Support creating combined bib from multiple files

Before, bog-create-combined-bib only collected citekeys from a single
buffer.  Extend it so that it also works with marked files in Dired.

In addition

- Rename combined bib buffer so that it includes "Bog" in the name.

- Offer to skip missing bib files instead of failing.

- Remove bog-collect-references and bog-collect-unique-references, which
  overlap with the newer bog-citekeys-in-buffer [1] and should have been
  removed when that function was added.

[1] ce74785920d6234072eb2ebef63bd140a25534c2

4 files changed, 30 insertions, 35 deletions

diff --git a/NEWS b/NEWS
index c11a25c..2052161 100644
--- a/NEWS
+++ b/NEWS
@@ -37,6 +37,9 @@
 - New command =bog-list-orphan-citekeys= finds citekeys that are
   referred to in the notes but don't have their own heading.
 
+- =bog-create-combined-bib= now supports collecting citekeys from
+  marked files in a Dired buffer.
+
 ** Other changes
 
 - =bog-goto-citekey-heading-in-buffer= and
diff --git a/bog-tests.el b/bog-tests.el
index c454da7..0532fc9 100644
--- a/bog-tests.el
+++ b/bog-tests.el
@@ -433,14 +433,6 @@ some text"
         (kill-buffer new-buffer)
         (delete-file new-file)))))
 
-;; `bog-collect-references'
-
-(ert-deftest bog-collect-unique-references ()
-  (with-temp-buffer
-    (insert  "abc1900word\nhij2000word\nefg1800word\n")
-    (should (equal (bog-collect-unique-references)
-                   '("abc1900word" "efg1800word" "hij2000word")))))
-
 ;; `bog-sort-topic-headings-in-buffer'
 
 (ert-deftest bog-sort-topic-headings-in-buffer ()
diff --git a/bog-todo b/bog-todo
index 7309776..452f302 100644
--- a/bog-todo
+++ b/bog-todo
@@ -40,7 +40,7 @@ as a heading, not a property.
 
 * BibTeX files
 
-** ENH Create combined bib from a suffix glob
+** DONE Create combined bib from a suffix glob
 
 For documents generated from multiple files
 
diff --git a/bog.el b/bog.el
index 89bba91..6fce190 100644
--- a/bog.el
+++ b/bog.el
@@ -587,32 +587,32 @@ one entry per BibTeX file."
 (defun bog-create-combined-bib ()
   "Create buffer that has entries for all citekeys in buffer."
   (interactive)
-  (let ((bib-buffer (get-buffer-create "*Bib*"))
-        (refs (-map 'bog-citekey-as-bib (bog-collect-unique-references))))
-    (--each refs (unless (file-exists-p it) (user-error "%s does not exist" it)))
-    (switch-to-buffer-other-window bib-buffer)
-    (--each refs
-      (insert "\n")
-      (insert-file-contents it)
-      (goto-char (point-max)))
-    (bibtex-mode)
-    (goto-char (point-min))))
-
-(defun bog-collect-unique-references ()
-  "Return names in buffer that match `bog-citekey-format'.
-Duplicates are removed and the entries are sorted
-alphabetically."
-  (-distinct (--sort (string-lessp it other) (bog-collect-references))))
-
-(defun bog-collect-references ()
-  "Return names in buffer that match `bog-citekey-format'."
-  (let (refs
-        case-fold-search)
-    (save-excursion
-      (goto-char (point-min))
-      (while (re-search-forward bog-citekey-format nil t)
-        (push (match-string-no-properties 0) refs))
-      refs)))
+  (let ((bib-buffer-name "*Bog combined bib*")
+        citekeys
+        bib-files)
+    (if (derived-mode-p 'dired-mode)
+        (--each (dired-get-marked-files)
+          (with-temp-buffer
+            (insert-file-contents it)
+            (setq citekeys (append (bog-citekeys-in-buffer) citekeys))))
+      (setq citekeys (bog-citekeys-in-buffer)))
+    (setq bib-files
+          (-map #'bog-citekey-as-bib
+                (-distinct (--sort (string-lessp it other) citekeys))))
+    (with-current-buffer (get-buffer-create bib-buffer-name)
+      (delete-region (point-min) (point-max))
+      (--each bib-files
+        (cond
+         ((file-exists-p it)
+          (insert "\n")
+          (insert-file-contents it)
+          (goto-char (point-max)))
+         ((not (y-or-n-p (format "%s does not exist.  Skip it?" it)))
+          (kill-buffer bib-buffer)
+          (user-error "Aborting"))))
+      (bibtex-mode)
+      (goto-char (point-min)))
+    (switch-to-buffer-other-window bib-buffer-name)))
 
 (defun bog-citekey-as-bib (citekey)
   "Return file name `bog-bib-directory'/CITEKEY.bib."