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+;;; python.el --- silly walks for Python
+
+;; Copyright (C) 2003, 04  Free Software Foundation, Inc.
+
+;; Author: Dave Love <fx@gnu.org>
+;; Created: Nov 2003
+;; Keywords: languages
+
+;; This file is part of GNU Emacs.
+
+;; This file 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.
+
+;; This file 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:
+
+;; Major mode for editing Python, with support for inferior processes.
+
+;; There is another Python mode, python-mode.el, used by XEmacs and
+;; maintained with Python.  That isn't covered by an FSF copyright
+;; assignment, unlike this code, and seems not to be well-maintained
+;; for Emacs (though I've submitted fixes).  This mode is rather
+;; simpler and is, perhaps, better in other ways.  In particular,
+;; using the syntax functions with text properties maintained by
+;; font-lock should make it more correct with arbitrary string and
+;; comment contents.
+
+;; This doesn't implement all the facilities of python-mode.el.  Some
+;; just need doing, e.g. catching exceptions in the inferior Python
+;; buffer (but see M-x pdb for debugging).  [Atually, the use of
+;; `compilation-minor-mode' now is probably enough for that.]  Others
+;; don't seem appropriate.  For instance, `forward-into-nomenclature'
+;; should be done separately, since it's not specific to Python, and
+;; I've installed a minor mode to do the job properly in Emacs 22.
+;; Other things seem more natural or canonical here, e.g. the
+;; {beginning,end}-of-defun implementation dealing with nested
+;; definitions, and the inferior mode following `cmuscheme'.  (The
+;; inferior mode should be able to find the source of errors from
+;; `python-send-region' & al via `compilation-minor-mode', but I can't
+;; make that work with the current (March '04) compile.el.)
+;; Successive TABs cycle between possible indentations for the line.
+
+;; Even where it has similar facilities, this is incompatible with
+;; python-mode.el in various respects.  For instance, various key
+;; bindings are changed to obey Emacs conventions, and things like
+;; marking blocks and `beginning-of-defun' behave differently.
+
+;;; Code:
+
+(require 'syntax)                       ; ensure appropriate version
+;; It's messy to autoload the relevant comint functions so that comint
+;; is only required when inferior Python is used.
+(require 'comint)
+
+(defgroup python nil
+  "Silly walks in the Python language"
+  :group 'languages
+  :link '(emacs-commentary-link "python"))
+
+;;;###autoload
+(add-to-list 'interpreter-mode-alist '("jython" . jython-mode))
+;;;###autoload
+(add-to-list 'interpreter-mode-alist '("python" . python-mode))
+;;;###autoload
+(add-to-list 'auto-mode-alist '("\\.py\\'" . python-mode))
+
+;;;; Font lock
+
+(defvar python-font-lock-keywords
+  `(,(rx (and word-start
+              ;; From v 2.3 reference.
+              ;; def and class dealt with separately below
+              (or "and" "assert" "break" "continue" "del" "elif" "else"
+                  "except" "exec" "finally" "for" "from" "global" "if"
+                  "import" "in" "is" "lambda" "not" "or" "pass" "print"
+                  "raise" "return" "try" "while" "yield"
+                  ;; Future keywords
+                  "as" "None")
+              word-end))
+   (,(rx (and word-start (group "class") (1+ space) (group (1+ word))))
+    (1 font-lock-keyword-face) (2 font-lock-type-face))
+   (,(rx (and word-start (group "def") (1+ space) (group (1+ word))))
+    (1 font-lock-keyword-face) (2 font-lock-function-name-face))))
+
+(defconst python-font-lock-syntactic-keywords
+  ;; Make outer chars of matching triple-quote sequences into generic
+  ;; string delimiters.  Fixme: Is there a better way?
+  `((,(rx (and (group (optional (any "uUrR"))) ; prefix gets syntax property
+               (optional (any "rR"))    ; possible second prefix
+               (group (syntax string-quote))    ; maybe gets property
+               (backref 2)                      ; per first quote
+               (group (backref 2))))            ; maybe gets property
+     (1 (python-quote-syntax 1)) (2 (python-quote-syntax 2))
+     (3 (python-quote-syntax 3)))
+    ;; This doesn't really help.
+;;;     (,(rx (and ?\\ (group ?\n))) (1 " "))
+    ))
+
+(defun python-quote-syntax (n)
+  "Put `syntax-table' property correctly on triple quote.
+Used for syntactic keywords.  N is the match number (1, 2 or 3)."
+  ;; Given a triple quote, we have to look backwards for a previous
+  ;; occurrence of the sequence to know whether this is an opening or
+  ;; closing triple.  We also have to sort out a possible prefix --
+  ;; well, we don't _have_ to, but I think it should be treated as
+  ;; part of the string.
+  (let ((tag (save-excursion
+               (goto-char (match-beginning 0))
+               (unless (eq ?\\ (char-before))
+                 (cond
+                  ;; Look for a previous string fence.
+                  ((or (zerop (skip-syntax-backward "^|"))
+                       (bobp))
+                   'start)              ; no previous string fence
+                  ;; Check fence on a matching quote.
+                  ((eq (char-before) (char-after (match-beginning 2)))
+                   (if (eq (char-before) (char-after))
+                       'end             ; fence ended string
+                     'start))           ; began string
+                  ;; Check for matching prefixed string.
+                  ((and (memq (char-before) '(?u ?U ?r ?R))
+                        (skip-chars-forward "rR"))
+                   (if (eq (char-after) (char-after (match-beginning 2)))
+                       'end))          ; else non-matching: return nil
+                  ;; For non-matching quote,  start new string.
+                  ((/= (char-before) (char-after))
+                   'start))))))
+    (if (if (eq tag 'start)             ; Maybe starts a new string.
+            ;; Initial property if this is the prefix (empty or not) or
+            ;; isn't the prefix and the prefix is empty.
+            (or (= n 1) (and (= n 2) (= (match-beginning 1) (match-end 1))))
+          (and (eq tag 'end)            ; Maybe ends existing string.
+               (= n 3)))                ; Match is at end.
+        (eval-when-compile (string-to-syntax "|"))
+      ;; Otherwise the property is nil, which is OK.
+      )))
+
+;; This isn't currently in `font-lock-defaults' as probably not worth
+;; it -- we basically only mess with a few normally-symbol characters.
+
+;; (defun python-font-lock-syntactic-face-function (state)
+;;   "`font-lock-syntactic-face-function' for Python mode.
+;; Returns the string or comment face as usual, with side effect of putting
+;; a `syntax-table' property on the inside of the string or comment which is
+;; the standard syntax table."
+;;   (if (nth 3 state)
+;;       (save-excursion
+;;      (goto-char (nth 8 state))
+;;      (condition-case nil
+;;          (forward-sexp)
+;;        (error nil))
+;;      (put-text-property (1+ (nth 8 state)) (1- (point))
+;;                         'syntax-table (standard-syntax-table))
+;;      'font-lock-string-face)
+;;     (put-text-property (1+ (nth 8 state)) (line-end-position)
+;;                         'syntax-table (standard-syntax-table))
+;;     'font-lock-comment-face))
+
+;;;; Keymap and syntax
+
+(defvar python-mode-map
+  (let ((map (make-sparse-keymap)))
+    ;; Mostly taken from python-mode.el.
+    (define-key map ":" 'python-electric-colon)
+    (define-key map "\177" 'python-backspace)
+    (define-key map "\C-c<" 'python-shift-left)
+    (define-key map "\C-c>" 'python-shift-right)
+    (define-key map "\C-c\C-k" 'python-mark-block)
+    (define-key map "\C-c\C-n" 'python-next-statement)
+    (define-key map "\C-c\C-p" 'python-previous-statement)
+    (define-key map "\C-c\C-u" 'python-beginning-of-block)
+    (define-key map "\C-c\C-f" 'python-describe-symbol)
+    (define-key map "\C-c\C-w" 'python-check)
+    (define-key map "\C-c\C-v" 'python-check) ; a la sgml-mode
+    (define-key map "\C-c\C-s" 'python-send-string)
+    (define-key map [?\C-\M-x] 'python-send-defun)
+    (define-key map "\C-c\C-r" 'python-send-region)
+    (define-key map "\C-c\M-r" 'python-send-region-and-go)
+    (define-key map "\C-c\C-c" 'python-send-buffer)
+    (define-key map "\C-c\C-z" 'python-switch-to-python)
+    (define-key map "\C-c\C-m" 'python-load-file)
+    (define-key map "\C-c\C-l" 'python-load-file) ; a la cmuscheme
+    ;; Fixme: Add :help to menu.
+    (easy-menu-define python-menu map "Python Mode menu"
+      '("Python"
+        ["Shift region left" python-shift-left :active mark-active]
+        ["Shift region right" python-shift-right :active mark-active]
+        "-"
+        ["Mark block" python-mark-block]
+        ["Mark def/class" mark-defun
+         :help "Mark innermost definition around point"]
+        "-"
+        ["Start of block" python-beginning-of-block]
+        ["End of block" python-end-of-block]
+        ["Start of def/class" beginning-of-defun
+         :help "Go to start of innermost definition around point"]
+        ["End of def/class" end-of-defun
+         :help "Go to end of innermost definition around point"]
+        "-"
+        ["Start interpreter" run-python
+         :help "Run `inferior' Python in separate buffer"]
+        ["Import/reload file" python-load-file
+         :help "Load into inferior Python session"]
+        ["Eval buffer" python-send-buffer
+         :help "Evaluate buffer en bloc in inferior Python session"]
+        ["Eval region" python-send-region :active mark-active
+         :help "Evaluate region en bloc in inferior Python session"]
+        ["Eval def/class" python-send-defun
+         :help "Evaluate current definition in inferior Python session"]
+        ["Switch to interpreter" python-switch-to-python
+         :help "Switch to inferior Python buffer"]
+        ["Check file" python-check :help "Run pychecker"]
+        ["Debugger" pdb :help "Run pdb under GUD"]
+        "-"
+        ["Help on symbol" python-describe-symbol
+         :help "Use pydoc on symbol at point"]))
+    map))
+
+(defvar python-mode-syntax-table
+  (let ((table (make-syntax-table)))
+    ;; Give punctuation syntax to ASCII that normally has symbol
+    ;; syntax or has word syntax and isn't a letter.
+    (let ((symbol (string-to-syntax "_"))
+          (sst (standard-syntax-table)))
+      (dotimes (i 128)
+        (unless (= i ?_)
+          (if (equal symbol (aref sst i))
+              (modify-syntax-entry i "." table)))))
+    (modify-syntax-entry ?$ "." table)
+    (modify-syntax-entry ?% "." table)
+    ;; exceptions
+    (modify-syntax-entry ?# "<" table)
+    (modify-syntax-entry ?\n ">" table)
+    (modify-syntax-entry ?' "\"" table)
+    (modify-syntax-entry ?` "$" table)
+    table))
+
+;;;; Utility stuff
+
+(defsubst python-in-string/comment ()
+  "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."
+  (syntax-ppss-context (syntax-ppss)))
+
+(defconst python-space-backslash-table
+  (let ((table (copy-syntax-table python-mode-syntax-table)))
+    (modify-syntax-entry ?\\ " " table)
+    table)
+  "`python-mode-syntax-table' with backslash given whitespace syntax.")
+
+(defun python-skip-comments/blanks (&optional backward)
+  "Skip comments and blank lines.
+BACKWARD non-nil means go backwards, otherwise go forwards.  Backslash is
+treated as whitespace so that continued blank lines are skipped.
+Doesn't move out of comments -- should be outside or at end of line."
+  (with-syntax-table python-space-backslash-table
+    (forward-comment (if backward
+                         most-negative-fixnum
+                       most-positive-fixnum))))
+
+(defun python-backslash-continuation-line-p ()
+  "Non-nil if preceding line ends with backslash that is not in a comment."
+  (and (eq ?\\ (char-before (line-end-position 0)))
+       (not (syntax-ppss-context (syntax-ppss)))))
+
+(defun python-continuation-line-p ()
+  "Return non-nil if current line continues a previous one.
+The criteria are that the previous line ends in a backslash outside
+comments and strings, or that the bracket/paren nesting depth is nonzero."
+  (or (and (eq ?\\ (char-before (line-end-position 0)))
+           (not (syntax-ppss-context (syntax-ppss))))
+      (/= 0 (syntax-ppss-depth
+             (save-excursion      ; syntax-ppss with arg changes point
+               (syntax-ppss (line-beginning-position)))))))
+
+(defun python-comment-line-p ()
+  "Return non-nil if current line has only a comment or is blank."
+  (save-excursion
+    (back-to-indentation)
+    (looking-at (rx (or (syntax comment-start) line-end)))))
+
+(defun python-beginning-of-string ()
+  "Go to beginning of string around point.
+Do nothing if not in string."
+  (let ((state (syntax-ppss)))
+    (when (nth 3 state)
+      (goto-char (nth 8 state)))))
+
+(defun python-open-block-statement-p (&optional bos)
+  "Return non-nil if statement at point opens a block.
+BOS non-nil means point is known to be at beginning of statement."
+  (save-excursion
+    (unless bos (python-beginning-of-statement))
+    (and (not (python-comment-line-p))
+         (re-search-forward (rx (and ?: (0+ space)
+                                     (optional (and (syntax comment-start)
+                                                    (0+ not-newline)))
+                                     line-end))
+                            (save-excursion (python-end-of-statement))
+                            t)
+         (not (python-in-string/comment)))))
+
+(defun python-close-block-statement-p (&optional bos)
+  "Return non-nil if current line is a statement closing a block.
+BOS non-nil means point is at beginning of statement.
+The criteria are that the line isn't a comment or in string and starts with
+keyword `raise', `break', `continue' or `pass'."
+  (save-excursion
+    (unless bos (python-beginning-of-statement))
+    (back-to-indentation)
+    (looking-at (rx (and (or "return" "raise" "break" "continue" "pass")
+                         word-end)))))
+
+(defun python-outdent-p ()
+  "Return non-nil if current line should outdent a level."
+  (save-excursion
+    (back-to-indentation)
+    (and (looking-at (rx (and (or (and (or "else" "finally") word-end)
+                                  (and (or "except" "elif") word-end
+                                       (1+ (not (any ?:)))))
+                              (optional space) ":" (optional space)
+                              (or (syntax comment-start) line-end))))
+         (progn (end-of-line)
+                (not (python-in-string/comment)))
+         ;; Ensure there's a previous statement and move to it.
+         (zerop (python-previous-statement))
+         (not (python-close-block-statement-p t))
+         ;; Fixme: check this
+         (not (looking-at (rx (and (or (and (or "if" "elif" "except"
+                                                "for" "while")
+                                            word-end (1+ (not (any ?:))))
+                                       (and "try" word-end))
+                                   (optional space) ":" (optional space)
+                                   (or (syntax comment-start) line-end)))))
+         (progn (end-of-line)
+                (not (python-in-string/comment))))))
+
+;;;; Indentation.
+
+(defcustom python-indent 4
+  "*Number of columns for a unit of indentation in Python mode.
+See also `\\[python-guess-indent]'"
+  :group 'python
+  :type 'integer)
+
+(defcustom python-guess-indent t
+  "*Non-nil means Python mode guesses `python-indent' for the buffer."
+  :type 'boolean
+  :group 'python)
+
+(defcustom python-indent-string-contents t
+  "*Non-nil means indent contents of multi-line strings together.
+This means indent them the same as the preceding non-blank line.
+Otherwise indent them to column zero."
+  :type '(choice (const :tag "Align with preceding" t)
+                 (const :tag "Indent to column 0" nil))
+  :group 'python)
+
+(defcustom python-honour-comment-indentation nil
+  "Non-nil means indent relative to preceding comment line.
+Only do this for comments where the leading comment character is followed
+by space."
+  :type 'boolean
+  :group 'python)
+
+(defcustom python-continuation-offset 4
+  "*Number of columns of additional indentation for continuation lines.
+Continuation lines follow a backslash-terminated line starting a statement."
+  :group 'python
+  :type 'integer)
+
+(defun python-guess-indent ()
+  "Guess step for indentation of current buffer.
+Set `python-indent' locally to the value guessed."
+  (interactive)
+  (save-excursion
+    (goto-char (point-min))
+    (let (done indent)
+      (while (and (not done) (not (eobp)))
+        (when (and (re-search-forward (rx (and ?: (0+ space)
+                                               (or (syntax comment-start)
+                                                   line-end)))
+                                      nil 'move)
+                   (python-open-block-statement-p))
+          (save-excursion
+            (python-beginning-of-statement)
+            (let ((initial (current-indentation)))
+              (if (zerop (python-next-statement))
+                  (setq indent (- (current-indentation) initial)))
+              (if (and (>= indent 2) (<= indent 8)) ; sanity check
+                  (setq done t))))))
+      (when done
+        (when (/= indent (default-value 'python-indent))
+          (set (make-local-variable 'python-indent) indent)
+          (unless (= tab-width python-indent)
+            (setq indent-tabs-mode nil)))
+        indent))))
+
+(defun python-calculate-indentation ()
+  "Calculate Python indentation for line at point."
+  (save-excursion
+    (beginning-of-line)
+    (let ((syntax (syntax-ppss))
+          start)
+      (cond
+       ((eq 'string (syntax-ppss-context syntax)) ; multi-line string
+        (if (not python-indent-string-contents)
+            0
+          (save-excursion
+            ;; Find indentation of preceding non-blank line within string.
+            (setq start (nth 8 syntax))
+            (forward-line -1)
+            (while (and (< start (point)) (looking-at "\\s-*$"))
+              (forward-line -1))
+            (current-indentation))))
+       ((python-continuation-line-p)
+        (let ((point (point))
+              (open-start (cadr syntax)))
+          (if open-start
+              ;; Inside bracketed expression.
+              (progn
+                (goto-char (1+ open-start))
+                ;; Look for first item in list (preceding point) and
+                ;; align with it, if found.
+                (if (with-syntax-table python-space-backslash-table
+                      (let ((parse-sexp-ignore-comments t))
+                        (condition-case ()
+                            (progn (forward-sexp)
+                                   (backward-sexp)
+                                   (< (point) point))
+                          (error nil))))
+                    (current-column)
+                  ;; Otherwise indent relative to statement start, one
+                  ;; level per bracketing level.
+                  (goto-char (1+ open-start))
+                  (python-beginning-of-statement)
+                  (+ (current-indentation) (* (car syntax) python-indent))))
+            ;; Otherwise backslash-continued.
+            (forward-line -1)
+            (if (python-continuation-line-p)
+                ;; We're past first continuation line.  Align with
+                ;; previous line.
+                (current-indentation)
+              ;; First continuation line.  Indent one step, with an
+              ;; extra one if statement opens a block.
+              (save-excursion
+                (python-beginning-of-statement)
+                (+ (current-indentation) python-continuation-offset
+                   (if (python-open-block-statement-p t)
+                       python-indent
+                     0)))))))
+       ((bobp) 0)
+       ;; Fixme: Like python-mode.el; not convinced by this.
+       ((looking-at (rx (and (0+ space) (syntax comment-start)
+                             (not (any " \t\n"))))) ; non-indentable comment
+        (current-indentation))
+       (t (let ((point (point)))
+            (if python-honour-comment-indentation
+                ;; Back over whitespace, newlines, non-indentable comments.
+                (catch 'done
+                  (while t
+                    (if (cond ((bobp))
+                              ;; not at comment start
+                              ((not (forward-comment -1))
+                               (python-beginning-of-statement)
+                               t)
+                              ;; trailing comment
+                              ((/= (current-column) (current-indentation))
+                               (python-beginning-of-statement)
+                               t)
+                              ;; indentable comment like python-mode.el
+                              ((and (looking-at (rx (and (syntax comment-start)
+                                                         (or space line-end))))
+                                    (/= 0 (current-column)))))
+                        (throw 'done t))))
+              ;; Else back over all comments.
+              (python-skip-comments/blanks t)
+              (python-beginning-of-statement))
+            ;; don't lose on bogus outdent
+            (max 0 (+ (current-indentation)
+                      (or (cond ((python-open-block-statement-p t)
+                                 python-indent)
+                                ((python-close-block-statement-p t)
+                                 (- python-indent)))
+                          (progn (goto-char point)
+                                 (if (python-outdent-p)
+                                     (- python-indent)))
+                          0)))))))))
+
+;;;; Cycling through the possible indentations with successive TABs.
+
+;; These don't need to be buffer-local since they're only relevant
+;; during a cycle.
+
+;; Alist of possible indentations and start of statement they would close.
+(defvar python-indent-list nil
+  "Internal use.")
+;; Length of the above
+(defvar python-indent-list-length nil
+  "Internal use.")
+;; Current index into the alist.
+(defvar python-indent-index nil
+  "Internal use.")
+
+(defun python-initial-text ()
+  "Text of line following indentation and ignoring any trailing comment."
+  (buffer-substring (+ (line-beginning-position) (current-indentation))
+                    (save-excursion
+                      (end-of-line)
+                      (forward-comment -1)
+                      (point))))
+
+(defun python-indentation-levels ()
+  "Return a list of possible indentations for this statement.
+Includes the default indentation and those which would close all
+enclosing blocks."
+  (save-excursion
+    (let ((levels (list (cons (current-indentation) nil))))
+      ;; Only one possibility if we immediately follow a block open or
+      ;; are in a continuation line.
+      (unless (or (python-continuation-line-p)
+                  (save-excursion (and (python-previous-statement)
+                                       (python-open-block-statement-p t))))
+        (while (python-beginning-of-block)
+          (push (cons (current-indentation) (python-initial-text))
+                levels)))
+      levels)))
+
+;; This is basically what `python-indent-line' would be if we didn't
+;; do the cycling.
+(defun python-indent-line-1 ()
+  "Subroutine of `python-indent-line'."
+  (let ((target (python-calculate-indentation))
+        (pos (- (point-max) (point))))
+    (if (= target (current-indentation))
+        (if (< (current-column) (current-indentation))
+            (back-to-indentation))
+      (beginning-of-line)
+      (delete-horizontal-space)
+      (indent-to target)
+      (if (> (- (point-max) pos) (point))
+          (goto-char (- (point-max) pos))))))
+
+;; Fixme: Is the arg necessary?
+(defun python-indent-line (&optional arg)
+  "Indent current line as Python code.
+When invoked via `indent-for-tab-command', cycle through possible
+indentations for current line.  The cycle is broken by a command different
+from `indent-for-tab-command', i.e. successive TABs do the cycling."
+  (interactive)
+  ;; Don't do extra work if invoked via `indent-region', for instance.
+  (if (not (eq this-command 'indent-for-tab-command))
+      (python-indent-line-1)
+    (if (eq last-command this-command)
+        (if (= 1 python-indent-list-length)
+            (message "Sole indentation")
+          (progn (setq python-indent-index (% (1+ python-indent-index)
+                                              python-indent-list-length))
+                 (beginning-of-line)
+                 (delete-horizontal-space)
+                 (indent-to (car (nth python-indent-index python-indent-list)))
+                 (let ((text (cdr (nth python-indent-index
+                                       python-indent-list))))
+                   (if text (message "Closes: %s" text)))))
+      (python-indent-line-1)
+      (setq python-indent-list (python-indentation-levels)
+            python-indent-list-length (length python-indent-list)
+            python-indent-index (1- python-indent-list-length)))))
+
+;;;; Movement.
+
+(defun python-beginning-of-defun ()
+  "`beginning-of-defun-function' for Python.
+Finds beginning of innermost nested class or method definition.
+Returns the name of the definition found at the end, or nil if reached
+start of buffer."
+  (let ((ci (current-indentation))
+        (def-re (rx (and line-start (0+ space) (or "def" "class")
+                         (1+ space)
+                         (group (1+ (or word (syntax symbol)))))))
+        point found lep def-line)
+    (if (python-comment-line-p)
+        (setq ci most-positive-fixnum))
+    (while (and (not (bobp)) (not found))
+      ;; Treat bol at beginning of function as outside function so
+      ;; that successive C-M-a makes progress backwards.
+      (setq def-line (looking-at def-re))
+      (unless (bolp) (end-of-line))
+      (setq lep (line-end-position))
+      (if (and (re-search-backward def-re nil 'move)
+               ;; Must be less indented or matching top level, or
+               ;; equally indented if we started on a definition line.
+               (let ((in (current-indentation)))
+               (or (and (zerop ci) (zerop in))
+                   (= lep (line-end-position)) ; on initial line
+                   (and def-line (= in ci))
+                   (< in ci)))
+               (not (python-in-string/comment)))
+          (setq found t)))))
+
+(defun python-end-of-defun ()
+  "`end-of-defun-function' for Python.
+Finds end of innermost nested class or method definition."
+  (let ((orig (point))
+        (pattern (rx (and line-start (0+ space)
+                          (or "def" "class") space))))
+    ;; Go to start of current block and check whether it's at top
+    ;; level.  If it is, and not a block start, look forward for
+    ;; definition statement.
+    (when (python-comment-line-p)
+      (end-of-line)
+      (forward-comment most-positive-fixnum))
+    (if (not (python-open-block-statement-p))
+        (python-beginning-of-block))
+    (if (zerop (current-indentation))
+        (unless (python-open-block-statement-p)
+          (while (and (re-search-forward pattern nil 'move)
+                      (python-in-string/comment))) ; just loop
+          (unless (eobp)
+            (beginning-of-line)))
+      ;; Don't move before top-level statement that would end defun.
+      (end-of-line)
+      (python-beginning-of-defun))
+    ;; If we got to the start of buffer, look forward for
+    ;; definition statement.
+    (if (and (bobp) (not (looking-at "def\\|class")))
+        (while (and (not (eobp))
+                    (re-search-forward pattern nil 'move)
+                    (python-in-string/comment)))) ; just loop
+    ;; We're at a definition statement (or end-of-buffer).
+    (unless (eobp)
+      (python-end-of-block)
+      ;; Count trailing space in defun (but not trailing comments).
+      (skip-syntax-forward " >")
+      (beginning-of-line))
+    ;; Catch pathological case like this, where the beginning-of-defun
+    ;; skips to a definition we're not in:
+    ;; if ...:
+    ;;     ...
+    ;; else:
+    ;;     ...  # point here
+    ;;     ...
+    ;;     def ...
+    (if (< (point) orig)
+        (goto-char (point-max)))))
+
+(defun python-beginning-of-statement ()
+  "Go to start of current statement.
+Accounts for continuation lines, multi-line strings, and multi-line bracketed
+expressions."
+  (beginning-of-line)
+  (python-beginning-of-string)
+  (while (python-continuation-line-p)
+    (beginning-of-line)
+    (if (python-backslash-continuation-line-p)
+        (while (python-backslash-continuation-line-p)
+          (forward-line -1))
+      (python-beginning-of-string)
+      ;; Skip forward out of nested brackets.
+      (condition-case ()                ; beware invalid syntax
+          (progn (backward-up-list (syntax-ppss-depth (syntax-ppss))) t)
+        (error (end-of-line)))))
+  (back-to-indentation))
+
+(defun python-end-of-statement ()
+  "Go to the end of the current statement and return point.
+Usually this is the start of the next line, but if this is a
+multi-line statement we need to skip over the continuation lines.
+On a comment line, go to end of line."
+  (end-of-line)
+  (while (let (comment)
+           ;; Move past any enclosing strings and sexps, or stop if
+           ;; we're in a comment.
+           (while (let ((s (syntax-ppss)))
+                    (cond ((eq 'comment (syntax-ppss-context s))
+                           (setq comment t)
+                           nil)
+                          ((eq 'string (syntax-ppss-context s))
+                           ;; Go to start of string and skip it.
+                           (goto-char (nth 8 s))
+                           (condition-case () ; beware invalid syntax
+                               (progn (forward-sexp) t)
+                             (error (end-of-line))))
+                          ((> (syntax-ppss-depth s) 0)
+                           ;; Skip forward out of nested brackets.
+                           (condition-case () ; beware invalid syntax
+                               (progn (backward-up-list
+                                       (- (syntax-ppss-depth s)))
+                                      t)
+                             (error (end-of-line))))))
+             (end-of-line))
+           (unless comment
+             (eq ?\\ (char-before))))   ; Line continued?
+    (end-of-line 2))                    ; Try next line.
+  (point))
+
+(defun python-previous-statement (&optional count)
+  "Go to start of previous statement.
+With argument COUNT, do it COUNT times.  Stop at beginning of buffer.
+Return count of statements left to move."
+  (interactive "p")
+  (unless count (setq count 1))
+  (if (< count 0)
+      (python-next-statement (- count))
+    (python-beginning-of-statement)
+    (while (and (> count 0) (not (bobp)))
+      (python-skip-comments/blanks t)
+      (python-beginning-of-statement)
+      (unless (bobp) (setq count (1- count))))
+    count))
+
+(defun python-next-statement (&optional count)
+  "Go to start of next statement.
+With argument COUNT, do it COUNT times.  Stop at end of buffer.
+Return count of statements left to move."
+  (interactive "p")
+  (unless count (setq count 1))
+  (if (< count 0)
+      (python-previous-statement (- count))
+    (beginning-of-line)
+    (while (and (> count 0) (not (eobp)))
+      (python-end-of-statement)
+      (python-skip-comments/blanks)
+      (setq count (1- count)))
+    count))
+
+(defun python-beginning-of-block (&optional arg)
+  "Go to start of current block.
+With numeric arg, do it that many times.  If ARG is negative, call
+`python-end-of-block' instead.
+If point is on the first line of a block, use its outer block.
+If current statement is in column zero, don't move and return nil.
+Otherwise return non-nil."
+  (interactive "p")
+  (unless arg (setq arg 1))
+  (cond
+   ((zerop arg))
+   ((< arg 0) (python-end-of-block (- arg)))
+   (t
+    (let ((point (point)))
+      (if (python-comment-line-p)
+          (python-skip-comments/blanks t))
+      (python-beginning-of-statement)
+      (let ((ci (current-indentation)))
+        (if (zerop ci)
+            (not (goto-char point))     ; return nil
+          ;; Look upwards for less indented statement.
+          (if (catch 'done
+;;; This is slower than the below.
+;;;       (while (zerop (python-previous-statement))
+;;;         (when (and (< (current-indentation) ci)
+;;;                    (python-open-block-statement-p t))
+;;;           (beginning-of-line)
+;;;           (throw 'done t)))
+                (while (and (zerop (forward-line -1)))
+                  (when (and (< (current-indentation) ci)
+                             (not (python-comment-line-p))
+                             ;; Move to beginning to save effort in case
+                             ;; this is in string.
+                             (progn (python-beginning-of-statement) t)
+                             (python-open-block-statement-p t))
+                    (beginning-of-line)
+                    (throw 'done t)))
+                (not (goto-char point))) ; Failed -- return nil
+              (python-beginning-of-block (1- arg)))))))))
+
+(defun python-end-of-block (&optional arg)
+  "Go to end of current block.
+With numeric arg, do it that many times.  If ARG is negative, call
+`python-beginning-of-block' instead.
+If current statement is in column zero and doesn't open a block, don't
+move and return nil.  Otherwise return t."
+  (interactive "p")
+  (unless arg (setq arg 1))
+  (if (< arg 0)
+      (python-beginning-of-block (- arg)))
+  (while (and (> arg 0)
+              (let* ((point (point))
+                     (_ (if (python-comment-line-p)
+                            (python-skip-comments/blanks t)))
+                     (ci (current-indentation))
+                     (open (python-open-block-statement-p)))
+                (if (and (zerop ci) (not open))
+                    (not (goto-char point))
+                  (catch 'done
+                    (while (zerop (python-next-statement))
+                      (when (or (and open (<= (current-indentation) ci))
+                                (< (current-indentation) ci))
+                        (python-skip-comments/blanks t)
+                        (beginning-of-line 2)
+                        (throw 'done t)))
+                    (not (goto-char point))))))
+    (setq arg (1- arg)))
+  (zerop arg))
+
+;;;; Imenu.
+
+(defun python-imenu-create-index ()
+  "`imenu-create-index-function' for Python.
+
+Makes nested Imenu menus from nested `class' and `def' statements.
+The nested menus are headed by an item referencing the outer
+definition; it has a space prepended to the name so that it sorts
+first with `imenu--sort-by-name'."
+  (unless (boundp 'recursing)           ; dynamically bound below
+    (goto-char (point-min)))            ; normal call from Imenu
+  (let (index-alist                     ; accumulated value to return
+        name is-class pos)
+    (while (re-search-forward
+            (rx (and line-start (0+ space) ; leading space
+                     (or (group "def") (group "class"))     ; type
+                     (1+ space) (group (1+ (or word ?_))))) ; name
+            nil t)
+      (unless (python-in-string/comment)
+        (let ((pos (match-beginning 0))
+              (name (match-string-no-properties 3)))
+          (if (match-beginning 2)       ; def or class?
+              (setq name (concat "class " name)))
+          (save-restriction
+            (narrow-to-defun)
+            (let* ((recursing t)
+                   (sublist (python-imenu-create-index)))
+              (if sublist
+                  (progn (push (cons (concat " " name) pos) sublist)
+                         (push (cons name sublist) index-alist))
+                (push (cons name pos) index-alist)))))))
+    (nreverse index-alist)))
+
+;;;; `Electric' commands.
+
+(defun python-electric-colon (arg)
+  "Insert a colon and maybe outdent the line if it is a statement like `else'.
+With numeric ARG, just insert that many colons.  With \\[universal-argument],
+just insert a single colon."
+  (interactive "*P")
+  (self-insert-command (if (not (integerp arg)) 1 arg))
+  (and (not arg)
+       (eolp)
+       (python-outdent-p)
+       (not (python-in-string/comment))
+       (> (current-indentation) (python-calculate-indentation))
+       (python-indent-line)))           ; OK, do it
+(put 'python-electric-colon 'delete-selection t)
+
+(defun python-backspace (arg)
+  "Maybe delete a level of indentation on the current line.
+If not at the end of line's indentation, or on a comment line, just call
+`backward-delete-char-untabify'.  With ARG, repeat that many times."
+  (interactive "*p")
+  (if (or (/= (current-indentation) (current-column))
+          (bolp)
+          (python-continuation-line-p))
+      (backward-delete-char-untabify arg)
+    (let ((indent 0))
+      (save-excursion
+        (while (and (> arg 0) (python-beginning-of-block))
+          (setq arg (1- arg)))
+        (when (zerop arg)
+          (setq indent (current-indentation))
+          (message "Closes %s" (python-initial-text))))
+      (delete-horizontal-space)
+      (indent-to indent))))
+(put 'python-backspace 'delete-selection 'supersede)
+
+;;;; pychecker
+
+(defcustom python-check-command "pychecker --stdlib"
+  "*Command used to check a Python file."
+  :type 'string
+  :group 'python)
+
+(defvar python-saved-check-command nil
+  "Internal use.")
+
+(autoload 'compilation-start "compile")
+
+;; After `sgml-validate-command'.
+(defun python-check (command)
+  "Check a Python file (default current buffer's file).
+Runs COMMAND, a shell command, as if by `compile'.
+See `python-check-command' for the default."
+  (interactive
+   (list (read-string "Checker command: "
+                      (or python-saved-check-command
+                          (concat python-check-command " "
+                                  (let ((name (buffer-file-name)))
+                                    (if name
+                                        (file-name-nondirectory name))))))))
+  (setq python-saved-check-command command)
+  (save-some-buffers (not compilation-ask-about-save) nil)
+  (compilation-start command))
+
+;;;; Inferior mode stuff (following cmuscheme).
+
+(defcustom python-python-command "python"
+  "*Shell command to run Python interpreter.
+Any arguments can't contain whitespace."
+  :group 'python
+  :type 'string)
+
+(defcustom python-jython-command "jython"
+  "*Shell command to run Jython interpreter.
+Any arguments can't contain whitespace."
+  :group 'python
+  :type 'string)
+
+(defvar python-command python-python-command
+  "Actual command used to run Python.
+May be `python-python-command' or `python-jython-command'.
+Additional arguments are added when the command is used by `run-python'
+et al.")
+
+(defvar python-buffer nil
+  "*The current python process buffer.
+To run multiple Python processes, start the first with \\[run-python].
+It will be in a buffer named *Python*.  Rename that with
+\\[rename-buffer].  Now start a new process with \\[run-python].  It
+will be in a new buffer, named *Python*.  Switch between the different
+process buffers with \\[switch-to-buffer].
+
+Commands that send text from source buffers to Python processes have
+to choose a process to send to.  This is determined by global variable
+`python-buffer'.  Suppose you have three inferior Pythons running:
+    Buffer      Process
+    foo         python
+    bar         python<2>
+    *Python*    python<3>
+If you do a \\[python-send-region-and-go] command on some Python source
+code, what process does it go to?
+
+- In a process buffer (foo, bar, or *Python*), send it to that process.
+- In some other buffer (e.g. a source file), send it to the process
+  attached to `python-buffer'.
+Process selection is done by function `python-proc'.
+
+Whenever \\[run-python] starts a new process, it resets `python-buffer'
+to be the new process's buffer.  If you only run one process, this will
+do the right thing.  If you run multiple processes, you can change
+`python-buffer' to another process buffer with \\[set-variable].")
+
+(define-derived-mode inferior-python-mode comint-mode "Inferior Python"
+  "Major mode for interacting with an inferior Python process.
+A Python process can be started with \\[run-python].
+
+Hooks `comint-mode-hook' and `inferior-python-mode-hook' are run in
+that order.
+
+You can send text to the inferior Python process from other buffers containing
+Python source.
+ * `python-switch-to-python' switches the current buffer to the Python
+    process buffer.
+ * `python-send-region' sends the current region to the Python process.
+ * `python-send-region-and-go' switches to the Python process buffer
+    after sending the text.
+For running multiple processes in multiple buffers, see `python-buffer'.
+
+\\{inferior-python-mode-map}"
+  :group 'python
+  (set-syntax-table python-mode-syntax-table)
+  (setq mode-line-process '(":%s"))
+  ;; Fixme: Maybe install some python-mode bindings too.
+  (define-key inferior-python-mode-map "\C-c\C-l" 'python-load-file)
+  (define-key inferior-python-mode-map "\C-c\C-z" 'python-switch-to-python)
+  (setq comint-input-filter #'python-input-filter))
+
+(defcustom inferior-python-filter-regexp "\\`\\s-*\\S-?\\S-?\\s-*\\'"
+  "*Input matching this regexp is not saved on the history list.
+Default ignores all inputs of 0, 1, or 2 non-blank characters."
+  :type 'regexp
+  :group 'python)
+
+(defvar python-orig-start-line nil
+  "Line number at start of region sent to inferior Python.")
+
+(defvar python-orig-file nil
+  "File name to associate with errors found in inferior Python.")
+
+(defun python-input-filter (str)
+  "`comint-input-filter' function for inferior Python.
+Don't save anything matching `inferior-python-filter-regexp'.
+Also resets variables for adjusting error messages."
+  (setq python-orig-file nil
+        python-orig-start-line 1)
+  (not (string-match inferior-python-filter-regexp str)))
+
+;; Fixme: Loses with quoted whitespace.
+(defun python-args-to-list (string)
+  (let ((where (string-match "[ \t]" string)))
+    (cond ((null where) (list string))
+          ((not (= where 0))
+           (cons (substring string 0 where)
+                 (python-args-to-list (substring string (+ 1 where)))))
+          (t (let ((pos (string-match "[^ \t]" string)))
+               (if pos (python-args-to-list (substring string pos))))))))
+
+(defvar compilation-minor-mode-map)
+(defvar compilation-error-list)
+(defvar compilation-parsing-end)
+
+(defconst python-compilation-regexp-alist
+  `((,(rx (and line-start (1+ (any " \t")) "File \""
+               (group (1+ (not (any "\"<")))) ; avoid `<stdin>' &c
+               "\", line " (group (1+ digit))))
+     1 python-compilation-line-number))
+  "`compilation-error-regexp-alist' for inferior Python.")
+
+(defun python-compilation-line-number (file col)
+  "Return error descriptor of error found for FILE, column COL.
+Used as line-number hook function in `python-compilation-regexp-alist'."
+  (let ((line (save-excursion
+                (goto-char (match-beginning 2))
+                (read (current-buffer)))))
+    (list (point-marker) (if python-orig-file
+                             (list python-orig-file default-directory)
+                           file)
+          (+ line (1- python-orig-start-line))
+          nil)))
+
+;;;###autoload
+(defun run-python (cmd)
+  "Run an inferior Python process, input and output via buffer *Python*.
+CMD is the Python command to run.
+If there is a process already running in `*Python*', switch to
+that buffer.  With argument, allows you to edit the initial
+command line (default is the value of `python-command'); `-i' and
+`-c' args will be added to this to support evaluations in the
+REPL.  Runs the hooks `inferior-python-mode-hook' \(after the
+`comint-mode-hook' is run).  \(Type \\[describe-mode] in the
+process buffer for a list of commands.)"
+  (interactive (list (if current-prefix-arg
+                         (read-string "Run Python: " python-command)
+                       python-command)))
+  ;; Fixme: Consider making `python-buffer' buffer-local as a buffer
+  ;; (not a name) in Python buffers from which `run-python' &c is
+  ;; invoked.  Would support multiple processes better.
+  (if (not (comint-check-proc "*Python*"))
+      (let ((cmdlist (append (python-args-to-list cmd)
+                             '("-i" "-c" "\
+from os import remove as _emacs_rem
+def _emacs_execfile (file):
+    try:
+        execfile (file)
+    finally:
+        _emacs_rem (file)
+"))))
+        (set-buffer (apply 'make-comint "Python" (car cmdlist) nil
+                           (cdr cmdlist)))
+        (inferior-python-mode)
+        (setq comint-output-filter-functions nil)))
+  (setq python-command cmd)
+  (setq python-buffer "*Python*")
+  (pop-to-buffer "*Python*")
+  (compilation-minor-mode 1)
+  (add-hook 'comint-input-filter-functions 'python-input-filter nil t)
+  ;; Avoid clobbering comint bindings.
+  (set (make-local-variable 'minor-mode-overriding-map-alist)
+       `((compilation-minor-mode
+          . ,(let ((map (make-sparse-keymap)))
+               ;; It would be useful to put keymap properties on the
+               ;; error lines so that we could use RET and mouse-2 on
+               ;; them directly.  These bindings will only DTRT with
+               ;; the font-lock-style compilation mode.
+               (define-key map [mouse-2] #'python-mouse-2-command)
+               (define-key map "\C-m" #'python-RET-command)
+               (if (boundp 'compilation-menu-map)
+                   (define-key map [menu-bar compilation]
+                     (cons "Errors" compilation-menu-map)))
+               map))))
+  (set (make-local-variable 'compilation-error-regexp-alist)
+       python-compilation-regexp-alist))
+
+(defun python-mouse-2-command (event)
+  "Command bound to `mouse-2' in inferior Python buffer.
+Selects Comint or Compilation mode command as appropriate."
+  (interactive "e")
+  ;; This only works with the font-lock-based compilation mode.
+  (call-interactively
+   (lookup-key (if (save-window-excursion
+                     (save-excursion
+                       (mouse-set-point event)
+                       (consp (get-text-property (line-beginning-position)
+                                                 'message))))
+                   compilation-mode-map
+                 comint-mode-map)
+               [mouse-2])))
+
+(defun python-RET-command ()
+  "Command bound to `RET' in inferior Python buffer.
+Selects Comint or Compilation mode command as appropriate."
+  (interactive)
+  ;; This only works with the font-lock-based compilation mode.
+  (call-interactively
+   (lookup-key (if (consp (get-text-property (line-beginning-position)
+                                             'message))
+                   compilation-mode-map
+                 comint-mode-map)
+               "\C-m")))
+
+(defun python-send-region (start end)
+  "Send the region to the inferior Python process."
+  ;; The region is evaluated from a temporary file.  This avoids
+  ;; problems with blank lines, which have different semantics
+  ;; interactively and in files.  It also saves the inferior process
+  ;; buffer filling up with interpreter prompts.  We need a function
+  ;; to remove the temporary file when it has been evaluated, which
+  ;; unfortunately means using a not-quite pristine interpreter
+  ;; initially.  Unfortunately we also get tracebacks which look like:
+  ;; 
+  ;; >>> Traceback (most recent call last):
+  ;;   File "<stdin>", line 1, in ?
+  ;;   File "<string>", line 4, in _emacs_execfile
+  ;;   File "/tmp/py7734RSB", line 11
+  ;;
+  ;; The compilation-minor-mode parsing takes care of relating the
+  ;; reference to the temporary file to the source.  Fixme:
+  ;; comint-filter the first two lines of the traceback?
+  (interactive "r")
+  (let* ((f (make-temp-file "py"))
+         (command (format "_emacs_execfile(%S)\n" f))
+         (orig-file (buffer-file-name))
+         (orig-line (save-restriction
+                      (widen)
+                      (line-number-at-pos start))))
+    (if (save-excursion
+          (goto-char start)
+          (/= 0 (current-indentation))) ; need dummy block
+        (write-region "if True:\n" nil f nil 'nomsg))
+    (write-region start end f t 'nomsg)
+    (when python-buffer
+      (with-current-buffer python-buffer
+        (let ((end (marker-position (process-mark
+                                     (get-buffer-process python-buffer)))))
+          (set (make-local-variable 'python-orig-file) orig-file)
+          (set (make-local-variable 'python-orig-start-line) orig-line)
+          (set (make-local-variable 'compilation-error-list) nil)
+          ;; (set (make-local-variable 'compilation-old-error-list) nil)
+          (let ((comint-input-filter-functions
+                 (delete 'python-input-filter comint-input-filter-functions)))
+            (comint-send-string (python-proc) command))
+          (set-marker compilation-parsing-end end)
+          (setq compilation-last-buffer (current-buffer)))))))
+
+(defun python-send-string (string)
+  "Evaluate STRING in inferior Python process."
+  (interactive "sPython command: ")
+  (comint-send-string (python-proc) string))
+
+(defun python-send-buffer ()
+  "Send the current buffer to the inferior Python process."
+  (interactive)
+  (python-send-region (point-min) (point-max)))
+
+(defun python-send-defun ()
+  "Send the current defun (class or method) to the inferior Python process."
+  (interactive)
+  (save-excursion (python-send-region (progn (beginning-of-defun) (point))
+                                      (progn (end-of-defun) (point)))))
+
+(defun python-switch-to-python (eob-p)
+  "Switch to the Python process buffer.
+With prefix arg, position cursor at end of buffer."
+  (interactive "P")
+  (if (get-buffer python-buffer)
+      (pop-to-buffer python-buffer)
+    (error "No current process buffer.  See variable `python-buffer'"))
+  (when eob-p
+    (push-mark)
+    (goto-char (point-max))))
+
+(add-to-list 'debug-ignored-errors "^No current process buffer.")
+
+(defun python-send-region-and-go (start end)
+  "Send the region to the inferior Python process.
+Then switch to the process buffer."
+  (interactive "r")
+  (python-send-region start end)
+  (python-switch-to-python t))
+
+(defcustom python-source-modes '(python-mode jython-mode)
+  "*Used to determine if a buffer contains Python source code.
+If it's loaded into a buffer that is in one of these major modes, it's
+considered a Python source file by `python-load-file'.
+Used by these commands to determine defaults."
+  :type '(repeat function)
+  :group 'python)
+
+(defvar python-prev-dir/file nil
+  "Caches (directory . file) pair used in the last `python-load-file' command.
+Used for determining the default in the next one.")
+
+(defun python-load-file (file-name)
+  "Load a Python file FILE-NAME into the inferior Python process.
+If the file has extension `.py' import or reload it as a module.
+Treating it as a module keeps the global namespace clean, provides
+function location information for debugging, and supports users of
+module-qualified names."
+  (interactive (comint-get-source "Load Python file: " python-prev-dir/file
+                                  python-source-modes
+                                  t)) ; because execfile needs exact name
+  (comint-check-source file-name) ; Check to see if buffer needs saved.
+  (setq python-prev-dir/file (cons (file-name-directory file-name)
+                                   (file-name-nondirectory file-name)))
+  (comint-send-string
+   (python-proc)
+   (if (string-match "\\.py\\'" file-name)
+       ;; Fixme: make sure the directory is in the path list
+       (let ((module (file-name-sans-extension
+                      (file-name-nondirectory file-name))))
+         (format "\
+if globals().has_key('%s'):
+    reload(%s)
+else:
+    import %s
+" module module module))
+     (format "execfile('%s')\n" filename))))
+
+;; Fixme: Should this start a process if there isn't one?  (Unlike cmuscheme.)
+(defun python-proc ()
+  "Return the current Python process.  See variable `python-buffer'."
+  (let ((proc (get-buffer-process (if (eq major-mode 'inferior-python-mode)
+                                      (current-buffer)
+                                    python-buffer))))
+    (or proc (error "No current process.  See variable `python-buffer'"))))
+
+;;;; Context-sensitive help.
+
+;; Fixme: Investigate adapting this to eldoc.
+
+(defun python-describe-symbol (symbol)
+  "Get help on SYMBOL using `pydoc'.
+Interactively, prompt for symbol."
+  (interactive
+   (let ((symbol (current-word))
+         (enable-recursive-minibuffers t)
+         val)
+     (setq val (read-string (if symbol
+                                (format "Describe variable (default %s): "
+                                      symbol)
+                              "Describe variable: ")
+                            nil nil symbol))
+     (list (or val symbol))))
+  (if (equal symbol "") (error "No symbol"))
+  (let* ((mod (if (string-match "\\(\\.[^.]+\\)\\'" symbol)
+                  (substring symbol 0 (match-beginning 1))))
+         (import (when mod (concat "import " mod "\n"))))
+    (with-output-to-temp-buffer "*Python Output*"
+      (princ (shell-command-to-string
+              (format "%s -c 'import pydoc %s
+try: pydoc.help(%S)
+except: print \"No help available on:\", %S'"
+                      ;; Fixme: Is this necessarily right?
+                      (car (split-string python-command))
+                      (or import "") symbol symbol))))))
+
+(add-to-list 'debug-ignored-errors "^No symbol")
+
+;;;; Info-look functionality.
+
+(require 'info-look)
+;; We should be able to add info-lookup specs without loading the file first.
+;; E.g. by setting a buffer-local var or something like that.  --Stef
+(let ((version (let ((s (shell-command-to-string (concat python-command
+                                                         " -V"))))
+                 (string-match "^Python \\([0-9]+\\.[0-9]+\\>\\)" s)
+                 (match-string 1 s)))
+      ;; Whether info files have a Python version suffix, e.g. in Debian.
+      (versioned (save-window-excursion
+                   (condition-case ()
+                       ;; The call to `info' might create a new frame if
+                       ;; pop-up-frames or special-display-buffers are used.
+                       ;; So I disabled it until we find a better way
+                       ;; to handle this situation.  Maybe Debian should just
+                       ;; fix their install somehow.  --Stef
+                       ;; (progn (info "(python2.3-lib)Miscellaneous Index")
+                       ;;             (Info-last)
+                       ;;             (Info-exit)
+                       ;;             t)
+                       nil
+                     (error nil)))))
+  (info-lookup-maybe-add-help
+   :mode 'python-mode
+   :regexp "[[:alnum:]_]+"
+   :doc-spec
+   ;; Fixme: Add python-ref?  Can this reasonably be made specific
+   ;; to indices with different rules?
+   (if versioned
+       '((,(concat "(python" version "-lib)Module Index"))
+         (,(concat "(python" version "-lib)Class-Exception-Object Index"))
+         (,(concat "(python" version "-lib)Function-Method-Variable Index"))
+         (,(concat "(python" version "-lib)Miscellaneous Index")))
+     '(("(python-lib)Module Index")
+       ("(python-lib)Class-Exception-Object Index")
+       ("(python-lib)Function-Method-Variable Index")
+       ("(python-lib)Miscellaneous Index")))))
+
+;;;; Miscellancy.
+
+(defcustom python-jython-packages '("java" "javax" "org" "com")
+  "Packages implying `jython-mode'.
+If these are imported near the beginning of the buffer, `python-mode'
+actually punts to `jython-mode'."
+  :type '(repeat string)
+  :group 'python)
+
+;; Called from `python-mode', this causes a recursive call of the
+;; mode.  See logic there to break out of the recursion.
+(defun python-maybe-jython ()
+  "Invoke `jython-mode' if the buffer appears to contain Jython code.
+The criterion is either a match for `jython-mode' via
+`interpreter-mode-alist' or an import of a module from the list
+`python-jython-packages'."
+  ;; The logic is taken from python-mode.el.
+  (save-excursion
+    (goto-char (point-min))
+    (let ((interpreter (if (looking-at auto-mode-interpreter-regexp)
+                           (match-string 2))))
+      (if (and interpreter (eq 'jython-mode
+                               (cdr (assoc (file-name-nondirectory interpreter)
+                                           interpreter-mode-alist))))
+          (jython-mode)
+        (if (catch 'done
+              (while (re-search-forward
+                      (rx (and line-start (or "import" "from") (1+ space)
+                               (group (1+ (not (any " \t\n."))))))
+                      (+ (point) 10000) ; Probably not worth customizing.
+                      t)
+                (if (member (match-string 1) python-jython-packages)
+                    (throw 'done t))))
+            (jython-mode))))))
+
+(defun python-fill-paragraph (&optional justify)
+  "Like \\[fill-paragraph], but handle comments and multi-line strings.
+If any of the current line is a comment, fill the comment or the
+paragraph of it that point is in, preserving the comment's indentation
+and initial comment characters."
+  (interactive "P")
+  (or (fill-comment-paragraph justify)
+      (let ((paragraph-start (concat paragraph-start
+                                     "\\|\\s-*\\(:?#\\s\"\\|\\s|\\|#")))
+        (fill-paragraph justify))
+      t))
+
+(defun python-shift-left (start end &optional count)
+  "Shift lines in region COUNT (the prefix arg) columns to the left.
+COUNT defaults to `python-indent'.  If region isn't active, just shift
+current line.  The region shifted includes the lines in which START and
+END lie.  It is an error if any lines in the region are indented less than
+COUNT columns."
+  (interactive (if mark-active
+                   (list (region-beginning) (region-end) current-prefix-arg)
+                 (list (point) (point) current-prefix-arg)))
+  (if count
+      (setq count (prefix-numeric-value count))
+    (setq count python-indent))
+  (when (> count 0)
+    (save-excursion
+      (goto-char start)
+      (while (< (point) end)
+        (if (and (< (current-indentation) count)
+                 (not (looking-at "[ \t]*$")))
+            (error "Can't shift all lines enough"))
+        (forward-line))
+      (indent-rigidly start end (- count)))))
+
+(add-to-list 'debug-ignored-errors "^Can't shift all lines enough")
+
+(defun python-shift-right (start end &optional count)
+  "Shift lines in region COUNT (the prefix arg) columns to the right.
+COUNT defaults to `python-indent'.  If region isn't active, just shift
+current line.  The region shifted includes the lines in which START and
+END lie."
+  (interactive (if mark-active
+                   (list (region-beginning) (region-end) current-prefix-arg)
+                 (list (point) (point) current-prefix-arg)))
+  (if count
+      (setq count (prefix-numeric-value count))
+    (setq count python-indent))
+  (indent-rigidly start end count))
+
+(defun python-outline-level ()
+  "`outline-level' function for Python mode.
+The level is the number of `python-indent' steps of indentation."
+  (/ (current-indentation) python-indent))
+
+;; Fixme: Consider top-level assignments, imports, &c.
+(defun python-current-defun ()
+  "`add-log-current-defun-function' for Python."
+  (save-excursion
+    ;; Move up the tree of nested `class' and `def' blocks until we
+    ;; get to zero indentation, accumulating the defined names.
+    (let ((start t)
+          accum)
+      (while (or start (> (current-indentation) 0))
+        (setq start nil)
+        (python-beginning-of-block)
+        (end-of-line)
+        (beginning-of-defun)
+        (if (looking-at (rx (and (0+ space) (or "def" "class") (1+ space)
+                                 (group (1+ (or word (syntax symbol))))
+                                 word-end)))
+            (push (match-string 1) accum)))
+      (if accum (mapconcat 'identity accum ".")))))
+
+(defun python-mark-block ()
+  "Mark the block around point.
+Uses `python-beginning-of-block', `python-end-of-block'."
+  (interactive)
+  (push-mark)
+  (python-beginning-of-block)
+  (push-mark (point) nil t)
+  (python-end-of-block)
+  (exchange-point-and-mark))
+
+;;;; Modes.
+
+;;;###autoload
+(define-derived-mode python-mode fundamental-mode "Python"
+  "Major mode for editing Python files.
+Turns on Font Lock mode unconditionally since it is required for correct
+parsing of the source.
+See also `jython-mode', which is actually invoked if the buffer appears to
+contain Jython code.
+
+The Emacs commands which work with `defun's, e.g. \\[beginning-of-defun], deal
+with nested `def' and `class' blocks.  They take the innermost one as
+current without distinguishing method and class definitions.
+\\<python-mode-map>
+Colon is electric: it outdents the line if appropriate, e.g. for
+an else statement.  \\[python-backspace] at the beginning of an indented statement
+deletes a level of indentation to close the current block; otherwise it
+deletes a charcter backward.  TAB indents the current line relative to
+the preceding code.  Successive TABs, with no intervening command, cycle
+through the possibilities for indentation on the basis of enclosing blocks.
+
+\\{python-mode-map}"
+  :group 'python
+  (set (make-local-variable 'font-lock-defaults)
+       '(python-font-lock-keywords nil nil ((?_ . "w")) nil
+                                   (font-lock-syntactic-keywords
+                                    . python-font-lock-syntactic-keywords)
+;;; This probably isn't worth it.
+;;;                                (font-lock-syntactic-face-function
+;;;                                 . python-font-lock-syntactic-face-function)
+                                   ))
+  (set (make-local-variable 'parse-sexp-lookup-properties) t)
+  (set (make-local-variable 'comment-start) "# ")
+  ;; Fixme: define a comment-indent-function?
+  (set (make-local-variable 'indent-line-function) #'python-indent-line)
+  (set (make-local-variable 'paragraph-start) "\\s-*$")
+  (set (make-local-variable 'fill-paragraph-function)
+       'python-fill-paragraph)
+  (set (make-local-variable 'require-final-newline) t)
+  (set (make-local-variable 'add-log-current-defun-function)
+       #'python-current-defun)
+  ;; Fixme: Generalize to do all blocks?
+  (set (make-local-variable 'outline-regexp) "\\s-+\\(def\\|class\\)\\>")
+  (set (make-local-variable 'outline-level) #'python-outline-level)
+  (set (make-local-variable 'open-paren-in-column-0-is-defun-start) nil)
+  (make-local-variable 'python-saved-check-command)
+  (set (make-local-variable 'beginning-of-defun-function)
+       'python-beginning-of-defun)
+  (set (make-local-variable 'end-of-defun-function) 'python-end-of-defun)
+  (setq imenu-create-index-function #'python-imenu-create-index)
+  (unless font-lock-mode (font-lock-mode 1))
+  (when python-guess-indent (python-guess-indent))
+  (set (make-local-variable 'python-command) python-python-command)
+  (unless (boundp 'python-mode-running) ; kill the recursion from jython-mode
+    (let ((python-mode-running t))
+      (python-maybe-jython))))
+
+(custom-add-option 'python-mode-hook 'imenu-add-menubar-index)
+(custom-add-option 'python-mode-hook
+                   '(lambda ()
+                      "Turn on Indent Tabs mode."
+                      (set (make-local-variable 'indent-tabs-mode) t)))
+
+;;;###autoload
+(define-derived-mode jython-mode python-mode  "Jython"
+  "Major mode for editing Jython files.
+Like `python-mode', but sets up parameters for Jython subprocesses.
+Runs `jython-mode-hook' after `python-mode-hook'."
+  :group 'python
+  (set (make-local-variable 'python-command) python-jython-command))
+
+(provide 'python)
+;; arch-tag: 6fce1d99-a704-4de9-ba19-c6e4912b0554
+;;; python.el ends here