;;; python-mode.el --- Major mode for editing Python programs

;; Copyright (C) 1992,1993,1994  Tim Peters

;; Author: 2003-2007 http://sf.net/projects/python-mode
;;         1995-2002 Barry A. Warsaw
;;         1992-1994 Tim Peters
;; Maintainer: python-mode@python.org
;; Created:    Feb 1992
;; Keywords:   python languages oop

(defconst py-version "$Revision: 60587 $"
  "`python-mode' version number.")

;; This software is provided as-is, without express or implied
;; warranty.  Permission to use, copy, modify, distribute or sell this
;; software, without fee, for any purpose and by any individual or
;; organization, is hereby granted, provided that the above copyright
;; notice and this paragraph appear in all copies.

;;; Commentary:

;; This is a major mode for editing Python programs.  It was developed by Tim
;; Peters after an original idea by Michael A. Guravage.  Tim subsequently
;; left the net and in 1995, Barry Warsaw inherited the mode.  Tim's now back
;; but disavows all responsibility for the mode.  In fact, we suspect he
;; doesn't even use Emacs any more.  In 2003, python-mode.el was moved to its
;; own SourceForge project apart from the Python project, and now is
;; maintained by the volunteers at the python-mode@python.org mailing list.

;; pdbtrack support contributed by Ken Manheimer, April 2001.  Skip Montanaro
;; has also contributed significantly to python-mode's development.

;; Please use the SourceForge Python project to submit bugs or
;; patches:
;;
;;     http://sourceforge.net/projects/python

;; INSTALLATION:

;; To install, just drop this file into a directory on your load-path and
;; byte-compile it.  To set up Emacs to automatically edit files ending in
;; ".py" using python-mode add the following to your ~/.emacs file (GNU
;; Emacs) or ~/.xemacs/init.el file (XEmacs):
;;    (setq auto-mode-alist (cons '("\\.py$" . python-mode) auto-mode-alist))
;;    (setq interpreter-mode-alist (cons '("python" . python-mode)
;;                                       interpreter-mode-alist))
;;    (autoload 'python-mode "python-mode" "Python editing mode." t)
;;
;; In XEmacs syntax highlighting should be enabled automatically.  In GNU
;; Emacs you may have to add these lines to your ~/.emacs file:
;;    (global-font-lock-mode t)
;;    (setq font-lock-maximum-decoration t)

;; FOR MORE INFORMATION:

;; There is some information on python-mode.el at

;;     http://www.python.org/emacs/python-mode/
;;
;; It does contain links to other packages that you might find useful,
;; such as pdb interfaces, OO-Browser links, etc.

;; BUG REPORTING:

;; As mentioned above, please use the SourceForge Python project for
;; submitting bug reports or patches.  The old recommendation, to use
;; C-c C-b will still work, but those reports have a higher chance of
;; getting buried in my mailbox.  Please include a complete, but
;; concise code sample and a recipe for reproducing the bug.  Send
;; suggestions and other comments to python-mode@python.org.

;; When in a Python mode buffer, do a C-h m for more help.  It's
;; doubtful that a texinfo manual would be very useful, but if you
;; want to contribute one, I'll certainly accept it!

;;; Code:

(require 'comint)
(require 'custom)
(require 'cl)
(require 'compile)
(require 'ansi-color)


;; user definable variables
;; vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv

(defgroup python nil
  "Support for the Python programming language, <http://www.python.org/>"
  :group 'languages
  :prefix "py-")

(defcustom py-tab-always-indent t
  "*Non-nil means TAB in Python mode should always reindent the current line,
regardless of where in the line point is when the TAB command is used."
  :type 'boolean
  :group 'python)

(defcustom py-python-command "python"
  "*Shell command used to start Python interpreter."
  :type 'string
  :group 'python)

(make-obsolete-variable 'py-jpython-command 'py-jython-command)
(defcustom py-jython-command "jython"
  "*Shell command used to start the Jython interpreter."
  :type 'string
  :group 'python
  :tag "Jython Command")

(defcustom py-default-interpreter 'cpython
  "*Which Python interpreter is used by default.
The value for this variable can be either `cpython' or `jython'.

When the value is `cpython', the variables `py-python-command' and
`py-python-command-args' are consulted to determine the interpreter
and arguments to use.

When the value is `jython', the variables `py-jython-command' and
`py-jython-command-args' are consulted to determine the interpreter
and arguments to use.

Note that this variable is consulted only the first time that a Python
mode buffer is visited during an Emacs session.  After that, use
\\[py-toggle-shells] to change the interpreter shell."
  :type '(choice (const :tag "Python (a.k.a. CPython)" cpython)
		 (const :tag "Jython" jython))
  :group 'python)

(defcustom py-python-command-args '("-i")
  "*List of string arguments to be used when starting a Python shell."
  :type '(repeat string)
  :group 'python)

(make-obsolete-variable 'py-jpython-command-args 'py-jython-command-args)
(defcustom py-jython-command-args '("-i")
  "*List of string arguments to be used when starting a Jython shell."
  :type '(repeat string)
  :group 'python
  :tag "Jython Command Args")

(defcustom py-indent-offset 4
  "*Amount of offset per level of indentation.
`\\[py-guess-indent-offset]' can usually guess a good value when
you're editing someone else's Python code."
  :type 'integer
  :group 'python)

(defcustom py-continuation-offset 4
  "*Additional amount of offset to give for some continuation lines.
Continuation lines are those that immediately follow a backslash
terminated line.  Only those continuation lines for a block opening
statement are given this extra offset."
  :type 'integer
  :group 'python)

(defcustom py-smart-indentation t
  "*Should `python-mode' try to automagically set some indentation variables?
When this variable is non-nil, two things happen when a buffer is set
to `python-mode':

    1. `py-indent-offset' is guessed from existing code in the buffer.
       Only guessed values between 2 and 8 are considered.  If a valid
       guess can't be made (perhaps because you are visiting a new
       file), then the value in `py-indent-offset' is used.

    2. `indent-tabs-mode' is turned off if `py-indent-offset' does not
       equal `tab-width' (`indent-tabs-mode' is never turned on by
       Python mode).  This means that for newly written code, tabs are
       only inserted in indentation if one tab is one indentation
       level, otherwise only spaces are used.

Note that both these settings occur *after* `python-mode-hook' is run,
so if you want to defeat the automagic configuration, you must also
set `py-smart-indentation' to nil in your `python-mode-hook'."
  :type 'boolean
  :group 'python)

(defcustom py-align-multiline-strings-p t
  "*Flag describing how multi-line triple quoted strings are aligned.
When this flag is non-nil, continuation lines are lined up under the
preceding line's indentation.  When this flag is nil, continuation
lines are aligned to column zero."
  :type '(choice (const :tag "Align under preceding line" t)
		 (const :tag "Align to column zero" nil))
  :group 'python)

(defcustom py-block-comment-prefix "##"
  "*String used by \\[comment-region] to comment out a block of code.
This should follow the convention for non-indenting comment lines so
that the indentation commands won't get confused (i.e., the string
should be of the form `#x...' where `x' is not a blank or a tab, and
`...' is arbitrary).  However, this string should not end in whitespace."
  :type 'string
  :group 'python)

(defcustom py-honor-comment-indentation t
  "*Controls how comment lines influence subsequent indentation.

When nil, all comment lines are skipped for indentation purposes, and
if possible, a faster algorithm is used (i.e. X/Emacs 19 and beyond).

When t, lines that begin with a single `#' are a hint to subsequent
line indentation.  If the previous line is such a comment line (as
opposed to one that starts with `py-block-comment-prefix'), then its
indentation is used as a hint for this line's indentation.  Lines that
begin with `py-block-comment-prefix' are ignored for indentation
purposes.

When not nil or t, comment lines that begin with a single `#' are used
as indentation hints, unless the comment character is in column zero."
  :type '(choice
	  (const :tag "Skip all comment lines (fast)" nil)
	  (const :tag "Single # `sets' indentation for next line" t)
	  (const :tag "Single # `sets' indentation except at column zero"
		 other)
	  )
  :group 'python)

(defcustom py-temp-directory
  (let ((ok '(lambda (x)
	       (and x
		    (setq x (expand-file-name x)) ; always true
		    (file-directory-p x)
		    (file-writable-p x)
		    x))))
    (or (funcall ok (getenv "TMPDIR"))
	(funcall ok "/usr/tmp")
	(funcall ok "/tmp")
	(funcall ok "/var/tmp")
	(funcall ok  ".")
	(error
	 "Couldn't find a usable temp directory -- set `py-temp-directory'")))
  "*Directory used for temporary files created by a *Python* process.
By default, the first directory from this list that exists and that you
can write into: the value (if any) of the environment variable TMPDIR,
/usr/tmp, /tmp, /var/tmp, or the current directory."
  :type 'string
  :group 'python)

(defcustom py-beep-if-tab-change t
  "*Ring the bell if `tab-width' is changed.
If a comment of the form

  \t# vi:set tabsize=<number>:

is found before the first code line when the file is entered, and the
current value of (the general Emacs variable) `tab-width' does not
equal <number>, `tab-width' is set to <number>, a message saying so is
displayed in the echo area, and if `py-beep-if-tab-change' is non-nil
the Emacs bell is also rung as a warning."
  :type 'boolean
  :group 'python)

(defcustom py-jump-on-exception t
  "*Jump to innermost exception frame in *Python Output* buffer.
When this variable is non-nil and an exception occurs when running
Python code synchronously in a subprocess, jump immediately to the
source code of the innermost traceback frame."
  :type 'boolean
  :group 'python)

(defcustom py-ask-about-save t
  "If not nil, ask about which buffers to save before executing some code.
Otherwise, all modified buffers are saved without asking."
  :type 'boolean
  :group 'python)

(defcustom py-backspace-function 'backward-delete-char-untabify
  "*Function called by `py-electric-backspace' when deleting backwards."
  :type 'function
  :group 'python)

(defcustom py-delete-function 'delete-char
  "*Function called by `py-electric-delete' when deleting forwards."
  :type 'function
  :group 'python)

(defcustom py-imenu-show-method-args-p nil
  "*Controls echoing of arguments of functions & methods in the Imenu buffer.
When non-nil, arguments are printed."
  :type 'boolean
  :group 'python)
(make-variable-buffer-local 'py-indent-offset)

(defcustom py-pdbtrack-do-tracking-p t
  "*Controls whether the pdbtrack feature is enabled or not.
When non-nil, pdbtrack is enabled in all comint-based buffers,
e.g. shell buffers and the *Python* buffer.  When using pdb to debug a
Python program, pdbtrack notices the pdb prompt and displays the
source file and line that the program is stopped at, much the same way
as gud-mode does for debugging C programs with gdb."
  :type 'boolean
  :group 'python)
(make-variable-buffer-local 'py-pdbtrack-do-tracking-p)

(defcustom py-pdbtrack-minor-mode-string " PDB"
  "*String to use in the minor mode list when pdbtrack is enabled."
  :type 'string
  :group 'python)

(defcustom py-import-check-point-max
  20000
  "Maximum number of characters to search for a Java-ish import statement.
When `python-mode' tries to calculate the shell to use (either a
CPython or a Jython shell), it looks at the so-called `shebang' line
-- i.e. #! line.  If that's not available, it looks at some of the
file heading imports to see if they look Java-like."
  :type 'integer
  :group 'python
  )

(make-obsolete-variable 'py-jpython-packages 'py-jython-packages)
(defcustom py-jython-packages
  '("java" "javax" "org" "com")
  "Imported packages that imply `jython-mode'."
  :type '(repeat string)
  :group 'python)

;; Not customizable
(defvar py-master-file nil
  "If non-nil, execute the named file instead of the buffer's file.
The intent is to allow you to set this variable in the file's local
variable section, e.g.:

    # Local Variables:
    # py-master-file: \"master.py\"
    # End:

so that typing \\[py-execute-buffer] in that buffer executes the named
master file instead of the buffer's file.  If the file name has a
relative path, the value of variable `default-directory' for the
buffer is prepended to come up with a file name.")
(make-variable-buffer-local 'py-master-file)

(defcustom py-pychecker-command "pychecker"
  "*Shell command used to run Pychecker."
  :type 'string
  :group 'python
  :tag "Pychecker Command")

(defcustom py-pychecker-command-args '("--stdlib")
  "*List of string arguments to be passed to pychecker."
  :type '(repeat string)
  :group 'python
  :tag "Pychecker Command Args")

(defvar py-shell-alist
  '(("jython" . 'jython)
    ("python" . 'cpython))
  "*Alist of interpreters and python shells. Used by `py-choose-shell'
to select the appropriate python interpreter mode for a file.")

(defcustom py-shell-input-prompt-1-regexp "^>>> "
  "*A regular expression to match the input prompt of the shell."
  :type 'string
  :group 'python)

(defcustom py-shell-input-prompt-2-regexp "^[.][.][.] "
  "*A regular expression to match the input prompt of the shell after the
  first line of input."
  :type 'string
  :group 'python)

(defcustom py-shell-switch-buffers-on-execute t
  "*Controls switching to the Python buffer where commands are
  executed.  When non-nil the buffer switches to the Python buffer, if
  not no switching occurs."
  :type 'boolean
  :group 'python)


;; ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
;; NO USER DEFINABLE VARIABLES BEYOND THIS POINT

(defvar py-line-number-offset 0
  "When an exception occurs as a result of py-execute-region, a
subsequent py-up-exception needs the line number where the region
started, in order to jump to the correct file line.  This variable is
set in py-execute-region and used in py-jump-to-exception.")

(defconst py-emacs-features
  (let (features)
   features)
  "A list of features extant in the Emacs you are using.
There are many flavors of Emacs out there, with different levels of
support for features needed by `python-mode'.")

;; Face for None, True, False, self, and Ellipsis
(defvar py-pseudo-keyword-face 'py-pseudo-keyword-face
  "Face for pseudo keywords in Python mode, like self, True, False, Ellipsis.")
(make-face 'py-pseudo-keyword-face)

;; PEP 318 decorators
(defvar py-decorators-face 'py-decorators-face
  "Face method decorators.")
(make-face 'py-decorators-face)

;; Face for builtins
(defvar py-builtins-face 'py-builtins-face
  "Face for builtins like TypeError, object, open, and exec.")
(make-face 'py-builtins-face)

;; XXX, TODO, and FIXME comments and such
(defvar py-XXX-tag-face 'py-XXX-tag-face
  "Face for XXX, TODO, and FIXME tags")
(make-face 'py-XXX-tag-face)

(defun py-font-lock-mode-hook ()
  (or (face-differs-from-default-p 'py-pseudo-keyword-face)
      (copy-face 'font-lock-keyword-face 'py-pseudo-keyword-face))
  (or (face-differs-from-default-p 'py-builtins-face)
      (copy-face 'font-lock-keyword-face 'py-builtins-face))
  (or (face-differs-from-default-p 'py-decorators-face)
      (copy-face 'py-pseudo-keyword-face 'py-decorators-face))
  (or (face-differs-from-default-p 'py-XXX-tag-face)
      (copy-face 'font-lock-comment-face 'py-XXX-tag-face))
  )
(add-hook 'font-lock-mode-hook 'py-font-lock-mode-hook)

(defvar python-font-lock-keywords
  (let ((kw1 (mapconcat 'identity
			'("and"      "assert"   "break"   "class"
			  "continue" "def"      "del"     "elif"
			  "else"     "except"   "exec"    "for"
			  "from"     "global"   "if"      "import"
			  "in"       "is"       "lambda"  "not"
			  "or"       "pass"     "print"   "raise"
			  "return"   "while"    "with"    "yield"
			  )
			"\\|"))
	(kw2 (mapconcat 'identity
			'("else:" "except:" "finally:" "try:")
			"\\|"))
	(kw3 (mapconcat 'identity
			;; Don't include True, False, None, or
			;; Ellipsis in this list, since they are
			;; already defined as pseudo keywords.
			'("__debug__"
			  "__import__" "__name__" "abs" "apply" "basestring"
			  "bool" "buffer" "callable" "chr" "classmethod"
			  "cmp" "coerce" "compile" "complex" "copyright"
			  "delattr" "dict" "dir" "divmod"
			  "enumerate" "eval" "execfile" "exit" "file"
			  "filter" "float" "getattr" "globals" "hasattr"
			  "hash" "hex" "id" "input" "int" "intern"
			  "isinstance" "issubclass" "iter" "len" "license"
			  "list" "locals" "long" "map" "max" "min" "object"
			  "oct" "open" "ord" "pow" "property" "range"
			  "raw_input" "reduce" "reload" "repr" "round"
			  "setattr" "slice" "staticmethod" "str" "sum"
			  "super" "tuple" "type" "unichr" "unicode" "vars"
			  "xrange" "zip")
			"\\|"))
	(kw4 (mapconcat 'identity
			;; Exceptions and warnings
			'("ArithmeticError" "AssertionError"
			  "AttributeError" "DeprecationWarning" "EOFError"
			  "EnvironmentError" "Exception"
			  "FloatingPointError" "FutureWarning" "IOError"
			  "ImportError" "IndentationError" "IndexError"
			  "KeyError" "KeyboardInterrupt" "LookupError"
			  "MemoryError" "NameError" "NotImplemented"
			  "NotImplementedError" "OSError" "OverflowError"
			  "OverflowWarning" "PendingDeprecationWarning"
			  "ReferenceError" "RuntimeError" "RuntimeWarning"
			  "StandardError" "StopIteration" "SyntaxError"
			  "SyntaxWarning" "SystemError" "SystemExit"
			  "TabError" "TypeError" "UnboundLocalError"
			  "UnicodeDecodeError" "UnicodeEncodeError"
			  "UnicodeError" "UnicodeTranslateError"
			  "UserWarning" "ValueError" "Warning"
			  "ZeroDivisionError")
			"\\|"))
	)
    (list
     '("^[ \t]*\\(@.+\\)" 1 'py-decorators-face)
     ;; keywords
     (cons (concat "\\<\\(" kw1 "\\)\\>[ \n\t(]") 1)
     ;; builtins when they don't appear as object attributes
     (list (concat "\\([^. \t]\\|^\\)[ \t]*\\<\\(" kw3 "\\)\\>[ \n\t(]") 2
	   'py-builtins-face)
     ;; block introducing keywords with immediately following colons.
     ;; Yes "except" is in both lists.
     (cons (concat "\\<\\(" kw2 "\\)[ \n\t(]") 1)
     ;; Exceptions
     (list (concat "\\<\\(" kw4 "\\)[ \n\t:,(]") 1 'py-builtins-face)
     ;; `as' but only in "import foo as bar" or "with foo as bar"
     '("[ \t]*\\(\\<from\\>.*\\)?\\<import\\>.*\\<\\(as\\)\\>" . 2)
     '("[ \t]*\\<with\\>.*\\<\\(as\\)\\>" . 1)
     ;; classes
     '("\\<class[ \t]+\\([a-zA-Z_]+[a-zA-Z0-9_]*\\)" 1 font-lock-type-face)
     ;; functions
     '("\\<def[ \t]+\\([a-zA-Z_]+[a-zA-Z0-9_]*\\)"
       1 font-lock-function-name-face)
     ;; pseudo-keywords
     '("\\<\\(self\\|None\\|True\\|False\\|Ellipsis\\)\\>"
       1 py-pseudo-keyword-face)
     ;; XXX, TODO, and FIXME tags
     '("XXX\\|TODO\\|FIXME" 0 py-XXX-tag-face t)
     ))
  "Additional expressions to highlight in Python mode.")
(put 'python-mode 'font-lock-defaults '(python-font-lock-keywords))

;; have to bind py-file-queue before installing the kill-emacs-hook
(defvar py-file-queue nil
  "Queue of Python temp files awaiting execution.
Currently-active file is at the head of the list.")

(defvar py-pdbtrack-is-tracking-p nil)

(defvar py-pychecker-history nil)



;; Constants

(defconst py-stringlit-re
  (concat
   ;; These fail if backslash-quote ends the string (not worth
   ;; fixing?).  They precede the short versions so that the first two
   ;; quotes don't look like an empty short string.
   ;;
   ;; (maybe raw), long single quoted triple quoted strings (SQTQ),
   ;; with potential embedded single quotes
   "[rR]?'''[^']*\\(\\('[^']\\|''[^']\\)[^']*\\)*'''"
   "\\|"
   ;; (maybe raw), long double quoted triple quoted strings (DQTQ),
   ;; with potential embedded double quotes
   "[rR]?\"\"\"[^\"]*\\(\\(\"[^\"]\\|\"\"[^\"]\\)[^\"]*\\)*\"\"\""
   "\\|"
   "[rR]?'\\([^'\n\\]\\|\\\\.\\)*'"	; single-quoted
   "\\|"				; or
   "[rR]?\"\\([^\"\n\\]\\|\\\\.\\)*\""	; double-quoted
   )
  "Regular expression matching a Python string literal.")

(defconst py-continued-re
  ;; This is tricky because a trailing backslash does not mean
  ;; continuation if it's in a comment
  (concat
   "\\(" "[^#'\"\n\\]" "\\|" py-stringlit-re "\\)*"
   "\\\\$")
  "Regular expression matching Python backslash continuation lines.")

(defconst py-blank-or-comment-re "[ \t]*\\($\\|#\\)"
  "Regular expression matching a blank or comment line.")

(defconst py-outdent-re
  (concat "\\(" (mapconcat 'identity
			   '("else:"
			     "except\\(\\s +.*\\)?:"
			     "finally:"
			     "elif\\s +.*:")
			   "\\|")
	  "\\)")
  "Regular expression matching statements to be dedented one level.")

(defconst py-block-closing-keywords-re
  "\\(return\\|raise\\|break\\|continue\\|pass\\)"
  "Regular expression matching keywords which typically close a block.")

(defconst py-no-outdent-re
  (concat
   "\\("
   (mapconcat 'identity
	      (list "try:"
		    "except\\(\\s +.*\\)?:"
		    "while\\s +.*:"
		    "for\\s +.*:"
		    "if\\s +.*:"
		    "elif\\s +.*:"
		    (concat py-block-closing-keywords-re "[ \t\n]")
		    )
	      "\\|")
	  "\\)")
  "Regular expression matching lines not to dedent after.")

(defvar py-traceback-line-re
  "[ \t]+File \"\\([^\"]+\\)\", line \\([0-9]+\\)"
  "Regular expression that describes tracebacks.")

;; pdbtrack constants
(defconst py-pdbtrack-stack-entry-regexp
;  "^> \\([^(]+\\)(\\([0-9]+\\))\\([?a-zA-Z0-9_]+\\)()"
  "^> \\(.*\\)(\\([0-9]+\\))\\([?a-zA-Z0-9_]+\\)()"
  "Regular expression pdbtrack uses to find a stack trace entry.")

(defconst py-pdbtrack-input-prompt "\n[(<]*[Pp]db[>)]+ "
  "Regular expression pdbtrack uses to recognize a pdb prompt.")

(defconst py-pdbtrack-track-range 10000
  "Max number of characters from end of buffer to search for stack entry.")



;; Major mode boilerplate

;; define a mode-specific abbrev table for those who use such things
(defvar python-mode-abbrev-table nil
  "Abbrev table in use in `python-mode' buffers.")
(define-abbrev-table 'python-mode-abbrev-table nil)

(defvar python-mode-hook nil
  "*Hook called by `python-mode'.")

(make-obsolete-variable 'jpython-mode-hook 'jython-mode-hook)
(defvar jython-mode-hook nil
  "*Hook called by `jython-mode'. `jython-mode' also calls
`python-mode-hook'.")

(defvar py-shell-hook nil
  "*Hook called by `py-shell'.")

;; In previous version of python-mode.el, the hook was incorrectly
;; called py-mode-hook, and was not defvar'd.  Deprecate its use.
(and (fboundp 'make-obsolete-variable)
     (make-obsolete-variable 'py-mode-hook 'python-mode-hook))

(defvar py-mode-map ()
  "Keymap used in `python-mode' buffers.")
(if py-mode-map
    nil
  (setq py-mode-map (make-sparse-keymap))
  ;; electric keys
  (define-key py-mode-map ":" 'py-electric-colon)
  ;; indentation level modifiers
  (define-key py-mode-map "\C-c\C-l"  'py-shift-region-left)
  (define-key py-mode-map "\C-c\C-r"  'py-shift-region-right)
  (define-key py-mode-map "\C-c<"     'py-shift-region-left)
  (define-key py-mode-map "\C-c>"     'py-shift-region-right)
  ;; subprocess commands
  (define-key py-mode-map "\C-c\C-c"  'py-execute-buffer)
  (define-key py-mode-map "\C-c\C-m"  'py-execute-import-or-reload)
  (define-key py-mode-map "\C-c\C-s"  'py-execute-string)
  (define-key py-mode-map "\C-c|"     'py-execute-region)
  (define-key py-mode-map "\e\C-x"    'py-execute-def-or-class)
  (define-key py-mode-map "\C-c!"     'py-shell)
  (define-key py-mode-map "\C-c\C-t"  'py-toggle-shells)
  ;; Caution!  Enter here at your own risk.  We are trying to support
  ;; several behaviors and it gets disgusting. :-( This logic ripped
  ;; largely from CC Mode.
  ;;
  ;; In XEmacs 19, Emacs 19, and Emacs 20, we use this to bind
  ;; backwards deletion behavior to DEL, which both Delete and
  ;; Backspace get translated to.  There's no way to separate this
  ;; behavior in a clean way, so deal with it!  Besides, it's been
  ;; this way since the dawn of time.
  (if (not (boundp 'delete-key-deletes-forward))
      (define-key py-mode-map "\177" 'py-electric-backspace)
    ;; However, XEmacs 20 actually achieved enlightenment.  It is
    ;; possible to sanely define both backward and forward deletion
    ;; behavior under X separately (TTYs are forever beyond hope, but
    ;; who cares?  XEmacs 20 does the right thing with these too).
    (define-key py-mode-map [delete]    'py-electric-delete)
    (define-key py-mode-map [backspace] 'py-electric-backspace))
  ;; Separate M-BS from C-M-h.  The former should remain
  ;; backward-kill-word.
  (define-key py-mode-map [(control meta h)] 'py-mark-def-or-class)
  (define-key py-mode-map "\C-c\C-k"  'py-mark-block)
  ;; Miscellaneous
  (define-key py-mode-map "\C-c:"     'py-guess-indent-offset)
  (define-key py-mode-map "\C-c\t"    'py-indent-region)
  (define-key py-mode-map "\C-c\C-d"  'py-pdbtrack-toggle-stack-tracking)
  (define-key py-mode-map "\C-c\C-n"  'py-next-statement)
  (define-key py-mode-map "\C-c\C-p"  'py-previous-statement)
  (define-key py-mode-map "\C-c\C-u"  'py-goto-block-up)
  (define-key py-mode-map "\C-c#"     'py-comment-region)
  (define-key py-mode-map "\C-c?"     'py-describe-mode)
  (define-key py-mode-map "\C-c\C-h"  'py-help-at-point)
  (define-key py-mode-map "\e\C-a"    'py-beginning-of-def-or-class)
  (define-key py-mode-map "\e\C-e"    'py-end-of-def-or-class)
  (define-key py-mode-map "\C-c-"     'py-up-exception)
  (define-key py-mode-map "\C-c="     'py-down-exception)
  ;; stuff that is `standard' but doesn't interface well with
  ;; python-mode, which forces us to rebind to special commands
  (define-key py-mode-map "\C-xnd"    'py-narrow-to-defun)
  ;; information
  (define-key py-mode-map "\C-c\C-b" 'py-submit-bug-report)
  (define-key py-mode-map "\C-c\C-v" 'py-version)
  (define-key py-mode-map "\C-c\C-w" 'py-pychecker-run)
  ;; shadow global bindings for newline-and-indent w/ the py- version.
  ;; BAW - this is extremely bad form, but I'm not going to change it
  ;; for now.
  (mapcar #'(lambda (key)
	      (define-key py-mode-map key 'py-newline-and-indent))
	  (where-is-internal 'newline-and-indent))
  ;; Force RET to be py-newline-and-indent even if it didn't get
  ;; mapped by the above code.  motivation: Emacs' default binding for
  ;; RET is `newline' and C-j is `newline-and-indent'.  Most Pythoneers
  ;; expect RET to do a `py-newline-and-indent' and any Emacsers who
  ;; dislike this are probably knowledgeable enough to do a rebind.
  ;; However, we do *not* change C-j since many Emacsers have already
  ;; swapped RET and C-j and they don't want C-j bound to `newline' to
  ;; change.
  (define-key py-mode-map "\C-m" 'py-newline-and-indent)
  )

(defvar py-mode-output-map nil
  "Keymap used in *Python Output* buffers.")
(if py-mode-output-map
    nil
  (setq py-mode-output-map (make-sparse-keymap))
  (define-key py-mode-output-map [button2]  'py-mouseto-exception)
  (define-key py-mode-output-map "\C-c\C-c" 'py-goto-exception)
  ;; TBD: Disable all self-inserting keys.  This is bogus, we should
  ;; really implement this as *Python Output* buffer being read-only
  (mapcar #' (lambda (key)
	       (define-key py-mode-output-map key
		 #'(lambda () (interactive) (beep))))
	     (where-is-internal 'self-insert-command))
  )

(defvar py-shell-map nil
  "Keymap used in *Python* shell buffers.")
(if py-shell-map
    nil
  (setq py-shell-map (copy-keymap comint-mode-map))
  (define-key py-shell-map [tab]   'tab-to-tab-stop)
  (define-key py-shell-map "\C-c-" 'py-up-exception)
  (define-key py-shell-map "\C-c=" 'py-down-exception)
  )

(defvar py-mode-syntax-table nil
  "Syntax table used in `python-mode' buffers.")
(when (not py-mode-syntax-table)
  (setq py-mode-syntax-table (make-syntax-table))
  (modify-syntax-entry ?\( "()" py-mode-syntax-table)
  (modify-syntax-entry ?\) ")(" py-mode-syntax-table)
  (modify-syntax-entry ?\[ "(]" py-mode-syntax-table)
  (modify-syntax-entry ?\] ")[" py-mode-syntax-table)
  (modify-syntax-entry ?\{ "(}" py-mode-syntax-table)
  (modify-syntax-entry ?\} "){" py-mode-syntax-table)
  ;; Add operator symbols misassigned in the std table
  (modify-syntax-entry ?\$ "."  py-mode-syntax-table)
  (modify-syntax-entry ?\% "."  py-mode-syntax-table)
  (modify-syntax-entry ?\& "."  py-mode-syntax-table)
  (modify-syntax-entry ?\* "."  py-mode-syntax-table)
  (modify-syntax-entry ?\+ "."  py-mode-syntax-table)
  (modify-syntax-entry ?\- "."  py-mode-syntax-table)
  (modify-syntax-entry ?\/ "."  py-mode-syntax-table)
  (modify-syntax-entry ?\< "."  py-mode-syntax-table)
  (modify-syntax-entry ?\= "."  py-mode-syntax-table)
  (modify-syntax-entry ?\> "."  py-mode-syntax-table)
  (modify-syntax-entry ?\| "."  py-mode-syntax-table)
  ;; For historical reasons, underscore is word class instead of
  ;; symbol class.  GNU conventions say it should be symbol class, but
  ;; there's a natural conflict between what major mode authors want
  ;; and what users expect from `forward-word' and `backward-word'.
  ;; Guido and I have hashed this out and have decided to keep
  ;; underscore in word class.  If you're tempted to change it, try
  ;; binding M-f and M-b to py-forward-into-nomenclature and
  ;; py-backward-into-nomenclature instead.  This doesn't help in all
  ;; situations where you'd want the different behavior
  ;; (e.g. backward-kill-word).
  (modify-syntax-entry ?\_ "w"  py-mode-syntax-table)
  ;; Both single quote and double quote are string delimiters
  (modify-syntax-entry ?\' "\"" py-mode-syntax-table)
  (modify-syntax-entry ?\" "\"" py-mode-syntax-table)
  ;; backquote is open and close paren
  (modify-syntax-entry ?\` "$"  py-mode-syntax-table)
  ;; comment delimiters
  (modify-syntax-entry ?\# "<"  py-mode-syntax-table)
  (modify-syntax-entry ?\n ">"  py-mode-syntax-table)
  )

;; An auxiliary syntax table which places underscore and dot in the
;; symbol class for simplicity
(defvar py-dotted-expression-syntax-table nil
  "Syntax table used to identify Python dotted expressions.")
(when (not py-dotted-expression-syntax-table)
  (setq py-dotted-expression-syntax-table
	(copy-syntax-table py-mode-syntax-table))
  (modify-syntax-entry ?_ "_" py-dotted-expression-syntax-table)
  (modify-syntax-entry ?. "_" py-dotted-expression-syntax-table))



;; Utilities
(defmacro py-safe (&rest body)
  "Safely execute BODY, return nil if an error occurred."
  (` (condition-case nil
	 (progn (,@ body))
       (error nil))))

(defsubst py-keep-region-active ()
  "Keep the region active in XEmacs."
  ;; Ignore byte-compiler warnings you might see.  Also note that
  ;; FSF's Emacs 19 does it differently; its policy doesn't require us
  ;; to take explicit action.
  (and (boundp 'zmacs-region-stays)
       (setq zmacs-region-stays t)))

(defsubst py-point (position)
  "Returns the value of point at certain commonly referenced POSITIONs.
POSITION can be one of the following symbols:

  bol  -- beginning of line
  eol  -- end of line
  bod  -- beginning of def or class
  eod  -- end of def or class
  bob  -- beginning of buffer
  eob  -- end of buffer
  boi  -- back to indentation
  bos  -- beginning of statement

This function does not modify point or mark."
  (let ((here (point)))
    (cond
     ((eq position 'bol) (beginning-of-line))
     ((eq position 'eol) (end-of-line))
     ((eq position 'bod) (py-beginning-of-def-or-class 'either))
     ((eq position 'eod) (py-end-of-def-or-class 'either))
     ;; Kind of funny, I know, but useful for py-up-exception.
     ((eq position 'bob) (beginning-of-buffer))
     ((eq position 'eob) (end-of-buffer))
     ((eq position 'boi) (back-to-indentation))
     ((eq position 'bos) (py-goto-initial-line))
     (t (error "Unknown buffer position requested: %s" position))
     )
    (prog1
	(point)
      (goto-char here))))

(defsubst py-highlight-line (from to file line)
  (cond
   ((fboundp 'make-extent)
    ;; XEmacs
    (let ((e (make-extent from to)))
      (set-extent-property e 'mouse-face 'highlight)
      (set-extent-property e 'py-exc-info (cons file line))
      (set-extent-property e 'keymap py-mode-output-map)))
   (t
    ;; Emacs -- Please port this!
    )
   ))

(defun py-in-literal (&optional lim)
  "Return non-nil if point is in a Python literal (a comment or string).
Optional argument LIM indicates the beginning of the containing form,
i.e. the limit on how far back to scan."
  ;; This is the version used for non-XEmacs, which has a nicer
  ;; interface.
  ;;
  ;; WARNING: Watch out for infinite recursion.
  (let* ((lim (or lim (py-point 'bod)))
	 (state (parse-partial-sexp lim (point))))
    (cond
     ((nth 3 state) 'string)
     ((nth 4 state) 'comment)
     (t nil))))

;; XEmacs has a built-in function that should make this much quicker.
;; In this case, lim is ignored
(defun py-fast-in-literal (&optional lim)
  "Fast version of `py-in-literal', used only by XEmacs.
Optional LIM is ignored."
  ;; don't have to worry about context == 'block-comment
  (buffer-syntactic-context))

(if (fboundp 'buffer-syntactic-context)
    (defalias 'py-in-literal 'py-fast-in-literal))



;; Menu definitions, only relevent if you have the easymenu.el package
;; (standard in the latest Emacs 19 and XEmacs 19 distributions).
(defvar py-menu nil
  "Menu for Python Mode.
This menu will get created automatically if you have the `easymenu'
package.  Note that the latest X/Emacs releases contain this package.")

(and (py-safe (require 'easymenu) t)
     (easy-menu-define
      py-menu py-mode-map "Python Mode menu"
      '("Python"
	["Comment Out Region"   py-comment-region  (mark)]
	["Uncomment Region"     (py-comment-region (point) (mark) '(4)) (mark)]
	"-"
	["Mark current block"   py-mark-block t]
	["Mark current def"     py-mark-def-or-class t]
	["Mark current class"   (py-mark-def-or-class t) t]
	"-"
	["Shift region left"    py-shift-region-left (mark)]
	["Shift region right"   py-shift-region-right (mark)]
	"-"
	["Import/reload file"   py-execute-import-or-reload t]
	["Execute buffer"       py-execute-buffer t]
	["Execute region"       py-execute-region (mark)]
	["Execute def or class" py-execute-def-or-class (mark)]
	["Execute string"       py-execute-string t]
	["Start interpreter..." py-shell t]
	"-"
	["Go to start of block" py-goto-block-up t]
	["Go to start of class" (py-beginning-of-def-or-class t) t]
	["Move to end of class" (py-end-of-def-or-class t) t]
	["Move to start of def" py-beginning-of-def-or-class t]
	["Move to end of def"   py-end-of-def-or-class t]
	"-"
	["Describe mode"        py-describe-mode t]
	)))



;; Imenu definitions
(defvar py-imenu-class-regexp
  (concat				; <<classes>>
   "\\("				;
   "^[ \t]*"				; newline and maybe whitespace
   "\\(class[ \t]+[a-zA-Z0-9_]+\\)"	; class name
					; possibly multiple superclasses
   "\\([ \t]*\\((\\([a-zA-Z0-9_,. \t\n]\\)*)\\)?\\)"
   "[ \t]*:"				; and the final :
   "\\)"				; >>classes<<
   )
  "Regexp for Python classes for use with the Imenu package."
  )

(defvar py-imenu-method-regexp
  (concat                               ; <<methods and functions>>
   "\\("                                ;
   "^[ \t]*"                            ; new line and maybe whitespace
   "\\(def[ \t]+"                       ; function definitions start with def
   "\\([a-zA-Z0-9_]+\\)"                ;   name is here
					;   function arguments...
;;   "[ \t]*(\\([-+/a-zA-Z0-9_=,\* \t\n.()\"'#]*\\))"
   "[ \t]*(\\([^:#]*\\))"
   "\\)"                                ; end of def
   "[ \t]*:"                            ; and then the :
   "\\)"                                ; >>methods and functions<<
   )
  "Regexp for Python methods/functions for use with the Imenu package."
  )

(defvar py-imenu-method-no-arg-parens '(2 8)
  "Indices into groups of the Python regexp for use with Imenu.

Using these values will result in smaller Imenu lists, as arguments to
functions are not listed.

See the variable `py-imenu-show-method-args-p' for more
information.")

(defvar py-imenu-method-arg-parens '(2 7)
  "Indices into groups of the Python regexp for use with imenu.
Using these values will result in large Imenu lists, as arguments to
functions are listed.

See the variable `py-imenu-show-method-args-p' for more
information.")

;; Note that in this format, this variable can still be used with the
;; imenu--generic-function. Otherwise, there is no real reason to have
;; it.
(defvar py-imenu-generic-expression
  (cons
   (concat
    py-imenu-class-regexp
    "\\|"				; or...
    py-imenu-method-regexp
    )
   py-imenu-method-no-arg-parens)
  "Generic Python expression which may be used directly with Imenu.
Used by setting the variable `imenu-generic-expression' to this value.
Also, see the function \\[py-imenu-create-index] for a better
alternative for finding the index.")

;; These next two variables are used when searching for the Python
;; class/definitions. Just saving some time in accessing the
;; generic-python-expression, really.
(defvar py-imenu-generic-regexp nil)
(defvar py-imenu-generic-parens nil)


(defun py-imenu-create-index-function ()
  "Python interface function for the Imenu package.
Finds all Python classes and functions/methods. Calls function
\\[py-imenu-create-index-engine].  See that function for the details
of how this works."
  (setq py-imenu-generic-regexp (car py-imenu-generic-expression)
	py-imenu-generic-parens (if py-imenu-show-method-args-p
				    py-imenu-method-arg-parens
				  py-imenu-method-no-arg-parens))
  (goto-char (point-min))
  ;; Warning: When the buffer has no classes or functions, this will
  ;; return nil, which seems proper according to the Imenu API, but
  ;; causes an error in the XEmacs port of Imenu.  Sigh.
  (py-imenu-create-index-engine nil))

(defun py-imenu-create-index-engine (&optional start-indent)
  "Function for finding Imenu definitions in Python.

Finds all definitions (classes, methods, or functions) in a Python
file for the Imenu package.

Returns a possibly nested alist of the form

	(INDEX-NAME . INDEX-POSITION)

The second element of the alist may be an alist, producing a nested
list as in

	(INDEX-NAME . INDEX-ALIST)

This function should not be called directly, as it calls itself
recursively and requires some setup.  Rather this is the engine for
the function \\[py-imenu-create-index-function].

It works recursively by looking for all definitions at the current
indention level.  When it finds one, it adds it to the alist.  If it
finds a definition at a greater indentation level, it removes the
previous definition from the alist. In its place it adds all
definitions found at the next indentation level.  When it finds a
definition that is less indented then the current level, it returns
the alist it has created thus far.

The optional argument START-INDENT indicates the starting indentation
at which to continue looking for Python classes, methods, or
functions.  If this is not supplied, the function uses the indentation
of the first definition found."
  (let (index-alist
	sub-method-alist
	looking-p
	def-name prev-name
	cur-indent def-pos
	(class-paren (first  py-imenu-generic-parens))
	(def-paren   (second py-imenu-generic-parens)))
    (setq looking-p
	  (re-search-forward py-imenu-generic-regexp (point-max) t))
    (while looking-p
      (save-excursion
	;; used to set def-name to this value but generic-extract-name
	;; is new to imenu-1.14. this way it still works with
	;; imenu-1.11
	;;(imenu--generic-extract-name py-imenu-generic-parens))
	(let ((cur-paren (if (match-beginning class-paren)
			     class-paren def-paren)))
	  (setq def-name
		(buffer-substring-no-properties (match-beginning cur-paren)
						(match-end cur-paren))))
	(save-match-data
	  (py-beginning-of-def-or-class 'either))
	(beginning-of-line)
	(setq cur-indent (current-indentation)))
      ;; HACK: want to go to the next correct definition location.  We
      ;; explicitly list them here but it would be better to have them
      ;; in a list.
      (setq def-pos
	    (or (match-beginning class-paren)
		(match-beginning def-paren)))
      ;; if we don't have a starting indent level, take this one
      (or start-indent
	  (setq start-indent cur-indent))
      ;; if we don't have class name yet, take this one
      (or prev-name
	  (setq prev-name def-name))
      ;; what level is the next definition on?  must be same, deeper
      ;; or shallower indentation
      (cond
       ;; Skip code in comments and strings
       ((py-in-literal))
       ;; at the same indent level, add it to the list...
       ((= start-indent cur-indent)
	(push (cons def-name def-pos) index-alist))
       ;; deeper indented expression, recurse
       ((< start-indent cur-indent)
	;; the point is currently on the expression we're supposed to
	;; start on, so go back to the last expression. The recursive
	;; call will find this place again and add it to the correct
	;; list
	(re-search-backward py-imenu-generic-regexp (point-min) 'move)
	(setq sub-method-alist (py-imenu-create-index-engine cur-indent))
	(if sub-method-alist
	    ;; we put the last element on the index-alist on the start
	    ;; of the submethod alist so the user can still get to it.
	    (let ((save-elmt (pop index-alist)))
	      (push (cons prev-name
			  (cons save-elmt sub-method-alist))
		    index-alist))))
       ;; found less indented expression, we're done.
       (t
	(setq looking-p nil)
	(re-search-backward py-imenu-generic-regexp (point-min) t)))
      ;; end-cond
      (setq prev-name def-name)
      (and looking-p
	   (setq looking-p
		 (re-search-forward py-imenu-generic-regexp
				    (point-max) 'move))))
    (nreverse index-alist)))



(defun py-choose-shell-by-shebang ()
  "Choose CPython or Jython mode by looking at #! on the first line.
Returns the appropriate mode function.
Used by `py-choose-shell', and similar to but distinct from
`set-auto-mode', though it uses `auto-mode-interpreter-regexp' (if available)."
  ;; look for an interpreter specified in the first line
  ;; similar to set-auto-mode (files.el)
  (let* ((re (if (boundp 'auto-mode-interpreter-regexp)
		 auto-mode-interpreter-regexp
	       ;; stolen from Emacs 21.2
	       "#![ \t]?\\([^ \t\n]*/bin/env[ \t]\\)?\\([^ \t\n]+\\)"))
	 (interpreter (save-excursion
			(goto-char (point-min))
			(if (looking-at re)
			    (match-string 2)
			  "")))
	 elt)
    ;; Map interpreter name to a mode.
    (setq elt (assoc (file-name-nondirectory interpreter)
		     py-shell-alist))
    (and elt (caddr elt))))



(defun py-choose-shell-by-import ()
  "Choose CPython or Jython mode based imports.
If a file imports any packages in `py-jython-packages', within
`py-import-check-point-max' characters from the start of the file,
return `jython', otherwise return nil."
  (let (mode)
    (save-excursion
      (goto-char (point-min))
      (while (and (not mode)
		  (search-forward-regexp
		   "^\\(\\(from\\)\\|\\(import\\)\\) \\([^ \t\n.]+\\)"
		   py-import-check-point-max t))
	(setq mode (and (member (match-string 4) py-jython-packages)
			'jython
			))))
    mode))


(defun py-choose-shell ()
  "Choose CPython or Jython mode. Returns the appropriate mode function.
This does the following:
 - look for an interpreter with `py-choose-shell-by-shebang'
 - examine imports using `py-choose-shell-by-import'
 - default to the variable `py-default-interpreter'"
  (interactive)
  (or (py-choose-shell-by-shebang)
      (py-choose-shell-by-import)
      py-default-interpreter
;      'cpython ;; don't use to py-default-interpreter, because default
;               ;; is only way to choose CPython
      ))


;;;###autoload
(defun python-mode ()
  "Major mode for editing Python files.
To submit a problem report, enter `\\[py-submit-bug-report]' from a
`python-mode' buffer.  Do `\\[py-describe-mode]' for detailed
documentation.  To see what version of `python-mode' you are running,
enter `\\[py-version]'.

This mode knows about Python indentation, tokens, comments and
continuation lines.  Paragraphs are separated by blank lines only.

COMMANDS
\\{py-mode-map}
VARIABLES

py-indent-offset\t\tindentation increment
py-block-comment-prefix\t\tcomment string used by `comment-region'
py-python-command\t\tshell command to invoke Python interpreter
py-temp-directory\t\tdirectory used for temp files (if needed)
py-beep-if-tab-change\t\tring the bell if `tab-width' is changed"
  (interactive)
  ;; set up local variables
  (kill-all-local-variables)
  (make-local-variable 'font-lock-defaults)
  (make-local-variable 'paragraph-separate)
  (make-local-variable 'paragraph-start)
  (make-local-variable 'require-final-newline)
  (make-local-variable 'comment-start)
  (make-local-variable 'comment-end)
  (make-local-variable 'comment-start-skip)
  (make-local-variable 'comment-column)
  (make-local-variable 'comment-indent-function)
  (make-local-variable 'indent-region-function)
  (make-local-variable 'indent-line-function)
  (make-local-variable 'add-log-current-defun-function)
  (make-local-variable 'fill-paragraph-function)
  ;;
  (set-syntax-table py-mode-syntax-table)
  (setq major-mode              'python-mode
	mode-name               "Python"
	local-abbrev-table      python-mode-abbrev-table
	font-lock-defaults      '(python-font-lock-keywords)
	paragraph-separate      "^[ \t]*$"
	paragraph-start         "^[ \t]*$"
	require-final-newline   t
	comment-start           "# "
	comment-end             ""
	comment-start-skip      "# *"
	comment-column          40
	comment-indent-function 'py-comment-indent-function
	indent-region-function  'py-indent-region
	indent-line-function    'py-indent-line
	;; tell add-log.el how to find the current function/method/variable
	add-log-current-defun-function 'py-current-defun

	fill-paragraph-function 'py-fill-paragraph
	)
  (use-local-map py-mode-map)
  ;; add the menu
  (if py-menu
      (easy-menu-add py-menu))
  ;; Emacs 19 requires this
  (if (boundp 'comment-multi-line)
      (setq comment-multi-line nil))
  ;; Install Imenu if available
  (when (py-safe (require 'imenu))
    (setq imenu-create-index-function #'py-imenu-create-index-function)
    (setq imenu-generic-expression py-imenu-generic-expression)
    (if (fboundp 'imenu-add-to-menubar)
	(imenu-add-to-menubar (format "%s-%s" "IM" mode-name)))
    )
  ;; Run the mode hook.  Note that py-mode-hook is deprecated.
  (if python-mode-hook
      (run-hooks 'python-mode-hook)
    (run-hooks 'py-mode-hook))
  ;; Now do the automagical guessing
  (if py-smart-indentation
    (let ((offset py-indent-offset))
      ;; It's okay if this fails to guess a good value
      (if (and (py-safe (py-guess-indent-offset))
	       (<= py-indent-offset 8)
	       (>= py-indent-offset 2))
	  (setq offset py-indent-offset))
      (setq py-indent-offset offset)
      ;; Only turn indent-tabs-mode off if tab-width !=
      ;; py-indent-offset.  Never turn it on, because the user must
      ;; have explicitly turned it off.
      (if (/= tab-width py-indent-offset)
	  (setq indent-tabs-mode nil))
      ))
  ;; Set the default shell if not already set
  (when (null py-which-shell)
    (py-toggle-shells (py-choose-shell))))


(make-obsolete 'jpython-mode 'jython-mode)
(defun jython-mode ()
  "Major mode for editing Jython/Jython files.
This is a simple wrapper around `python-mode'.
It runs `jython-mode-hook' then calls `python-mode.'
It is added to `interpreter-mode-alist' and `py-choose-shell'.
"
  (interactive)
  (python-mode)
  (py-toggle-shells 'jython)
  (when jython-mode-hook
      (run-hooks 'jython-mode-hook)))


;; It's handy to add recognition of Python files to the
;; interpreter-mode-alist and to auto-mode-alist.  With the former, we
;; can specify different `derived-modes' based on the #! line, but
;; with the latter, we can't.  So we just won't add them if they're
;; already added.
;;;###autoload
(let ((modes '(("jython" . jython-mode)
	       ("python" . python-mode))))
  (while modes
    (when (not (assoc (car modes) interpreter-mode-alist))
      (push (car modes) interpreter-mode-alist))
    (setq modes (cdr modes))))
;;;###autoload
(when (not (or (rassq 'python-mode auto-mode-alist)
	       (rassq 'jython-mode auto-mode-alist)))
  (push '("\\.py$" . python-mode) auto-mode-alist))



;; electric characters
(defun py-outdent-p ()
  "Returns non-nil if the current line should dedent one level."
  (save-excursion
    (and (progn (back-to-indentation)
		(looking-at py-outdent-re))
	 ;; short circuit infloop on illegal construct
	 (not (bobp))
	 (progn (forward-line -1)
		(py-goto-initial-line)
		(back-to-indentation)
		(while (or (looking-at py-blank-or-comment-re)
			   (bobp))
		  (backward-to-indentation 1))
		(not (looking-at py-no-outdent-re)))
	 )))

(defun py-electric-colon (arg)
  "Insert a colon.
In certain cases the line is dedented appropriately.  If a numeric
argument ARG is provided, that many colons are inserted
non-electrically.  Electric behavior is inhibited inside a string or
comment."
  (interactive "*P")
  (self-insert-command (prefix-numeric-value arg))
  ;; are we in a string or comment?
  (if (save-excursion
	(let ((pps (parse-partial-sexp (save-excursion
					 (py-beginning-of-def-or-class)
					 (point))
				       (point))))
	  (not (or (nth 3 pps) (nth 4 pps)))))
      (save-excursion
	(let ((here (point))
	      (outdent 0)
	      (indent (py-compute-indentation t)))
	  (if (and (not arg)
		   (py-outdent-p)
		   (= indent (save-excursion
			       (py-next-statement -1)
			       (py-compute-indentation t)))
		   )
	      (setq outdent py-indent-offset))
	  ;; Don't indent, only dedent.  This assumes that any lines
	  ;; that are already dedented relative to
	  ;; py-compute-indentation were put there on…