;;; octave-mod.el --- editing Octave source files under Emacs

;; Copyright (C) 1997 Free Software Foundation, Inc.

;; Author: Kurt Hornik <Kurt.Hornik@ci.tuwien.ac.at>
;; Author: John Eaton <jwe@bevo.che.wisc.edu>
;; Maintainer: Kurt Hornik <Kurt.Hornik@ci.tuwien.ac.at>
;; Keywords: languages

;; This file is part of GNU Emacs.

;; GNU Emacs is free software; you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation; either version 2, or (at your option)
;; any later version.

;; GNU Emacs is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;; GNU General Public License for more details.

;; You should have received a copy of the GNU General Public License
;; along with GNU Emacs; see the file COPYING.  If not, write to the
;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
;; Boston, MA 02111-1307, USA.

;;; Commentary:

;; This package provides Emacs support for Octave.
;; It defines Octave mode, a major mode for editing
;; Octave code.

;; The file octave-hlp.el provides `octave-help', a facility for looking up
;; documentation on a symbol in the Octave info files.

;; The file octave-inf.el contains code for interacting with an inferior
;; Octave process using comint.

;; See the documentation of `octave-mode', `octave-help' and
;; `run-octave' for further information on usage and customization.

;;; Code:
(require 'custom)

(defgroup octave nil
  "Major mode for editing Octave source files."
  :group 'languages)

(defvar inferior-octave-output-list nil)
(defvar inferior-octave-output-string nil)
(defvar inferior-octave-receive-in-progress nil)

(defconst octave-maintainer-address
  "Kurt Hornik <Kurt.Hornik@ci.tuwien.ac.at>, bug-gnu-emacs@gnu.org"
  "Current maintainer of the Emacs Octave package.")

(defvar octave-abbrev-table nil
  "Abbrev table for Octave's reserved words.
Used in octave-mode and inferior-octave-mode buffers.
All Octave abbrevs start with a grave accent (`).")
(if octave-abbrev-table
    ()
  (let ((ac abbrevs-changed))
    (define-abbrev-table 'octave-abbrev-table ())
    (define-abbrev octave-abbrev-table "`a" "all_va_args" nil)
    (define-abbrev octave-abbrev-table "`b" "break" nil)
    (define-abbrev octave-abbrev-table "`cs" "case" nil)
    (define-abbrev octave-abbrev-table "`ca" "catch" nil)
    (define-abbrev octave-abbrev-table "`c" "continue" nil)
    (define-abbrev octave-abbrev-table "`el" "else" nil)
    (define-abbrev octave-abbrev-table "`eli" "elseif" nil)
    (define-abbrev octave-abbrev-table "`et" "end_try_catch" nil)
    (define-abbrev octave-abbrev-table "`eu" "end_unwind_protect" nil)
    (define-abbrev octave-abbrev-table "`ef" "endfor" nil)
    (define-abbrev octave-abbrev-table "`efu" "endfunction" nil)
    (define-abbrev octave-abbrev-table "`ei" "endif" nil)
    (define-abbrev octave-abbrev-table "`es" "endswitch" nil)
    (define-abbrev octave-abbrev-table "`ew" "endwhile" nil)
    (define-abbrev octave-abbrev-table "`f" "for" nil)
    (define-abbrev octave-abbrev-table "`fu" "function" nil)
    (define-abbrev octave-abbrev-table "`gl" "global" nil)
    (define-abbrev octave-abbrev-table "`gp" "gplot" nil)
    (define-abbrev octave-abbrev-table "`gs" "gsplot" nil)
    (define-abbrev octave-abbrev-table "`if" "if ()" nil)
    (define-abbrev octave-abbrev-table "`o" "otherwise" nil)
    (define-abbrev octave-abbrev-table "`rp" "replot" nil)
    (define-abbrev octave-abbrev-table "`r" "return" nil)
    (define-abbrev octave-abbrev-table "`s" "switch" nil)
    (define-abbrev octave-abbrev-table "`t" "try" nil)
    (define-abbrev octave-abbrev-table "`up" "unwind_protect" nil)
    (define-abbrev octave-abbrev-table "`upc" "unwind_protect_cleanup" nil)
    (define-abbrev octave-abbrev-table "`w" "while ()" nil)
    (setq abbrevs-changed ac)))

(defvar octave-comment-char ?#
  "Character to start an Octave comment.")
(defvar octave-comment-start
  (concat (make-string 1 octave-comment-char) " ")
  "String to insert to start a new Octave in-line comment.")
(defvar octave-comment-start-skip "\\s<+\\s-*"
  "Regexp to match the start of an Octave comment up to its body.")

(defvar octave-begin-keywords
  '("for" "function" "if" "switch" "try" "unwind_protect" "while"))
(defvar octave-else-keywords
  '("case" "catch" "else" "elseif" "otherwise" "unwind_protect_cleanup"))
(defvar octave-end-keywords
  '("end" "endfor" "endfunction" "endif" "endswitch" "end_try_catch"
    "end_unwind_protect" "endwhile"))

(defvar octave-reserved-words
  (append octave-begin-keywords
	  octave-else-keywords
	  octave-end-keywords
	  '("all_va_args" "break" "continue" "global" "gplot" "gsplot"
	    "replot" "return"))
  "Reserved words in Octave.")

(defvar octave-text-functions
  '("casesen" "cd" "chdir" "clear" "diary" "dir" "document" "echo"
    "edit_history" "format" "gset" "gshow" "help" "history" "hold"
    "load" "ls" "more" "run_history" "save" "set" "show" "type"
    "which" "who" "whos")
  "Text functions in Octave (these names are also reserved).")

(defvar octave-variables
  '("EDITOR" "EXEC_PATH" "F_DUPFD" "F_GETFD" "F_GETFL" "F_SETFD"
    "F_SETFL" "I" "IMAGEPATH" "INFO_FILE" "INFO_PROGRAM" "Inf" "J"
    "LOADPATH" "NaN" "OCTAVE_VERSION" "O_APPEND" "O_CREAT" "O_EXCL"
    "O_NONBLOCK" "O_RDONLY" "O_RDWR" "O_TRUNC" "O_WRONLY" "PAGER" "PS1"
    "PS2" "PS4" "PWD" "SEEK_CUR" "SEEK_END" "SEEK_SET" "__F_DUPFD__"
    "__F_GETFD__" "__F_GETFL__" "__F_SETFD__" "__F_SETFL__" "__I__"
    "__Inf__" "__J__" "__NaN__" "__OCTAVE_VERSION__" "__O_APPEND__"
    "__O_CREAT__" "__O_EXCL__" "__O_NONBLOCK__" "__O_RDONLY__"
    "__O_RDWR__" "__O_TRUNC__" "__O_WRONLY__" "__PWD__" "__SEEK_CUR__"
    "__SEEK_END__" "__SEEK_SET__" "__argv__" "__e__" "__eps__"
    "__error_text__" "__i__" "__inf__" "__j__" "__nan__" "__pi__"
    "__program_invocation_name__" "__program_name__" "__realmax__"
    "__realmin__" "__stderr__" "__stdin__" "__stdout__" "ans" "argv"
    "automatic_replot" "beep_on_error" "completion_append_char"
    "default_return_value" "default_save_format"
    "define_all_return_values" "do_fortran_indexing" "e"
    "echo_executing_commands" "empty_list_elements_ok" "eps"
    "error_text" "gnuplot_binary" "gnuplot_has_multiplot" "history_file"
    "history_size" "ignore_function_time_stamp" "implicit_str_to_num_ok"
    "inf" "nan" "nargin" "ok_to_lose_imaginary_part"
    "output_max_field_width" "output_precision"
    "page_output_immediately" "page_screen_output" "pi"
    "prefer_column_vectors" "prefer_zero_one_indexing"
    "print_answer_id_name" "print_empty_dimensions"
    "program_invocation_name" "program_name" "propagate_empty_matrices"
    "realmax" "realmin" "resize_on_range_error"
    "return_last_computed_value" "save_precision" "saving_history"
    "silent_functions" "split_long_rows" "stderr" "stdin" "stdout"
    "string_fill_char" "struct_levels_to_print"
    "suppress_verbose_help_message" "treat_neg_dim_as_zero"
    "warn_assign_as_truth_value" "warn_comma_in_global_decl"
    "warn_divide_by_zero" "warn_function_name_clash"
    "warn_missing_semicolon" "whitespace_in_literal_matrix")
  "Builtin variables in Octave.")

(defvar octave-function-header-regexp
  (concat "^\\s-*\\<\\(function\\)\\>"
	  "\\([^=;\n]*=[ \t]*\\|[ \t]*\\)\\(\\w+\\)\\>")
  "Regexp to match an Octave function header.
The string `function' and its name are given by the first and third
parenthetical grouping.")

(defvar octave-font-lock-keywords
  (list
   ;; Fontify all builtin keywords.
   (cons (concat "\\<\\("
		 (mapconcat 'identity octave-reserved-words "\\|")
		 (mapconcat 'identity octave-text-functions "\\|")
		 "\\)\\>")
	 'font-lock-keyword-face)
   ;; Fontify all builtin operators.
   (cons "\\(&\\||\\|<=\\|>=\\|==\\|<\\|>\\|!=\\|!\\)"
	 (if (boundp 'font-lock-builtin-face)
	     'font-lock-builtin-face
	   'font-lock-preprocessor-face))
   ;; Fontify all builtin variables.
   (cons (concat "\\<\\("
		 (mapconcat 'identity octave-variables "\\|")
		 "\\)\\>")
	 'font-lock-variable-name-face)
   ;; Fontify all function declarations.
   (list octave-function-header-regexp
	 '(1 font-lock-keyword-face)
	 '(3 font-lock-function-name-face nil t)))
  "Additional Octave expressions to highlight.")

(defcustom inferior-octave-buffer "*Inferior Octave*"
  "*Name of buffer for running an inferior Octave process."
  :type 'string
  :group 'octave-inferior)

(defvar inferior-octave-process nil)

(defvar octave-mode-map nil
  "Keymap used in Octave mode.")
(if octave-mode-map
    ()
  (let ((map (make-sparse-keymap)))
    (define-key map "`" 'octave-abbrev-start)
    (define-key map ";" 'octave-electric-semi)
    (define-key map " " 'octave-electric-space)
    (define-key map "\n" 'octave-reindent-then-newline-and-indent)
    (define-key map "\t" 'indent-according-to-mode)
    (define-key map "\e;" 'octave-indent-for-comment)
    (define-key map "\e\n" 'octave-indent-new-comment-line)
    (define-key map "\e\t" 'octave-complete-symbol)
    (define-key map "\M-\C-a" 'octave-beginning-of-defun)
    (define-key map "\M-\C-e" 'octave-end-of-defun)
    (define-key map "\M-\C-h" 'octave-mark-defun)
    (define-key map "\M-\C-q" 'octave-indent-defun)
    (define-key map "\C-c;" 'octave-comment-region)
    (define-key map "\C-c:" 'octave-uncomment-region)
    (define-key map "\C-c\C-b" 'octave-submit-bug-report)
    (define-key map "\C-c\C-p" 'octave-previous-code-line)
    (define-key map "\C-c\C-n" 'octave-next-code-line)
    (define-key map "\C-c\C-a" 'octave-beginning-of-line)
    (define-key map "\C-c\C-e" 'octave-end-of-line)
    (define-key map "\C-c\M-\C-n" 'octave-forward-block)
    (define-key map "\C-c\M-\C-p" 'octave-backward-block)
    (define-key map "\C-c\M-\C-u" 'octave-backward-up-block)
    (define-key map "\C-c\M-\C-d" 'octave-down-block)
    (define-key map "\C-c\M-\C-h" 'octave-mark-block)
    (define-key map "\C-c]" 'octave-close-block)
    (define-key map "\C-cf" 'octave-insert-defun)
    (define-key map "\C-c\C-h" 'octave-help)
    (define-key map "\C-cil" 'octave-send-line)
    (define-key map "\C-cib" 'octave-send-block)
    (define-key map "\C-cif" 'octave-send-defun)
    (define-key map "\C-cir" 'octave-send-region)
    (define-key map "\C-cis" 'octave-show-process-buffer)
    (define-key map "\C-cih" 'octave-hide-process-buffer)
    (define-key map "\C-cik" 'octave-kill-process)
    (setq octave-mode-map map)))

(defvar octave-mode-menu
  (list "Octave"
	(list "Lines"
	      ["Previous Code Line"	octave-previous-code-line t]
	      ["Next Code Line"		octave-next-code-line t]
	      ["Begin of Continuation"	octave-beginning-of-line t]
	      ["End of Continuation"	octave-end-of-line t]
	      ["Split Line at Point"	octave-indent-new-comment-line t])
	(list "Blocks"
	      ["Next Block"		octave-forward-block t]
	      ["Previous Block"		octave-backward-block t]
	      ["Down Block"		octave-down-block t]
	      ["Up Block"		octave-backward-up-block t]
	      ["Mark Block"		octave-mark-block t]
	      ["Close Block"		octave-close-block t])
	(list "Functions"
	      ["Begin of Function"	octave-beginning-of-defun t]
	      ["End of Function"	octave-end-of-defun t]
	      ["Mark Function"		octave-mark-defun t]
	      ["Indent Function"	octave-indent-defun t]
	      ["Insert Function"	octave-insert-defun t])
	"-"
	(list "Debug"
	      ["Send Current Line"	octave-send-line t]
	      ["Send Current Block"	octave-send-block t]
	      ["Send Current Function"	octave-send-defun t]
	      ["Send Region"		octave-send-region t]
	      ["Show Process Buffer"	octave-show-process-buffer t]
	      ["Hide Process Buffer"	octave-hide-process-buffer t]
	      ["Kill Process"		octave-kill-process t])
	"-"
	["Indent Line"			indent-according-to-mode t]
	["Complete Symbol"		octave-complete-symbol t]
	"-"
	["Toggle Abbrev Mode"		abbrev-mode t]
	["Toggle Auto-Fill Mode"	auto-fill-mode t]
	"-"
	["Submit Bug Report"		octave-submit-bug-report t]
	"-"
	["Describe Octave Mode"		octave-describe-major-mode t]
	["Lookup Octave Index"		octave-help t])
  "Menu for Octave mode.")

(defvar octave-mode-syntax-table nil
  "Syntax table in use in octave-mode buffers.")
(if octave-mode-syntax-table
    ()
  (let ((table (make-syntax-table)))
    (modify-syntax-entry ?\r " "  table)
    (modify-syntax-entry ?+ "."   table)
    (modify-syntax-entry ?- "."   table)
    (modify-syntax-entry ?= "."   table)
    (modify-syntax-entry ?* "."   table)
    (modify-syntax-entry ?/ "."   table)
    (modify-syntax-entry ?> "."   table)
    (modify-syntax-entry ?< "."   table)
    (modify-syntax-entry ?& "."   table)
    (modify-syntax-entry ?| "."   table)
    (modify-syntax-entry ?! "."   table)
    (modify-syntax-entry ?\\ "\\" table)
    (modify-syntax-entry ?\' "."  table)
    (modify-syntax-entry ?\` "w"  table)
    (modify-syntax-entry ?\" "\"" table)
    (modify-syntax-entry ?. "w"   table)
    (modify-syntax-entry ?_ "w"   table)
    (modify-syntax-entry ?\% "."  table)
    (modify-syntax-entry ?\# "<"  table)
    (modify-syntax-entry ?\n ">"  table)
    (setq octave-mode-syntax-table table)))

(defcustom octave-auto-indent nil
  "*Non-nil means indent line after a semicolon or space in Octave mode."
  :type 'boolean
  :group 'octave)

(defcustom octave-auto-newline nil
  "*Non-nil means automatically newline after a semicolon in Octave mode."
  :type 'boolean
  :group 'octave)

(defcustom octave-blink-matching-block t
  "*Control the blinking of matching Octave block keywords.
Non-nil means show matching begin of block when inserting a space,
newline or semicolon after an else or end keyword."
  :type 'boolean
  :group 'octave)
(defcustom octave-block-offset 2
  "*Extra indentation applied to statements in Octave block structures."
  :type 'integer
  :group 'octave)

(defvar octave-block-begin-regexp
  (concat "\\<\\("
	  (mapconcat 'identity octave-begin-keywords "\\|")
	  "\\)\\>"))
(defvar octave-block-else-regexp
  (concat "\\<\\("
	  (mapconcat 'identity octave-else-keywords "\\|")
	  "\\)\\>"))
(defvar octave-block-end-regexp
  (concat "\\<\\("
	  (mapconcat 'identity octave-end-keywords "\\|")
	  "\\)\\>"))
(defvar octave-block-begin-or-end-regexp
  (concat octave-block-begin-regexp "\\|" octave-block-end-regexp))
(defvar octave-block-else-or-end-regexp
  (concat octave-block-else-regexp "\\|" octave-block-end-regexp))
(defvar octave-block-match-alist
  '(("for" . ("end" "endfor"))
    ("function" . ("end" "endfunction"))
    ("if" . ("else" "elseif" "end" "endif"))
    ("switch" . ("case" "otherwise" "end" "endswitch"))
    ("try" . ("catch" "end" "end_try_catch"))
    ("unwind_protect" . ("unwind_protect_cleanup" "end"
			 "end_unwind_protect"))
    ("while" . ("end" "endwhile")))
  "Alist with Octave's matching block keywords.
Has Octave's begin keywords as keys and a list of the matching else or
end keywords as associated values.")

(defvar octave-block-comment-start
  (concat (make-string 2 octave-comment-char) " ")
  "String to insert to start a new Octave comment on an empty line.")

(defcustom octave-continuation-offset 4
  "*Extra indentation applied to Octave continuation lines."
  :type 'integer
  :group 'octave)
(defvar octave-continuation-regexp
  "[^#%\n]*\\(\\\\\\|\\.\\.\\.\\)\\s-*\\(\\s<.*\\)?$")
(defcustom octave-continuation-string "\\"
  "*Character string used for Octave continuation lines.  Normally \\."
  :type 'string
  :group 'octave)

(defvar octave-completion-alist nil
  "Alist of Octave symbols for completion in Octave mode.
Each element looks like (VAR . VAR), where the car and cdr are the same
symbol (an Octave command or variable name).
Currently, only builtin variables can be completed.")

(defvar octave-mode-imenu-generic-expression
  (list
   ;; Functions
   (list nil octave-function-header-regexp 3))
  "Imenu expression for Octave mode.  See `imenu-generic-expression'.")

(defcustom octave-mode-startup-message t
  "*Nil means do not display the Octave mode startup message."
  :type 'boolean
  :group 'octave)

(defcustom octave-mode-hook nil
  "*Hook to be run when Octave mode is started."
  :type 'hook
  :group 'octave)

(defcustom octave-send-show-buffer t
  "*Non-nil means display `inferior-octave-buffer' after sending to it."
  :type 'boolean
  :group 'octave)
(defcustom octave-send-line-auto-forward t
  "*Control auto-forward after sending to the inferior Octave process.
Non-nil means always go to the next Octave code line after sending."
  :type 'boolean
  :group 'octave)
(defcustom octave-send-echo-input t
  "*Non-nil means echo input sent to the inferior Octave process."
  :type 'boolean
  :group 'octave)


;;;###autoload
(defun octave-mode ()
  "Major mode for editing Octave code.

This mode makes it easier to write Octave code by helping with
indentation, doing some of the typing for you (with Abbrev mode) and by
showing keywords, comments, strings, etc. in different faces (with
Font Lock mode on terminals that support it).

Octave itself is a high-level language, primarily intended for numerical
computations.  It provides a convenient command line interface for
solving linear and nonlinear problems numerically.  Function definitions
can also be stored in files, and it can be used in a batch mode (which
is why you need this mode!).

The latest released version of Octave is always available via anonymous
ftp from bevo.che.wisc.edu in the directory `/pub/octave'.  Complete
source and binaries for several popular systems are available.

Type \\[list-abbrevs] to display the built-in abbrevs for Octave keywords.

Keybindings
===========

\\{octave-mode-map}

Variables you can use to customize Octave mode
==============================================

octave-auto-indent
  Non-nil means indent current line after a semicolon or space.
  Default is nil.

octave-auto-newline
  Non-nil means auto-insert a newline and indent after a semicolon.
  Default is nil.

octave-blink-matching-block
  Non-nil means show matching begin of block when inserting a space,
  newline or semicolon after an else or end keyword.  Default is t.

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

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

octave-continuation-string
  String used for Octave continuation lines.
  Default is a backslash.

octave-mode-startup-message
  Nil means do not display the Octave mode startup message.
  Default is t.

octave-send-echo-input
  Non-nil means always display `inferior-octave-buffer' after sending a
  command to the inferior Octave process.

octave-send-line-auto-forward
  Non-nil means always go to the next unsent line of Octave code after
  sending a line to the inferior Octave process.

octave-send-echo-input
  Non-nil means echo input sent to the inferior Octave process.

Turning on Octave mode runs the hook `octave-mode-hook'.

To begin using this mode for all `.m' files that you edit, add the
following lines to your `.emacs' file:

  (autoload 'octave-mode \"octave-mod\" nil t)
  (setq auto-mode-alist
        (cons '(\"\\\\.m$\" . octave-mode) auto-mode-alist))

To automatically turn on the abbrev, auto-fill and font-lock features,
add the following lines to your `.emacs' file as well:

  (add-hook 'octave-mode-hook
	    (lambda ()
	      (abbrev-mode 1)
	      (auto-fill-mode 1)
	      (if (eq window-system 'x)
		  (font-lock-mode 1))))

To submit a problem report, enter \\[octave-submit-bug-report] from \
an Octave mode buffer.
This automatically sets up a mail buffer with version information
already added.  You just need to add a description of the problem,
including a reproducible test case and send the message."
  (interactive)
  (kill-all-local-variables)

  (use-local-map octave-mode-map)
  (setq major-mode 'octave-mode)
  (setq mode-name "Octave")
  (setq local-abbrev-table octave-abbrev-table)
  (set-syntax-table octave-mode-syntax-table)

  (make-local-variable 'indent-line-function)
  (setq indent-line-function 'octave-indent-line)

  (make-local-variable 'comment-start)
  (setq comment-start octave-comment-start)
  (make-local-variable 'comment-end)
  (setq comment-end "")
  (make-local-variable 'comment-column)
  (setq comment-column 32)
  (make-local-variable 'comment-start-skip)
  (setq comment-start-skip "\\s<+\\s-*")
  (make-local-variable 'comment-indent-function)
  (setq comment-indent-function 'octave-comment-indent)

  (make-local-variable 'parse-sexp-ignore-comments)
  (setq parse-sexp-ignore-comments t)
  (make-local-variable 'paragraph-start)
  (setq paragraph-start (concat "\\s-*$\\|" page-delimiter))
  (make-local-variable 'paragraph-separate)
  (setq paragraph-separate paragraph-start)
  (make-local-variable 'paragraph-ignore-fill-prefix)
  (setq paragraph-ignore-fill-prefix t)
  (make-local-variable 'fill-paragraph-function)
  (setq fill-paragraph-function 'octave-fill-paragraph)
  (make-local-variable 'adaptive-fill-regexp)
  (setq adaptive-fill-regexp nil)
  (make-local-variable 'fill-column)
  (setq fill-column 72)
  (make-local-variable 'normal-auto-fill-function)
  (setq normal-auto-fill-function 'octave-auto-fill)

  (make-local-variable 'font-lock-defaults)
  (setq font-lock-defaults '(octave-font-lock-keywords nil nil))

  (make-local-variable 'imenu-generic-expression)
  (setq imenu-generic-expression octave-mode-imenu-generic-expression
        imenu-case-fold-search nil)

  (octave-add-octave-menu)
  (octave-initialize-completions)
  (run-hooks 'octave-mode-hook))

;;; Miscellaneous useful functions
(defun octave-describe-major-mode ()
  "Describe the current major mode."
  (interactive)
  (describe-function major-mode))

(defun octave-point (position)
  "Returns the value of point at certain positions."
  (save-excursion
    (cond
     ((eq position 'bol)  (beginning-of-line))
     ((eq position 'eol)  (end-of-line))
     ((eq position 'boi)  (back-to-indentation))
     ((eq position 'bonl) (forward-line 1))
     ((eq position 'bopl) (forward-line -1))
     (t (error "unknown buffer position requested: %s" position)))
    (point)))

(defsubst octave-in-comment-p ()
  "Returns t if point is inside an Octave comment, nil otherwise."
  (interactive)
  (save-excursion
    (nth 4 (parse-partial-sexp (octave-point 'bol) (point)))))

(defsubst octave-in-string-p ()
  "Returns t if point is inside an Octave string, nil otherwise."
  (interactive)
  (save-excursion
    (nth 3 (parse-partial-sexp (octave-point 'bol) (point)))))

(defsubst octave-not-in-string-or-comment-p ()
  "Returns t iff point is not inside an Octave string or comment."
  (let ((pps (parse-partial-sexp (octave-point 'bol) (point))))
    (not (or (nth 3 pps) (nth 4 pps)))))

(defun octave-in-block-p ()
  "Returns t if point is inside an Octave block, nil otherwise.
The block is taken to start at the first letter of the begin keyword and
to end after the end keyword."
  (let ((pos (point)))
    (save-excursion
      (condition-case nil
	  (progn
	    (skip-syntax-forward "w")
	    (octave-up-block -1)
	    (octave-forward-block)
	    t)
	(error nil))
      (< pos (point)))))

(defun octave-in-defun-p ()
  "Returns t iff point is inside an Octave function declaration.
The function is taken to start at the `f' of `function' and to end after
the end keyword."
  (let ((pos (point)))
    (save-excursion
      (or (and (looking-at "\\<function\\>")
	       (octave-not-in-string-or-comment-p))
	  (and (octave-beginning-of-defun)
	       (condition-case nil
		   (progn
		     (octave-forward-block)
		     t)
		 (error nil))
	       (< pos (point)))))))

(defun octave-maybe-insert-continuation-string ()
  (if (or (octave-in-comment-p)
	  (save-excursion
	    (beginning-of-line)
	    (looking-at octave-continuation-regexp)))
      nil
    (delete-horizontal-space)
    (insert (concat " " octave-continuation-string))))

(defvar octave-xemacs-p
  (string-match "XEmacs\\|Lucid" emacs-version))

;;; Comments
(defun octave-comment-region (beg end &optional arg)
  "Comment or uncomment each line in the region as Octave code.
See `comment-region'."
  (interactive "r\nP")
  (let ((comment-start (char-to-string octave-comment-char)))
    (comment-region beg end arg)))

(defun octave-uncomment-region (beg end &optional arg)
  "Uncomment each line in the region as Octave code."
  (interactive "r\nP")
  (or arg (setq arg 1))
  (octave-comment-region beg end (- arg)))


;;; Indentation
(defun calculate-octave-indent ()
  "Return appropriate indentation for current line as Octave code.
Returns an integer (the column to indent to) unless the line is a
comment line with fixed goal golumn.  In that case, returns a list whose
car is the column to indent to, and whose cdr is the current indentation
level."
  (let ((is-continuation-line
	 (save-excursion
	   (if (zerop (octave-previous-code-line))
	       (looking-at octave-continuation-regexp))))
	(icol 0))
    (save-excursion
      (beginning-of-line)
      ;; If we can move backward out one level of parentheses, take 1
      ;; plus the indentation of that parenthesis.  Otherwise, go back
      ;; to the beginning of the previous code line, and compute the
      ;; offset this line gives.
      (if (condition-case nil
	      (progn
		(up-list -1)
		t)
	    (error nil))
	  (setq icol (+ 1 (current-column)))
	(if (zerop (octave-previous-code-line))
	    (progn
	      (octave-beginning-of-line)
	      (back-to-indentation)
	      (setq icol (current-column))
	      (let ((bot (point))
		    (eol (octave-point 'eol)))
		(while (< (point) eol)
		  (if (octave-not-in-string-or-comment-p)
		      (cond
		       ((looking-at "\\<switch\\>")
			(setq icol (+ icol (* 2 octave-block-offset))))
		       ((looking-at octave-block-begin-regexp)
			(setq icol (+ icol octave-block-offset)))
		       ((looking-at octave-block-else-regexp)
			(if (= bot (point))
			    (setq icol (+ icol octave-block-offset))))
		       ((looking-at octave-block-end-regexp)
			(if (not (= bot (point)))
			    (setq icol (- icol
					  (octave-block-end-offset)))))))
		  (forward-char)))
	      (if is-continuation-line
		  (setq icol (+ icol octave-continuation-offset)))))))
    (save-excursion
      (back-to-indentation)
      (cond
       ((and (looking-at octave-block-else-regexp)
	     (octave-not-in-string-or-comment-p))
	(setq icol (- icol octave-block-offset)))
       ((and (looking-at octave-block-end-regexp)
	     (octave-not-in-string-or-comment-p))
	(setq icol (- icol (octave-block-end-offset))))
       ((or (looking-at "\\s<\\s<\\s<\\S<")
	    (octave-before-magic-comment-p))
	(setq icol (list 0 icol)))
       ((looking-at "\\s<\\S<")
	(setq icol (list comment-column icol)))))
    icol))

(defun octave-block-end-offset ()
  (save-excursion
    (octave-backward-up-block 1)
    (* octave-block-offset
       (if (string-match (match-string 0) "switch") 2 1))))

(defun octave-before-magic-comment-p ()
  (save-excursion
    (beginning-of-line)
    (and (bobp) (looking-at "\\s-*#!"))))

(defun octave-comment-indent ()
  (if (or (looking-at "\\s<\\s<\\s<")
	  (octave-before-magic-comment-p))
      0
    (if (looking-at "\\s<\\s<")
	(calculate-octave-indent)
      (skip-syntax-backward " ")
      (max (if (bolp) 0 (+ 1 (current-column)))
	   comment-column))))

(defun octave-indent-for-comment ()
  "Maybe insert and indent an Octave comment.
If there is no comment already on this line, create a code-level comment
(started by two comment characters) if the line is empty, or an in-line
comment (started by one comment character) otherwise.
Point is left after the start of the comment which is properly aligned."
  (interactive)
  (indent-for-comment)
  (indent-according-to-mode))

(defun octave-indent-line (&optional arg)
  "Indent current line as Octave code.
With optional ARG, use this as offset unless this line is a comment with
fixed goal column."
  (interactive)
  (or arg (setq arg 0))
  (let ((icol (calculate-octave-indent))
	(relpos (- (current-column) (current-indentation))))
    (if (listp icol)
	(setq icol (car icol))
      (setq icol (+ icol arg)))
    (if (< icol 0)
	(error "Unmatched end keyword")
      (indent-line-to icol)
      (if (> relpos 0)
	  (move-to-column (+ icol relpos))))))

(defun octave-indent-new-comment-line ()
  "Break Octave line at point, continuing comment if within one.
If within code, insert `octave-continuation-string' before breaking the
line.  If within a string, signal an error.
The new line is properly indented."
  (interactive)
  (delete-horizontal-space)
  (cond
   ((octave-in-comment-p)
    (indent-new-comment-line))
   ((octave-in-string-p)
    (error "Cannot split a code line inside a string"))
   (t
    (insert (concat " " octave-continuation-string))
    (octave-reindent-then-newline-and-indent))))

(defun octave-indent-defun ()
  "Properly indents the Octave function which contains point."
  (interactive)
  (save-excursion
    (octave-mark-defun)
    (message "Indenting function...")
    (indent-region (point) (mark) nil))
  (message "Indenting function...done."))


;;; Motion
(defun octave-next-code-line (&optional arg)
  "Move ARG lines of Octave code forward (backward if ARG is negative).
Skips past all empty and comment lines.  Default for ARG is 1.

On success, return 0.  Otherwise, go as far as possible and return -1."
  (interactive "p")
  (or arg (setq arg 1))
  (beginning-of-line)
  (let ((n 0)
	(inc (if (> arg 0) 1 -1)))
    (while (and (/= arg 0) (= n 0))
      (setq n (forward-line inc))
      (while (and (= n 0)
		  (looking-at "\\s-*\\($\\|\\s<\\)"))
	(setq n (forward-line inc)))
      (setq arg (- arg inc)))
    n))

(defun octave-previous-code-line (&optional arg)
  "Move ARG lines of Octave code backward (forward if ARG is negative).
Skips past all empty and comment lines.  Default for ARG is 1.

On success, return 0.  Otherwise, go as far as possible and return -1."
  (interactive "p")
  (or arg (setq arg 1))
  (octave-next-code-line (- arg)))

(defun octave-beginning-of-line ()
  "Move point to beginning of current Octave line.
If on an empty or comment line, go to the beginning of that line.
Otherwise, move backward to the beginning of the first Octave code line
which is not inside a continuation statement, i.e., which does not
follow a code line ending in `...' or `\\', or is inside an open
parenthesis list."
  (interactive)
  (beginning-of-line)
  (if (not (looking-at "\\s-*\\($\\|\\s<\\)"))
      (while (or (condition-case nil
		     (progn
		       (up-list -1)
		       (beginning-of-line)
		       t)
		   (error nil))
		 (and (or (looking-at "\\s-*\\($\\|\\s<\\)")
			  (save-excursion
			    (if (zerop (octave-previous-code-line))
				(looking-at octave-continuation-regexp))))
		      (zerop (forward-line -1)))))))

(defun octave-end-of-line ()
  "Move point to end of current Octave line.
If on an empty or comment line, go to the end of that line.
Otherwise, move forward to the end of the first Octave code line which
does not end in `...' or `\\' or is inside an open parenthesis list."
  (interactive)
  (end-of-line)
  (if (save-excursion
	(beginning-of-line)
	(looking-at "\\s-*\\($\\|\\s<\\)"))
      ()
    (while (or (condition-case nil
		   (progn
		     (up-list 1)
		     (end-of-line)
		     t)
		 (error nil))
	       (and (save-excursion
		      (beginning-of-line)
		      (or (looking-at "\\s-*\\($\\|\\s<\\)")
			  (looking-at octave-continuation-regexp)))
		    (zerop (forward-line 1)))))
    (end-of-line)))

(defun octave-scan-blocks (from count depth)
  "Scan from character number FROM by COUNT Octave begin-end blocks.
Returns the character number of the position thus found.

If DEPTH is nonzero, block depth begins counting from that value.
Only places where the depth in blocks becomes zero are candidates for
stopping; COUNT such places are counted.

If the beginning or end of the buffer is reached and the depth is wrong,
an error is signaled."
  (let ((min-depth (if (> depth 0) 0 depth))
	(inc (if (> count 0) 1 -1)))
    (save-excursion
      (while (/= count 0)
	(catch 'foo
	  (while (or (re-search-forward
		      octave-block-begin-or-end-regexp nil 'move inc)
		     (if (/= depth 0)
			 (error "Unbalanced block")))
	    (if (octave-not-in-string-or-comment-p)
		(progn
		  (cond
		   ((match-end 1)
		    (setq depth (+ depth inc)))
		   ((match-end 2)
		    (setq depth (- depth inc))))
		  (if (< depth min-depth)
		      (error "Containing expression ends prematurely"))
		  (if (= depth 0)
		      (throw 'foo nil))))))
	(setq count (- count inc)))
      (point))))

(defun octave-forward-block (&optional arg)
  "Move forward across one balanced Octave begin-end block.
With argument, do it that many times.
Negative arg -N means move backward across N blocks."
  (interactive "p")
  (or arg (setq arg 1))
  (goto-char (or (octave-scan-blocks (point) arg 0) (buffer-end arg))))

(defun octave-backward-block (&optional arg)
  "Move backward across one balanced Octave begin-end block.
With argument, do it that many times.
Negative arg -N means move forward across N blocks."
  (interactive "p")
  (or arg (setq arg 1))
  (octave-forward-block (- arg)))

(defun octave-down-block (arg)
  "Move forward down one begin-end block level of Octave code.
With argument, do this that many times.
A negative argument means move backward but still go down a level.
In Lisp programs, an argument is required."
  (interactive "p")
  (let ((inc (if (> arg 0) 1 -1)))
    (while (/= arg 0)
      (goto-char (or (octave-scan-blocks (point) inc -1)
		     (buffer-end arg)))
      (setq arg (- arg inc)))))

(defun octave-backward-up-block (arg)
  "Move backward out of one begin-end block level of Octave code.
With argument, do this that many times.
A negative argument means move forward but still to a less deep spot.
In Lisp programs, an argument is required."
  (interactive "p")
  (octave-up-block (- arg)))

(defun octave-up-block (arg)
  "Move forward out of one begin-end block level of Octave code.
With argument, do this that many times.
A negative argument means move backward but still to a less deep spot.
In Lisp programs, an argument is required."
  (interactive "p")
  (let ((inc (if (> arg 0) 1 -1)))
    (while (/= arg 0)
      (goto-char (or (octave-scan-blocks (point) inc 1)
		     (buffer-end arg)))
      (setq arg (- arg inc)))))

(defun octave-mark-block ()
  "Put point at the beginning of this Octave block, mark at the end.
The block marked is the one that contains point or follows point."
  (interactive)
  (let ((pos (point)))
    (if (or (and (octave-in-block-p)
		 (skip-syntax-forward "w"))
	    (condition-case nil
		(progn
		  (octave-down-block 1)
		  (octave-in-block-p))
	      (error nil)))
	(progn
	  (octave-up-block -1)
	  (push-mark (point))
	  (octave-forward-block)
	  (exchange-point-and-mark))
      (goto-char pos)
      (message "No block to mark found"))))

(defun octave-close-block ()
  "Close the current Octave block on a separate line.
An error is signaled if no block to close is found."
  (interactive)
  (let (bb-keyword)
    (condition-case nil
	(progn
	  (save-excursion
	    (octave-backward-up-block 1)
	    (setq bb-keyword (buffer-substring-no-properties
			      (match-beginning 1) (match-end 1))))
	  (if (save-excursion
		(beginning-of-line)
		(looking-at "^\\s-*$"))
	      (indent-according-to-mode)
	    (octave-reindent-then-newline-and-indent))
	  (insert (car (reverse
			(assoc bb-keyword
			       octave-block-match-alist))))
	  (octave-reindent-then-newline-and-indent)
	  t)
      (error (message "No block to close found")))))

(defun octave-blink-matching-block-open ()
  "Blink the matching Octave begin block keyword.
If point is right after an Octave else or end type block keyword, move
cursor momentarily to the corresponding begin keyword.
Signal an error if the keywords are incompatible."
  (interactive)
  (let (bb-keyword bb-arg eb-keyword pos eol)
    (if (and (octave-not-in-string-or-comment-p)
	     (looking-at "\\>")
	     (save-excursion
	       (skip-syntax-backward "w")
	       (looking-at octave-block-else-or-end-regexp)))
	(save-excursion
	  (cond
	   ((match-end 1)
	    (setq eb-keyword
		  (buffer-substring-no-properties
		   (match-beginning 1) (match-end 1)))
	    (octave-backward-up-block 1))
	   ((match-end 2)
	    (setq eb-keyword
		  (buffer-substring-no-properties
		   (match-beginning 2) (match-end 2)))
	    (octave-backward-block)))
	  (setq pos (match-end 0)
		bb-keyword
		(buffer-substring-no-properties
		 (match-beginning 0) pos)
		pos (+ pos 1)
		eol (octave-point 'eol)
		bb-arg
		(save-excursion
		  (save-restriction
		    (goto-char pos)
		    (while (and (skip-syntax-forward "^<" eol)
				(octave-in-string-p)
				(not (forward-char 1))))
		    (skip-syntax-backward " ")
		    (buffer-substring-no-properties pos (point)))))
	  (if (member eb-keyword
		      (cdr (assoc bb-keyword octave-block-match-alist)))
	      (progn
		(message "Matches `%s %s'" bb-keyword bb-arg)
		(if (pos-visible-in-window-p)
		    (sit-for blink-matching-delay)))
	    (error "Block keywords `%s' and `%s' do not match"
		   bb-keyword eb-keyword))))))

(defun octave-beginning-of-defun (&optional arg)
  "Move backward to the beginning of an Octave function.
With positive ARG, do it that many times.  Negative argument -N means
move forward to Nth following beginning of a function.
Returns t unless search stops at the beginning or end of the buffer."
  (interactive "p")
  (let* ((arg (or arg 1))
	 (inc (if (> arg 0) 1 -1))
	 (found))
    (and (not (eobp))
	 (not (and (> arg 0) (looking-at "\\<function\\>")))
	 (skip-syntax-forward "w"))
    (while (and (/= arg 0)
		(setq found
		      (re-search-backward "\\<function\\>" nil 'move inc)))
      (if (octave-not-in-string-or-comment-p)
	  (setq arg (- arg inc))))
    (if found
	(progn
	  (and (< inc 0) (goto-char (match-beginning 0)))
	  t))))

(defun octave-end-of-defun (&optional arg)
  "Move forward to the end of an Octave function.
With positive ARG, do it that many times.  Negative argument -N means
move back to Nth preceding end of a function.

An end of a function occurs right after the end keyword matching the
`function' keyword that starts the function."
  (interactive "p")
  (or arg (setq arg 1))
  (and (< arg 0) (skip-syntax-backward "w"))
  (and (> arg 0) (skip-syntax-forward "w"))
  (if (octave-in-defun-p)
      (setq arg (- arg 1)))
  (if (= arg 0) (setq arg -1))
  (if (octave-beginning-of-defun (- arg))
      (octave-forward-block)))

(defun octave-mark-defun ()
  "Put point at the beginning of this Octave function, mark at its end.
The function marked is the one containing point or following point."
  (interactive)
  (let ((pos (point)))
    (if (or (octave-in-defun-p)
	    (and (octave-beginning-of-defun -1)
		 (octave-in-defun-p)))
	(progn
	  (skip-syntax-forward "w")
	  (octave-beginning-of-defun)
	  (push-mark (point))
	  (octave-end-of-defun)
	  (exchange-point-and-mark))
      (goto-char pos)
      (message "No function to mark found"))))


;;; Filling
(defun octave-auto-fill ()
  "Perform auto-fill in Octave mode.
Returns nil if no feasible place to break the line could be found, and t
otherwise."
  (let (fc give-up)
    (if (or (null (setq fc (current-fill-column)))
	    (save-excursion
	      (beginning-of-line)
	      (and auto-fill-inhibit-regexp
		   (looking-at auto-fill-inhibit-regexp))))
	nil				; Can't do anything
      (if (and (not (octave-in-comment-p))
	       (> (current-column) fc))
	  (setq fc (- fc (+ (length octave-continuation-string) 1))))
      (while (and (not give-up) (> (current-column) fc))
	(let* ((opoint (point))
	       (fpoint
		(save-excursion
		  (move-to-column (+ fc 1))
		  (skip-chars-backward "^ \t\n")
		  ;; If we're at the beginning of the line, break after
		  ;; the first word
		  (if (bolp)
		      (re-search-forward "[ \t]" opoint t))
		  ;; If we're in a comment line, don't break after the
		  ;; comment chars
		  (if (save-excursion
			(skip-syntax-backward " <")
			(bolp))
		      (re-search-forward "[ \t]" (octave-point 'eol)
					 'move))
		  ;; If we're not in a comment line and just ahead the
		  ;; continuation string, don't break here.
		  (if (and (not (octave-in-comment-p))
			   (looking-at
			    (concat "\\s-*"
				    (regexp-quote
				     octave-continuation-string)
				    "\\s-*$")))
		      (end-of-line))
		  (skip-chars-backward " \t")
		  (point))))
	  (if (save-excursion
		(goto-char fpoint)
		(not (or (bolp) (eolp))))
	      (let ((prev-column (current-column)))
		(if (save-excursion
		      (skip-chars-backward " \t")
		      (= (point) fpoint))
		    (progn
		      (octave-maybe-insert-continuation-string)
		      (indent-new-comment-line t))
		  (save-excursion
		    (goto-char fpoint)
		    (octave-maybe-insert-continuation-string)
		    (indent-new-comment-line t)))
		(if (>= (current-column) prev-column)
		    (setq give-up t)))
	    (setq give-up t))))
      (not give-up))))

(defun octave-fill-paragraph (&optional arg)
 "Fill paragraph of Octave code, handling Octave comments."
 (interactive "P")
 (save-excursion
   (let ((end (progn (forward-paragraph) (point)))
	 (beg (progn
		(forward-paragraph -1)
		(skip-chars-forward " \t\n")
		(beginning-of-line)
		(point)))
	 (cfc (current-fill-column))
	 (ind (calculate-octave-indent))
	 comment-prefix)
     (save-restriction
       (goto-char beg)
       (narrow-to-region beg end)
       (if (listp ind) (setq ind (nth 1 ind)))
       (while (not (eobp))
	 (condition-case nil
	     (octave-indent-line ind)
	   (error nil))
	 (if (and (> ind 0)
		  (not
		   (save-excursion
		     (beginning-of-line)
		     (looking-at "^\\s-*\\($\\|\\s<+\\)"))))
	     (setq ind 0))
	 (move-to-column cfc)
	 ;; First check whether we need to combine non-empty comment lines
	 (if (and (< (current-column) cfc)
		  (octave-in-comment-p)
		  (not (save-excursion
			 (beginning-of-line)
			 (looking-at "^\\s-*\\s<+\\s-*$"))))
	     ;; This is a nonempty comment line which does not extend
	     ;; past the fill column.  If it is followed by a nonempty
	     ;; comment line with the same comment prefix, try to
	     ;; combine them, and repeat this until either we reach the
	     ;; fill-column or there is nothing more to combine.
	     (progn
	       ;; Get the comment prefix
	       (save-excursion
		 (beginning-of-line)
		 (while (and (re-search-forward "\\s<+")
			     (not (octave-in-comment-p))))
		 (setq comment-prefix (match-string 0)))
	       ;; And keep combining ...
	       (while (and (< (current-column) cfc)
			   (save-excursion
			     (forward-line 1)
			     (and (looking-at
				   (concat "^\\s-*"
					   comment-prefix
					   "\\S<"))
				  (not (looking-at
					(concat "^\\s-*"
						comment-prefix
						"\\s-*$"))))))
		 (delete-char 1)
		 (re-search-forward comment-prefix)
		 (delete-region (match-beginning 0) (match-end 0))
		 (fixup-whitespace)
		 (move-to-column cfc))))
	 ;; We might also try to combine continued code lines>  Perhaps
	 ;; some other time ...
	 (skip-chars-forward "^ \t\n")
	 (delete-horizontal-space)
	 (if (or (< (current-column) cfc)
		 (and (= (current-column) cfc) (eolp)))
	     (forward-line 1)
	   (if (not (eolp)) (insert " "))
	   (or (octave-auto-fill)
	       (forward-line 1)))))
     t)))


;;; Completions
(defun octave-initialize-completions ()
  "Create an alist for Octave completions."
  (if octave-completion-alist
      ()
    (setq octave-completion-alist
	  (mapcar '(lambda (var) (cons var var))
		  (append octave-reserved-words
			  octave-text-functions
			  octave-variables)))))

(defun octave-complete-symbol ()
  "Perform completion on Octave symbol preceding point.
Compare that symbol against Octave's reserved words and builtin
variables."
  ;; This code taken from lisp-complete-symbol
  (interactive)
  (let* ((end (point))
	 (beg (save-excursion (backward-sexp 1) (point)))
	 (string (buffer-substring-no-properties beg end))
	 (completion (try-completion string octave-completion-alist)))
    (cond ((eq completion t))		; ???
	  ((null completion)
	   (message "Can't find completion for \"%s\"" string)
	   (ding))
	  ((not (string= string completion))
           (delete-region beg end)
           (insert completion))
	  (t
	   (let ((list (all-completions string octave-completion-alist))
		 (conf (current-window-configuration)))
	     ;; Taken from comint.el
	     (message "Making completion list...")
	     (with-output-to-temp-buffer "*Completions*"
	       (display-completion-list list))
	     (message "Hit space to flush")
	     (let (key first)
	       (if (save-excursion
		     (set-buffer (get-buffer "*Completions*"))
		     (setq key (read-key-sequence nil)
			   first (aref key 0))
		     (and (consp first) (consp (event-start first))
			  (eq (window-buffer (posn-window (event-start
							   first)))
			      (get-buffer "*Completions*"))
			  (eq (key-binding key) 'mouse-choose-completion)))
		   (progn
		     (mouse-choose-completion first)
		     (set-window-configuration conf))
		 (if (eq first ?\ )
		     (set-window-configuration conf)
		   (setq unread-command-events
			 (listify-key-sequence key))))))))))


;;; Electric characters && friends
(defun octave-reindent-then-newline-and-indent ()
  "Reindent current Octave line, insert newline, and indent the new line.
If Abbrev mode is on, expand abbrevs first."
  (interactive)
  (if abbrev-mode (expand-abbrev))
  (if octave-blink-matching-block
      (octave-blink-matching-block-open))
  (save-excursion
    (delete-region (point) (progn (skip-chars-backward " \t") (point)))
    (indent-according-to-mode))
  (insert "\n")
  (indent-according-to-mode))

(defun octave-electric-semi ()
  "Insert a semicolon in Octave mode.
Maybe expand abbrevs and blink matching block open keywords.
Reindent the line of `octave-auto-indent' is non-nil.
Insert a newline if `octave-auto-newline' is non-nil."
  (interactive)
  (if (not (octave-not-in-string-or-comment-p))
      (insert ";")
    (if abbrev-mode (expand-abbrev))
    (if octave-blink-matching-block
	(octave-blink-matching-block-open))
    (if octave-auto-indent
	(indent-according-to-mode))
    (insert ";")
    (if octave-auto-newline
	(newline-and-indent))))

(defun octave-electric-space ()
  "Insert a space in Octave mode.
Maybe expand abbrevs and blink matching block open keywords.
Reindent the line of `octave-auto-indent' is non-nil."
  (interactive)
  (setq last-command-char ? )
  (if (not (octave-not-in-string-or-comment-p))
      (progn
	(indent-according-to-mode)
	(self-insert-command 1))
    (if abbrev-mode (expand-abbrev))
    (if octave-blink-matching-block
	(octave-blink-matching-block-open))
    (if (and octave-auto-indent
	     (save-excursion
	       (skip-syntax-backward " ")
	       (not (bolp))))
	(indent-according-to-mode))
    (self-insert-command 1)))

(defun octave-abbrev-start ()
  "Start entering an Octave abbreviation.
If Abbrev mode is turned on, typing ` (grave accent) followed by ? or
\\[help-command] lists all Octave abbrevs.  Any other key combination is
executed normally.
Note that all Octave mode abbrevs start with a grave accent."
  (interactive)
  (if (not abbrev-mode)
      (self-insert-command 1)
    (let (c)
      (insert last-command-char)
      (if (if octave-xemacs-p
	      (or (eq (event-to-character (setq c (next-event))) ??)
		  (eq (event-to-character c) help-char))
	    (or (eq (setq c (read-event)) ??)
		(eq c help-char)))
	  (let ((abbrev-table-name-list '(octave-abbrev-table)))
	    (list-abbrevs))
	(setq unread-command-events (list c))))))

(defun octave-insert-defun (name args vals)
  "Insert an Octave function skeleton.
Prompt for the function's name, arguments and return values (to be
entered without parens)."
  (interactive
   (list
    (read-from-minibuffer "Function name: "
			  (substring (buffer-name) 0 -2))
    (read-from-minibuffer "Arguments: ")
    (read-from-minibuffer "Return values: ")))
  (let ((string (format "%s %s (%s)"
			(cond
			 ((string-equal vals "")
			  vals)
			 ((string-match "[ ,]" vals)
			  (concat " [" vals "] ="))
			 (t
			  (concat " " vals " =")))
			name
			args))
	(prefix octave-block-comment-start))
    (if (not (bobp)) (newline))
    (insert "function" string)
    (indent-according-to-mode)
    (newline 2)
    (insert prefix "usage: " string)
    (reindent-then-newline-and-indent)
    (insert prefix)
    (reindent-then-newline-and-indent)
    (insert prefix)
    (indent-according-to-mode)
    (save-excursion
      (newline 2)
      (insert "endfunction")
      (indent-according-to-mode))))


;;; Menu
(defun octave-add-octave-menu ()
  "Adds the `Octave' menu to the menu bar in Octave mode."
  (require 'easymenu)
  (easy-menu-define octave-mode-menu-map octave-mode-map
		    "Menu keymap for Octave mode." octave-mode-menu)
  (easy-menu-add octave-mode-menu-map octave-mode-map))


;;; Communication with the inferior Octave process
(defun octave-kill-process ()
  "Kill inferior Octave process and its buffer."
  (interactive)
  (if inferior-octave-process
      (progn
	(process-send-string inferior-octave-process "quit;\n")
	(accept-process-output inferior-octave-process)))
  (if inferior-octave-buffer
      (kill-buffer inferior-octave-buffer)))

(defun octave-show-process-buffer ()
  "Make sure that `inferior-octave-buffer' is displayed."
  (interactive)
  (if (get-buffer inferior-octave-buffer)
      (display-buffer inferior-octave-buffer)
    (message "No buffer named %s" inferior-octave-buffer)))

(defun octave-hide-process-buffer ()
  "Delete all windows that display `inferior-octave-buffer'."
  (interactive)
  (if (get-buffer inferior-octave-buffer)
      (delete-windows-on inferior-octave-buffer)
    (message "No buffer named %s" inferior-octave-buffer)))

(defun octave-send-region (beg end)
  "Send current region to the inferior Octave process."
  (interactive "r")
  (inferior-octave t)
  (let ((proc inferior-octave-process)
	(string (buffer-substring-no-properties beg end))
	line)
    (save-excursion
      (set-buffer inferior-octave-buffer)
      (setq inferior-octave-output-list nil)
      (while (not (string-equal string ""))
	(if (string-match "\n" string)
	    (setq line (substring string 0 (match-beginning 0))
		  string (substring string (match-end 0)))
	  (setq line string string ""))
	(setq inferior-octave-receive-in-progress t)
	(inferior-octave-send-list-and-digest (list (concat line "\n")))
	(while inferior-octave-receive-in-progress
	  (accept-process-output proc))
	(insert-before-markers
	 (mapconcat 'identity
		    (append
		     (if octave-send-echo-input (list line) (list ""))
		     (mapcar 'inferior-octave-strip-ctrl-g
			     inferior-octave-output-list)
		     (list inferior-octave-output-string))
		    "\n")))))
  (if octave-send-show-buffer
      (display-buffer inferior-octave-buffer)))

(defun octave-send-block ()
  "Send current Octave block to the inferior Octave process."
  (interactive)
  (save-excursion
    (octave-mark-block)
    (octave-send-region (point) (mark))))

(defun octave-send-defun ()
  "Send current Octave function to the inferior Octave process."
  (interactive)
  (save-excursion
    (octave-mark-defun)
    (octave-send-region (point) (mark))))

(defun octave-send-line (&optional arg)
  "Send current Octave code line to the inferior Octave process.
With positive prefix ARG, send that many lines.
If `octave-send-line-auto-forward' is non-nil, go to the next unsent
code line."
  (interactive "P")
  (or arg (setq arg 1))
  (if (> arg 0)
      (let (beg end)
	(beginning-of-line)
	(setq beg (point))
	(octave-next-code-line (- arg 1))
	(end-of-line)
	(setq end (point))
	(if octave-send-line-auto-forward
	    (octave-next-code-line 1))
	(octave-send-region beg end))))

(defun octave-eval-print-last-sexp ()
  "Evaluate Octave sexp before point and print value into current buffer."
  (interactive)
  (inferior-octave t)
  (let ((standard-output (current-buffer))
	(print-escape-newlines nil)
	(opoint (point)))
    (terpri)
    (prin1
     (save-excursion
       (forward-sexp -1)
       (inferior-octave-send-list-and-digest
	(list (concat (buffer-substring-no-properties (point) opoint)
		      "\n")))
       (mapconcat 'identity inferior-octave-output-list "\n")))
    (terpri)))

;;; Bug reporting
(defun octave-submit-bug-report ()
  "Submit a bug report on the Emacs Octave package via mail."
  (interactive)
  (require 'reporter)
  (and
   (y-or-n-p "Do you want to submit a bug report? ")
   (reporter-submit-bug-report
    octave-maintainer-address
    (concat "Emacs version " emacs-version)
    (list
     'octave-auto-indent
     'octave-auto-newline
     'octave-blink-matching-block
     'octave-block-offset
     'octave-comment-char
     'octave-continuation-offset
     'octave-continuation-string
     'octave-help-files
     'octave-mode-startup-message
     'octave-send-echo-input
     'octave-send-line-auto-forward
     'octave-send-show-buffer))))

;;; provide ourself

(provide 'octave-mod)

;;; octave-mod.el ends here
