[PATCH 2/2] bibtex.el: Add support for DOI URLs.

["Rüdiger Sonderfeld" <ruediger@c-plusplus.de>]

Digital object identifier (DOI) are commonly used to provide
persistent citations.  Therefore it seems to be a good idea to provide
default support for them in bibtex.el.

* lisp/textmodes/bibtex.el (bibtex-doi-server-url): New variable.
  (bibtex-generate-url-list): Add support for DOI URLs.

Signed-off-by: Rüdiger Sonderfeld <ruediger@c-plusplus.de>
---
 lisp/textmodes/bibtex.el | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/lisp/textmodes/bibtex.el b/lisp/textmodes/bibtex.el
index 6280e19..b498da9 100644
--- a/lisp/textmodes/bibtex.el
+++ b/lisp/textmodes/bibtex.el
@@ -1223,8 +1223,20 @@ (defcustom bibtex-summary-function 'bibtex-summary
   :type '(choice (const :tag "Default" bibtex-summary)
                  (function :tag "Personalized function")))
 
+(defcustom bibtex-doi-server-url (if (boundp 'org-doi-server-url)
+                                     org-doi-server-url
+                                   "http://dx.doi.org/")
+  "The URL of the DOI server."
+  :group 'bibtex
+  :version "24.4"
+  :type 'string)
+
 (defcustom bibtex-generate-url-list
-  '((("url" . ".*:.*")))
+  '((("url" . ".*:.*"))
+    (("doi" . "10\\.[0-9]+/.+")
+     ("doi" ".*"
+      (lambda (text)
+        (concat bibtex-doi-server-url text)))))
   "List of schemes for generating the URL of a BibTeX entry.
 These schemes are used by `bibtex-url'.
 
@@ -1261,6 +1273,7 @@ (defcustom bibtex-generate-url-list
      (\"volume\" \".*\" 0)
      (\"pages\" \"\\`[A-Z]?[0-9]+\" 0)))"
   :group 'bibtex
+  :version "24.4"
   :type '(repeat
           (cons :tag "Scheme"
                 (cons :tag "Matcher" :extra-offset 4
-- 
1.8.3