[Orgmode] [PATCH] Sitemap publish with chronological ordering

[Manuel Giraud]

Here's a patch that add an option to sort files in the sitemap
chronologically. A "#+DATE" driven sorting is still missing IMO.

--8<---------------cut here---------------start------------->8---
diff --git a/lisp/org-publish.el b/lisp/org-publish.el
index c66cd29..74afa87 100644
--- a/lisp/org-publish.el
+++ b/lisp/org-publish.el
@@ -186,8 +186,9 @@ sitemap of files or summary page for a given project.
                            Set this to `first' (default) or `last' to
                            display folders first or last, respectively.
                            Any other value will mix files and folders.
-  :sitemap-alphabetically  The site map is normally sorted alphabetically.
-                           Set this explicitly to nil to turn off sorting.
+  :sitemap-sort-files      The site map is normally sorted alphabetically.
+                           You can change this behaviour setting this to
+                           `chronologically', `anti-chronologically' or nil.
   :sitemap-ignore-case     Should sorting be case-sensitive?  Default nil.
 
 The following properties control the creation of a concept index.
@@ -233,13 +234,18 @@ Any changes made by this hook will be saved."
   :group 'org-publish
   :type 'hook)
 
-(defcustom org-publish-sitemap-sort-alphabetically t
-  "Should sitemaps be sorted alphabetically by default?
+(defcustom org-publish-sitemap-sort-files 'alphabetically
+  "How sitemaps files should be sorted by default?
+Possible values are `alphabetically', `chronologically', 
`anti-chronologically' and nil.
+If `alphabetically', files will be sorted alphabetically.
+If `chronologically', files will be sorted with older modification time first.
+If `anti-chronologically', files will be sorted with newer modification time 
first.
+nil won't sort files.
 
 You can overwrite this default per project in your
-`org-publish-project-alist', using `:sitemap-alphabetically'."
+`org-publish-project-alist', using `:sitemap-sort-files'."
   :group 'org-publish
-  :type 'boolean)
+  :type 'symbol)
 
 (defcustom org-publish-sitemap-sort-folders 'first
   "A symbol, denoting if folders are sorted first in sitemaps.
@@ -360,30 +366,37 @@ This splices all the components into the list."
     (nreverse (org-publish-delete-dups (delq nil rtn)))))
 
 
-(defvar sitemap-alphabetically)
+(defvar sitemap-sort-files)
 (defvar sitemap-sort-folders)
 (defvar sitemap-ignore-case)
 (defvar sitemap-requested)
 (defun org-publish-compare-directory-files (a b)
-  "Predicate for `sort', that sorts folders-first/last and alphabetically."
+  "Predicate for `sort', that sorts folders and files for sitemap."
   (let ((retval t))
-    (when (or sitemap-alphabetically sitemap-sort-folders)
-      ;; First we sort alphabetically:
-      (when sitemap-alphabetically
-        (let* ((adir (file-directory-p a))
-               (aorg (and (string-match "\\.org$" a) (not adir)))
-               (bdir (file-directory-p b))
-               (borg (and (string-match "\\.org$" b) (not bdir)))
-               (A (if aorg
-                      (concat (file-name-directory a)
-                              (org-publish-find-title a)) a))
-               (B (if borg
-                      (concat (file-name-directory b)
-                              (org-publish-find-title b)) b)))
-          (setq retval (if sitemap-ignore-case
-                          (not (string-lessp (upcase B) (upcase A)))
-                        (not (string-lessp B A))))))
-
+    (when (or sitemap-sort-files sitemap-sort-folders)
+      ;; First we sort files:
+      (when sitemap-sort-files
+       (cond ((equal sitemap-sort-files 'alphabetically)
+              (let* ((adir (file-directory-p a))
+                     (aorg (and (string-match "\\.org$" a) (not adir)))
+                     (bdir (file-directory-p b))
+                     (borg (and (string-match "\\.org$" b) (not bdir)))
+                     (A (if aorg
+                            (concat (file-name-directory a)
+                                    (org-publish-find-title a)) a))
+                     (B (if borg
+                            (concat (file-name-directory b)
+                                    (org-publish-find-title b)) b)))
+                (setq retval (if sitemap-ignore-case
+                                 (not (string-lessp (upcase B) (upcase A)))
+                               (not (string-lessp B A))))))
+               ((or (equal sitemap-sort-files 'chronologically)
+                    (equal sitemap-sort-files 'anti-chronologically))
+                (let ((A (org-publish-find-date a))
+                      (B (org-publish-find-date b)))
+                  (setq retval (if (equal sitemap-sort-files 'chronologically)
+                                   (<= A B)
+                                 (>= A B)))))))
       ;; Directory-wise wins:
       (when sitemap-sort-folders
         ;; a is directory, b not:
@@ -438,10 +451,10 @@ matching filenames."
          (if (plist-member project-plist :sitemap-sort-folders)
              (plist-get project-plist :sitemap-sort-folders)
            org-publish-sitemap-sort-folders))
-        (sitemap-alphabetically
-         (if (plist-member project-plist :sitemap-alphabetically)
-             (plist-get project-plist :sitemap-alphabetically)
-           org-publish-sitemap-sort-alphabetically))
+        (sitemap-sort-files
+         (if (plist-member project-plist :sitemap-sort-files)
+             (plist-get project-plist :sitemap-sort-files)
+           org-publish-sitemap-sort-files))
         (sitemap-ignore-case
          (if (plist-member project-plist :sitemap-ignore-case)
              (plist-get project-plist :sitemap-ignore-case)
@@ -780,6 +793,11 @@ Default for SITEMAP-FILENAME is 'sitemap.org'."
     (org-publish-cache-set-file-property file :title title)
     title)))
 
+(defun org-publish-find-date (file)
+  "Find the date of FILE in project."
+  ;; FIXME add a support for user defined date based on #+DATE keyword.
+  (org-publish-cache-ctime-of-src file))
+
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;;; Interactive publishing functions
--8<---------------cut here---------------end--------------->8--- 

-- 
Manuel Giraud