From 6428103e7199acbf947cacaa5860ac39b3b78b46 Mon Sep 17 00:00:00 2001
From: Aaron Ecay <aaronecay@gmail.com>
Date: Fri, 8 Mar 2013 13:41:00 -0500
Subject: [PATCH 2/3] Support bibliographies for export

* lisp/ox.el (org-export-options-alist): Add BIBLIOGRAPHY
* lisp/ox-latex.el (org-latex-template): Support bibliographies
* lisp/ox-bib.el: Add file

Add export support for bibliographies.  Currently only works for
BibLaTeX, using the latex backend.  To use, put
#+BIBLIOGRAPHY: file.bib
in the header of the document, and (require 'ox-bib).  Then use
links of the form:
[[textcite:bibtex-key&&pre=foo&&post=bar][whatever]]
which will be exported to:
\textcite[foo][bar]{bibtex-key}
Using parencite as a link type is also supported.

The BIBLIOGRAPHY keyword in the header will be translated to an
appropriate \addbibresource command.
---
 lisp/ox-bib.el   | 89 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 lisp/ox-latex.el |  8 +++++
 lisp/ox.el       |  1 +
 3 files changed, 98 insertions(+)
 create mode 100644 lisp/ox-bib.el

diff --git a/lisp/ox-bib.el b/lisp/ox-bib.el
new file mode 100644
index 0000000..a3f9de9
--- /dev/null
+++ b/lisp/ox-bib.el
@@ -0,0 +1,89 @@
+(require 'bibtex)
+(require 'ox)
+
+(defvar ox-bib-find-entries-in-org-file nil
+  "Whether to look for bibliogrpahy entries in an org mode file
+or a bibtex file.")
+
+(defun ox-bib-get-bibliography ()
+  (mapcar (lambda (s)
+            (org-no-properties s))
+	  ;; Don't explode if before the first headline
+          (or
+           (condition-case nil
+               (plist-get (org-export-get-environment nil t) :bibliography)
+             (error nil))
+           (save-excursion
+             (widen)
+             (goto-char (point-min))
+             (plist-get (org-export-get-environment) :bibliography)))))
+
+;; Adapted from org-find-entry-with-custom-id; there might be a better
+;; way to do this
+(defun org-find-entry-with-custom-id (ident)
+  (let ((id ident)
+        (case-fold-search nil))
+    (save-excursion
+      (save-restriction
+        (widen)
+        (goto-char (point-min))
+        (when (re-search-forward
+               (concat "^[ \t]*:CUSTOM_ID:[ \t]+" (regexp-quote id) "[ \t]*$")
+               nil t)
+          (org-back-to-heading t)
+          (point))))))
+
+(defun ox-bib-cite-follow (path)
+  (let* ((files (ox-bib-get-bibliography))
+	 (key (ox-bib-get-key path))
+	 file done)
+    (when ox-bib-find-entries-in-org-file
+      (setq files
+	    (mapcar (lambda (s)
+		      (replace-regexp-in-string "\\.bib\\'" ".org" s))
+		    files)))
+    (while (and (car-safe files) (not done))
+      (setq file (car-safe files))
+      (when (file-exists-p file)
+        (let* ((buf (find-file-noselect file))
+
+	       (pos (with-current-buffer buf
+		      (cond
+		       (ox-bib-find-entries-in-org-file
+			(org-find-entry-with-custom-id key))
+		       (t (bibtex-search-entry key))))))
+	  (when pos
+	    (setq done (cons buf pos)))))
+      (setq files (cdr files)))
+    (if done
+	(progn
+          (pop-to-buffer (car done))
+	  (goto-char (cdr done))
+          (when ox-bib-find-entries-in-org-file
+            (org-show-context)))
+      (message "Citation not found: %s" key))))
+
+(defun ox-bib-textcite-export (path desc format &optional props)
+  (cond
+   ((org-export-derived-backend-p format 'latex)
+    (format "\\textcite[%s][%s]{%s}"
+	    (plist-get props :pre)
+	    (plist-get props :post)
+	    key))
+   (t
+    (format "[textcite to: %s]" path))))
+
+(defun ox-bib-parencite-export (path desc format &optional props)
+  (cond
+   ((org-export-derived-backend-p format 'latex)
+    (format "\\parencite[%s][%s]{%s}"
+            (plist-get props :pre)
+            (plist-get props :post)
+            key))
+   (t
+    (format "[parencite to: %s]" path))))
+
+(org-add-link-type "textcite" #'ox-bib-cite-follow #'ox-bib-textcite-export)
+(org-add-link-type "parencite" #'ox-bib-cite-follow #'ox-bib-parencite-export)
+
+(provide 'ox-bib)
diff --git a/lisp/ox-latex.el b/lisp/ox-latex.el
index a1cacf0..08cdd18 100644
--- a/lisp/ox-latex.el
+++ b/lisp/ox-latex.el
@@ -1192,6 +1192,14 @@ holding export options."
 	       (or (plist-get info :description) "")
 	       (if (not (plist-get info :with-creator)) ""
 		 (plist-get info :creator))))
+     ;; Bibliography
+     (let* ((bibs (plist-get info :bibliography))
+            (bib-cmds (mapconcat (lambda (s)
+                                   (format "\\addbibresource{%s}" s))
+                                 bibs "\n")))
+       (if bibs
+	   (concat bib-cmds "\n")
+	 ""))
      ;; Document start.
      "\\begin{document}\n\n"
      ;; Title command.
diff --git a/lisp/ox.el b/lisp/ox.el
index 40c0617..f405eff 100644
--- a/lisp/ox.el
+++ b/lisp/ox.el
@@ -118,6 +118,7 @@
     (:select-tags "SELECT_TAGS" nil org-export-select-tags split)
     (:time-stamp-file nil "timestamp" org-export-time-stamp-file)
     (:title "TITLE" nil nil space)
+    (:bibliography "BIBLIOGRAPHY" nil nil split)
     (:with-archived-trees nil "arch" org-export-with-archived-trees)
     (:with-author nil "author" org-export-with-author)
     (:with-clocks nil "c" org-export-with-clocks)
-- 
1.8.1.5