FUN-NAME to cause function FUN-NAME to enter the debugger as
                    448: soon as it is called.  Use `M-x cancel-debug-on-entry' to make the function
                    449: stop entering the debugger when called.  (Redefining the function also does
                    450: this.)  To enter the debugger from some other place in Lisp code, you must
                    451: insert the expression `(debug)' there and install the changed code with
                    452: `C-M-x'.  *Note Lisp Eval::.
                    453: 
                    454:   When the debugger is entered, it displays the previously selected buffer
                    455: in one window and a buffer named `*Backtrace*' in another window.  The
                    456: backtrace buffer contains one line for each level of Lisp function
                    457: execution currently going on.  At the beginning of this buffer is a message
                    458: describing the reason that the debugger was invoked (such as, what error
                    459: message if it was invoked due to an error).
                    460: 
                    461:   The backtrace buffer is read-only, and is in a special major mode,
                    462: Backtrace mode, in which letters are defined as debugger commands.  The
                    463: usual Emacs editing commands are available; you can switch windows to
                    464: examine the buffer that was being edited at the time of the error, and you
                    465: can also switch buffers, visit files, and do any other sort of editing.
                    466: However, the debugger is a recursive editing level (*Note Recursive Edit::)
                    467: and it is wise to go back to the backtrace buffer and exit the debugger
                    468: officially when you don't want to use it any more.  Exiting the debugger
                    469: kills the backtrace buffer.
                    470: 
                    471:   The contents of the backtrace buffer show you the functions that are
                    472: executing and the arguments that were given to them.  It has the additional
                    473: purpose of allowing you to specify a stack frame by moving point to the line
                    474: describing that frame.  The frame whose line point is on is considered the
                    475: "current frame".  Some of the debugger commands operate on the current
                    476: frame.  Debugger commands are mainly used for stepping through code an
                    477: expression at a time.  Here is a list of them.
                    478: 
                    479: `c'     
                    480:      Exit the debugger and continue execution.  In most cases, execution of
                    481:      the program continues as if the debugger had never been entered (aside
                    482:      from the effect of any variables or data structures you may have
                    483:      changed while inside the debugger).  This includes entry to the
                    484:      debugger due to function entry or exit, explicit invocation, quitting
                    485:      or certain errors.  Most errors cannot be continued; trying to
                    486:      continue one of them causes the same error to occur again.
                    487: `d'     
                    488:      Continue execution, but enter the debugger the next time a Lisp
                    489:      function is called.  This allows you to step through the
                    490:      subexpressions of an expression, seeing what values the subexpressions
                    491:      compute and what else they do.
                    492:      
                    493:      The stack frame made for the function call which enters the debugger
                    494:      in this way will be flagged automatically for the debugger to be called
                    495:      when the frame is exited.  You can use the `u' command to cancel
                    496:      this flag.
                    497: `b'     
                    498:      Set up to enter the debugger when the current frame is exited.  Frames
                    499:      that will invoke the debugger on exit are flagged with stars.
                    500: `u'     
                    501:      Don't enter the debugger when the current frame is exited.  This
                    502:      cancels a `b' command on that frame.
                    503: `e'     
                    504:      Read a Lisp expression in the minibuffer, evaluate it, and print the
                    505:      value in the echo area.  This is the same as the command `M-ESC',
                    506:      except that `e' is not normally disabled like `M-ESC'.
                    507: `q'     
                    508:      Terminate the program being debugged; return to top-level Emacs
                    509:      command execution.
                    510:      
                    511:      If the debugger was entered due to a `C-g' but you really want
                    512:      to quit, not to debug, use the `q' command.
                    513: `r'     
                    514:      Return a value from the debugger.  The value is computed by reading an
                    515:      expression with the minibuffer and evaluating it.
                    516:      
                    517:      The value returned by the debugger makes a difference when the debugger
                    518:      was invoked due to exit from a Lisp call frame (as requested with `b');
                    519:      then the value specified in the `r' command is used as the value of
                    520:      that frame.
                    521:      
                    522:      The debugger's return value also matters with many errors.  For example,
                    523:      `wrong-type-argument' errors will use the debugger's return value
                    524:      instead of the invalid argument; `no-catch' errors will use the
                    525:      debugger value as a throw tag instead of the tag that was not found.
                    526:      If an error was signaled by calling the Lisp function `signal',
                    527:      the debugger's return value is returned as the value of `signal'.
                    528: 
                    529: 
                    530: File: emacs  Node: Lisp Interaction, Prev: Lisp Debug, Up: Running, Next: External Lisp
                    531: 
                    532: Lisp Interaction Buffers
                    533: ========================
                    534: 
                    535:   The buffer `*scratch*' which is selected when Emacs starts up is
                    536: provided for evaluating Lisp expressions interactively inside Emacs.  Both
                    537: the expressions you evaluate and their output goes in the buffer.
                    538: 
                    539:   The `*scratch*' buffer's major mode is Lisp Interaction mode, which
                    540: is the same as Emacs-Lisp mode except for one command, LFD.  In
                    541: Emacs-Lisp mode, LFD is an indentation command, as usual.  In Lisp
                    542: Interaction mode, LFD is bound to `eval-print-last-sexp'.  This
                    543: function reads the Lisp expression before point, evaluates it, and inserts
                    544: the value in printed representation before point.
                    545: 
                    546:   Thus, the way to use the `*scratch*' buffer is to insert Lisp expressions
                    547: at the end, ending each one with LFD so that it will be evaluated.
                    548: The result is a complete typescript of the expressions you have evaluated
                    549: and their values.
                    550: 
                    551:   The rationale for this feature is that Emacs must have a buffer when it
                    552: starts up, but that buffer is not useful for editing files since a new
                    553: buffer is made for every file that you visit.  The Lisp interpreter
                    554: typescript is the most useful thing I can think of for the initial buffer
                    555: to do.  `M-x lisp-interaction-mode' will put any buffer in Lisp
                    556: Interaction mode.
                    557: 
                    558: 
                    559: File: emacs  Node: External Lisp, Prev: Lisp Interaction, Up: Running
                    560: 
                    561: Running an External Lisp
                    562: ========================
                    563: 
                    564:   Emacs has facilities for running programs in other Lisp systems.  You can
                    565: run a Lisp process as an inferior of Emacs, and pass expressions to it to
                    566: be evaluated.  You can also pass changed function definitions directly from
                    567: the Emacs buffers in which you edit the Lisp programs to the inferior Lisp
                    568: process.
                    569: 
                    570:   To run an inferior Lisp process, type `M-x run-lisp'.  This runs the
                    571: program named `lisp', the same program you would run by typing
                    572: `lisp' as a shell command, with both input and output going through an
                    573: Emacs buffer named `*lisp*'.  That is to say, any "terminal output"
                    574: from Lisp will go into the buffer, advancing point, and any "terminal
                    575: input" for Lisp comes from text in the buffer.  To give input to Lisp, go
                    576: to the end of the buffer and type the input, terminated by RET.  The
                    577: `*lisp*' buffer is in Inferior Lisp mode, a mode which has all the
                    578: special characteristics of Lisp mode and Shell mode (*Note Shell Mode::).
                    579: 
                    580:   For the source files of programs to run in external Lisps, use Lisp mode.
                    581: This mode can be selected with `M-x lisp-mode', and is used automatically
                    582: for files whose names end in `.l' or `.lisp', as most Lisp
                    583: systems usually expect.
                    584: 
                    585:   When you edit a function in a Lisp program you are running, the easiest
                    586: way to send the changed definition to the inferior Lisp process is the key
                    587: `C-M-x'.  In Lisp mode, this runs the function `lisp-send-defun',
                    588: which finds the defun around or following point and sends it as input to
                    589: the Lisp process.  (Emacs can send input to any inferior process regardless
                    590: of what buffer is current.)
                    591: 
                    592:   Contrast the meanings of `C-M-x' in Lisp mode (for editing programs
                    593: to be run in another Lisp system) and Emacs-Lisp mode (for editing Lisp
                    594: programs to be run in Emacs): in both modes it has the effect of installing
                    595: the function definition that point is in, but the way of doing so is
                    596: different according to where the relevant Lisp environment is found.
                    597: *Note Lisp Modes::.
                    598: 
                    599: 
                    600: File: emacs  Node: Abbrevs, Prev: Running, Up: Top, Next: Picture
                    601: 
                    602: Abbrevs
                    603: *******
                    604: 
                    605:   An "abbrev" is a word which "expands", if you insert it, into some
                    606: different text.  Abbrevs are defined by the user to expand in specific
                    607: ways.  For example, you might define `foo' as an abbrev expanding to
                    608: `find outer otter'.  With this abbrev defined, you would be able to
                    609: get `find outer otter ' into the buffer by typing `f o o SPC'.
                    610: 
                    611:   Abbrevs expand only when Abbrev mode (a minor mode) is enabled.
                    612: Disabling Abbrev mode does not cause abbrev definitions to be forgotten,
                    613: but they do not expand until Abbrev mode is enabled again.  The command
                    614: `M-x abbrev-mode' toggles Abbrev mode; with a numeric argument, it
                    615: turns Abbrev mode on if the argument is positive, off otherwise.
                    616: *Note Minor Modes::.  `abbrev-mode' is also a variable; Abbrev mode is
                    617: on when the variable is non-`nil'.  The variable `abbrev-mode'
                    618: automatically becomes local to the current buffer when it is set.
                    619: 
                    620:   Abbrev definitions can be "mode-specific"---active only in one major
                    621: mode.  Abbrevs can also have "global" definitions that are active in
                    622: all major modes.  The same abbrev can have a global definition and various
                    623: mode-specific definitions for different major modes.  A mode specific
                    624: definition for the current major mode overrides a global definition.
                    625: 
                    626:   Abbrevs can be defined interactively during the editing session.  Lists
                    627: of abbrev definitions can also be saved in files and reloaded in later
                    628: sessions.  Some users keep extensive lists of abbrevs that they load in
                    629: every session.
                    630: 
                    631:   A second kind of abbreviation facility is called the "dynamic
                    632: expansion".  Dynamic abbrev expansion happens only when you give an
                    633: explicit command and the result of the expansion depends only on the
                    634: current contents of the buffer.  *Note Dynamic Abbrevs::.
                    635: 
                    636: * Menu:
                    637: 
                    638: * Defining Abbrevs::  Defining an abbrev, so it will expand when typed.
                    639: * Expanding Abbrevs:: Controlling expansion: prefixes, canceling expansion.
                    640: * Editing Abbrevs::   Viewing or editing the entire list of defined abbrevs.
                    641: * Saving Abbrevs::    Saving the entire list of abbrevs for another session.
                    642: * Dynamic Abbrevs::   Abbreviations for words already in the buffer.
                    643: 
                    644: 
                    645: File: emacs  Node: Defining Abbrevs, Prev: Abbrevs, Up: Abbrevs, Next: Expanding Abbrevs
                    646: 
                    647: Defining Abbrevs
                    648: ================
                    649: 
                    650: `C-x +'     
                    651:      Define an abbrev to expand into some text before point
                    652:      (`add-global-abbrev').
                    653: `C-x C-a'     
                    654:      Similar, but define an abbrev available only in the current major mode
                    655:      (`add-mode-abbrev').
                    656: `C-x -'     
                    657:      Define a word in the buffer as an abbrev (`inverse-add-global-abbrev').
                    658: `C-x C-h'     
                    659:      Define a word in the buffer as a mode-specific abbrev
                    660:      (`inverse-add-mode-abbrev').
                    661: `M-x kill-all-abbrevs'     
                    662:      After this command, there are no abbrev definitions in effect.
                    663: 
                    664:   The usual way to define an abbrev is to enter the text you want the
                    665: abbrev to expand to, position point after it, and type `C-x +'
                    666: (`add-global-abbrev').  This reads the abbrev itself using the
                    667: minibuffer, and then defines it as an abbrev for one or more words before
                    668: point.  Use a numeric argument to say how many words before point should be
                    669: taken as the expansion.  For example, to define the abbrev `foo' as
                    670: mentioned above, insert the text `find outer otter' and then type
                    671: `C-u 3 C-x + f o o RET'.
                    672: 
                    673:   An argument of zero to `C-x +' means to use the contents of the
                    674: region as the expansion of the abbrev being defined.
                    675: 
                    676:   The command `C-x C-a' (`add-mode-abbrev') is similar, but
                    677: defines a mode-specific abbrev.  Mode specific abbrevs are active only in a
                    678: particular major mode.  `C-x C-a' defines an abbrev for the major mode
                    679: in effect at the time `C-x C-a' is typed.  The arguments work the same
                    680: as for `C-x +'.
                    681: 
                    682:   If the text of the abbrev you want is already in the buffer instead of
                    683: the expansion, use command `C-x -' (`inverse-add-global-abbrev') instead of
                    684: `C-x +', or use `C-x C-h' (`inverse-add-mode-abbrev') instead of `C-x C-a'.
                    685: These commands are called "inverse" because they invert the meaning of the
                    686: argument found in the buffer and the argument read using the minibuffer.
                    687: 
                    688:   To change the definition of an abbrev, just add the new definition.  You
                    689: will be asked to confirm if the abbrev has a prior definition.  To remove
                    690: an abbrev definition, give a negative argument to `C-x +' or `C-x
                    691: C-a'.  You must choose the command to specify whether to kill a global
                    692: definition or a mode-specific definition for the current mode, since those
                    693: two definitions are independent for one abbrev.
                    694: 
                    695:   `M-x kill-all-abbrevs' removes all the abbrev definitions there are.
                    696: 
                    697: 
                    698: File: emacs  Node: Expanding Abbrevs, Prev: Defining Abbrevs, Up: Abbrevs, Next: Editing Abbrevs
                    699: 
                    700: Controlling Abbrev Expansion
                    701: ============================
                    702: 
                    703:   An abbrev expands whenever it is present in the buffer just before point
                    704: and a self-inserting punctuation character (SPC, comma, etc.) is
                    705: typed.  Most often the way an abbrev is used is to insert the abbrev
                    706: followed by punctuation.
                    707: 
                    708:   Abbrev expansion preserves case; thus, `foo' expands into `find outer
                    709: otter'; `Foo' into `Find outer otter', and `FOO' into `FIND OUTER OTTER' or
                    710: `Find Outer Otter' according to the variable `abbrev-all-caps' (a non-`nil'
                    711: value chooses the first of the two expansions).
                    712: 
                    713:   These two commands are used to control abbrev expansion:
                    714: 
                    715: `M-''     
                    716:      Separate a prefix from a following abbrev to be expanded
                    717:      (`abbrev-prefix-mark').
                    718: `C-x ''     
                    719:      Expand the abbrev before point (`expand-abbrev').
                    720:      This is effective even when Abbrev mode is not enabled.
                    721: `M-x unexpand-abbrev'     
                    722:      Undo last abbrev expansion.
                    723: `M-x expand-region-abbrevs'     
                    724:      Expand some or all abbrevs found in the region.
                    725: 
                    726:   You may wish to expand an abbrev with a prefix attached; for example, if
                    727: `cnst' expands into `construction', you might want to use it to enter
                    728: `reconstruction'.  It does not work to type `recnst', because that is not
                    729: necessarily a defined abbrev.  What does work is to use the command `M-''
                    730: (`abbrev-prefix-mark') in between the prefix `re' and the abbrev `cnst'.
                    731: First, insert `re'.  Then type `M-''; this inserts a minus sign in the
                    732: buffer to indicate that it has done its work.  Then insert the abbrev
                    733: `cnst'; the buffer now contains `re-cnst'.  Now insert a punctuation
                    734: character to expand the abbrev `cnst' into `construction'.  The minus sign
                    735: is deleted at this point, because `M-'' left word for this to be done.  The
                    736: resulting text is the desired `reconstruction'.
                    737: 
                    738:   If you actually want the text of the abbrev in the buffer, rather than
                    739: its expansion, you can accomplish this by inserting the following
                    740: punctuation with `C-q'.  Thus, `foo C-q -' leaves `foo-' in the
                    741: buffer.
                    742: 
                    743:   If you expand an abbrev by mistake, you can undo the expansion (replace
                    744: the expansion by the original abbrev text) with `M-x unexpand-abbrev'.
                    745: `C-_' (`undo') can also be used to undo the expansion; but first
                    746: it will undo the insertion of the following punctuation character!
                    747: 
                    748:   `M-x expand-region-abbrevs' searches through the region for defined
                    749: abbrevs, and for each one found offers to replace it with its expansion.
                    750: This command is useful if you have typed in text using abbrevs but forgot
                    751: to turn on Abbrev mode first.  It may also be useful together with a
                    752: special set of abbrev definitions for making several global replacements at
                    753: once.  This command is effective even if Abbrev mode is not enabled.
                    754:   
                    755: 
                    756: File: emacs  Node: Editing Abbrevs, Prev: Expanding Abbrevs, Up: Abbrevs, Next: Saving Abbrevs
                    757: 
                    758: Examining and Editing Abbrevs
                    759: =============================
                    760: 
                    761: `M-x list-abbrevs'     
                    762:      Print a list of all abbrev definitions.
                    763: `M-x edit-abbrevs'     
                    764:      Edit a list of abbrevs; you can add, alter or remove definitions.
                    765: 
                    766:   The output from `M-x list-abbrevs' looks like this:
                    767: 
                    768:      (lisp-mode-abbrev-table)
                    769:      "dk"             0    "define-key"
                    770:      (global-abbrev-table)
                    771:      "dfn"            0    "definition"
                    772: 
                    773: (Some blank lines of no semantic significance, and some other abbrev
                    774: tables, have been omitted.)
                    775: 
                    776:   A line containing a name in parentheses is the header for abbrevs in a
                    777: particular abbrev table; `global-abbrev-table' contains all the global
                    778: abbrevs, and the other abbrev tables that are named after major modes
                    779: contain the mode-specific abbrevs.
                    780: 
                    781:   Within each abbrev table, each nonblank line defines one abbrev.  The
                    782: word at the beginning is the abbrev.  The number that appears is the number
                    783: of times the abbrev has been expanded.  Emacs keeps track of this to help
                    784: you see which abbrevs you actually use, in case you decide to eliminate
                    785: those that you don't use often.  The string at the end of the line is the
                    786: expansion.
                    787: 
                    788:   `M-x edit-abbrevs' allows you to add, change or kill abbrev
                    789: definitions by editing a list of them in an Emacs buffer.  The list has the
                    790: same format described above.  The buffer of abbrevs is called `*Abbrevs*',
                    791: and is in Edit-Abbrevs mode.  This mode redefines the key `C-c C-c' to
                    792: install the abbrev definitions as specified in the buffer.  The command
                    793: that does this is `edit-abbrevs-redefine'.  Any abbrevs not described
                    794: in the buffer are eliminated when this is done.
                    795: 
                    796:   `edit-abbrevs' is actually the same as `list-abbrevs' except
                    797: that it selects the buffer `*Abbrevs*' whereas `list-abbrevs'
                    798: merely displays it in another window.
                    799: 
                    800: 
                    801: File: emacs  Node: Saving Abbrevs, Prev: Editing Abbrevs, Up: Abbrevs, Next: Dynamic Abbrevs
                    802: 
                    803: Saving Abbrevs
                    804: ==============
                    805: 
                    806:   These commands allow you to keep abbrev definitions between editing
                    807: sessions.
                    808: 
                    809: `M-x write-abbrev-file'     
                    810:      Write a file describing all defined abbrevs.
                    811: `M-x read-abbrev-file'     
                    812:      Read such a file and define abbrevs as specified there.
                    813: `M-x quietly-read-abbrev-file'     
                    814:      Similar but do not display a message about what is going on.
                    815: `M-x define-abbrevs'     
                    816:      Define abbrevs from buffer.
                    817: `M-x insert-abbrevs'     
                    818:      Insert all abbrevs and their expansions into the buffer.
                    819: 
                    820:   `M-x write-abbrev-file' reads a file name using the minibuffer and
                    821: writes a description of all current abbrev definitions into that file.  The
                    822: text stored in the file looks like the output of `M-x list-abbrevs'.
                    823: This is used to save abbrev definitions for use in a later session.
                    824: 
                    825:   `M-x read-abbrev-file' reads a file name using the minibuffer and
                    826: reads the file, defining abbrevs according to the contents of the file.
                    827: `M-x quietly-read-abbrev-file' is the same except that it does not
                    828: display a message in the echo area saying that it is doing its work; it
                    829: is actually useful primarily in the `.emacs' file.  If an empty
                    830: argument is given to either of these functions, the file name used is the
                    831: value of the variable `abbrev-file-name', which is by default
                    832: `"~/.abbrev_defs"'.
                    833: 
                    834:   Emacs will offer to save abbrevs automatically if you have changed any of
                    835: them, whenever it offers to save all files (for `C-x s' or `C-x
                    836: C-c').  This feature can be inhibited by setting the variable
                    837: `save-abbrevs' to `nil'.
                    838: 
                    839:   The commands `M-x insert-abbrevs' and `M-x define-abbrevs' are similar to
                    840: the previous commands but work on text in an Emacs buffer.  `M-x
                    841: insert-abbrevs' inserts text into the current buffer before point,
                    842: describing all current abbrev definitions; `M-x define-abbrevs' parses the
                    843: entire current buffer and defines abbrevs accordingly.
                    844: 
                    845: 
                    846: File: emacs  Node: Dynamic Abbrevs, Prev: Saving Abbrevs, Up: Abbrevs
                    847: 
                    848: Dynamic Abbrev Expansion
                    849: ========================
                    850: 
                    851:   The abbrev facility described above operates automatically as you insert
                    852: text, but all abbrevs must be defined explicitly.  By contrast,
                    853: "dynamic abbrevs" allow the meanings of abbrevs to be determined
                    854: automatically from the contents of the buffer, but dynamic abbrev expansion
                    855: happens only when you request it explicitly.
                    856: 
                    857: `M-/'     
                    858:      Expand the word in the buffer before point as a "dynamic abbrev",
                    859:      by searching in the buffer for words starting with that abbreviation
                    860:      (`dabbrev-expand').
                    861: 
                    862:   For example, if the buffer contains `does this follow ' and you type
                    863: `f o M-/', the effect is to insert `follow' because that is the
                    864: last word in the buffer that starts with `fo'.  A numeric argument to
                    865: `M-/' says to take the second, third, etc. distinct expansion found
                    866: looking backward from point.  Repeating `M-/' searches for an
                    867: alternative expansion by looking farther back.  After the entire buffer
                    868: before point has been considered, the buffer after point is searched.
                    869: 
                    870:   Dynamic abbrev expansion is completely independent of Abbrev mode; the
                    871: expansion of a word with `M-/' is completely independent of whether it
                    872: has a definition as an ordinary abbrev.
                    873: 
                    874: 
                    875: File: emacs  Node: Picture, Prev: Abbrevs, Up: Top, Next: Sending Mail
                    876: 
                    877: Editing Pictures
                    878: ****************
                    879: 
                    880:   If you want to create a picture made out of text characters (for example,
                    881: a picture of the division of a register into fields, as a comment in a
                    882: program), use the command `edit-picture' to enter Picture mode.
                    883: 
                    884:   In Picture mode, editing is based on the "quarter-plane" model of
                    885: text, according to which the text characters lie studded on an area that
                    886: stretches infinitely far to the right and downward.  The concept of the end
                    887: of a line does not exist in this model; the most you can say is where the
                    888: last nonblank character on the line is found.
                    889: 
                    890:   Of course, Emacs really always considers text as a sequence of
                    891: characters, and lines really do have ends.  But in Picture mode most
                    892: frequently-used keys are rebound to commands that simulate the
                    893: quarter-plane model of text.  They do this by inserting spaces or by
                    894: converting tabs to spaces.
                    895: 
                    896:   Most of the basic editing commands of Emacs are redefined by Picture mode
                    897: to do essentially the same thing but in a quarter-plane way.  In addition,
                    898: Picture mode defines various keys starting with the `C-c' prefix to
                    899: run special picture editing commands.
                    900: 
                    901:   One of these keys, `C-c C-c', is pretty important.  Often a picture
                    902: is part of a larger file that is usually edited in some other major mode.
                    903: `M-x edit-picture' records the name of the previous major mode, and
                    904: then you can use the `C-c C-c' command (`picture-mode-exit') to
                    905: restore that mode.  `C-c C-c' also deletes spaces from the ends of
                    906: lines, unless given a numeric argument.
                    907: 
                    908:   The commands used in Picture mode all work in other modes (provided the
                    909: `picture' library is loaded), but are not bound to keys except in
                    910: Picture mode.  Note that the descriptions below talk of moving "one
                    911: column" and so on, but all the picture mode commands handle numeric
                    912: arguments as their normal equivalents do.
                    913: 
                    914:   Turning on Picture mode calls the value of the variable `picture-mode-hook'
                    915: as a function, with no arguments, if that value exists and is non-`nil'.
                    916: 
                    917: * Menu:
                    918: 
                    919: * Basic Picture::         Basic concepts and simple commands of Picture Mode.
                    920: * Insert in Picture::     Controlling direction of cursor motion
                    921:                            after "self-inserting" characters.
                    922: * Tabs in Picture::       Various features for tab stops and indentation.
                    923: * Rectangles in Picture:: Clearing and superimposing rectangles.
                    924: 
                    925: 
                    926: File: emacs  Node: Basic Picture, Prev: Picture, Up: Picture, Next: Insert in Picture
                    927: 
                    928: Basic Editing in Picture Mode
                    929: =============================
                    930: 
                    931:   Most keys do the same thing in Picture mode that they usually do, but do
                    932: it in a quarter-plane style.  For example, `C-f' is rebound to run
                    933: `picture-forward-column', which is defined to move point one column to the
                    934: right, by inserting a space if necessary, so that the actual end of the
                    935: line makes no difference.  `C-b' is rebound to run
                    936: `picture-backward-column', which always moves point left one column,
                    937: converting a tab to multiple spaces if necessary.  `C-n' and `C-p' are
                    938: rebound to run `picture-move-down' and `picture-move-up', which can either
                    939: insert spaces or convert tabs as necessary to make sure that point stays in
                    940: exactly the same column.  `C-e' runs `picture-end-of-line', which moves to
                    941: after the last nonblank character on the line.  There is no need to change
                    942: `C-a', as the choice of screen model does not affect beginnings of lines.
                    943: 
                    944:   Insertion of text is adapted to the quarter-plane screen model through
                    945: the use of Overwrite mode (*Note Minor Modes::).  Self-inserting characters
                    946: replace existing text, column by column, rather than pushing existing text
                    947: to the right.  RET runs `picture-newline', which just moves to
                    948: the beginning of the following line so that new text will replace that
                    949: line.
                    950: 
                    951:   Deletion and killing of text are replaced with erasure.  DEL
                    952: (`picture-backward-clear-column') replaces the preceding character with a
                    953: space rather than removing it.  `C-d' (`picture-clear-column') does the
                    954: same thing in a forward direction.  `C-k' (`picture-clear-line') really
                    955: kills the contents of lines, but does not ever remove the newlines from the
                    956: buffer.
                    957: 
                    958:   To do actual insertion, you must use special commands.  `C-o'
                    959: (`picture-open-line') still creates a blank line, but does so after the
                    960: current line; it never splits a line.  `C-M-o', `split-line', makes sense
                    961: in Picture mode, so it is not changed.  LFD (`picture-duplicate-line')
                    962: inserts below the current line another line with the same contents.
                    963: 
                    964:   Real deletion can be done with `C-w', or with `C-c C-d' (which is
                    965: defined as `delete-char', as `C-d' is in other modes), or with one
                    966: of the picture rectangle commands (*Note Rectangles in Picture::).
                    967: 
                    968: 
                    969: File: emacs  Node: Insert in Picture, Prev: Basic Picture, Up: Picture, Next: Tabs in Picture
                    970: 
                    971: Controlling Motion after Insert
                    972: ===============================
                    973: 
                    974:   Since "self-inserting" characters in Picture mode just overwrite and
                    975: move point, there is no essential restriction on how point should be moved.
                    976: Normally point moves right, but you can specify any of the eight orthogonal
                    977: or diagonal directions for motion after a "self-inserting" character.
                    978: This is useful for drawing lines in the buffer.
                    979: 
                    980: `C-c <'     
                    981:      Move left after insertion (`picture-movement-left').
                    982: `C-c >'     
                    983:      Move right after insertion (`picture-movement-right').
                    984: `C-c ^'     
                    985:      Move up after insertion (`picture-movement-up').
                    986: `C-c .'     
                    987:      Move down after insertion (`picture-movement-down').
                    988: `C-c `'     
                    989:      Move up and left ("northwest") after insertion (`picture-movement-nw').
                    990: `C-c ''     
                    991:      Move up and right ("northeast") after insertion 
                    992:      (`picture-movement-ne').
                    993: `C-c /'     
                    994:      Move down and left ("southwest") after insertion
                    995:      (`picture-movement-sw').
                    996: `C-c \'     
                    997:      Move down and right ("southeast") after insertion
                    998:      (`picture-movement-se').
                    999: 
                   1000:   Two motion commands move based on the current Picture insertion
                   1001: direction.  The command `C-c C-f' (`picture-motion') moves in the
                   1002: same direction as motion after "insertion" currently does, while `C-c
                   1003: C-b' (`picture-motion-reverse') moves in the opposite direction.
                   1004: 
                   1005: 
                   1006: File: emacs  Node: Tabs in Picture, Prev: Insert in Picture, Up: Picture, Next: Rectangles in Picture
                   1007: 
                   1008: Picture Mode Tabs
                   1009: =================
                   1010: 
                   1011:   Two kinds of tab-like action are provided in Picture mode.  Context-based
                   1012: tabbing is done with `M-TAB' (`picture-tab-search').  With no argument, it
                   1013: moves to a point underneath the next "interesting" character that follows
                   1014: whitespace in the previous nonblank line.  "Next" here means "appearing at
                   1015: a horizontal position greater than the one point starts out at".  With an
                   1016: argument, as in `C-u M-TAB', this command moves to the next such
                   1017: interesting character in the current line.  `M-TAB' does not change the
                   1018: text; it only moves point.  "Interesting" characters are defined by the
                   1019: variable `picture-tab-chars', which contains a string whose characters are
                   1020: all considered interesting.  Its default value is `"!-~"'.
                   1021: 
                   1022:   TAB itself runs `picture-tab', which operates based on the
                   1023: current tab stop settings; it is the Picture mode equivalent of
                   1024: `tab-to-tab-stop'.  Normally it just moves point, but with a numeric
                   1025: argument it clears the text that it moves over.
                   1026: 
                   1027:   The context-based and tab-stop-based forms of tabbing are brought
                   1028: together by the command `C-c TAB', `picture-set-tab-stops'.
                   1029: This command sets the tab stops to the positions which `M-TAB'
                   1030: would consider significant in the current line.  The use of this command,
                   1031: together with TAB, can get the effect of context-based tabbing.  But
                   1032: `M-TAB' is more convenient in the cases where it is sufficient.
                   1033: 
                   1034: 
                   1035: File: emacs  Node: Rectangles in Picture, Prev: Tabs in Picture, Up: Picture
                   1036: 
                   1037: Picture Mode Rectangle Commands
                   1038: ===============================
                   1039: 
                   1040:   Picture mode defines commands for working on rectangular pieces of the
                   1041: text in ways that fit with the quarter-plane model.  The standard rectangle
                   1042: commands may also be useful (*Note Rectangles::).
                   1043: 
                   1044: `C-c C-k'     
                   1045:      Clear out the region-rectangle (`picture-clear-rectangle').  With
                   1046:      argument, kill it.
                   1047: `C-c C-w R'     
                   1048:      Similar but save rectangle contents in register R first
                   1049:      (`picture-clear-rectangle-to-register').
                   1050: `C-c C-y'     
                   1051:      Copy last killed rectangle into the buffer by overwriting, with upper
                   1052:      left corner at point (`picture-yank-rectangle').  With argument,
                   1053:      insert instead.
                   1054: `C-c C-x R'     
                   1055:      Similar, but use the rectangle in register R
                   1056:      (`picture-yank-rectangle-from-register').
                   1057: 
                   1058:   The picture rectangle commands `C-c C-k' (`picture-clear-rectangle') and
                   1059: `C-c C-w' (`picture-clear-rectangle-to-register') differ from the standard
                   1060: rectangle commands in that they normally clear the rectangle instead of
                   1061: deleting it; this is analogous with the way `C-d' is changed in Picture
                   1062: mode.
                   1063: 
                   1064:   However, deletion of rectangles can be useful in Picture mode, so these
                   1065: commands delete the rectangle if given a numeric argument.
                   1066: 
                   1067:   The Picture mode commands for yanking rectangles differ from the standard
                   1068: ones in overwriting instead of inserting.  This is the same way that
                   1069: Picture mode insertion of other text is different from other modes.
                   1070: `C-c C-y' (`picture-yank-rectangle') inserts (by overwriting) the
                   1071: rectangle that was most recently killed, while `C-c C-x'
                   1072: (`picture-yank-rectangle-from-register') does likewise for the
                   1073: rectangle found in a specified register.
                   1074: 
                   1075: 
                   1076: File: emacs  Node: Sending Mail, Prev: Picture, Up: Top, Next: Rmail
                   1077: 
                   1078: Sending Mail
                   1079: ************
                   1080: 
                   1081:   To send a message in Emacs, you start by typing a command (`C-x m')
                   1082: to select and initialize the `*mail*' buffer.  Then you edit the text
                   1083: and headers of the message in this buffer, and type another command
                   1084: (`C-c C-c') to send the message.
                   1085: 
                   1086: `C-x m'     
                   1087:      Begin composing a message to send (`mail').
                   1088: `C-x 4 m'     
                   1089:      Likewise, but display the message in another window
                   1090:      (`mail-other-window').
                   1091: `C-c C-c'     
                   1092:      In Mail mode, send the message and switch to another buffer
                   1093:      (`mail-send-and-exit').
                   1094: 
                   1095:   The command `C-x m' (`mail') selects a buffer named `*mail*' and
                   1096: initializes it with the skeleton of an outgoing message.  `C-x 4 m'
                   1097: (`mail-other-window') selects the `*mail*' buffer in a different window,
                   1098: leaving the previous current buffer visible.
                   1099: 
                   1100:   Because the mail composition buffer is an ordinary Emacs buffer, you can
                   1101: switch to other buffers while in the middle of composing mail, and switch
                   1102: back later (or never).  If you use the `C-x m' command again when you
                   1103: have been composing another message but have not sent it, you are asked to
                   1104: confirm before the old message is erased.  If you answer `n', the
                   1105: `*mail*' buffer is left selected with its old contents, so you can
                   1106: finish the old message and send it.  `C-u C-x m' is another way to do
                   1107: this.  Sending the message marks the `*mail*' buffer "unmodified",
                   1108: which avoids the need for confirmation when `C-x m' is next used.
                   1109: 
                   1110:   If you are composing a message in the `*mail*' buffer and want to
                   1111: send another message before finishing the first, rename the `*mail*'
                   1112: buffer using `M-x rename-buffer' (*Note Misc Buffer::).
                   1113: 
                   1114: * Menu:
                   1115: 
                   1116: * Format: Mail Format.    Format of the mail being composed.
                   1117: * Headers: Mail Headers.  Details of allowed mail header fields.
                   1118: * Mode: Mail Mode.        Special commands for editing mail being composed.
                   1119: 
                   1120: 

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