(bibtex-pop): New generic function which unifies the

functionality of bibtex-pop-previous and bibtex-pop-next.  Now,
bibtex-pop moves to the end of field after the pop.  Concatenated
strings are now handled correctly.  Delimiters are not added to
non-delimited entries.  Changed occurences of
bibtex-text-in-cfield to bibtex-text-in-field.
(bibtex-pop-previous, bibtex-pop-next): Call bibtex-pop.
(bibtex-complete-string): Fixed bug that removed delimiters
around the following field if current field is already
undelimited on completion.
(bibtex-complete-string, bibtex-remove-double-quotes-or-braces):
Only remove delimiters if field text is not concatenated.
(bibtex-font-lock-keywords): Use the same regexps used
in all other places of bibtex.el to parse the buffer.
(bibtex-mode): Changed the definition of font-lock-defaults,
so that quote-delimited entries aren't fontified as strings anymore.
(bibtex-parse-keys): Changed the regexp used for finding crossref entries.
(bibtex-field-const, bibtex-reference-key): Fixed the regexp
to match more of the characters allowed here by BibTeX/LaTeX.
(bibtex-field-name): Made it less restrictive.
(bibtex-field-string): Changed so that quote-delimited entries
with quotes inside aren't a problem anymore.  Changed nesting
level of braces in entries to support three inner braces.
(bibtex-validate-buffer): By giving an optional argument, the
user can now let it not validate the whole buffer, but only
the portion starting at point.  Small modification in strategy
used to find next entry.
(bibtex-print-help-message): Ignore case in field name when
searching for help text.
(bibtex-submit-bug-report): New function.

1 files changed, 359 insertions, 227 deletions

diff --git a/lisp/textmodes/bibtex.el b/lisp/textmodes/bibtex.el
index 700bf46bac0..645cb1ceb67 100644
--- a/lisp/textmodes/bibtex.el
+++ b/lisp/textmodes/bibtex.el
@@ -1,13 +1,13 @@
 ;;; bibtex.el --- BibTeX mode for GNU Emacs
 
-;; Copyright (C) 1992, 1994, 1995 Free Software Foundation, Inc.
+;; Copyright (C) 1992, 1994, 1995, 1996 Free Software Foundation, Inc.
 
-;; Author: Stefan Schoef <schoef@informatik.uni-oldenburg.de>
+;; Author: Stefan Schoef <schoef@offis.uni-oldenburg.de>
 ;;      Bengt Martensson <bengt@mathematik.uni-Bremen.de>
 ;;	Mark Shapiro <shapiro@corto.inria.fr>
 ;;	Mike Newton <newton@gumby.cs.caltech.edu>
 ;;	Aaron Larson <alarson@src.honeywell.com>
-;; Maintainer: Stefan Schoef <schoef@informatik.uni-oldenburg.de>
+;; Maintainer: Stefan Schoef <schoef@offis.uni-oldenburg.de>
 ;; Keywords: BibTeX, LaTeX, TeX
 
 ;; This file is part of GNU Emacs.
@@ -45,12 +45,8 @@
 ;;   2. Calling bibtex-find-text in a string entry results in the
 ;;      error message "Can't find enclosing Bibtex field" instead of
 ;;      moving to the empty string. [reported by gernot@cs.unsw.oz.au]
-;;   3. Quotes inside quote-parenthesized fields (like
-;;      `author = "Stefan Sch{\"o}f"') break bibtex-validate-buffer.
-;;      Further, you must use braces here, if you want to set
-;;      bibtex-maintain-sorted-entries to a non-nil value.
 
-;; (current keeper: schoef@informatik.uni-oldenburg.de
+;; (current keeper: schoef@offis.uni-oldenburg.de
 ;;  previous: alarson@src.honeywell.com)
 
 ;;; Code:
@@ -409,19 +405,10 @@ See the documentation of function bibtex-generate-autokey for further detail.")
 (defvar bibtex-autokey-edit-before-use t
   "*If non-nil, user is allowed to edit the generated key before it is used.")
 
-(defvar bibtex-font-lock-keywords
-  (list
-   '("\\(^@\\sw+\\)[ \t]*[({][ \t]*\\([^ \t\n,]*\\)"
-     (1 font-lock-keyword-face) (2 font-lock-reference-face))
-   ;; reference type and reference label
-   '("^[ \t]*\\(OPT\\sw+\\)[ \t]*="
-     1 font-lock-comment-face)
-   ;; optional field names (treated as comments)
-   '("^[ \t]*\\(\\sw+\\)[ \t]*="
-     1 font-lock-variable-name-face)
-   ;; field names
-   )
-  "*Default expressions to highlight in BibTeX mode.")
+;; bibtex-font-lock-keywords is a user option as well, but since the
+;; patterns used to define this variable are defined in a later
+;; section of this file, its definition comes later.
+
 
 ;; Syntax Table, Keybindings and BibTeX Entry List
 (defvar bibtex-mode-syntax-table
@@ -504,6 +491,12 @@ See the documentation of function bibtex-generate-autokey for further detail.")
   '("Clean Up Entry" . bibtex-clean-entry))
 (define-key bibtex-mode-map [menu-bar bibtex-edit bibtex-sort-entries]
   '("Sort Entries" . bibtex-sort-entries))
+(define-key bibtex-mode-map
+  [menu-bar bibtex-edit bibtex-validate-buffer-from-point]
+  '("Validate Entries Starting at Point" .
+    (lambda ()
+      (interactive)
+      (bibtex-validate-buffer t))))
 (define-key bibtex-mode-map [menu-bar bibtex-edit bibtex-validate-buffer]
   '("Validate Entries" . bibtex-validate-buffer))
 
@@ -540,6 +533,12 @@ See the documentation of function bibtex-generate-autokey for further detail.")
 (define-key bibtex-mode-map [menu-bar entry-types bibtex-Article]
   '("Article in Journal" . bibtex-Article))
 
+
+;; Bug Reporting
+
+(defconst
+  bibtex-maintainer-address "Stefan Schoef <schoef@offis.uni-oldenburg.de>")
+;; current maintainer
 
 
 ;; Internal Variables
@@ -568,7 +567,6 @@ See the documentation of function bibtex-generate-autokey for further detail.")
 ;; was parsed for keys the last time.
 (make-variable-buffer-local 'bibtex-keys)
 
-
 
 ;; Functions to Parse the BibTeX Entries
 
@@ -585,21 +583,85 @@ See the documentation of function bibtex-generate-autokey for further detail.")
 (defconst bibtex-text-in-cfield 2)
 ;; The regexp subexpression number of the text part in bibtex-cfield.
 
-(defconst bibtex-field-name "[A-Za-z_-][A-Za-z0-9_-]*")
+(defconst bibtex-field-name "[^\"#%'(),={} \t\n0-9][^\"#%'(),={} \t\n]*")
 ;; Regexp defining the name part of a BibTeX field.
 
-(defconst bibtex-field-const "[0-9A-Za-z][A-Za-z0-9:_+-]*"
-  "Format of a bibtex field constant.")
+(defconst bibtex-field-const "[][A-Za-z0-9.:;?!`'()/*@_+=|<>-]+")
+;; Format of a bibtex field constant (same as bibtex-reference-key (see below))
 
-(defconst bibtex-field-string
+(defconst bibtex-field-string-part-not-braced
+  "[^{}]")
+;; Match field string part without braces
+
+(defconst bibtex-field-string-part-no-inner-braces
+  (concat
+   "{"
+   "\\(" bibtex-field-string-part-not-braced "\\)*"
+   "}"))
+;; Match field string part with no inner braces
+
+(defconst bibtex-field-string-part-1-inner-brace
   (concat
+   "{"
    "\\("
-   "{\\(\\({\\(\\({[^}]*}\\)\\|\\([^{}]\\)\\)*}\\)\\|\\([^{}]\\)\\)*}"
-   ;; maximal twice nested {}
-   "\\)\\|\\("
-   "\"[^\"]*[^\\\\]\"\\|\"\""
-   "\\)"))
-;; Match either a string or an empty string.
+     "\\(" bibtex-field-string-part-not-braced "\\)"
+     "\\|"
+     "\\(" bibtex-field-string-part-no-inner-braces "\\)"
+   "\\)*"
+   "}"))
+;; Match field string part with at most 1 inner brace
+
+(defconst bibtex-field-string-part-2-inner-braces
+  (concat
+   "{"
+   "\\("
+     "\\(" bibtex-field-string-part-not-braced "\\)"
+     "\\|"
+     "\\(" bibtex-field-string-part-no-inner-braces "\\)"
+     "\\|"
+     "\\(" bibtex-field-string-part-1-inner-brace "\\)"
+   "\\)*"
+   "}"))
+;; Match field string part with at most 2 inner braces
+
+(defconst bibtex-field-string-part-3-inner-braces
+  (concat
+   "{"
+   "\\("
+     "\\(" bibtex-field-string-part-not-braced "\\)"
+     "\\|"
+     "\\(" bibtex-field-string-part-no-inner-braces "\\)"
+     "\\|"
+     "\\(" bibtex-field-string-part-1-inner-brace "\\)"
+     "\\|"
+     "\\(" bibtex-field-string-part-2-inner-braces "\\)"
+   "\\)*"
+   "}"))
+;; Match field string part with at most 3 inner braces
+
+(defconst bibtex-field-string-braced
+  bibtex-field-string-part-3-inner-braces)
+;; Match braced field string with inner nesting level of braces at most 3
+
+(defconst bibtex-field-string-quoted
+  (concat
+   "\""
+   "\\("
+     "\\(" "[^\"\\]" "\\)"      ;; every character except quote or backslash
+     "\\|"
+     "\\(" "\"[A-Za-z-]" "\\)"  ;; a quote followed by a letter or dash 
+     "\\|"
+     "\\(" "\\\\.\\|\n"  "\\)"  ;; a backslash followed by any character
+   "\\)*"
+   "\""))
+;; Match quoted field string
+
+(defconst bibtex-field-string
+  (concat
+   "\\(" bibtex-field-string-braced "\\)"
+   "\\|"
+   "\\(" bibtex-field-string-quoted "\\)"))
+;; Match a braced or quoted string
 
 (defconst bibtex-field-string-or-const
   (concat bibtex-field-const "\\|" bibtex-field-string))
@@ -608,7 +670,7 @@ See the documentation of function bibtex-generate-autokey for further detail.")
 (defconst bibtex-field-text
   (concat
     "\\(" bibtex-field-string-or-const "\\)"
-        "\\([ \t\n]+#[ \t\n]+\\(" bibtex-field-string-or-const "\\)\\)*"))
+    "\\([ \t\n]+#[ \t\n]+\\(" bibtex-field-string-or-const "\\)\\)*"))
 ;; Regexp defining the text part of a BibTeX field: either a string,
 ;; or an empty string, or a constant followed by one or more # /
 ;; constant pairs.
@@ -626,8 +688,9 @@ See the documentation of function bibtex-generate-autokey for further detail.")
 (defconst bibtex-reference-type "@[A-Za-z]+")
 ;; Regexp defining the type part of a BibTeX reference entry.
 
-(defconst bibtex-reference-key "[A-Za-z][A-Za-z0-9.:;?!`'/*@_+-]*")
-;; Regexp defining the label part of a BibTeX reference entry.
+(defconst bibtex-reference-key "[][A-Za-z0-9.:;?!`'()/*@_+=|<>-]+")
+;; Regexp defining the label part of a BibTeX reference entry (same as
+;; bibtex-field-const (see above))
 
 (defconst bibtex-reference-head
   (concat "^\\( \\|\t\\)*\\("
@@ -679,6 +742,21 @@ See the documentation of function bibtex-generate-autokey for further detail.")
 (defconst bibtex-text-in-string 2)
 ;; The regexp subexpression of the text part in bibtex-string.
 
+(defvar bibtex-font-lock-keywords
+  (list
+   (list bibtex-reference-maybe-empty-head
+         (list bibtex-type-in-head 'font-lock-function-name-face)
+         (list bibtex-key-in-head 'font-lock-reference-face nil t))
+   ;; reference type and reference label
+   (list (concat "^[ \t]*\\(OPT" bibtex-field-name "\\)[ \t]*=")
+         1 'font-lock-comment-face)
+   ;; optional field names (treated as comments)
+   (list (concat "^[ \t]*\\(" bibtex-field-name "\\)[ \t]*=")
+         1 'font-lock-variable-name-face)
+   ;; field names
+   "*Default expressions to highlight in BibTeX mode."))
+;; now all needed patterns are defined
+
 (defconst bibtex-name-alignment 2)
 ;; Alignment for the name part in BibTeX fields. Chosen on aesthetic
 ;; grounds only.
@@ -687,7 +765,6 @@ See the documentation of function bibtex-generate-autokey for further detail.")
 ;; Alignment for the text part in BibTeX fields. Equal to the space
 ;; needed for the longest name part.
 
-
 
 ;; Helper Functions
 
@@ -878,7 +955,7 @@ See the documentation of function bibtex-generate-autokey for further detail.")
   ;; REGEXP is not found, signals search-failed; point is left in an
   ;; undefined location.
   ;; Doesn't something like this exist already?
-  ; compute reasonable limits for the loop
+  ;; compute reasonable limits for the loop
   (let* ((initial (point))
 	 (right (if (re-search-forward regexp (point-max) t)
 		    (match-end 0)
@@ -1199,10 +1276,23 @@ The generation algorithm works as follows:
                  (while
                      (re-search-forward
                       (concat
+                       "\\(" bibtex-reference-head "\\)"
+                       "\\|"
                        "\\("
-                       bibtex-reference-head
-                       "\\)\\|\\("
-                       "^[ \t\n]*crossref[ \t\n]*=[ \t\n]*[{\"]\\([A-Za-z][]A-Za-z0-9.:;?!`'()/*@_+-]*\\)[}\"],?$"
+                         "^[ \t]*crossref[ \t\n]*=[ \t\n]*"
+                         "\\("
+                           "\\({"
+                           bibtex-reference-key
+                           ;; every valid crossref entry must have the
+                           ;; form of a reference key, so we need no
+                           ;; nesting of brace etc. here
+                           "}\\)"
+                           "\\|"
+                           "\\(\""
+                           bibtex-reference-key
+                           "\"\\)"
+                         "\\)"
+                         ",?$"
                        "\\)")
                       nil t)
                    (if (and
@@ -1218,8 +1308,8 @@ The generation algorithm works as follows:
                      (setq
                       label
                       (buffer-substring-no-properties
-                       (match-beginning (+ 3 bibtex-key-in-head))
-                       (match-end (+ 3 bibtex-key-in-head)))))
+                       (1+ (match-beginning (+ 3 bibtex-key-in-head)))
+                       (1- (match-end (+ 3 bibtex-key-in-head))))))
                    (if (not (assoc label labels))
                        (setq labels
                              (cons (list label) labels))))))
@@ -1235,13 +1325,17 @@ The generation algorithm works as follows:
   (let ((fill-prefix (make-string (+ bibtex-text-alignment 1) ? )))
     (do-auto-fill)))
 
-
 
 ;; Interactive Functions:
 
 ;;;###autoload
 (defun bibtex-mode () 
   "Major mode for editing BibTeX files.
+To submit a problem report, enter `\\[bibtex-submit-bug-report]' from a
+bibtex-mode buffer.  This automatically sets up a mail buffer with
+version information already added.  You just need to add a description
+of the problem, including a reproducable test case and send the
+message.
 
 \\{bibtex-mode-map}
 
@@ -1383,9 +1477,79 @@ non-nil."
   (setq auto-fill-function 'bibtex-auto-fill-function)
   (set (make-local-variable 'font-lock-defaults)
        '(bibtex-font-lock-keywords
-         nil t ((?_ . "w") (?- . "w") (?$ . "\""))))
+         nil t ((?$ . "\"")
+                ;; Mathematical expressions should be fontified as strings
+                (?\" . ".")
+                ;; Quotes are field delimiters and quote-delimited
+                ;; entries should be fontified in the same way as
+                ;; brace-delimited ones
+                )))
   (run-hooks 'bibtex-mode-hook))
 
+(defun bibtex-submit-bug-report ()
+  "Submit via mail a bug report on bibtex.el."
+  (interactive)
+  (if (y-or-n-p "Do you want to submit a bug report on BibTeX mode? ")
+      (progn
+        (require 'reporter)
+        (let ((reporter-prompt-for-summary-p t))
+          (reporter-submit-bug-report
+           bibtex-maintainer-address
+           "bibtex.el"
+           (list
+            'system-configuration
+            'system-configuration-options
+            'bibtex-sort-ignore-string-entries
+            'bibtex-maintain-sorted-entries
+            'bibtex-field-left-delimiter
+            'bibtex-field-right-delimiter
+            ;; Possible sorting and parsing bugs
+            'bibtex-mode-user-optional-fields
+            ;; Possible format error
+            'bibtex-predefined-strings
+            'bibtex-string-files
+            ;; Possible format error
+            'bibtex-font-lock-keywords
+            ;; Possible bugs regarding fontlocking
+            'bibtex-autokey-names
+            'bibtex-autokey-name-change-strings
+            'bibtex-autokey-name-length
+            'bibtex-autokey-name-separator
+            'bibtex-autokey-year-length
+            'bibtex-autokey-titlewords
+            'bibtex-autokey-title-terminators
+            'bibtex-autokey-titlewords-stretch
+            'bibtex-autokey-titleword-first-ignore
+            'bibtex-autokey-titleword-abbrevs
+            'bibtex-autokey-titleword-change-strings
+            'bibtex-autokey-titleword-length
+            'bibtex-autokey-titleword-separator
+            'bibtex-autokey-name-year-separator
+            'bibtex-autokey-year-title-separator
+            'bibtex-autokey-edit-before-use
+            ;; Possible bugs regarding automatic labels
+            'bibtex-entry-field-alist
+            ;; Possible format error
+            'bibtex-help-message
+            'bibtex-include-OPTcrossref
+            'bibtex-include-OPTkey
+            'bibtex-include-OPTannote
+            'bibtex-clean-entry-zap-empty-opts
+            ;; User variables which shouldn't cause any errors
+            )
+           nil nil
+           (concat "Hi Stefan,
+ 
+I want to report a bug on Emacs BibTeX mode.
+I've read the `Bugs' section in the `Emacs' info page, so I know how
+to make a clear and unambiguous report. I have started a fresh Emacs
+via `"invocation-name " --no-init-file --no-site-file', thereafter (in
+case I'm reporting on a version of `bibtex.el' which is not part of
+the standard emacs distribution) I loaded the questionable version
+of `bibtex.el' with `M-x load-file', and then, to produce the buggy
+behaviour, I did the following:")))
+        (message nil))))
+
 (defun bibtex-entry (entry-type &optional required optional)
   "Inserts a new BibTeX entry.
 Calls the value of bibtex-add-entry-hook if that value is non-nil."
@@ -1487,9 +1651,10 @@ Calls the value of bibtex-add-entry-hook if that value is non-nil."
                                '(("key"
                                   "Key used for label creation if author and editor fields are missing"))))))
     (goto-char pnt)
-    (if (assoc field-name list-of-entries)
-        (message (elt (assoc field-name list-of-entries) 1))
-      (message "NO COMMENT AVAILABLE"))))
+    (let ((comment (assoc-ignore-case field-name list-of-entries)))
+      (if comment
+          (message (elt comment 1))
+        (message "NO COMMENT AVAILABLE")))))
 
 (defun bibtex-make-field (e-t)
   "Makes a field named E-T in current BibTeX entry."
@@ -1560,7 +1725,6 @@ of the previous entry."
     (narrow-to-region (progn (bibtex-beginning-of-entry) (point))
 		      (progn (bibtex-end-of-entry) (point)))))
 
-
 (defun bibtex-hide-entry-bodies (&optional arg)
   "Hide all lines between first and last BibTeX entries not beginning with @.
 With argument, show all text."
@@ -1704,16 +1868,22 @@ occurred, and t in all other cases."
               (goto-char right))))
       t)))    
 
-(defun bibtex-validate-buffer ()
+(defun bibtex-validate-buffer (&optional from-point)
   "Validate if the current BibTeX buffer is syntactically correct.
 Any garbage (e.g. comments) before the first \"@\" is not tested (so
-you can put comments here)."
-  (interactive)
+you can put comments here).
+With non-nil FROM-POINT it starts with entry enclosing point."
+  (interactive "P")
   (let ((pnt (point))
-        (max (point-max)))
+        (starting-point
+         (progn
+           (if from-point
+               (bibtex-beginning-of-entry)
+             (beginning-of-first-bibtex-entry))
+           (point))))
     ;; looking if entries fit syntactical structure
-    (goto-char (point-min))
-    (while (< (re-search-forward "@\\|\\'") max)
+    (goto-char starting-point)
+    (while (re-search-forward "^@" nil t)
       (forward-char -1)
       (let ((p (point)))
         (if (or
@@ -1729,7 +1899,7 @@ you can put comments here)."
     ;; looking if entries are balanced (a single non-escaped quote
     ;; inside braces is not detected by the former check, but
     ;; bibtex-sort-entries stumbles about it
-    (goto-char (point-min))
+    (goto-char starting-point)
     (map-bibtex-entries
      (function
       (lambda (current)
@@ -1737,10 +1907,9 @@ you can put comments here)."
         (forward-sexp 2))))
     ;; looking for correct sort order and duplicates
     (if bibtex-maintain-sorted-entries
-        (let ((entry-name (make-string 10 255))
-              (previous nil)
+        (let (previous
               point)
-          (beginning-of-first-bibtex-entry)
+          (goto-char starting-point)
           (map-bibtex-entries
            (function
             (lambda (current)
@@ -1753,7 +1922,9 @@ you can put comments here)."
                     (t
                      (error "Entries out of order here!"))))))))
     (goto-char pnt)
-    (message "BibTeX buffer is syntactically correct")))
+    (if from-point
+        (message "Part of BibTeX buffer starting at point is syntactically correct")
+      (message "BibTeX buffer is syntactically correct"))))
 
 (defun bibtex-next-field (arg)
   "Finds end of text of next BibTeX field; with arg, to its beginning."
@@ -1812,14 +1983,18 @@ you can put comments here)."
     (bibtex-inside-field)
     (bibtex-enclosing-field)
     (let ((start (match-beginning bibtex-text-in-field))
-	  (stop (match-end  bibtex-text-in-field)))
-      (goto-char stop)
-      (forward-char -1)
-      (if (looking-at "[}\"]")
-	  (delete-char 1))
+	  (stop (match-end bibtex-text-in-field)))
       (goto-char start)
-      (if (looking-at "[{\"]")
-	  (delete-char 1)))))
+      (while (re-search-forward bibtex-field-string stop t)
+        (let ((beg (match-beginning 0))
+              (end (match-end 0)))
+          (goto-char end)
+          (forward-char -1)
+          (if (looking-at "[}\"]")
+              (delete-char 1))
+          (goto-char beg)
+          (if (looking-at "[{\"]")
+              (delete-char 1)))))))
 
 (defun bibtex-kill-optional-field ()
   "Kill the entire enclosing optional BibTeX field."
@@ -1847,14 +2022,13 @@ you can put comments here)."
                   bibtex-field-right-delimiter)) 
   (bibtex-find-text t))
 
-(defun bibtex-pop-previous (arg)
-  "Replace text of current field with the text of similar field in previous entry.
-With arg, go up ARG entries.  Repeated, goes up so many times.  May be
-intermixed with \\[bibtex-pop-next] (bibtex-pop-next)."
-  (interactive "p")
-  (bibtex-inside-field)
+(defun bibtex-pop (arg direction)
+  ;; generic function to be used by bibtex-pop-previous and bibtex-pop-next
+  (let (bibtex-help-message)
+    (bibtex-find-text nil))
   (save-excursion
-    ; parse current field
+    ;; parse current field
+    (bibtex-inside-field)
     (bibtex-enclosing-field)
     (let ((start-old-text (match-beginning bibtex-text-in-field))
 	  (stop-old-text  (match-end bibtex-text-in-field))
@@ -1862,7 +2036,8 @@ intermixed with \\[bibtex-pop-next] (bibtex-pop-next)."
 	  (stop-name (match-end bibtex-name-in-field))
 	  (new-text))
       (goto-char start-name)
-      ; construct regexp for previous field with same name as this one
+      ;; construct regexp for field with same name as this one,
+      ;; ignoring possible OPT's 
       (let ((matching-entry
 	     (bibtex-cfield
 	      (buffer-substring-no-properties (if (looking-at "OPT")
@@ -1870,135 +2045,84 @@ intermixed with \\[bibtex-pop-next] (bibtex-pop-next)."
                                                 (point))
                                               stop-name)
 	      bibtex-field-text)))
-	; if executed several times in a row, start each search where the
-	; last one finished
-	(cond ((or (eq last-command 'bibtex-pop-previous)
-		   (eq last-command 'bibtex-pop-next))
-	       t
-	       )
+	;; if executed several times in a row, start each search where
+        ;; the last one was finished
+	(cond ((eq last-command 'bibtex-pop)
+               t
+               )
 	      (t
 	       (bibtex-enclosing-reference-maybe-empty-head)
 	       (setq bibtex-pop-previous-search-point (point))
 	       (setq bibtex-pop-next-search-point (match-end 0))))
-	(goto-char bibtex-pop-previous-search-point)
-	; Now search for arg'th previous similar field
+	(if (eq direction 'previous)
+            (goto-char bibtex-pop-previous-search-point)
+          (goto-char bibtex-pop-next-search-point))
+        ;; Now search for arg'th previous/next similar field
 	(cond
-	 ((re-search-backward matching-entry (point-min) t arg)
-	  (setq new-text
+         ((if (eq direction 'previous)
+              (re-search-backward matching-entry (point-min) t arg)
+            (re-search-forward matching-entry (point-max) t arg))
+          ;; Found a matching field. Remember boundaries.
+	  (setq bibtex-pop-previous-search-point (match-beginning 0))
+	  (setq bibtex-pop-next-search-point (match-end 0))
+          (setq new-text
 		(buffer-substring-no-properties
-                 (match-beginning bibtex-text-in-cfield)
-                 (match-end bibtex-text-in-cfield)))
+                 (match-beginning bibtex-text-in-field)
+                 (match-end bibtex-text-in-field)))
           ;; change delimiters, if any changes needed
-          (cond
-           ((and
-             (equal bibtex-field-left-delimiter "{")
-             (eq (aref new-text 0) ?\")
-             (eq (aref new-text (1- (length new-text))) ?\"))
-            (aset new-text 0 ?\{)
-            (aset new-text (1- (length new-text)) ?\}))
-           ((and
-             (equal bibtex-field-left-delimiter "\"")
-             (eq (aref new-text 0) ?\{)
-             (eq (aref new-text (1- (length new-text))) ?\}))
-            (aset new-text 0 ?\")
-            (aset new-text (1- (length new-text)) ?\"))
-           ((or
-             (not (eq (aref new-text 0)
-                      (aref bibtex-field-left-delimiter 0)))
-             (not (eq (aref new-text (1- (length new-text)))
-                      (aref bibtex-field-right-delimiter 0))))
-            (setq new-text (concat bibtex-field-left-delimiter
-                                   new-text 
-                                   bibtex-field-right-delimiter))))
-	  ; Found a matching field. Remember boundaries.
-	  (setq bibtex-pop-next-search-point (match-end 0))
-	  (setq bibtex-pop-previous-search-point (match-beginning 0))
+          (let ((start 0)
+                old-open
+                new-open
+                old-close
+                new-close)
+            (if (equal bibtex-field-left-delimiter "{")
+                (setq old-open ?\"
+                      new-open ?\{
+                      old-close ?\"
+                      new-close ?\})
+              (setq old-open ?\{
+                    new-open ?\"
+                    old-close ?\}
+                    new-close ?\"))
+            (while (string-match bibtex-field-string new-text start)
+              (let ((beg (match-beginning 0))
+                    (end (1- (match-end 0))))
+                (if (and
+                     (eq (aref new-text beg) old-open)
+                     (eq (aref new-text end) old-close))
+                    (progn
+                      (aset new-text beg new-open)
+                      (aset new-text end new-close))))
+              (setq start (match-end 0))))
 	  (bibtex-flash-head)
-	  ; Go back to where we started, delete old text, and pop new.
+          ;; Go back to where we started, delete old text, and pop new.
 	  (goto-char stop-old-text)
 	  (delete-region start-old-text stop-old-text)
 	  (insert new-text))
-	 (t				; search failed
-	  (error "No previous matching BibTeX field."))))))
-  (setq this-command 'bibtex-pop-previous))
+	 (t
+          ;; search failed
+	  (error (concat "No "
+                         (if (eq direction 'previous)
+                             "previous"
+                           "next")
+                         " matching BibTeX field.")))))))
+  (let (bibtex-help-message)
+    (bibtex-find-text nil))
+  (setq this-command 'bibtex-pop))
+
+(defun bibtex-pop-previous (arg)
+  "Replace text of current field with the text of similar field in previous entry.
+With arg, goes up ARG entries. Repeated, goes up so many times. May be
+intermixed with \\[bibtex-pop-next] (bibtex-pop-next)."
+  (interactive "p")
+  (bibtex-pop arg 'previous))
 
 (defun bibtex-pop-next (arg)
   "Replace text of current field with the text of similar field in next entry.
-With arg, go up ARG entries.  Repeated, goes up so many times.  May be
+With arg, goes down ARG entries. Repeated, goes down so many times. May be
 intermixed with \\[bibtex-pop-previous] (bibtex-pop-previous)."
   (interactive "p")
-  (bibtex-inside-field)
-  (save-excursion
-    ; parse current field
-    (bibtex-enclosing-field)
-    (let ((start-old-text (match-beginning bibtex-text-in-field))
-	  (stop-old-text  (match-end bibtex-text-in-field))
-	  (start-name (match-beginning bibtex-name-in-field))
-	  (stop-name (match-end bibtex-name-in-field))
-	  (new-text))
-      (goto-char start-name)
-      ; construct regexp for next field with same name as this one,
-      ; ignoring possible OPT's
-      (let ((matching-entry
-	     (bibtex-cfield
-	      (buffer-substring-no-properties (if (looking-at "OPT")
-                                                  (+ (point) (length "OPT"))
-                                                (point))
-                                              stop-name)
-	      bibtex-field-text)))
-	
-	; if executed several times in a row, start each search where the
-	; last one finished
-	(cond ((or (eq last-command 'bibtex-pop-next)
-		   (eq last-command 'bibtex-pop-previous))
-	       t
-	       )
-	      (t
-	       (bibtex-enclosing-reference-maybe-empty-head)
-	       (setq bibtex-pop-previous-search-point (point))
-	       (setq bibtex-pop-next-search-point (match-end 0))))
-	(goto-char bibtex-pop-next-search-point)
-	
-	; Now search for arg'th next similar field
-	(cond
-	 ((re-search-forward matching-entry (point-max) t arg)
-	  (setq new-text
-		(buffer-substring-no-properties
-                 (match-beginning bibtex-text-in-cfield)
-                 (match-end bibtex-text-in-cfield)))
-          ;; change delimiters, if any changes needed
-          (cond
-           ((and
-             (equal bibtex-field-left-delimiter "{")
-             (eq (aref new-text 0) ?\")
-             (eq (aref new-text (1- (length new-text))) ?\"))
-            (aset new-text 0 ?\{)
-            (aset new-text (1- (length new-text)) ?\}))
-           ((and
-             (equal bibtex-field-left-delimiter "\"")
-             (eq (aref new-text 0) ?\{)
-             (eq (aref new-text (1- (length new-text))) ?\}))
-            (aset new-text 0 ?\")
-            (aset new-text (1- (length new-text)) ?\"))
-           ((or
-             (not (eq (aref new-text 0)
-                      (aref bibtex-field-left-delimiter 0)))
-             (not (eq (aref new-text (1- (length new-text)))
-                      (aref bibtex-field-right-delimiter 0))))
-            (setq new-text (concat bibtex-field-left-delimiter
-                                   new-text 
-                                   bibtex-field-right-delimiter))))
-	  ; Found a matching field. Remember boundaries.
-	  (setq bibtex-pop-next-search-point (match-end 0))
-	  (setq bibtex-pop-previous-search-point (match-beginning 0))
-	  (bibtex-flash-head)
-	  ; Go back to where we started, delete old text, and pop new.
-	  (goto-char stop-old-text)
-	  (delete-region start-old-text stop-old-text)
-	  (insert new-text))
-	 (t				; search failed
-	  (error "No next matching BibTeX field."))))))
-  (setq this-command 'bibtex-pop-next))
+  (bibtex-pop arg 'next))
 
 (defun bibtex-clean-entry (&optional arg)
   "Finish editing the current BibTeX entry and clean it up.
@@ -2023,10 +2147,7 @@ given, calculate a new entry label."
           (if (looking-at "\\(OPTcrossref\\)\\|\\(crossref\\)")
               (progn
                 (goto-char begin-text)
-                (if (not (looking-at
-                          (concat
-                           bibtex-field-left-delimiter
-                           bibtex-field-right-delimiter)))
+                (if (not (looking-at "\\(\"\"\\)\\|\\({}\\)"))
                     (setq crossref-there t))))))
       (bibtex-enclosing-reference-maybe-empty-head)
       (re-search-forward bibtex-reference-type)
@@ -2046,10 +2167,7 @@ given, calculate a new entry label."
                     (looking-at "OPT")
                     bibtex-clean-entry-zap-empty-opts)
                    (goto-char begin-text)
-                   (if (looking-at
-                        (concat
-                         bibtex-field-left-delimiter
-                         bibtex-field-right-delimiter))
+                   (if (looking-at "\\(\"\"\\)\\|\\({}\\)")
                        ;; empty: delete whole field if really optional
                        ;; (missing crossref handled) or complain
                        (if (and
@@ -2087,26 +2205,25 @@ given, calculate a new entry label."
                        (search-forward "=")
                        (delete-horizontal-space)
                        (indent-to-column bibtex-text-alignment))
-                     (goto-char begin-field) ; and loop to go through next test
+                     (goto-char begin-field)
+                     ;; and loop to go through next test
                      ))
                   (t
                    (goto-char begin-text)
-                   (cond ((looking-at (concat
-                                       bibtex-field-left-delimiter
-                                       "[0-9]+"
-                                       bibtex-field-right-delimiter))
+                   (cond ((looking-at "\\(\"[0-9]+\"\\)\\|\\({[0-9]+}\\)")
                           ;; if numerical,
                           (goto-char end-text)
-                          (delete-char -1) ; delete enclosing double-quotes
+                          (delete-char -1)
                           (goto-char begin-text)
                           (delete-char 1)
-                          (goto-char end-field) ; go to end for next search
-                          (forward-char -2) ; to compensate for the 2 quotes deleted
+                          ;; delete enclosing delimiters
+                          (goto-char end-field)
+                          ;; go to end for next search
+                          (forward-char -2)
+                          ;; to compensate for the 2 delimiters deleted
                           )
-                         ((looking-at (concat
-                                       bibtex-field-left-delimiter
-                                       bibtex-field-right-delimiter))
-                          ;; if empty quotes, complain
+                         ((looking-at "\\(\"\"\\)\\|\\({}\\)")
+                          ;; if empty field, complain
                           (forward-char 1)
                           (if (not (or (equal (buffer-substring-no-properties
                                                begin-name
@@ -2190,32 +2307,49 @@ If point is not after the part of a word, all strings are listed."
          (string-list (copy-sequence bibtex-completion-candidates))
          (case-fold-search t)
          (completion (save-excursion
-                       (progn
-                         (while (re-search-backward
-                                 bibtex-string (point-min) t)
-                           (setq string-list
-                                 (cons
-                                  (list
-                                   (buffer-substring-no-properties
-                                   (match-beginning bibtex-key-in-string)
-                                   (match-end bibtex-key-in-string)))
-                                  string-list)))
+                       (while (re-search-backward
+                               bibtex-string (point-min) t)
                          (setq string-list
-                               (sort string-list
-                                     (lambda(x y)
-                                       (string-lessp
-                                        (car x)
-                                        (car y)))))
-                         (try-completion part-of-word string-list)))))
+                               (cons
+                                (list
+                                 (buffer-substring-no-properties
+                                  (match-beginning bibtex-key-in-string)
+                                  (match-end bibtex-key-in-string)))
+                                string-list)))
+                       (setq string-list
+                             (sort string-list
+                                   (lambda(x y)
+                                     (string-lessp
+                                      (car x)
+                                      (car y)))))
+                       (try-completion part-of-word string-list))))
     (cond ((eq completion t)
-           (bibtex-remove-double-quotes-or-braces))
+           ;; remove double-quotes or braces if field is no concatenation
+           (save-excursion
+             (bibtex-inside-field)
+             (bibtex-enclosing-field)
+             (let ((end (match-end bibtex-text-in-field)))
+               (goto-char (match-beginning bibtex-text-in-field))
+               (if (and
+                    (looking-at bibtex-field-string)
+                    (equal (match-end 0) end))
+                   (bibtex-remove-double-quotes-or-braces)))))
           ((null completion)
            (error "Can't find completion for \"%s\"" part-of-word))
           ((not (string= part-of-word completion))
            (delete-region beg end)
            (insert completion)
            (if (assoc completion string-list)
-               (bibtex-remove-double-quotes-or-braces)))
+               ;; remove double-quotes or braces if field is no concatenation
+               (save-excursion
+                 (bibtex-inside-field)
+                 (bibtex-enclosing-field)
+                 (let ((end (match-end bibtex-text-in-field)))
+                   (goto-char (match-beginning bibtex-text-in-field))
+                   (if (and
+                        (looking-at bibtex-field-string)
+                        (equal (match-end 0) end))
+                       (bibtex-remove-double-quotes-or-braces))))))
           (t
            (message "Making completion list...")
            (let ((list (all-completions part-of-word string-list)))
@@ -2294,11 +2428,9 @@ If point is not after the part of a word, all strings are listed."
   (forward-line -1)
   (forward-char 10))
 
-
 
 ;; Make BibTeX a Feature
 
 (provide 'bibtex)
 
-
 ;;; bibtex.el ends here