Added wording for the regex files and the --ignore-case-regex option.

[emacs.git] / lisp / hippie-exp.el

;;; hippie-exp.el --- expand text trying various ways to find its expansion.

;; Copyright (C) 1992 Free Software Foundation, Inc.

;; Author: Anders Holst <aho@sans.kth.se>
;; Last change: 3 March 1998
;; Version: 1.6
;; Keywords: abbrev convenience

;; This file is part of GNU Emacs.

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

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

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

;;; Commentary:

;;  `hippie-expand' is a single function for a lot of different kinds
;;  of completions and expansions.  Called repeatedly it tries all
;;  possible completions in succession. 
;;  Which kinds of completions to try, and in which order, is
;;  determined by the contents of `hippie-expand-try-functions-list'.
;;  Much customization of `hippie-expand' can be made by changing the
;;  order of, removing, or inserting new functions in this list.
;;  Given a positive numeric argument, `hippie-expand' jumps directly
;;  ARG functions forward in this list.  Given some other argument
;;  (a negative argument or just Ctrl-U) it undoes the tried
;;  completion.
;;
;;  If the variable `hippie-expand-verbose' is non-nil, `hippie-expand'
;;  outputs in a message which try-function in the list that is used
;;  currently (ie. was used currently and will be tried first the next
;;  time).
;;  The variable `hippie-expand-max-buffers' determines in how many
;;  buffers, apart from the current, to search for expansions in.  It
;;  is used by the try-functions named "-all-buffers".
;;  The variable `hippie-expand-ignore-buffers' is a list of regexps
;;  matching buffer names (as strings) or major modes (as atoms) of
;;  buffers that should not be searched by the try-functions named
;;  "-all-buffers".
;;  If set, the variable `hippie-expand-only-buffers' does the opposite
;;  of `hippie-expand-ignore-buffers', in that the search is restricted
;;  to only the kind of buffers listed.
;;  If the variable `hippie-expand-no-restriction' is non-nil, narrowed
;;  buffers are widened before they are searched.
;;  The variable `hippie-expand-dabbrev-skip-space' controls whether
;;  trailing spaces will be included in the abbreviation to search for,
;;  which then gives the same behavior as the original `dabbrev-expand'.
;;  The variable `hippie-expand-dabbrev-as-symbol' controls whether
;;  characters of syntax '_' is considered part of the words to expand
;;  dynamically.
;;  See also the macro `make-hippie-expand-function' below.
;;  
;;  A short description of the current try-functions in this file:
;;    `try-complete-file-name' : very convenient to have in any buffer,
;;      and not just in the minibuffer or (some) shell-mode.  It goes
;;      through all possible completions instead of just completing as
;;      much as is unique.
;;    `try-complete-file-name-partially' : To insert in the list just
;;      before `try-complete-file-name' for those who want first to get
;;      a file name completed only as many characters as is unique.
;;    `try-expand-all-abbrevs' : can be removed if you don't use abbrevs.
;;      Otherwise it looks through all abbrev-tables, starting with
;;      the local followed by the global. 
;;    `try-expand-line' : Searches the buffer for an entire line that 
;;      begins exactly as the current line.  Convenient sometimes, for 
;;      example as a substitute for (or complement to) the history
;;      list in shell-like buffers.  At other times, only confusing.
;;    `try-expand-line-all-buffers' : Like `try-expand-line' but searches
;;      in all buffers (except the current).  (This may be a little
;;      slow, don't use it unless you are really fond of `hippie-expand'.)
;;    `try-expand-list' : Tries to expand the text back to the nearest
;;      open delimiter, to a whole list from the buffer. Convenient for
;;      example when writing lisp or TeX.
;;    `try-expand-list-all-buffers' : Like `try-expand-list' but searches 
;;      in all buffers (except the current).  
;;    `try-expand-dabbrev' : works exactly as dabbrev-expand (but of
;;      course in a way compatible with the other try-functions).
;;    `try-expand-dabbrev-all-buffers' : perhaps the most useful of them,
;;      like `dabbrev-expand' but searches all Emacs buffers (except the
;;      current) for matching words.  (No, I don't find this one
;;      particularly slow.) 
;;    `try-expand-dabbrev-visible': Searches the currently visible parts of
;;      all windows.  Can be put before `try-expand-dabbrev-all-buffers' to
;;      first try the expansions you can see.
;;    `try-expand-dabbrev-from-kill': Searches the kill ring for a suitable
;;      completion of the word.  Good to have, just in case the word was not
;;      found elsewhere.
;;    `try-expand-whole-kill' : Tries to complete text with a whole entry
;;      from the kill ring.  May be good if you don't know how far up in
;;      the kill-ring the required entry is, and don't want to mess with
;;      "Choose Next Paste".
;;    `try-complete-lisp-symbol' : like `lisp-complete-symbol', but goes
;;      through all possibilities instead of completing what is unique.
;;      Might be tedious (usually a lot of possible completions) and
;;      since its function is much like `lisp-complete-symbol', which
;;      already has a key of its own, you might want to remove this.
;;    `try-complete-lisp-symbol-partially' : To insert in the list just
;;      before `try-complete-lisp-symbol' for those who first want to get
;;      completion of what is unique in the name.  
;;
;;  Not all of the above functions are by default in
;;  `hippie-expand-try-functions-list'.  This variable is better set
;;  in ".emacs" to make `hippie-expand' behave maximally convenient
;;  according to personal taste.  Also, instead of loading the
;;  variable with all kinds of try-functions above, it might be an
;;  idea to use `make-hippie-expand-function' to construct different
;;  `hippie-expand'-like functions, with different try-lists and bound
;;  to different keys. It is also possible to make
;;  `hippie-expand-try-functions-list' a buffer local variable, and
;;  let it depend on the mode (by setting it in the mode-hooks).
;;
;;  To write new try-functions, consider the following:
;;  Each try-function takes one argument OLD which is nil the first
;;  time the function is called and true in succeeding calls for the
;;  same string to complete.  The first time the function has to
;;  extract the string before point to complete, and substitute the
;;  first completion alternative for it.  On following calls it has to
;;  substitute the next possible completion for the last tried string.
;;  The try-function is to return t as long as it finds new
;;  possible completions.  When there are no more alternatives it has
;;  to restore the text before point to its original contents, and
;;  return nil (don't beep or message or anything).
;;  The try-function can (should) use the following functions:
;;    `he-init-string' : Initializes the text to substitute to the
;;      contents of the region BEGIN to END.  Also sets the variable
;;      `he-search-string' to the text to expand.
;;    `he-substitute-string' : substitutes STR into the region
;;      initialized with `he-init-string'.  (An optional second argument
;;      TRANS-CASE non-nil, means transfer of case from the abbreviation
;;      to the expansion is ok if that is enabled in the buffer.)
;;    `he-reset-string' : Resets the initialized region to its original
;;      contents.
;;  There is also a variable: `he-tried-table' which is meant to contain
;;  all tried expansions so far.  The try-function can check this 
;;  variable to see whether an expansion has already been tried
;;  (hint: `he-string-member').
;;
;;  Known bugs
;;
;;  It may happen that some completion suggestion occurs twice, in
;;  spite of the use of `he-tried-table' to prevent that.  This is 
;;  because different try-functions may try to complete different
;;  lengths of text, and thus put different amounts of the
;;  text in `he-tried-table'.  Anyway this seems to occur seldom enough
;;  not to be too disturbing.  Also it should NOT be possible for the
;;  opposite situation to occur, that `hippie-expand' misses some
;;  suggestion because it thinks it has already tried it.
;;
;;  Acknowledgement
;;
;;  I want to thank Mikael Djurfeldt in discussions with whom the idea
;;  of this function took form.
;;  I am also grateful to all those who have given me suggestions on
;;  how to improve it, and all those who helped to find and remove bugs.
;;

;;; Code:

(defgroup hippie-expand nil
  "Expand text trying various ways to find its expansion."
  :group 'abbrev
  :group 'convenience)

(defvar he-num -1)

(defvar he-string-beg (make-marker))

(defvar he-string-end (make-marker))

(defvar he-search-string ())

(defvar he-expand-list ())

(defvar he-tried-table ())

(defvar he-search-loc (make-marker))

(defvar he-search-loc2 ())

(defvar he-search-bw ())

(defvar he-search-bufs ())

(defvar he-searched-n-bufs ())

(defvar he-search-window ())

;;;###autoload
(defvar hippie-expand-try-functions-list '(try-complete-file-name-partially
                                           try-complete-file-name
                                           try-expand-all-abbrevs
                                           try-expand-list
                                           try-expand-line
                                           try-expand-dabbrev
                                           try-expand-dabbrev-all-buffers
                                           try-expand-dabbrev-from-kill
                                           try-complete-lisp-symbol-partially
                                           try-complete-lisp-symbol)
  "The list of expansion functions tried in order by `hippie-expand'.
To change the behavior of `hippie-expand', remove, change the order of,
or insert functions in this list.")

;;;###autoload
(defcustom hippie-expand-verbose t
  "*Non-nil makes `hippie-expand' output which function it is trying."
  :type 'boolean
  :group 'hippie-expand)

;;;###autoload
(defcustom hippie-expand-dabbrev-skip-space nil
  "*Non-nil means tolerate trailing spaces in the abbreviation to expand."
  :group 'hippie-expand
  :type 'boolean)

;;;###autoload
(defcustom hippie-expand-dabbrev-as-symbol t
  "*Non-nil means expand as symbols, i.e. syntax `_' is considered a letter."
  :group 'hippie-expand
  :type 'boolean)

;;;###autoload
(defcustom hippie-expand-no-restriction t
  "*Non-nil means that narrowed buffers are widened during search."
  :group 'hippie-expand
  :type 'boolean)

;;;###autoload
(defcustom hippie-expand-max-buffers ()
  "*The maximum number of buffers (apart from the current) searched.
If nil, all buffers are searched."
  :type '(choice (const :tag "All" nil)
                 integer)
  :group 'hippie-expand)

;;;###autoload
(defcustom hippie-expand-ignore-buffers '("^ \\*.*\\*$" dired-mode)
  "*A list specifying which buffers not to search (if not current).
Can contain both regexps matching buffer names (as strings) and major modes
\(as atoms)"
  :type '(repeat (choice regexp (symbol :tag "Major Mode")))
  :group 'hippie-expand)

;;;###autoload
(defcustom hippie-expand-only-buffers ()
  "*A list specifying the only buffers to search (in addition to current).
Can contain both regexps matching buffer names (as strings) and major modes
\(as atoms). If non-NIL, this variable overrides the variable
`hippie-expand-ignore-buffers'."
  :type '(repeat (choice regexp (symbol :tag "Major Mode")))
  :group 'hippie-expand)

;;;###autoload
(defun hippie-expand (arg)
  "Try to expand text before point, using multiple methods.
The expansion functions in `hippie-expand-try-functions-list' are
tried in order, until a possible expansion is found.  Repeated
application of `hippie-expand' inserts successively possible
expansions.  
With a positive numeric argument, jumps directly to the ARG next
function in this list.  With a negative argument or just \\[universal-argument], 
undoes the expansion." 
  (interactive "P")
  (if (or (not arg) 
          (and (integerp arg) (> arg 0)))
      (let ((first (or (= he-num -1)
                       (not (equal this-command last-command)))))
        (if first
            (progn
              (setq he-num -1)
              (setq he-tried-table nil)))
        (if arg
            (if (not first) (he-reset-string))
            (setq arg 0))
        (let ((i (max (+ he-num arg) 0)))
          (while (not (or (>= i (length hippie-expand-try-functions-list))
                          (apply (nth i hippie-expand-try-functions-list) 
                                 (list (= he-num i)))))
            (setq i (1+ i)))
          (setq he-num i))
        (if (>= he-num (length hippie-expand-try-functions-list))
            (progn
              (setq he-num -1)
              (if first
                  (message "No expansion found")
                  (message "No further expansions found"))
              (ding))
            (if (and hippie-expand-verbose
                     (not (window-minibuffer-p (selected-window))))
                (message "Using %s"
                         (nth he-num hippie-expand-try-functions-list)))))
      (if (and (>= he-num 0)
               (eq (marker-buffer he-string-beg) (current-buffer)))
          (progn
            (setq he-num -1)
            (he-reset-string)
            (if (and hippie-expand-verbose
                     (not (window-minibuffer-p (selected-window))))
                (message "Undoing expansions"))))))

;; Initializes the region to expand (to between BEG and END).
(defun he-init-string (beg end)
  (set-marker he-string-beg beg)
  (set-marker he-string-end end)
  (setq he-search-string (buffer-substring-no-properties beg end)))

;; Resets the expanded region to its original contents.
(defun he-reset-string ()
  (let ((newpos (point-marker)))
    (goto-char he-string-beg)
    (insert he-search-string)
    (delete-region (point) he-string-end)
    (goto-char newpos)))

;; Substitutes an expansion STR into the correct region (the region
;; initialized with `he-init-string'). 
;; An optional argument TRANS-CASE means that it is ok to transfer case
;; from the abbreviation to the expansion if that is possible, and is
;; enabled in the buffer.
(defun he-substitute-string (str &optional trans-case)
  (let ((trans-case (and trans-case
                         case-replace
                         case-fold-search))
        (newpos (point-marker))
        (subst ()))
    (goto-char he-string-beg)
    (setq subst (if trans-case (he-transfer-case he-search-string str) str))
    (setq he-tried-table (cons subst he-tried-table))
    (insert subst)
    (delete-region (point) he-string-end)
    (goto-char newpos)))

(defun he-capitalize-first (str)
  (save-match-data
    (if (string-match "\\Sw*\\(\\sw\\).*" str)
        (let ((res (downcase str))
              (no (match-beginning 1)))
          (aset res no (upcase (aref str no)))
          res)
      str)))

(defun he-ordinary-case-p (str)
  (or (string= str (downcase str))
      (string= str (upcase str))
      (string= str (capitalize str))
      (string= str (he-capitalize-first str))))

(defun he-transfer-case (from-str to-str)
  (cond ((string= from-str (substring to-str 0 (min (length from-str)
                                                    (length to-str))))
         to-str)
        ((not (he-ordinary-case-p to-str))
         to-str)
        ((string= from-str (downcase from-str))
         (downcase to-str))
        ((string= from-str (upcase from-str))
         (upcase to-str))
        ((string= from-str (he-capitalize-first from-str))
         (he-capitalize-first to-str))
        ((string= from-str (capitalize from-str))
         (capitalize to-str))
        (t
         to-str)))


;; Check if STR is a member of LST.
;; Transform to the final case if optional TRANS-CASE is non-NIL.
(defun he-string-member (str lst &optional trans-case)
  (if str
      (member (if (and trans-case
                       case-replace
                       case-fold-search)
                  (he-transfer-case he-search-string str)
                str)
              lst)))

;; Check if current buffer matches any atom or regexp in LST.
;; Atoms are interpreted as major modes, strings as regexps mathing the name.
(defun he-buffer-member (lst)
  (or (memq major-mode lst)
      (progn
        (while (and lst
                    (or (not (stringp (car lst)))
                        (not (string-match (car lst) (buffer-name)))))
          (setq lst (cdr lst)))
        lst)))

;;  For the real hippie-expand enthusiast: A macro that makes it
;;  possible to use many functions like hippie-expand, but with
;;  different try-functions-lists.
;;  Usage is for example:
;;    (fset 'my-complete-file (make-hippie-expand-function
;;                             '(try-complete-file-name-partially
;;                               try-complete-file-name)))
;;    (fset 'my-complete-line (make-hippie-expand-function
;;                             '(try-expand-line
;;                               try-expand-line-all-buffers)))
;;  
;;;###autoload
(defmacro make-hippie-expand-function (try-list &optional verbose)
  "Construct a function similar to `hippie-expand'.
Make it use the expansion functions in TRY-LIST.  An optional second
argument VERBOSE non-nil makes the function verbose."
  (` (function (lambda (arg)
       (, (concat 
           "Try to expand text before point, using the following functions: \n"
           (mapconcat 'prin1-to-string (eval try-list) ", ")))
       (interactive "P")
       (let ((hippie-expand-try-functions-list (, try-list))
             (hippie-expand-verbose (, verbose)))
         (hippie-expand arg))))))


;;;  Here follows the try-functions and their requisites:


(defun try-complete-file-name (old)
  "Try to complete text as a file name.
The argument OLD has to be nil the first call of this function, and t
for subsequent calls (for further possible completions of the same
string).  It returns t if a new completion is found, nil otherwise."
  (if (not old)
      (progn 
        (he-init-string (he-file-name-beg) (point))
        (let ((name-part (he-file-name-nondirectory he-search-string))
              (dir-part (expand-file-name (or (he-file-name-directory
                                               he-search-string) ""))))
          (if (not (he-string-member name-part he-tried-table))
              (setq he-tried-table (cons name-part he-tried-table)))
          (if (and (not (equal he-search-string ""))
                   (he-file-directory-p dir-part))
              (setq he-expand-list (sort (file-name-all-completions 
                                          name-part
                                          dir-part)
                                         'string-lessp))
              (setq he-expand-list ())))))

  (while (and he-expand-list
              (he-string-member (car he-expand-list) he-tried-table))
    (setq he-expand-list (cdr he-expand-list)))
  (if (null he-expand-list)
      (progn
        (if old (he-reset-string))
        ())
      (let ((filename (he-concat-directory-file-name
                       (he-file-name-directory he-search-string)
                       (car he-expand-list))))
        (he-substitute-string filename)
        (setq he-tried-table (cons (car he-expand-list) (cdr he-tried-table)))
        (setq he-expand-list (cdr he-expand-list))
        t)))

(defun try-complete-file-name-partially (old)
  "Try to complete text as a file name, as many characters as unique.
The argument OLD has to be nil the first call of this function.  It
returns t if a unique, possibly partial, completion is found, nil 
otherwise."
  (let ((expansion ()))
    (if (not old)
        (progn 
          (he-init-string (he-file-name-beg) (point))
          (let ((name-part (he-file-name-nondirectory he-search-string))
                (dir-part (expand-file-name (or (he-file-name-directory
                                                 he-search-string) ""))))
            (if (and (not (equal he-search-string ""))
                     (he-file-directory-p dir-part))
                (setq expansion (file-name-completion name-part
                                                      dir-part)))
            (if (or (eq expansion t)
                    (string= expansion name-part)
                    (he-string-member expansion he-tried-table))
                (setq expansion ())))))

    (if (not expansion)
        (progn
          (if old (he-reset-string))
          ())
        (let ((filename (he-concat-directory-file-name
                         (he-file-name-directory he-search-string)
                         expansion)))
          (he-substitute-string filename)
          (setq he-tried-table (cons expansion (cdr he-tried-table)))
          t))))

(defvar he-file-name-chars
  (cond ((memq system-type '(vax-vms axp-vms))
         "-a-zA-Z0-9_/.,~^#$+=:\\[\\]")
        ((memq system-type '(ms-dos windows-nt))
         "-a-zA-Z0-9_/.,~^#$+=:\\\\")
        (t                          ;; More strange file formats ?
         "-a-zA-Z0-9_/.,~^#$+="))
  "Characters that are considered part of the file name to expand.")

(defun he-file-name-beg ()
  (let ((op (point)))
    (save-excursion
      (skip-chars-backward he-file-name-chars)
      (if (> (skip-syntax-backward "w") 0)  ;; No words with non-file chars
          op
        (point)))))

;; Thanks go to Richard Levitte <levitte@e.kth.se> who helped to make these
;; work under VMS, and to David Hughes <ukchugd@ukpmr.cs.philips.nl> who 
;; helped to make it work on PC.
(defun he-file-name-nondirectory (file)
  "Fix to make `file-name-nondirectory' work for hippie-expand under VMS."
  (if (memq system-type '(axp-vms vax-vms))
      (let ((n (file-name-nondirectory file)))
        (if (string-match "^\\(\\[.*\\)\\.\\([^\\.]*\\)$" n)
            (concat "[." (substring n (match-beginning 2) (match-end 2)))
          n))
    (file-name-nondirectory file)))

(defun he-file-name-directory (file)
  "Fix to make `file-name-directory' work for hippie-expand under VMS."
  (if (memq system-type '(axp-vms vax-vms))
      (let ((n (file-name-nondirectory file))
            (d (file-name-directory file)))
        (if (string-match "^\\(\\[.*\\)\\.\\([^\\.]*\\)$" n)
            (concat d (substring n (match-beginning 1) (match-end 1)) "]")
          d))
    (file-name-directory file)))

(defun he-file-directory-p (file)
  "Fix to make `file-directory-p' work for hippie-expand under VMS."
  (if (memq system-type '(vax-vms axp-vms))
      (or (file-directory-p file)
          (file-directory-p (concat file "[000000]")))
    (file-directory-p file)))
  
(defun he-concat-directory-file-name (dir-part name-part)
  "Try to slam together two parts of a file specification, system dependently."
  (cond ((null dir-part) name-part)
        ((memq system-type '(axp-vms vax-vms))
         (if (and (string= (substring dir-part -1) "]")
                  (string= (substring name-part 0 2) "[."))
             (concat (substring dir-part 0 -1) (substring name-part 1))
           (concat dir-part name-part)))
        ((memq system-type '(ms-dos w32))
         (if (and (string-match "\\\\" dir-part)
                  (not (string-match "/" dir-part))
                  (= (aref name-part (1- (length name-part))) ?/))
             (aset name-part (1- (length name-part)) ?\\))
         (concat dir-part name-part))
        (t 
         (concat dir-part name-part))))
                        
(defun try-complete-lisp-symbol (old)
  "Try to complete word as an Emacs Lisp symbol.
The argument OLD has to be nil the first call of this function, and t
for subsequent calls (for further possible completions of the same
string).  It returns t if a new completion is found, nil otherwise."
  (if (not old)
      (progn 
        (he-init-string (he-lisp-symbol-beg) (point))
        (if (not (he-string-member he-search-string he-tried-table))
            (setq he-tried-table (cons he-search-string he-tried-table)))
        (setq he-expand-list 
              (and (not (equal he-search-string ""))
                   (sort (all-completions he-search-string obarray
                                          (function (lambda (sym)
                                            (or (boundp sym)
                                                (fboundp sym)
                                                (symbol-plist sym)))))
                         'string-lessp)))))
  (while (and he-expand-list
              (he-string-member (car he-expand-list) he-tried-table))
    (setq he-expand-list (cdr he-expand-list)))
  (if (null he-expand-list)
      (progn
        (if old (he-reset-string))
        ())
      (progn
        (he-substitute-string (car he-expand-list))
        (setq he-expand-list (cdr he-expand-list))
        t)))

(defun try-complete-lisp-symbol-partially (old)
  "Try to complete as an Emacs Lisp symbol, as many characters as unique.
The argument OLD has to be nil the first call of this function.  It
returns t if a unique, possibly partial, completion is found, nil 
otherwise."
  (let ((expansion ()))
    (if (not old)
        (progn 
          (he-init-string (he-lisp-symbol-beg) (point))
          (if (not (string= he-search-string ""))
              (setq expansion 
                    (try-completion he-search-string obarray
                                    (function (lambda (sym)
                                      (or (boundp sym)
                                          (fboundp sym)
                                          (symbol-plist sym)))))))
          (if (or (eq expansion t)
                  (string= expansion he-search-string)
                  (he-string-member expansion he-tried-table))
              (setq expansion ()))))

  (if (not expansion)
      (progn
        (if old (he-reset-string))
        ())
      (progn
        (he-substitute-string expansion)
        t))))

(defun he-lisp-symbol-beg ()
  (save-excursion
    (skip-syntax-backward "w_")
    (point)))

(defun try-expand-line (old)
  "Try to complete the current line to an entire line in the buffer.
The argument OLD has to be nil the first call of this function, and t
for subsequent calls (for further possible completions of the same
string).  It returns t if a new completion is found, nil otherwise."
  (let ((expansion ())
        (strip-prompt (and (get-buffer-process (current-buffer))
                           comint-prompt-regexp)))
    (if (not old)
        (progn
          (he-init-string (he-line-beg strip-prompt) (point))
          (set-marker he-search-loc he-string-beg)
          (setq he-search-bw t)))

    (if (not (equal he-search-string ""))
        (save-excursion
          (save-restriction
            (if hippie-expand-no-restriction
                (widen))
            ;; Try looking backward unless inhibited.
            (if he-search-bw
                (progn 
                  (goto-char he-search-loc)
                  (setq expansion (he-line-search he-search-string
                                                  strip-prompt t))
                  (set-marker he-search-loc (point))
                  (if (not expansion)
                      (progn
                        (set-marker he-search-loc he-string-end)
                        (setq he-search-bw ())))))

            (if (not expansion) ; Then look forward.
                (progn 
                  (goto-char he-search-loc)
                  (setq expansion (he-line-search he-search-string 
                                                  strip-prompt nil))
                  (set-marker he-search-loc (point)))))))

    (if (not expansion)
        (progn
          (if old (he-reset-string))
          ())
        (progn
          (he-substitute-string expansion t)
          t))))

(defun try-expand-line-all-buffers (old)
  "Try to complete the current line, searching all other buffers.
The argument OLD has to be nil the first call of this function, and t
for subsequent calls (for further possible completions of the same
string).  It returns t if a new completion is found, nil otherwise."
  (let ((expansion ())
        (strip-prompt (and (get-buffer-process (current-buffer))
                           comint-prompt-regexp))
        (buf (current-buffer))
        (orig-case-fold-search case-fold-search))
    (if (not old)
        (progn
          (he-init-string (he-line-beg strip-prompt) (point))
          (setq he-search-bufs (buffer-list))
          (setq he-searched-n-bufs 0)
          (set-marker he-search-loc 1 (car he-search-bufs))))

    (if (not (equal he-search-string ""))
        (while (and he-search-bufs 
                    (not expansion)
                    (or (not hippie-expand-max-buffers)
                        (< he-searched-n-bufs hippie-expand-max-buffers)))
          (set-buffer (car he-search-bufs))
          (if (and (not (eq (current-buffer) buf))
                   (if hippie-expand-only-buffers
                       (he-buffer-member hippie-expand-only-buffers)
                     (not (he-buffer-member hippie-expand-ignore-buffers))))
              (save-excursion
                (save-restriction
                  (if hippie-expand-no-restriction
                      (widen))
                  (goto-char he-search-loc)
                  (setq strip-prompt (and (get-buffer-process (current-buffer))
                                          comint-prompt-regexp))
                  (setq expansion 
                        (let ((case-fold-search orig-case-fold-search))
                          (he-line-search he-search-string
                                          strip-prompt nil)))
                  (set-marker he-search-loc (point))
                  (if (not expansion)
                      (progn
                        (setq he-search-bufs (cdr he-search-bufs))
                        (setq he-searched-n-bufs (1+ he-searched-n-bufs))
                        (set-marker he-search-loc 1 (car he-search-bufs))))))
            (setq he-search-bufs (cdr he-search-bufs))
            (set-marker he-search-loc 1 (car he-search-bufs)))))

    (set-buffer buf)
    (if (not expansion)
        (progn
          (if old (he-reset-string))
          ())
        (progn
          (he-substitute-string expansion t)
          t))))

(defun he-line-search (str strip-prompt reverse) 
  (let ((result ()))
    (while (and (not result)
                (if reverse
                    (re-search-backward 
                     (he-line-search-regexp str strip-prompt)
                     nil t)
                    (re-search-forward
                     (he-line-search-regexp str strip-prompt)
                     nil t)))
      (setq result (buffer-substring-no-properties (match-beginning 2)
                                                   (match-end 2)))
      (if (he-string-member result he-tried-table t)
          (setq result nil)))               ; if already in table, ignore
    result))

(defun he-line-beg (strip-prompt)
  (save-excursion
    (if (re-search-backward (he-line-search-regexp "" strip-prompt) 
                            (save-excursion (beginning-of-line)
                                            (point)) t)
        (match-beginning 2)
      (point))))

(defun he-line-search-regexp (pat strip-prompt)
  (if strip-prompt
      (concat "\\(" comint-prompt-regexp "\\|^\\s-*\\)\\("
              (regexp-quote pat)
              "[^\n]*[^ \t\n]\\)")
      (concat "^\\(\\s-*\\)\\(" 
              (regexp-quote pat)
              "[^\n]*[^ \t\n]\\)")))

(defun try-expand-list (old)
  "Try to complete the current beginning of a list.
The argument OLD has to be nil the first call of this function, and t
for subsequent calls (for further possible completions of the same
string).  It returns t if a new completion is found, nil otherwise."
  (let ((expansion ()))
    (if (not old)
        (progn
          (he-init-string (he-list-beg) (point))
          (set-marker he-search-loc he-string-beg)
          (setq he-search-bw t)))

    (if (not (equal he-search-string ""))
        (save-excursion
          (save-restriction
            (if hippie-expand-no-restriction
                (widen))
            ;; Try looking backward unless inhibited.
            (if he-search-bw
                (progn 
                  (goto-char he-search-loc)
                  (setq expansion (he-list-search he-search-string t))
                  (set-marker he-search-loc (point))
                  (if (not expansion)
                      (progn
                        (set-marker he-search-loc he-string-end)
                        (setq he-search-bw ())))))

            (if (not expansion) ; Then look forward.
                (progn 
                  (goto-char he-search-loc)
                  (setq expansion (he-list-search he-search-string nil))
                  (set-marker he-search-loc (point)))))))

    (if (not expansion)
        (progn
          (if old (he-reset-string))
          ())
        (progn
          (he-substitute-string expansion t)
          t))))

(defun try-expand-list-all-buffers (old)
  "Try to complete the current list, searching all other buffers.
The argument OLD has to be nil the first call of this function, and t
for subsequent calls (for further possible completions of the same
string).  It returns t if a new completion is found, nil otherwise."
  (let ((expansion ())
        (buf (current-buffer))
        (orig-case-fold-search case-fold-search))
    (if (not old)
        (progn
          (he-init-string (he-list-beg) (point))
          (setq he-search-bufs (buffer-list))
          (setq he-searched-n-bufs 0)
          (set-marker he-search-loc 1 (car he-search-bufs))))

    (if (not (equal he-search-string ""))
        (while (and he-search-bufs 
                    (not expansion)
                    (or (not hippie-expand-max-buffers)
                        (< he-searched-n-bufs hippie-expand-max-buffers)))
          (set-buffer (car he-search-bufs))
          (if (and (not (eq (current-buffer) buf))
                   (if hippie-expand-only-buffers
                       (he-buffer-member hippie-expand-only-buffers)
                     (not (he-buffer-member hippie-expand-ignore-buffers))))
              (save-excursion
                (save-restriction
                  (if hippie-expand-no-restriction
                      (widen))
                  (goto-char he-search-loc)
                  (setq expansion 
                        (let ((case-fold-search orig-case-fold-search))
                          (he-list-search he-search-string nil)))
                  (set-marker he-search-loc (point))
                  (if (not expansion)
                      (progn
                        (setq he-search-bufs (cdr he-search-bufs))
                        (setq he-searched-n-bufs (1+ he-searched-n-bufs))
                        (set-marker he-search-loc 1 (car he-search-bufs))))))
            (setq he-search-bufs (cdr he-search-bufs))
            (set-marker he-search-loc 1 (car he-search-bufs)))))

    (set-buffer buf)
    (if (not expansion)
        (progn
          (if old (he-reset-string))
          ())
        (progn
          (he-substitute-string expansion t)
          t))))

(defun he-list-search (str reverse) 
  (let ((result ())
        beg pos err)
    (while (and (not result)
                (if reverse
                    (search-backward str nil t)
                    (search-forward str nil t)))
      (setq pos (point))
      (setq beg (match-beginning 0))
      (goto-char beg)
      (setq err ())
      (condition-case ()
          (forward-list 1)
        (error (setq err t)))
      (if (and reverse 
               (> (point) he-string-beg))
          (setq err t))
      (if (not err)
          (progn
            (setq result (buffer-substring-no-properties beg (point)))
            (if (he-string-member result he-tried-table t)
                (setq result nil))))           ; if already in table, ignore
      (goto-char pos))
    result))

(defun he-list-beg ()
  (save-excursion
    (condition-case ()
        (backward-up-list 1)
      (error ()))
    (point)))

(defun try-expand-all-abbrevs (old)
  "Try to expand word before point according to all abbrev tables.
The argument OLD has to be nil the first call of this function, and t
for subsequent calls (for further possible expansions of the same
string).  It returns t if a new expansion is found, nil otherwise."
  (if (not old)
      (progn
        (he-init-string (he-dabbrev-beg) (point))
        (setq he-expand-list 
              (and (not (equal he-search-string ""))
                   (mapcar (function (lambda (sym)
                             (if (and (boundp sym) (vectorp (eval sym)))
                                 (abbrev-expansion (downcase he-search-string)
                                                   (eval sym)))))
                           (append '(local-abbrev-table 
                                     global-abbrev-table)
                                   abbrev-table-name-list))))))
  (while (and he-expand-list
              (or (not (car he-expand-list))
                  (he-string-member (car he-expand-list) he-tried-table t)))
    (setq he-expand-list (cdr he-expand-list)))
  (if (null he-expand-list)
      (progn
        (if old (he-reset-string))
        ())
      (progn
        (he-substitute-string (car he-expand-list) t)
        (setq he-expand-list (cdr he-expand-list))
        t)))

(defun try-expand-dabbrev (old)
  "Try to expand word \"dynamically\", searching the current buffer.
The argument OLD has to be nil the first call of this function, and t
for subsequent calls (for further possible expansions of the same
string).  It returns t if a new expansion is found, nil otherwise."
  (let ((expansion ()))
    (if (not old)
        (progn
          (he-init-string (he-dabbrev-beg) (point))
          (set-marker he-search-loc he-string-beg)
          (setq he-search-bw t)))

    (if (not (equal he-search-string ""))
        (save-excursion
          (save-restriction
            (if hippie-expand-no-restriction
                (widen))
            ;; Try looking backward unless inhibited.
            (if he-search-bw
                (progn 
                  (goto-char he-search-loc)
                  (setq expansion (he-dabbrev-search he-search-string t))
                  (set-marker he-search-loc (point))
                  (if (not expansion)
                      (progn
                        (set-marker he-search-loc he-string-end)
                        (setq he-search-bw ())))))

            (if (not expansion) ; Then look forward.
                (progn 
                  (goto-char he-search-loc)
                  (setq expansion (he-dabbrev-search he-search-string nil))
                  (set-marker he-search-loc (point)))))))
        
    (if (not expansion)
        (progn
          (if old (he-reset-string))
          ())
        (progn
          (he-substitute-string expansion t)
          t))))

(defun try-expand-dabbrev-all-buffers (old)
  "Tries to expand word \"dynamically\", searching all other buffers.
The argument OLD has to be nil the first call of this function, and t
for subsequent calls (for further possible expansions of the same
string).  It returns t if a new expansion is found, nil otherwise."
  (let ((expansion ())
        (buf (current-buffer))
        (orig-case-fold-search case-fold-search))
    (if (not old)
        (progn
          (he-init-string (he-dabbrev-beg) (point))
          (setq he-search-bufs (buffer-list))
          (setq he-searched-n-bufs 0)
          (set-marker he-search-loc 1 (car he-search-bufs))))

    (if (not (equal he-search-string ""))
        (while (and he-search-bufs 
                    (not expansion)
                    (or (not hippie-expand-max-buffers)
                        (< he-searched-n-bufs hippie-expand-max-buffers)))
          (set-buffer (car he-search-bufs))
          (if (and (not (eq (current-buffer) buf))
                   (if hippie-expand-only-buffers
                       (he-buffer-member hippie-expand-only-buffers)
                     (not (he-buffer-member hippie-expand-ignore-buffers))))
              (save-excursion
                (save-restriction
                  (if hippie-expand-no-restriction
                      (widen))
                  (goto-char he-search-loc)
                  (setq expansion
                        (let ((case-fold-search orig-case-fold-search))
                          (he-dabbrev-search he-search-string nil)))
                  (set-marker he-search-loc (point))
                  (if (not expansion)
                      (progn
                        (setq he-search-bufs (cdr he-search-bufs))
                        (setq he-searched-n-bufs (1+ he-searched-n-bufs))
                        (set-marker he-search-loc 1 (car he-search-bufs))))))
            (setq he-search-bufs (cdr he-search-bufs))
            (set-marker he-search-loc 1 (car he-search-bufs)))))

    (set-buffer buf)
    (if (not expansion)
        (progn
          (if old (he-reset-string))
          ())
        (progn
          (he-substitute-string expansion t)
          t))))

;; Thanks go to Jeff Dairiki <dairiki@faraday.apl.washington.edu> who
;; suggested this one.
(defun try-expand-dabbrev-visible (old)
  "Try to expand word \"dynamically\", searching visible window parts.
The argument OLD has to be nil the first call of this function, and t
for subsequent calls (for further possible expansions of the same
string).  It returns t if a new expansion is found, nil otherwise."
  (let ((expansion ())
        (buf (current-buffer))
        (flag (if (frame-visible-p (window-frame (selected-window)))
                  'visible t)))
    (if (not old)
        (progn
           (he-init-string (he-dabbrev-beg) (point))
           (setq he-search-window (selected-window))
           (set-marker he-search-loc
                       (window-start he-search-window)
                       (window-buffer he-search-window))))

    (while (and (not (equal he-search-string ""))
                (marker-position he-search-loc)
                (not expansion))
      (save-excursion
        (set-buffer (marker-buffer he-search-loc))
        (goto-char he-search-loc)
        (setq expansion (he-dabbrev-search he-search-string ()
                                           (window-end he-search-window)))
        (if (and expansion
                 (eq (marker-buffer he-string-beg) (current-buffer))
                 (eq (marker-position he-string-beg) (match-beginning 0)))
            (setq expansion (he-dabbrev-search he-search-string ()
                                               (window-end he-search-window))))
        (set-marker he-search-loc (point) (current-buffer)))
      (if (not expansion)
          (progn 
            (setq he-search-window (next-window he-search-window nil flag))
            (if (eq he-search-window (selected-window))
                (set-marker he-search-loc nil)
              (set-marker he-search-loc (window-start he-search-window)
                          (window-buffer he-search-window))))))
    
    (set-buffer buf)
    (if (not expansion)
        (progn
          (if old (he-reset-string))
          ())
        (progn
          (he-substitute-string expansion t)
          t))))

(defun he-dabbrev-search (pattern &optional reverse limit)
  (let ((result ())
        (regpat (cond ((not hippie-expand-dabbrev-as-symbol)
                       (concat "\\<" (regexp-quote pattern) "\\sw+"))
                      ((eq (char-syntax (aref pattern 0)) ?_)
                       (concat (regexp-quote pattern) "\\(\\sw\\|\\s_\\)+"))
                      (t
                       (concat "\\<" (regexp-quote pattern)
                               "\\(\\sw\\|\\s_\\)+")))))
    (while (and (not result) 
                (if reverse
                     (re-search-backward regpat limit t)
                     (re-search-forward regpat limit t)))
      (setq result (buffer-substring-no-properties (match-beginning 0)
                                                   (match-end 0)))
      (if (or (and hippie-expand-dabbrev-as-symbol
                   (> (match-beginning 0) (point-min))
                   (memq (char-syntax (char-after (1- (match-beginning 0))))
                         '(?_ ?w)))
              (he-string-member result he-tried-table t))
          (setq result nil)))     ; ignore if bad prefix or already in table
    result))

(defun he-dabbrev-beg ()
  (let ((op (point)))
    (save-excursion
      (if hippie-expand-dabbrev-skip-space
          (skip-syntax-backward ". "))
      (if (= (skip-syntax-backward (if hippie-expand-dabbrev-as-symbol
                                       "w_" "w"))
             0)
          op
        (point)))))

(defun try-expand-dabbrev-from-kill (old)
  "Try to expand word \"dynamically\", searching the kill ring.
The argument OLD has to be nil the first call of this function, and t
for subsequent calls (for further possible completions of the same
string).  It returns t if a new completion is found, nil otherwise."
  (let ((expansion ()))
    (if (not old)
        (progn 
          (he-init-string (he-dabbrev-beg) (point))
          (setq he-expand-list
                (if (not (equal he-search-string ""))
                    kill-ring))
          (setq he-search-loc2 0)))
    (if (not (equal he-search-string ""))
        (setq expansion (he-dabbrev-kill-search he-search-string)))
    (if (not expansion)
        (progn
          (if old (he-reset-string))
          ())
        (progn
          (he-substitute-string expansion t)
          t))))

(defun he-dabbrev-kill-search (pattern)
  (let ((result ())
        (regpat (cond ((not hippie-expand-dabbrev-as-symbol)
                       (concat "\\<" (regexp-quote pattern) "\\sw+"))
                      ((eq (char-syntax (aref pattern 0)) ?_)
                       (concat (regexp-quote pattern) "\\(\\sw\\|\\s_\\)+"))
                      (t
                       (concat "\\<" (regexp-quote pattern)
                               "\\(\\sw\\|\\s_\\)+"))))
        (killstr (car he-expand-list)))
    (while (and (not result) 
                he-expand-list)
      (while (and (not result)
                  (string-match regpat killstr he-search-loc2))
        (setq result (substring killstr (match-beginning 0) (match-end 0)))
        (set-text-properties 0 (length result) () result)
        (setq he-search-loc2 (1+ (match-beginning 0)))
        (if (or (and hippie-expand-dabbrev-as-symbol
                     (> (match-beginning 0) 0)
                     (memq (char-syntax (aref killstr (1- (match-beginning 0))))
                           '(?_ ?w)))
                (he-string-member result he-tried-table t))
            (setq result nil)))     ; ignore if bad prefix or already in table
      (if (and (not result) 
                he-expand-list)
          (progn
            (setq he-expand-list (cdr he-expand-list)) 
            (setq killstr (car he-expand-list))
            (setq he-search-loc2 0))))
    result))

(defun try-expand-whole-kill (old)
  "Try to complete text with something from the kill ring.
The argument OLD has to be nil the first call of this function, and t
for subsequent calls (for further possible completions of the same
string).  It returns t if a new completion is found, nil otherwise."
  (let ((expansion ()))
    (if (not old)
        (progn 
          (he-init-string (he-kill-beg) (point))
          (if (not (he-string-member he-search-string he-tried-table))
              (setq he-tried-table (cons he-search-string he-tried-table)))
          (setq he-expand-list 
                (if (not (equal he-search-string ""))
                    kill-ring))
          (setq he-search-loc2 ())))
    (if (not (equal he-search-string ""))
        (setq expansion (he-whole-kill-search he-search-string)))
    (if (not expansion)
        (progn
          (if old (he-reset-string))
          ())
        (progn
          (he-substitute-string expansion)
          t))))

(defun he-whole-kill-search (str)
  (let ((case-fold-search ())
        (result ())
        (str (regexp-quote str))
        (killstr (car he-expand-list))
        (pos -1))
    (while (and (not result)
                he-expand-list)
      (if (not he-search-loc2)
          (while (setq pos (string-match str killstr (1+ pos)))
            (setq he-search-loc2 (cons pos he-search-loc2))))
      (while (and (not result)
                  he-search-loc2)
        (setq pos (car he-search-loc2))
        (setq he-search-loc2 (cdr he-search-loc2))
        (save-excursion
          (goto-char he-string-beg)
          (if (and (>= (- (point) pos) (point-min))   ; avoid some string GC
                   (eq (char-after (- (point) pos)) (aref killstr 0))
                   (search-backward (substring killstr 0 pos)
                                    (- (point) pos) t))
              (progn
                (setq result (substring killstr pos))
                (set-text-properties 0 (length result) () result))))
        (if (and result
                 (he-string-member result he-tried-table))
            (setq result nil)))     ; ignore if already in table
      (if (and (not result)
                he-expand-list)
          (progn
            (setq he-expand-list (cdr he-expand-list)) 
            (setq killstr (car he-expand-list))
            (setq pos -1))))
    result))

(defun he-kill-beg ()
  (let ((op (point)))
    (save-excursion
      (skip-syntax-backward "^w_")
      (if (= (skip-syntax-backward "w_") 0)
          op
        (point)))))


(provide 'hippie-exp)

;;; hippie-exp.el ends here