\input texinfo                  @c -*-texinfo-*-
@c %**start of header
@setfilename ../../info/octave-mode.info
@settitle Octave Mode
@include docstyle.texi
@c %**end of header

@copying
Copyright @copyright{} 1996--2021 Free Software Foundation, Inc.

@quotation
Permission is granted to copy, distribute and/or modify this document
under the terms of the GNU Free Documentation License, Version 1.3 or
any later version published by the Free Software Foundation; with no
Invariant Sections, with the Front-Cover Texts being ``A GNU Manual,''
and with the Back-Cover Texts as in (a) below.  A copy of the license
is included in the section entitled ``GNU Free Documentation License.''

(a) The FSF's Back-Cover Text is: ``You have the freedom to copy and
modify this GNU manual.''
@end quotation
@end copying

@dircategory Emacs editing modes
@direntry
* Octave mode: (octave-mode).   Emacs mode for editing GNU Octave files.
@end direntry

@finalout

@titlepage
@title Octave Mode
@subtitle An Emacs mode for programming in GNU Octave

@page
@vskip 0pt plus 1filll
@insertcopying
@end titlepage

@contents

@ifnottex
@node Top
@top Octave Mode

@insertcopying
@end ifnottex

@menu
* Overview::
* Using Octave Mode::
* Running Octave from Within Emacs::
* GNU Free Documentation License::
* Key Index::
* Variable Index::
* Lisp Function Index::
* Concept Index::
@end menu

@node Overview
@chapter Overview

The development of Octave code can greatly be facilitated using Emacs
with Octave mode, a major mode for editing Octave files which can
e.g.@: automatically indent the code, do some of the typing (with
Abbrev mode) and show keywords, comments, strings, etc.@: in different
faces (with Font-lock mode on devices that support it).

It is also possible to run Octave from within Emacs, either by
directly entering commands at the prompt in a buffer in Inferior
Octave mode, or by interacting with Octave from within a file with
Octave code.  This is useful in particular for debugging Octave code.

@node Using Octave Mode
@chapter Using Octave Mode
@cindex Using Octave Mode

In Octave mode, the following special Emacs commands can be used in
addition to the standard Emacs commands.

@table @kbd
@item C-M-j
@kindex C-M-j
@findex octave-indent-new-comment-line
@vindex octave-continuation-string
@vindex octave-string-continuation-marker
Break Octave line at point, continuing comment if within one.  Insert
@code{octave-continuation-string} before breaking the line unless
inside a list.  If within a double-quoted string, insert
@code{octave-string-continuation-marker} instead.  Signal an error if
within a single-quoted string.

@item C-c ;
@kindex C-c ;
@findex octave-update-function-file-comment
Query replace function names in function file comment.

@item C-c C-p
@kindex C-c C-p
@findex octave-previous-code-line
Move one line of Octave code backward, skipping empty and comment
lines (@code{octave-previous-code-line}).  With numeric prefix
argument @var{n}, move that many code lines backward (forward if
@var{n} is negative).

@item C-c C-n
@kindex C-c C-n
@findex octave-next-code-line
Move one line of Octave code forward, skipping empty and comment lines
(@code{octave-next-code-line}).  With numeric prefix argument @var{n},
move that many code lines forward (backward if @var{n} is negative).

@item C-c C-a
@kindex C-c C-a
@findex octave-beginning-of-line
Move to the beginning of the physical line
(@code{octave-beginning-of-line}).  If point is in an empty or comment
line, simply go to its beginning; otherwise, move backwards to the
beginning of the first code line which is not inside a continuation
statement, i.e., which does not follow a code line ending in
@samp{...}  or @samp{\}, or is inside an open parenthesis list.

@item C-c C-e
@kindex C-c C-e
@findex octave-end-of-line
Move to the end of the physical line (@code{octave-end-of-line}).  If
point is in a code line, move forward to the end of the first Octave
code line which does not end in @samp{...} or @samp{\} or is inside an
open parenthesis list.  Otherwise, simply go to the end of the current
line.

@item C-c M-C-h
@kindex C-c M-C-h
@findex octave-mark-block
Put point at the beginning of this block, mark at the end
(@code{octave-mark-block}).  The block marked is the one that contains
point or follows point.

@item C-c ]
@kindex C-c ]
Close the current block on a separate line (@code{smie-close-block}).
An error is signaled if no block to close is found.

@item C-c C-f
@kindex C-c C-f
@findex octave-insert-defun
Insert a function skeleton, prompting for the function's name, arguments
and return values which have to be entered without parentheses
(@code{octave-insert-defun}).
@noindent
in one of your Emacs startup files.
@end table

The following variables can be used to customize Octave mode.

@vtable @code
@item octave-blink-matching-block
Non-@code{nil} means show matching begin of block when inserting a space,
newline or @samp{;} after an else or end keyword.  Default is @code{t}.
This is an extremely useful feature for automatically verifying that the
keywords match---if they don't, an error message is displayed.

@item octave-block-offset
Extra indentation applied to statements in block structures.
Default is 2.

@item octave-continuation-offset
Extra indentation applied to Octave continuation lines.
Default is 4.

@item octave-font-lock-texinfo-comment
Highlight texinfo comment blocks.  The default value is @code{t}.
@end vtable

If Font Lock mode is enabled, Octave mode will display

@itemize @bullet
@item
strings in @code{font-lock-string-face}

@item
comments in @code{font-lock-comment-face}

@item
the Octave reserved words (such as all block keywords) and the text
functions (such as @samp{cd} or @samp{who}) which are also reserved
using @code{font-lock-keyword-face}

@item
the built-in operators (@samp{&&}, @samp{==}, @dots{}) using
@code{font-lock-reference-face}

@item
and the function names in function declarations in
@code{font-lock-function-name-face}.

@item
Function comments blocks in @code{octave-function-comment-block}
@end itemize

@cindex Imenu Support
There is also rudimentary support for Imenu (@pxref{Imenu,,, emacs,
The GNU Emacs Manual}).  Currently, function names can be indexed.

@cindex ElDoc Mode Support
@vindex octave-eldoc-message-style
ElDoc mode (@pxref{Lisp Doc,,, emacs, The GNU Emacs Manual}) is
supported.  By customizing @code{octave-eldoc-message-style} it can be
changed from displaying one or multi line hints.

@c @cindex TAGS
@c @cindex Emacs TAGS files
@c @cindex @file{octave-tags}
@c You can generate TAGS files for Emacs from Octave @file{.m} files using
@c the shell script @file{octave-tags} that is installed alongside your copy of
@c Octave.
@c
@vindex octave-mode-hook
Customization of Octave mode can be performed by modification of the
variable @code{octave-mode-hook}.

@node Running Octave from Within Emacs
@chapter Running Octave from Within Emacs
@cindex Inferior Octave Mode

Octave mode provides commands for running an inferior
Octave process in a special Emacs buffer.  Use
@lisp
M-x run-octave
@end lisp
@noindent
to directly start an inferior Octave process.

@vindex inferior-octave-buffer
This will start Octave in a special buffer the name of which is
specified by the variable @code{inferior-octave-buffer} and defaults
to @file{*Inferior Octave*}.  From within this buffer, you can
interact with the inferior Octave process ``as usual'', i.e., by
entering Octave commands at the prompt.  The buffer is in Inferior
Octave mode, which is derived from the standard Comint mode, a major
mode for interacting with an inferior interpreter.  See the
documentation for @code{comint-mode} for more details, and use
@kbd{C-h b} to find out about available special keybindings.

You can also communicate with an inferior Octave process from within
files with Octave code (i.e., buffers in Octave mode), using the
following commands.

@table @kbd
@item C-c C-i l
@kindex C-c C-i l
@findex octave-send-line
@vindex octave-send-line-auto-forward
Send the current line to the inferior Octave process
(@code{octave-send-line}).  With positive prefix argument @var{n},
send that many lines.  If @code{octave-send-line-auto-forward} is
non-@code{nil}, go to the next unsent code line.

@item C-c C-i b
@kindex C-c C-i b
@findex octave-send-block
Send the current block to the inferior Octave process
(@code{octave-send-block}).

@item C-c C-i f
@kindex C-c C-i f
@findex octave-send-defun
Send the current function to the inferior Octave process
(@code{octave-send-defun}).

@item C-c C-i r
@kindex C-c C-i r
@findex octave-send-region
Send the region to the inferior Octave process
(@code{octave-send-region}).

@item C-c C-i a
@kindex C-c C-i a
@findex octave-send-buffer
Send the entire buffer to the inferior Octave process
(@code{octave-send-buffer}).  If the buffer is associated with a file
then sourcing the buffer by using @kbd{C-c C-l}
(@code{octave-source-file}) should be preferred.

@item C-c C-i s
@kindex C-c C-i s
@findex octave-show-process-buffer
Make sure that @code{inferior-octave-buffer} is displayed
(@code{octave-show-process-buffer}).

@item C-c C-i q
@kindex C-c C-i q
@findex octave-hide-process-buffer
Delete all windows that display the inferior Octave buffer
(@code{octave-hide-process-buffer}).

@item C-c C-i k
@kindex C-c C-i k
@findex octave-kill-process
Kill the inferior Octave process and its buffer
(@code{octave-kill-process}).

@item C-c C-l
@kindex C-c C-l
@findex octave-source-file
Parse and execute the current file in the inferior Octave buffer
(@code{octave-source-file}).  This is done using Octave's
@code{source} function.

@item M-.
@kindex M-.
@findex octave-find-definition
@vindex octave-source-directories
Find the definition of a function or variable.  Functions implemented
in C++ can be found if variable @code{octave-source-directories} is
set correctly (@code{octave-find-definition}).

@item C-h d
@kindex C-h d
@findex octave-help
@vindex octave-help-buffer
Display the documentation for function (@code{octave-help}).  The
buffer name can be changed by customizing @code{octave-help-buffer}.

@item C-h a
@kindex C-h a
@findex octave-lookfor
Search for a given string in all the first sentence of function help
strings (@code{octave-lookfor}).  With a @code{universal-argument} the
entire help string is searched.

@end table

The effect of the commands which send code to the Octave process can be
customized by the following variables.

@vtable @code
@item octave-send-echo-input
Non-@code{nil} means echo input sent to the inferior Octave process.
Default is @code{t}.

@item octave-send-show-buffer
Non-@code{nil} means display the buffer running the Octave process after
sending a command (but without selecting it).
Default is @code{t}.
@end vtable

If you send code and there is no inferior Octave process yet, it will
be started automatically.

@vindex inferior-octave-startup-args
The startup of the inferior Octave process is highly customizable.
The variable @code{inferior-octave-startup-args} can be used for
specifying command lines arguments to be passed to Octave on startup
as a list of strings.  For example, to suppress the startup message
and use ``traditional'' mode, set this to @code{("-q" "--traditional")}.
You can also specify a startup file of Octave commands to be loaded on
startup; note that these commands will not produce any visible output
in the process buffer.  Which file to use is controlled by the
variable @code{inferior-octave-startup-file}.  The default is
@file{~/.emacs-octave} or if this file is not found
@file{~/.emacs.d/init_octave.m}.

@vindex inferior-octave-prompt-read-only
By customizing @code{inferior-octave-prompt-read-only} the prompt can
be changed to be read only.  The default value is the same as
@code{comint-prompt-read-only}.

@vindex inferior-octave-mode-hook
And finally, @code{inferior-octave-mode-hook} is run after starting
the process and putting its buffer into Inferior Octave mode.  Hence,
if you like the up and down arrow keys to behave in the interaction
buffer as in the shell, and you want this buffer to use nice colors,
add
@lisp
(add-hook 'inferior-octave-mode-hook
          (lambda ()
            (define-key inferior-octave-mode-map [up]
              'comint-previous-input)
            (define-key inferior-octave-mode-map [down]
              'comint-next-input)))
@end lisp
@noindent
to your @file{.emacs} or @file{init.el} file.  You could also swap the
roles of @kbd{C-a} (@code{beginning-of-line}) and @code{C-c C-a}
(@code{comint-bol}) using this hook.

@vindex inferior-octave-prompt
@quotation
@strong{Note} that if you set your Octave prompts to something different
from the defaults, make sure that @code{inferior-octave-prompt} matches
them.  Otherwise, @emph{nothing} will work, because Emacs will not know
when Octave is waiting for input, or done sending output.
@end quotation

@node GNU Free Documentation License
@chapter GNU Free Documentation License
@include doclicense.texi

@node Key Index
@unnumbered Key Index

@printindex ky

@node Variable Index
@unnumbered Variable Index

@printindex vr

@node Lisp Function Index
@unnumbered Function Index

@printindex fn

@node Concept Index
@unnumbered Concept Index

@printindex cp


@bye

@c TODO Update

@c @node Using the Emacs Info Reader for Octave
@c @chapter Using the Emacs Info Reader for Octave

@c You may also use the Emacs Info reader with Octave's @code{doc} function.

@c If @file{gnuserv} is installed, add the lines
@c @lisp
@c (autoload 'octave-help "octave-hlp" nil t)
@c (require 'gnuserv)
@c (gnuserv-start)
@c @end lisp
@c @noindent
@c to your @file{.emacs} file.

@c You can use either 'plain' Emacs Info or the function @code{octave-help}
@c as your Octave info reader (for @samp{help -i}).  In the former case,
@c use @code{info_program ("info-emacs-info")}.
@c The latter is perhaps more attractive because it allows you to look up keys
@c in the indices of @emph{several} info files related to Octave (provided
@c that the Emacs variable @code{octave-help-files} is set correctly).  In
@c this case, use @code{info_program ("info-emacs-octave-help")}.

@c If you use Octave from within Emacs, it is best to add these settings to
@c your @file{~/.emacs-octave} startup file (or the file pointed to by the
@c Emacs variable @code{inferior-octave-startup-file}).