comint.el

;;; comint.el --- general command interpreter in a window stuff

;; Copyright (C) 1988, 1990, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
;;   2000, 2001, 2002, 2003, 2004, 2005 Free Software Foundation, Inc.

;; Author: Olin Shivers <shivers@cs.cmu.edu>
;;	Simon Marshall <simon@gnu.org>
;; Maintainer: FSF
;; Keywords: processes

;; 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., 51 Franklin Street, Fifth Floor,
;; Boston, MA 02110-1301, USA.

;;; Commentary:

;; This file defines a general command-interpreter-in-a-buffer package
;; (comint mode).  The idea is that you can build specific process-in-a-buffer
;; modes on top of comint mode -- e.g., Lisp, shell, scheme, T, soar, ....
;; This way, all these specific packages share a common base functionality,
;; and a common set of bindings, which makes them easier to use (and
;; saves code, implementation time, etc., etc.).

;; Several packages are already defined using comint mode:
;; - shell.el defines a shell-in-a-buffer mode.
;; - cmulisp.el defines a simple lisp-in-a-buffer mode.
;;
;; - The file cmuscheme.el defines a scheme-in-a-buffer mode.
;; - The file tea.el tunes scheme and inferior-scheme modes for T.
;; - The file soar.el tunes Lisp and inferior-lisp modes for Soar.
;; - cmutex.el defines TeX and LaTeX modes that invoke TeX, LaTeX, BibTeX,
;;   previewers, and printers from within Emacs.
;; - background.el allows csh-like job control inside Emacs.
;; It is pretty easy to make new derived modes for other processes.

;; For documentation on the functionality provided by Comint mode, and
;; the hooks available for customising it, see the comments below.
;; For further information on the standard derived modes (shell,
;; inferior-lisp, inferior-scheme, ...), see the relevant source files.

;; For hints on converting existing process modes (e.g., tex-mode,
;; background, dbx, gdb, kermit, prolog, telnet) to use comint-mode
;; instead of shell-mode, see the notes at the end of this file.


;; Brief Command Documentation:
;;============================================================================
;; Comint Mode Commands: (common to all derived modes, like shell & cmulisp
;; mode)
;;
;; M-p	   comint-previous-input	   Cycle backwards in input history
;; M-n	   comint-next-input		   Cycle forwards
;; M-r     comint-previous-matching-input  Previous input matching a regexp
;; M-s     comint-next-matching-input      Next input that matches
;; M-C-l   comint-show-output		   Show last batch of process output
;; RET	   comint-send-input
;; C-d	   comint-delchar-or-maybe-eof     Delete char unless at end of buff
;; C-c C-a comint-bol-or-process-mark      First time, move point to bol;
;;					    second time, move to process-mark.
;; C-c C-u comint-kill-input		    ^u
;; C-c C-w backward-kill-word		    ^w
;; C-c C-c comint-interrupt-subjob	    ^c
;; C-c C-z comint-stop-subjob		    ^z
;; C-c C-\ comint-quit-subjob		    ^\
;; C-c C-o comint-delete-output		    Delete last batch of process output
;; C-c C-r comint-show-output		    Show last batch of process output
;; C-c C-l comint-dynamic-list-input-ring  List input history
;;
;; Not bound by default in comint-mode (some are in shell mode)
;; comint-run				Run a program under comint-mode
;; send-invisible			Read a line w/o echo, and send to proc
;; comint-dynamic-complete-filename	Complete filename at point.
;; comint-dynamic-list-filename-completions List completions in help buffer.
;; comint-replace-by-expanded-filename	Expand and complete filename at point;
;;					replace with expanded/completed name.
;; comint-replace-by-expanded-history	Expand history at point;
;;					replace with expanded name.
;; comint-magic-space                  Expand history and add (a) space(s).
;; comint-kill-subjob			No mercy.
;; comint-show-maximum-output          Show as much output as possible.
;; comint-continue-subjob		Send CONT signal to buffer's process
;;					group.  Useful if you accidentally
;;					suspend your process (with C-c C-z).
;; comint-get-next-from-history        Fetch successive input history lines
;; comint-accumulate		       Combine lines to send them together
;;					as input.
;; comint-goto-process-mark	       Move point to where process-mark is.
;; comint-set-process-mark	       Set process-mark to point.

;; comint-mode-hook is the Comint mode hook.  Basically for your keybindings.

;;; Code:

(require 'ring)

;; Buffer Local Variables:
;;============================================================================
;; Comint mode buffer local variables:
;;  comint-prompt-regexp		string	comint-bol uses to match prompt
;;  comint-delimiter-argument-list	list	For delimiters and arguments
;;  comint-last-input-start		marker	Handy if inferior always echoes
;;  comint-last-input-end		marker	For comint-delete-output command
;;  comint-input-ring-size		integer	For the input history
;;  comint-input-ring			ring	mechanism
;;  comint-input-ring-index		number	...
;;  comint-save-input-ring-index	number	...
;;  comint-input-autoexpand		symbol	...
;;  comint-input-ignoredups		boolean	...
;;  comint-dynamic-complete-functions	hook   For the completion mechanism
;;  comint-completion-fignore		list	...
;;  comint-file-name-chars		string	...
;;  comint-file-name-quote-list		list	...
;;  comint-get-old-input		function Hooks for specific
;;  comint-input-filter-functions	hook	process-in-a-buffer
;;  comint-output-filter-functions	hook	function modes.
;;  comint-preoutput-filter-functions   hook
;;  comint-input-filter			function ...
;;  comint-input-sender			function ...
;;  comint-eol-on-send			boolean	...
;;  comint-process-echoes		boolean	...
;;  comint-scroll-to-bottom-on-input	symbol	For scroll behavior
;;  comint-scroll-to-bottom-on-output	symbol	...
;;  comint-scroll-show-maximum-output	boolean	...
;;  comint-accum-marker			maker	  For comint-accumulate
;;
;; Comint mode non-buffer local variables:
;;  comint-completion-addsuffix		boolean/cons	For file name
;;  comint-completion-autolist		boolean		completion behavior
;;  comint-completion-recexact		boolean		...

(defgroup comint nil
  "General command interpreter in a window stuff."
  :group 'processes)

(defgroup comint-completion nil
  "Completion facilities in comint."
  :group 'comint)

(defgroup comint-source nil
  "Source finding facilities in comint."
  :prefix "comint-"
  :group 'comint)

(defvar comint-prompt-regexp "^"
  "Regexp to recognize prompts in the inferior process.
Defaults to \"^\", the null string at BOL.

This variable is only used if the variable
`comint-use-prompt-regexp' is non-nil.

Good choices:
  Canonical Lisp: \"^[^> \\n]*>+:? *\" (Lucid, franz, kcl, T, cscheme, oaklisp)
  Lucid Common Lisp: \"^\\\\(>\\\\|\\\\(->\\\\)+\\\\) *\"
  franz: \"^\\\\(->\\\\|<[0-9]*>:\\\\) *\"
  kcl: \"^>+ *\"
  shell: \"^[^#$%>\\n]*[#$%>] *\"
  T: \"^>+ *\"

This is a good thing to set in mode hooks.")

(defcustom comint-prompt-read-only nil
  "If non-nil, the comint prompt is read only.
The read only region includes the newline before the prompt.
This does not affect existing prompts.
Certain derived modes may override this option.

If you set this option to t, then the safe way to temporarily
override the read-only-ness of comint prompts is to call
`comint-kill-whole-line' or `comint-kill-region' with no
narrowing in effect.  This way you will be certain that none of
the remaining prompts will be accidentally messed up.  You may
wish to put something like the following in your `.emacs' file:

\(add-hook 'comint-mode-hook
	  (lambda ()
	    (define-key comint-mode-map \"\\C-w\" 'comint-kill-region)
	    (define-key comint-mode-map [C-S-backspace]
	      'comint-kill-whole-line)))

If you sometimes use comint-mode on text-only terminals or with `emacs -nw',
you might wish to use another binding for `comint-kill-whole-line'."
  :type 'boolean
  :group 'comint
  :version "22.1")

(defvar comint-delimiter-argument-list ()
  "List of characters to recognize as separate arguments in input.
Strings comprising a character in this list will separate the arguments
surrounding them, and also be regarded as arguments in their own right (unlike
whitespace).  See `comint-arguments'.
Defaults to the empty list.

For shells, a good value is (?\\| ?& ?< ?> ?\\( ?\\) ?;).

This is a good thing to set in mode hooks.")

(defcustom comint-input-autoexpand nil
  "*If non-nil, expand input command history references on completion.
This mirrors the optional behavior of tcsh (its autoexpand and histlist).

If the value is `input', then the expansion is seen on input.
If the value is `history', then the expansion is only when inserting
into the buffer's input ring.  See also `comint-magic-space' and
`comint-dynamic-complete'.

This variable is buffer-local."
  :type '(choice (const :tag "off" nil)
		 (const input)
		 (const history)
		 (other :tag "on" t))
  :group 'comint)

(defface comint-highlight-input '((t (:weight bold)))
  "Face to use to highlight user input."
  :group 'comint)

(defface comint-highlight-prompt
  '((((min-colors 88) (background dark)) (:foreground "cyan1"))
    (((background dark)) (:foreground "cyan"))
    (t (:foreground "dark blue")))
  "Face to use to highlight prompts."
  :group 'comint)

(defcustom comint-input-ignoredups nil
  "*If non-nil, don't add input matching the last on the input ring.
This mirrors the optional behavior of bash.

This variable is buffer-local."
  :type 'boolean
  :group 'comint)

(defcustom comint-input-ring-file-name nil
  "*If non-nil, name of the file to read/write input history.
See also `comint-read-input-ring' and `comint-write-input-ring'.

This variable is buffer-local, and is a good thing to set in mode hooks."
  :type '(choice (const :tag "nil" nil)
		 file)
  :group 'comint)

(defcustom comint-scroll-to-bottom-on-input nil
  "*Controls whether input to interpreter causes window to scroll.
If nil, then do not scroll.  If t or `all', scroll all windows showing buffer.
If `this', scroll only the selected window.

The default is nil.

See `comint-preinput-scroll-to-bottom'.  This variable is buffer-local."
  :type '(choice (const :tag "off" nil)
		 (const t)
		 (const all)
		 (const this))
  :group 'comint)

(defcustom comint-move-point-for-output nil
  "*Controls whether interpreter output moves point to the end of the output.
If nil, then output never moves point to the output.
 (If the output occurs at point, it is inserted before point.)
If t or `all', move point in all windows showing the buffer.
If `this', move point only the selected window.
If `others', move point only in other windows, not in the selected window.

The default is nil.

See the variable `comint-scroll-show-maximum-output' and the function
`comint-postoutput-scroll-to-bottom'.
This variable is buffer-local in all Comint buffers."
  :type '(choice (const :tag "off" nil)
		 (const t)
		 (const all)
		 (const this)
		 (const others))
  :group 'comint)

(defvaralias 'comint-scroll-to-bottom-on-output 'comint-move-point-for-output)

(defcustom comint-scroll-show-maximum-output t
  "*Controls how to scroll due to interpreter output.
This variable applies when point is at the end of the buffer
\(either because it was originally there, or because
`comint-move-point-for-output' said to move it there)
and output from the subprocess is inserted.

Non-nil means scroll so that the window is full of text
and point is on the last line.  A value of nil
means don't do anything special--scroll normally.

See also the variable `comint-move-point-for-output' and the function
`comint-postoutput-scroll-to-bottom'.
This variable is buffer-local in all Comint buffers."
  :type 'boolean
  :group 'comint)

(defcustom comint-buffer-maximum-size 1024
  "*The maximum size in lines for Comint buffers.
Comint buffers are truncated from the top to be no greater than this number, if
the function `comint-truncate-buffer' is on `comint-output-filter-functions'."
  :type 'integer
  :group 'comint)

(defvar comint-input-ring-size 150
  "Size of input history ring.")

(defvar comint-input-ring-separator "\n"
  "Separator between commands in the history file.")

(defvar comint-input-history-ignore "^#"
  "Regexp for history entries that should be ignored when Comint initializes.")

(defcustom comint-process-echoes nil
  "*If non-nil, assume that the subprocess echoes any input.
If so, delete one copy of the input so that only one copy eventually
appears in the buffer.

This variable is buffer-local."
  :type 'boolean
  :group 'comint)

;; AIX puts the name of the person being su'd to in front of the prompt.
;; kinit prints a prompt like `Password for devnull@GNU.ORG: '.
;; ksu prints a prompt like `Kerberos password for devnull/root@GNU.ORG: '.
;; ssh-add prints a prompt like `Enter passphrase: '.
;; Some implementations of passwd use "Password (again)" as the 2nd prompt.
(defcustom comint-password-prompt-regexp
  "\\(\\([Oo]ld \\|[Nn]ew \\|'s \\|login \\|\
Kerberos \\|CVS \\|UNIX \\| SMB \\|^\\)\
\[Pp]assword\\( (again)\\)?\\|\
pass phrase\\|\\(Enter\\|Repeat\\|Bad\\) passphrase\\)\
\\(?:, try again\\)?\\(?: for [^:]+\\)?:\\s *\\'"
  "*Regexp matching prompts for passwords in the inferior process.
This is used by `comint-watch-for-password-prompt'."
  :type 'regexp
  :group 'comint)

;; Here are the per-interpreter hooks.
(defvar comint-get-old-input (function comint-get-old-input-default)
  "Function that returns old text in Comint mode.
This function is called when return is typed while the point is in old
text.  It returns the text to be submitted as process input.  The
default is `comint-get-old-input-default', which either grabs the
current input field or grabs the current line and strips off leading
text matching `comint-prompt-regexp', depending on the value of
`comint-use-prompt-regexp'.")

(defvar comint-dynamic-complete-functions
  '(comint-replace-by-expanded-history comint-dynamic-complete-filename)
  "List of functions called to perform completion.
Functions should return non-nil if completion was performed.
See also `comint-dynamic-complete'.

This is a good thing to set in mode hooks.")

(defvar comint-input-filter
  (function (lambda (str) (not (string-match "\\`\\s *\\'" str))))
  "Predicate for filtering additions to input history.
Takes one argument, the input.  If non-nil, the input may be saved on the input
history list.  Default is to save anything that isn't all whitespace.")

(defvar comint-input-filter-functions '()
  "Abnormal hook run before input is sent to the process.
These functions get one argument, a string containing the text to send.")

;;;###autoload
(defvar comint-output-filter-functions '(comint-postoutput-scroll-to-bottom comint-watch-for-password-prompt)
  "Functions to call after output is inserted into the buffer.
One possible function is `comint-postoutput-scroll-to-bottom'.
These functions get one argument, a string containing the text as originally
inserted.  Note that this might not be the same as the buffer contents between
`comint-last-output-start' and the buffer's `process-mark', if other filter
functions have already modified the buffer.

See also `comint-preoutput-filter-functions'.

You can use `add-hook' to add functions to this list
either globally or locally.")

(defvar comint-input-sender-no-newline nil
  "Non-nil directs the `comint-input-sender' function not to send a newline.")

(defvar comint-input-sender (function comint-simple-send)
  "Function to actually send to PROCESS the STRING submitted by user.
Usually this is just `comint-simple-send', but if your mode needs to
massage the input string, put a different function here.
`comint-simple-send' just sends the string plus a newline.
\(If `comint-input-sender-no-newline' is non-nil, it omits the newline.)
This is called from the user command `comint-send-input'.")

(defcustom comint-eol-on-send t
  "*Non-nil means go to the end of the line before sending input.
See `comint-send-input'."
  :type 'boolean
  :group 'comint)

;; Note: If it is decided to purge comint-prompt-regexp from the source
;; entirely, searching for uses of this variable will help to identify
;; places that need attention.
(defcustom comint-use-prompt-regexp nil
  "*If non-nil, use `comint-prompt-regexp' to recognize prompts.
If nil, then program output and user-input are given different `field'
properties, which Emacs commands can use to distinguish them (in
particular, common movement commands such as `beginning-of-line'
respect field boundaries in a natural way)."
  :type 'boolean
  :group 'comint)

;; Autoload is necessary for Custom to recognize old alias.
;;;###autoload
(define-obsolete-variable-alias 'comint-use-prompt-regexp-instead-of-fields
    'comint-use-prompt-regexp "22.1")

(defcustom comint-mode-hook nil
  "Hook run upon entry to `comint-mode'.
This is run before the process is cranked up."
  :type 'hook
  :group 'comint)

(defcustom comint-exec-hook '()
  "Hook run each time a process is exec'd by `comint-exec'.
This is called after the process is cranked up.  It is useful for things that
must be done each time a process is executed in a Comint mode buffer (e.g.,
`(process-kill-without-query)').  In contrast, the `comint-mode-hook' is only
executed once when the buffer is created."
  :type 'hook
  :group 'comint)

(defvar comint-mode-map
  (let ((map (make-sparse-keymap)))
    ;; Keys:
    (define-key map "\ep" 	  'comint-previous-input)
    (define-key map "\en" 	  'comint-next-input)
    (define-key map [C-up] 	  'comint-previous-input)
    (define-key map [C-down] 	  'comint-next-input)
    (define-key map "\er" 	  'comint-previous-matching-input)
    (define-key map "\es" 	  'comint-next-matching-input)
    (define-key map [?\C-c ?\M-r] 'comint-previous-matching-input-from-input)
    (define-key map [?\C-c ?\M-s] 'comint-next-matching-input-from-input)
    (define-key map "\e\C-l" 	  'comint-show-output)
    (define-key map "\C-m" 	  'comint-send-input)
    (define-key map "\C-d" 	  'comint-delchar-or-maybe-eof)
    (define-key map "\C-c " 	  'comint-accumulate)
    (define-key map "\C-c\C-x" 	  'comint-get-next-from-history)
    (define-key map "\C-c\C-a" 	  'comint-bol-or-process-mark)
    (define-key map "\C-c\C-u" 	  'comint-kill-input)
    (define-key map "\C-c\C-w" 	  'backward-kill-word)
    (define-key map "\C-c\C-c" 	  'comint-interrupt-subjob)
    (define-key map "\C-c\C-z" 	  'comint-stop-subjob)
    (define-key map "\C-c\C-\\"   'comint-quit-subjob)
    (define-key map "\C-c\C-m" 	  'comint-insert-input)
    (define-key map "\C-c\C-o" 	  'comint-delete-output)
    (define-key map "\C-c\C-r" 	  'comint-show-output)
    (define-key map "\C-c\C-e" 	  'comint-show-maximum-output)
    (define-key map "\C-c\C-l" 	  'comint-dynamic-list-input-ring)
    (define-key map "\C-c\C-n" 	  'comint-next-prompt)
    (define-key map "\C-c\C-p" 	  'comint-previous-prompt)
    (define-key map "\C-c\C-d" 	  'comint-send-eof)
    (define-key map "\C-c\C-s" 	  'comint-write-output)
    (define-key map "\C-c." 	  'comint-insert-previous-argument)
    ;; Mouse Buttons:
    (define-key map [mouse-2]     'comint-insert-input)
    ;; Menu bars:
    ;; completion:
    (define-key map [menu-bar completion]
      (cons "Complete" (make-sparse-keymap "Complete")))
    (define-key map [menu-bar completion complete-expand]
      '("Expand File Name" . comint-replace-by-expanded-filename))
    (define-key map [menu-bar completion complete-listing]
      '("File Completion Listing" . comint-dynamic-list-filename-completions))
    (define-key map [menu-bar completion complete-file]
      '("Complete File Name" . comint-dynamic-complete-filename))
    (define-key map [menu-bar completion complete]
      '("Complete Before Point" . comint-dynamic-complete))
    ;; Input history:
    (define-key map [menu-bar inout]
      (cons "In/Out" (make-sparse-keymap "In/Out")))
    (define-key map [menu-bar inout delete-output]
      '("Delete Current Output Group" . comint-delete-output))
    (define-key map [menu-bar inout append-output-to-file]
      '("Append Current Output Group to File" . comint-append-output-to-file))
    (define-key map [menu-bar inout write-output]
      '("Write Current Output Group to File" . comint-write-output))
    (define-key map [menu-bar inout next-prompt]
      '("Forward Output Group" . comint-next-prompt))
    (define-key map [menu-bar inout previous-prompt]
      '("Backward Output Group" . comint-previous-prompt))
    (define-key map [menu-bar inout show-maximum-output]
      '("Show Maximum Output" . comint-show-maximum-output))
    (define-key map [menu-bar inout show-output]
      '("Show Current Output Group" . comint-show-output))
    (define-key map [menu-bar inout kill-input]
      '("Kill Current Input" . comint-kill-input))
    (define-key map [menu-bar inout copy-input]
      '("Copy Old Input" . comint-insert-input))
    (define-key map [menu-bar inout forward-matching-history]
      '("Forward Matching Input..." . comint-forward-matching-input))
    (define-key map [menu-bar inout backward-matching-history]
      '("Backward Matching Input..." . comint-backward-matching-input))
    (define-key map [menu-bar inout next-matching-history]
      '("Next Matching Input..." . comint-next-matching-input))
    (define-key map [menu-bar inout previous-matching-history]
      '("Previous Matching Input..." . comint-previous-matching-input))
    (define-key map [menu-bar inout next-matching-history-from-input]
      '("Next Matching Current Input" . comint-next-matching-input-from-input))
    (define-key map [menu-bar inout previous-matching-history-from-input]
      '("Previous Matching Current Input" . comint-previous-matching-input-from-input))
    (define-key map [menu-bar inout next-history]
      '("Next Input" . comint-next-input))
    (define-key map [menu-bar inout previous-history]
      '("Previous Input" . comint-previous-input))
    (define-key map [menu-bar inout list-history]
      '("List Input History" . comint-dynamic-list-input-ring))
    (define-key map [menu-bar inout expand-history]
      '("Expand History Before Point" . comint-replace-by-expanded-history))
    ;; Signals
    (let ((signals-map (make-sparse-keymap "Signals")))
      (define-key map [menu-bar signals] (cons "Signals" signals-map))
      (define-key signals-map [eof]   '("EOF"   . comint-send-eof))
      (define-key signals-map [kill]  '("KILL"  . comint-kill-subjob))
      (define-key signals-map [quit]  '("QUIT"  . comint-quit-subjob))
      (define-key signals-map [cont]  '("CONT"  . comint-continue-subjob))
      (define-key signals-map [stop]  '("STOP"  . comint-stop-subjob))
      (define-key signals-map [break] '("BREAK" . comint-interrupt-subjob)))
    ;; Put them in the menu bar:
    (setq menu-bar-final-items (append '(completion inout signals)
				       menu-bar-final-items))
    map))

;; Fixme: Is this still relevant?
(defvar comint-ptyp t
  "Non-nil if communications via pty; false if by pipe.  Buffer local.
This is to work around a bug in Emacs process signaling.")

(defvar comint-input-ring nil)
(defvar comint-last-input-start nil)
(defvar comint-last-input-end nil)
(defvar comint-last-output-start nil)
(defvar comint-input-ring-index nil
  "Index of last matched history element.")
(defvar comint-matching-input-from-input-string ""
  "Input previously used to match input history.")
(defvar comint-save-input-ring-index
  "Last input ring index which you copied.
This is to support the command \\[comint-get-next-from-history].")

(defvar comint-accum-marker nil
  "Non-nil if you are accumulating input lines to send as input together.
The command \\[comint-accumulate] sets this.")

(put 'comint-replace-by-expanded-history 'menu-enable 'comint-input-autoexpand)
(put 'comint-input-ring 'permanent-local t)
(put 'comint-input-ring-index 'permanent-local t)
(put 'comint-save-input-ring-index 'permanent-local t)
(put 'comint-input-autoexpand 'permanent-local t)
(put 'comint-input-filter-functions 'permanent-local t)
(put 'comint-output-filter-functions 'permanent-local t)
(put 'comint-preoutput-filter-functions 'permanent-local t)
(put 'comint-scroll-to-bottom-on-input 'permanent-local t)
(put 'comint-move-point-for-output 'permanent-local t)
(put 'comint-scroll-show-maximum-output 'permanent-local t)
(put 'comint-ptyp 'permanent-local t)

(put 'comint-mode 'mode-class 'special)

(define-derived-mode comint-mode fundamental-mode "Comint"
  "Major mode for interacting with an inferior interpreter.
Interpreter name is same as buffer name, sans the asterisks.
Return at end of buffer sends line as input.
Return not at end copies rest of line to end and sends it.
Setting variable `comint-eol-on-send' means jump to the end of the line
before submitting new input.

This mode is customized to create major modes such as Inferior Lisp
mode, Shell mode, etc.  This can be done by setting the hooks
`comint-input-filter-functions', `comint-input-filter', `comint-input-sender'
and `comint-get-old-input' to appropriate functions, and the variable
`comint-prompt-regexp' to the appropriate regular expression.

An input history is maintained of size `comint-input-ring-size', and
can be accessed with the commands \\[comint-next-input], \\[comint-previous-input], and \\[comint-dynamic-list-input-ring].
Input ring history expansion can be achieved with the commands
\\[comint-replace-by-expanded-history] or \\[comint-magic-space].
Input ring expansion is controlled by the variable `comint-input-autoexpand',
and addition is controlled by the variable `comint-input-ignoredups'.

Commands with no default key bindings include `send-invisible',
`comint-dynamic-complete', `comint-dynamic-list-filename-completions', and
`comint-magic-space'.

Input to, and output from, the subprocess can cause the window to scroll to
the end of the buffer.  See variables `comint-output-filter-functions',
`comint-preoutput-filter-functions', `comint-scroll-to-bottom-on-input',
and `comint-move-point-for-output'.

If you accidentally suspend your process, use \\[comint-continue-subjob]
to continue it.

\\{comint-mode-map}

Entry to this mode runs the hooks on `comint-mode-hook'."
  (setq mode-line-process '(":%s"))
  (set (make-local-variable 'comint-last-input-start) (point-min-marker))
  (set (make-local-variable 'comint-last-input-end) (point-min-marker))
  (set (make-local-variable 'comint-last-output-start) (make-marker))
  (make-local-variable 'comint-last-prompt-overlay)
  (make-local-variable 'comint-prompt-regexp)        ; Don't set; default
  (make-local-variable 'comint-input-ring-size)      ; ...to global val.
  (make-local-variable 'comint-input-ring)
  (make-local-variable 'comint-input-ring-file-name)
  (or (and (boundp 'comint-input-ring) comint-input-ring)
      (setq comint-input-ring (make-ring comint-input-ring-size)))
  (make-local-variable 'comint-input-ring-index)
  (make-local-variable 'comint-save-input-ring-index)
  (or (and (boundp 'comint-input-ring-index) comint-input-ring-index)
      (setq comint-input-ring-index nil))
  (or (and (boundp 'comint-save-input-ring-index) comint-save-input-ring-index)
      (setq comint-save-input-ring-index nil))
  (make-local-variable 'comint-matching-input-from-input-string)
  (make-local-variable 'comint-input-autoexpand)
  (make-local-variable 'comint-input-ignoredups)
  (make-local-variable 'comint-delimiter-argument-list)
  (make-local-variable 'comint-completion-fignore)
  (make-local-variable 'comint-get-old-input)
  (make-local-variable 'comint-input-filter)
  (make-local-variable 'comint-input-sender)
  (make-local-variable 'comint-eol-on-send)
  (make-local-variable 'comint-scroll-to-bottom-on-input)
  (make-local-variable 'comint-move-point-for-output)
  (make-local-variable 'comint-scroll-show-maximum-output)
  ;; This makes it really work to keep point at the bottom.
  (make-local-variable 'scroll-conservatively)
  (setq scroll-conservatively 10000)
  (add-hook 'pre-command-hook 'comint-preinput-scroll-to-bottom t t)
  (make-local-variable 'comint-ptyp)
  (make-local-variable 'comint-process-echoes)
  (make-local-variable 'comint-file-name-chars)
  (make-local-variable 'comint-file-name-quote-list)
  (set (make-local-variable 'comint-accum-marker) (make-marker))
  (add-hook 'change-major-mode-hook 'font-lock-defontify nil t)
  ;; This behavior is not useful in comint buffers, and is annoying
  (set (make-local-variable 'next-line-add-newlines) nil))

(defun comint-check-proc (buffer)
  "Return non-nil if there is a living process associated w/buffer BUFFER.
Living means the status is `open', `run', or `stop'.
BUFFER can be either a buffer or the name of one."
  (let ((proc (get-buffer-process buffer)))
    (and proc (memq (process-status proc) '(open run stop)))))

;;;###autoload
(defun make-comint-in-buffer (name buffer program &optional startfile &rest switches)
  "Make a Comint process NAME in BUFFER, running PROGRAM.
If BUFFER is nil, it defaults to NAME surrounded by `*'s.
PROGRAM should be either a string denoting an executable program to create
via `start-process', or a cons pair of the form (HOST . SERVICE) denoting a TCP
connection to be opened via `open-network-stream'.  If there is already a
running process in that buffer, it is not restarted.  Optional fourth arg
STARTFILE is the name of a file to send the contents of to the process.

If PROGRAM is a string, any more args are arguments to PROGRAM."
  (or (fboundp 'start-process)
      (error "Multi-processing is not supported for this system"))
  (setq buffer (get-buffer-create (or buffer (concat "*" name "*"))))
  ;; If no process, or nuked process, crank up a new one and put buffer in
  ;; comint mode.  Otherwise, leave buffer and existing process alone.
  (unless (comint-check-proc buffer)
    (with-current-buffer buffer
      (unless (derived-mode-p 'comint-mode)
	(comint-mode))) ; Install local vars, mode, keymap, ...
    (comint-exec buffer name program startfile switches))
  buffer)

;;;###autoload
(defun make-comint (name program &optional startfile &rest switches)
  "Make a Comint process NAME in a buffer, running PROGRAM.
The name of the buffer is made by surrounding NAME with `*'s.
PROGRAM should be either a string denoting an executable program to create
via `start-process', or a cons pair of the form (HOST . SERVICE) denoting a TCP
connection to be opened via `open-network-stream'.  If there is already a
running process in that buffer, it is not restarted.  Optional third arg
STARTFILE is the name of a file to send the contents of the process to.

If PROGRAM is a string, any more args are arguments to PROGRAM."
  (apply #'make-comint-in-buffer name nil program startfile switches))

;;;###autoload
(defun comint-run (program)
  "Run PROGRAM in a Comint buffer and switch to it.
The buffer name is made by surrounding the file name of PROGRAM with `*'s.
The file name is used to make a symbol name, such as `comint-sh-hook', and any
hooks on this symbol are run in the buffer.
See `make-comint' and `comint-exec'."
  (interactive "sRun program: ")
  (let ((name (file-name-nondirectory program)))
    (switch-to-buffer (make-comint name program))
    (run-hooks (intern-soft (concat "comint-" name "-hook")))))

(defun comint-exec (buffer name command startfile switches)
  "Start up a process named NAME in buffer BUFFER for Comint modes.
Runs the given COMMAND with SWITCHES with output to STARTFILE.
Blasts any old process running in the buffer.  Doesn't set the buffer mode.
You can use this to cheaply run a series of processes in the same Comint
buffer.  The hook `comint-exec-hook' is run after each exec."
  (with-current-buffer buffer
    (let ((proc (get-buffer-process buffer)))	; Blast any old process.
      (if proc (delete-process proc)))
    ;; Crank up a new process
    (let ((proc
	   (if (consp command)
	       (open-network-stream name buffer (car command) (cdr command))
	     (comint-exec-1 name buffer command switches))))
      (set-process-filter proc 'comint-output-filter)
      (make-local-variable 'comint-ptyp)
      (setq comint-ptyp process-connection-type) ; t if pty, nil if pipe.
      ;; Jump to the end, and set the process mark.
      (goto-char (point-max))
      (set-marker (process-mark proc) (point))
      ;; Feed it the startfile.
      (cond (startfile
	     ;;This is guaranteed to wait long enough
	     ;;but has bad results if the comint does not prompt at all
	     ;;	     (while (= size (buffer-size))
	     ;;	       (sleep-for 1))
	     ;;I hope 1 second is enough!
	     (sleep-for 1)
	     (goto-char (point-max))
	     (insert-file-contents startfile)
	     (setq startfile (buffer-substring (point) (point-max)))
	     (delete-region (point) (point-max))
	     (comint-send-string proc startfile)))
    (run-hooks 'comint-exec-hook)
    buffer)))

;; This auxiliary function cranks up the process for comint-exec in
;; the appropriate environment.

(defun comint-exec-1 (name buffer command switches)
  (let ((process-environment
	 (nconc
	  ;; If using termcap, we specify `emacs' as the terminal type
	  ;; because that lets us specify a width.
	  ;; If using terminfo, we specify `dumb' because that is
	  ;; a defined terminal type.  `emacs' is not a defined terminal type
	  ;; and there is no way for us to define it here.
	  ;; Some programs that use terminfo get very confused
	  ;; if TERM is not a valid terminal type.
	  ;; ;; There is similar code in compile.el.
	  (if (and (boundp 'system-uses-terminfo) system-uses-terminfo)
	      (list "TERM=dumb" "TERMCAP="
		    (format "COLUMNS=%d" (window-width)))
	    (list "TERM=emacs"
		  (format "TERMCAP=emacs:co#%d:tc=unknown:" (window-width))))
	  (if (getenv "EMACS") nil (list "EMACS=t"))
	  process-environment))
	(default-directory
	  (if (file-accessible-directory-p default-directory)
	      default-directory
	    "/"))
	proc decoding encoding changed)
    (let ((exec-path (if (file-name-directory command)
			 ;; If the command has slashes, make sure we
			 ;; first look relative to the current directory.
			 (cons default-directory exec-path) exec-path)))
      (setq proc (apply 'start-process name buffer command switches)))
    (let ((coding-systems (process-coding-system proc)))
      (setq decoding (car coding-systems)
	    encoding (cdr coding-systems)))
    ;; If start-process decided to use some coding system for decoding
    ;; data sent from the process and the coding system doesn't
    ;; specify EOL conversion, we had better convert CRLF to LF.
    (if (vectorp (coding-system-eol-type decoding))
	(setq decoding (coding-system-change-eol-conversion decoding 'dos)
	      changed t))
    ;; Even if start-process left the coding system for encoding data
    ;; sent from the process undecided, we had better use the same one
    ;; as what we use for decoding.  But, we should suppress EOL
    ;; conversion.
    (if (and decoding (not encoding))
	(setq encoding (coding-system-change-eol-conversion decoding 'unix)
	      changed t))
    (if changed
	(set-process-coding-system proc decoding encoding))
    proc))

(defun comint-insert-input (&optional event)
  "In a Comint buffer, set the current input to the previous input at point."
  ;; This doesn't use "e" because it is supposed to work
  ;; for events without parameters.
  (interactive (list last-input-event))
  (let ((pos (point)))
    (if event (mouse-set-point event))
    (if (not (eq (get-char-property (point) 'field) 'input))
	;; No input at POS, fall back to the global definition.
	(let* ((keys (this-command-keys))
	       (last-key (and (vectorp keys) (aref keys (1- (length keys)))))
	       (fun (and last-key (lookup-key global-map (vector last-key)))))
	  (goto-char pos)
	  (and fun (call-interactively fun)))
      (setq pos (point))
      ;; There's previous input at POS, insert it at the end of the buffer.
      (goto-char (point-max))
      ;; First delete any old unsent input at the end
      (delete-region
       (or (marker-position comint-accum-marker)
	   (process-mark (get-buffer-process (current-buffer))))
       (point))
      ;; Insert the input at point
      (insert (buffer-substring-no-properties
	       (previous-single-char-property-change (1+ pos) 'field)
	       (next-single-char-property-change pos 'field))))))


;; Input history processing in a buffer
;; ===========================================================================
;; Useful input history functions, courtesy of the Ergo group.

;; Eleven commands:
;; comint-dynamic-list-input-ring	List history in help buffer.
;; comint-previous-input		Previous input...
;; comint-previous-matching-input	...matching a string.
;; comint-previous-matching-input-from-input ... matching the current input.
;; comint-next-input			Next input...
;; comint-next-matching-input		...matching a string.
;; comint-next-matching-input-from-input     ... matching the current input.
;; comint-backward-matching-input      Backwards input...
;; comint-forward-matching-input       ...matching a string.
;; comint-replace-by-expanded-history	Expand history at point;
;;					replace with expanded history.
;; comint-magic-space			Expand history and insert space.
;;
;; Three functions:
;; comint-read-input-ring              Read into comint-input-ring...
;; comint-write-input-ring             Write to comint-input-ring-file-name.
;; comint-replace-by-expanded-history-before-point Workhorse function.

(defun comint-read-input-ring (&optional silent)
  "Set the buffer's `comint-input-ring' from a history file.
The name of the file is given by the variable `comint-input-ring-file-name'.
The history ring is of size `comint-input-ring-size', regardless of file size.
If `comint-input-ring-file-name' is nil this function does nothing.

If the optional argument SILENT is non-nil, we say nothing about a
failure to read the history file.

This function is useful for major mode commands and mode hooks.

The commands stored in the history file are separated by the
`comint-input-ring-separator', and entries that match
`comint-input-history-ignore' are ignored.  The most recent command
comes last.

See also `comint-input-ignoredups' and `comint-write-input-ring'."