New variable `org-default-extensions' is regulating which extensions will be loaded.

Also: New file CONTRIB/lisp/org-id.el for global ids in entries.

CONTRIB/lisp/org-id.el

@@ -27,110 +27,115 @@
 ;;; Commentary:
 
 ;; This file implements globally unique identifiers for Org-mode entries.
-;; Identifiers are tored in the entry as an :ID: property.  This file
-;; provides functions to create and retrieve such identifies.
+;; Identifiers are stored in the entry as an :ID: property.  This file
+;; provides functions to create and retrieve such identifiers.
 
 ;; It provides the following API:
-
+;;
+;;
+;; Higer-level-functions
+;;
+;; org-id-create
+;;        Create an ID for the entry at point if it does not yet have one.
+;;        Returns the ID (old or new).  This function can be used
+;;        interactively, with prefix argument the creation of a new ID is
+;;        forced, even if there was an old one.
+;;
 ;; org-id-get
 ;;        Get the ID property of an entry.  Using appropriate arguments
-;;        to the function, it can also create the id for this entry.
+;;        to the function, it can also create the ID for this entry.
+;;
+;; org-id-goto
+;;        Command to go to a specific ID, this command can be used
+;;        interactively.
+;;
+;; org-id-get-with-outline-path-completion
+;;        Retrieve the ID of an entry, using outline path completion.
+;;        This function can work for multiple files.
+;;
+;; org-id-get-with-outline-drilling
+;;        Retrieve the ID of an entry, using outline path completion.
+;;        This function only works for the current file.
+;;
+;; org-id-find
+;;        Find the location of an entry with specific id.
 ;;
-;; FIXME: more to describe
 ;; TODO:
-;; get/create id at current entry, safe in kill or so.
+;; - get/create id at current entry, safe in kill or so.
 
 (require 'org)
 
+
+;;; Customization
+
 (defgroup org-id nil
   "Options concerning global entry identifiers in Org-mode."
   :tag "Org ID"
   :group 'org)
 
+(defcustom org-id-structure (list "Org" (user-login-name) t 4)
+  "Components of globaly unique id's created by Org-mode.
+An Org-mode ID has 4 components:
+
+prefix       A prefix to identify the ID type (default \"Org\".
+creator      The creator of the ID, defaults to the users login name.
+incremental  An incremental number, specific for the creator.
+random       A random sequence of characters, to make sure ID created
+             in distributed development will still be unique.
+             This may be a short random sequence, or an md5 sum created
+             based on the current time, the current computer, and the user."
+  :group 'org-id
+  :type '(list
+	  (string :tag "Prefix")
+	  (string :tag "Creator")
+	  (boolean :tag "Incremental")
+	  (choice :tag "Random part"
+		  (const :tag "No random part" nil)
+		  (integer :tag "N characters")
+		  (const :tag "MD5 digest" md5))))
+
 (defcustom org-id-tracking-file "~/.org-id"
-  "The file for remembering the last ID number generated."
+  "The file for remembering the last ID number generated, for each type."
   :group 'org-id
   :type 'file)
 
-(defcustom org-id-prefix (user-login-name)
-  "The string prefix of global id's created by a user.
-When working with other people, make sure everyone has their own
-ID prefix, in order to guarantee that id's created by differnt people
-will always be distinct."
-  :group 'org-id
-  :type 'string)
+(defvar org-id-values nil
+  "Association list of ID types+creator with largest index used so far.")
 
-(defcustom org-id-random-length 4
-  "Non-nil means, insert a random part into id's.
-This will be a random alpha-numeric string with as many characters
-as given by this option."
+(defcustom org-id-locations-file "~/.org-id-locations"
+  "The file for remembering the last ID number generated."
   :group 'org-id
-  :type 'integer)
+  :type 'file)
 
-(defun org-id-random-string (n)
-  "Return a string of N random characters."
-  (let ((rtn "") x)
-    (while (>= (setq n (1- n)) 0)
-      (setq x (random 62))
-      (setq rtn (concat rtn (cond
-			     ((< x 10) (char-to-string (+ ?0 x)))
-			     ((< x 36) (char-to-string (+ ?A x -10)))
-			     ((< x 62) (char-to-string (+ ?a x -36)))
-			     (t (error "xxx"))))))
-    rtn))
+(defvar org-id-locations nil
+  "List of files with ID's in those files.")
 
-(defvar org-id-values nil
-  "Association list of id keywords with largest index used.")
+(defcustom org-id-extra-files 'org-agenda-multi-occur-extra-files
+  "Files to be searched for ID's, besides the agenda files."
+  :group 'org-id
+  :type
+  '(choice
+    (symbol :tag "Variable")
+    (repeat :tag "List of files"
+	    (file))))
 
-(defun org-id-save ()
-  "Save `org-id-values' in `org-id-tracking-file'."
-  (with-temp-file org-id-tracking-file
-    (print org-id-values (current-buffer))))
 
-(defun org-id-load ()
-  "Read the data from `org-id-tracking-file'."
-  (setq org-id-values nil)
-  (with-temp-buffer
-    (condition-case nil
-        (progn
-          (insert-file-contents-literally org-id-tracking-file)
-          (goto-char (point-min))
-          (setq org-id-values (read (current-buffer))))
-      (error
-       (message "Could not read org-id-values from %s. Setting it to nil."
-                org-id-tracking-file)))))
+;;; The API functions
 
-(defun org-id-new (&optional type nrandom)
-  "Create a new globally unique id.
-The id is a string with two or three colon-separated parts:
-
-1. The type or prefix, given by the argument TYPE, or the value
-   of `org-id-prefix' (which defaults to the user name).
-2. A hopefully unique number.  This is a number that runs for each ID type
-   from 1 up, each time a new ID is created.  Org-mode keeps track
-   of these numbers in the file `org-id-tracking-file',  so if you
-   only work on a single computer or synchronize this file, this is enough
-   as a unique identifier.  If you work with other people, or on different
-   computers, the uniqueness of this number is not certain.  In this case
-   you should use a value larger than 0 for NRADNOM (which defaults
-   to `org-id-random-length').
-3. A random string with NRANDOM or `org-id-random-length' characters.
-   If that length is 0, the random part will be omitted from the ID.
-
-So a typical ID could look like \"dominik:105:2HtZ\"."
-  (org-id-load)
-  (let* ((type (or type org-id-prefix))
-	 (ass (assoc type org-id-values))
-	 (n (1+ (or (cdr ass) 0)))
-	 (nrandom (or nrandom org-id-random-length))
-	 (random (org-id-random-string nrandom)))
-    (if ass
-	(setcdr ass n)
-      (push (cons type n) org-id-values))
-    (org-id-save)
-    (concat type ":"
-	    (number-to-string n)
-	    (if (> nrandom 0) (concat ":" random)))))
+(defun org-id-create (&optional force)
+  "Create an ID for the current entry and return it.
+If the entry already has an ID, just return it.
+With optional argument FORCE, force the creation of a new ID."
+  (interactive "P")
+  (when force
+    (org-entry-put (point) "ID" nil))
+  (org-id-get (point) 'create))
+  
+(defun org-id-copy ()
+  "Copy the ID of the entry at point to the kill ring.
+Create an ID if necessary."
+  (interactive)
+  (kill-new (org-id-get nil 'create)))  
 
 (defun org-id-get (&optional pom create type nrandom)
   "Get the ID property of the entry at point-or-marker POM.
@@ -139,18 +144,23 @@ If the entry does not have an ID, the function returns nil.
 However, when CREATE is non nil, create an ID if none is present already.
 TYPE and NRANDOM will be passed through to `org-id-new'.
 In any case, the ID of the entry is returned."
-  (or (org-entry-get pom "ID")
-      (and create
-	   (let ((id (org-id-new type nrandom)))
-	     (org-entry-put pom "ID" id)
-	     id))))
+  (let ((id (org-entry-get pom "ID")))
+    (cond
+     ((and id (stringp id) (string-match "\\S-" id))
+      id)
+     (create
+      (setq id (org-id-new type nrandom))
+      (org-entry-put pom "ID" id)
+      (org-id-add-location id (buffer-file-name (buffer-base-buffer)))
+      id)
+     (t nil))))
 
 (defun org-id-get-with-outline-path-completion (&optional targets)
-  "Use outline-path-completion to retrieve the id of an entry.
+  "Use outline-path-completion to retrieve the ID of an entry.
 TARGETS may be a setting for `org-refile-targets' to define the elegible
 headlines.  When omitted, all headlines in all agenda files are
 elegible.
-It returns the id of the entry.  If necessary, the id is created."
+It returns the ID of the entry.  If necessary, the ID is created."
   (let* ((org-refile-targets (or targets '((nil . (:maxlevel . 10)))))
 	 (org-refile-use-outline-path 
 	  (if (caar org-refile-targets) 'file t))
@@ -161,40 +171,146 @@ It returns the id of the entry.  If necessary, the id is created."
     (move-marker pom nil)))
 
 (defun org-id-get-with-outline-drilling (&optional targets)
-  "Use an outline-cycling interface to retrieve the id of an entry.
+  "Use an outline-cycling interface to retrieve the ID of an entry.
 This only finds entries in the current buffer, using `org-get-location'.
-It returns the id of the entry.  If necessary, the id is created."
+It returns the ID of the entry.  If necessary, the ID is created."
   (let* ((spos (org-get-location (current-buffer) org-goto-help))
 	 (pom (and spos (move-marker (make-marker) (car spos)))))
     (org-id-get pom 'create)
     (move-marker pom nil)))
 
-(defvar org-id-locations nil
-  "Association list of id's with files.")
+(defun org-id-goto (id)
+  "Switch to the buffer containing the entry with id ID.
+Move the cursor to that entry in that buffer."
+  (interactive)
+  (let ((m (org-id-find id 'marker)))
+    (unless m
+      (error "Cannot find entry with ID \"%s\"" id))
+    (switch-to-buffer (marker-buffer m))
+    (goto-char m)
+    (org-show-context)))    
 
-(defcustom org-id-extra-files 'org-agenda-multi-occur-extra-files
-  "Files to be searched for ID's, besides the agenda files."
-  :group 'org-id
-  :type
-  '(choice
-    (symbol :tag "Variable")
-    (repeat :tag "List of files"
-	    (file))))
+(defun org-id-find (id &optional markerp)
+  "Return the location of the entry with the id ID.
+The return value is a cons cell (file-name . position), or nil
+if there is no entry with that ID.
+With optional argument MARKERP, return the position as a markerp."
+  (let ((file (org-id-find-id-file id))
+	org-agenda-new-buffers where)
+    (when file
+      (setq where (org-id-find-id-in-file id file markerp)))
+    (unless where
+      (org-id-update-id-locations)
+      (setq file (org-id-find-id-file id))
+      (when file
+	(setq where (org-id-find-id-in-file id file markerp))))
+    where))
 
-(defcustom org-id-locations-file "~/.org-id-locations"
-  "The file for remembering the last ID number generated."
-  :group 'org-id
-  :type 'file)
+;;; Internal functions
+
+;; Creating new ids
+
+(defun org-id-new (&optional type creator n xrandom)
+  "Create a new globally unique ID.
+The ID is a string with four colon-separated parts:
+
+1. The type or prefix, given by the argument TYPE, or by the first element
+
+2. The creator, given by the argument CREATOR, or by the second element
+   of `org-id-structure' (default is the user's login name).
+3. An incremental number linked to the ID type.  This is a number that
+   runs for each ID type from 1 up, each time a new ID is created.
+   Org-mode keeps track of these numbers in the file `org-id-tracking-file',
+   so if you only work on a single computer or synchronize this file,
+   this is enough as a unique identifier.  If you work with other people,
+   or on different computers, the uniqueness of this number is not certain.
+   A specific value for N can be forces by passing it into the function.
+4. An extra string guaranteeing the uniqueness of the ID.
+   This is either a random string of XRANDOM characters if XRANDOM is an
+   integer.  If XRANDOM is the symbol `md5', the extra string is a MD5 digest
+   of a string consisting of ID info, the current time, and a random number.
+   If you are sure the sequence number (component 3) is unique in your
+   setting, the random part can be omitted from the ID.
+
+So a typical ID could look like \"Org:dominik:105:2HtZ\"."
+  (unless n (org-id-load))
+  (let* ((type (or type (car org-id-structure)))
+	 (creator (or creator (nth 1 org-id-structure)))
+	 (n-p n)
+	 (key (concat type ":" creator))
+	 (ass (and (not n-p) (assoc key org-id-values)))
+	 (n (or n (1+ (or (cdr ass) 0))))
+	 (xrandom (or xrandom (nth 3 org-id-structure)))
+	 (random
+	  (cond
+	   ((not xrandom) nil)
+	   ((eq xrandom 'none) nil)
+	   ((integerp xrandom) (org-id-random-string xrandom))
+	   ((eq xrandom 'md5) (org-id-md5 type creator n))
+	   (t nil))))
+    (unless n-p
+      (if ass
+	  (setcdr ass n)
+	(push (cons key n) org-id-values))
+      (org-id-save))
+    (concat type
+	    ":" creator
+	    ":" (number-to-string n)
+	    (if random (concat ":" random)))))
+
+(defun org-id-random-string (n)
+  "Return a string of N random characters."
+  (let ((rtn "") x)
+    (while (>= (setq n (1- n)) 0)
+      (setq x (random 62))
+      (setq rtn (concat rtn (cond
+			     ((< x 10) (char-to-string (+ ?0 x)))
+			     ((< x 36) (char-to-string (+ ?A x -10)))
+			     ((< x 62) (char-to-string (+ ?a x -36)))
+			     (t (error "xxx"))))))
+    rtn))
+
+(defun org-id-md5 (type creator n)
+  "Return the md5 digest of a string.
+This function concatenates ID info with random stuff like the time
+and then computes the md5 digest.  The result should be unique."
+  (md5 (concat type ":" creator ":" (number-to-string (or n 0)) ":"
+	       (system-name) ":"
+	       (prin1-to-string (current-time)) ":"
+	       (number-to-string (random)))))
+
+;; Storing id indices
+
+(defun org-id-save ()
+  "Save `org-id-values' in `org-id-tracking-file'."
+  (with-temp-file org-id-tracking-file
+    (print org-id-values (current-buffer))))
+
+(defun org-id-load ()
+  "Read the data from `org-id-tracking-file'."
+  (setq org-id-values nil)
+  (with-temp-buffer
+    (condition-case nil
+        (progn
+          (insert-file-contents-literally org-id-tracking-file)
+          (goto-char (point-min))
+          (setq org-id-values (read (current-buffer))))
+      (error
+       (message "Could not read org-id-values from %s. Setting it to nil."
+                org-id-tracking-file)))))
 
+;; Storing ID locations (files)
 
 (defun org-id-update-id-locations ()
-  "FIXME"
+  "Scan relevant files for ID's.
+Store the relation between files and corresponding ID's."
+  (interactive)
   (let ((files (append (org-agenda-files)
 		       (if (symbolp org-id-extra-files)
 			   (symbol-value org-id-extra-files)
 			 org-id-extra-files)))
 	org-agenda-new-buffers
-	file ids reg)
+	file ids reg found id)
     (while (setq file (pop files))
       (setq ids nil)
       (with-current-buffer (org-get-agenda-file-buffer file)
@@ -204,7 +320,11 @@ It returns the id of the entry.  If necessary, the id is created."
 	    (goto-char (point-min))
 	    (while (re-search-forward "^[ \t]*:ID:[ \t]+\\(\\S-+\\)[ \t]*$"
 				      nil t)
-	      (push (match-string 1) ids))
+	      (setq id (org-match-string-no-properties 1))
+	      (if (member id found)
+		  (error "Duplicate ID \"%s\"" id))
+	      (push id found)
+	      (push id ids))
 	    (push (cons file ids) reg)))))
     (org-release-buffers org-agenda-new-buffers)
     (setq org-agenda-new-buffers nil)
@@ -230,23 +350,27 @@ It returns the id of the entry.  If necessary, the id is created."
                 org-id-locations-file)))))
 
 (defun org-id-add-location (id file)
-  "Add the ID with location FILE to the database of id loations."
+  "Add the ID with location FILE to the database of ID loations."
+  (unless org-id-locations (org-id-locations-load))
   (catch 'exit
     (let ((locs org-id-locations) list)
       (while (setq list (pop locs))
 	(when (equal (file-truename file) (file-truename (car list)))
-	  (setcdr list (cons id list))
+	  (setcdr list (cons id (cdr list)))
 	  (throw 'exit t)))
       (push (list file id) org-id-locations))
     (org-id-locations-save)))
 
+;; Finding entries with specified id
+
 (defun org-id-find-id-file (id)
   "Query the id database for the file in which this ID is located."
   (unless org-id-locations (org-id-locations-load))
   (catch 'found
     (mapc (lambda (x) (if (member id (cdr x))
 			  (throw 'found (car x))))
-	  org-id-locations)))
+	  org-id-locations)
+    nil))
 
 (defun org-id-find-id-in-file (id file &optional markerp)
   "Return the position of the entry ID in FILE.
@@ -254,36 +378,17 @@ If that files does not exist, or if it does not contain this ID,
 return nil.
 The position is returned as a cons cell (file-name . position).  With
 optional argument MARKERP, return the position as a marker."
-  (let (org-agenda-new-buffers m buf)
+  (let (org-agenda-new-buffers m buf pos)
     (cond
      ((not file) nil)
      ((not (file-exists-p file)) nil)
      (t (with-current-buffer (setq buf (org-get-agenda-file-buffer file))
 	  (setq pos (org-find-entry-with-id id))
 	  (when pos
-	    (cons file pos (move-marker (make-marker) pos buf))))))))
+	    (if markerp
+		(move-marker (make-marker) pos buf)
+	      (cons file pos))))))))
 
-(defun org-id-find (id &optional markerp)
-  "Return the location of the entry with the id ID.
-The return value is a cons cell (file-name . position), or nil
-if there is no entry with that ID.
-With optional argument MARKERP, return the position as a markerp."
-  (let ((file (org-id-find-id-file id))
-	org-agenda-new-buffers where)
-    (when file
-      (setq where (org-id-find-id-in-file id file markerp)))
-    (unless where
-      (org-id-update-id-locations)
-      (setq file (org-id-find-id-file id))
-      (when file
-	(setq where (org-id-find-id-in-file id file markerp))))
-    where))
-
-(defun org-id-goto (id)
-  "Switch to the buffer containing the entry with id ID.
-Move the cursor to that entry in that buffer."
-  (interactive))
-    
 
 (provide 'org-id)
 

ChangeLog

@@ -1,3 +1,13 @@
+2008-02-27  Carsten Dominik  <dominik@science.uva.nl>
+
+	* org-irc.el: Modified the installation instructions.
+
+	* org.el (org-store-link): Removed the (require 'org-irc), this is
+	now handled by `org-default-extensions'.
+	(org-load-hook): This hok is now exlicitly defined and made
+	customizable.
+	(org-default-extensions): New option.
+
 2008-02-26  Carsten Dominik  <dominik@science.uva.nl>
 
 	* org.el (org-agenda-to-appt): Set `org-deadline-warning-days' to

Makefile

@@ -228,7 +228,7 @@ relup:
 
 clean:
 	rm -f $(ELCFILES) org.pdf org org.html orgcard.pdf orgcard.ps
-	rm -f *~ 
+	rm -f *~ */*~ */*/*~
 	rm -f *.aux *.cp *.cps *.dvi *.fn *.fns *.ky *.kys *.pg *.pgs
 	rm -f *.toc *.tp *.tps *.vr *.vrs *.log *.html *.ps
 	rm -f orgcard_letter.tex orgcard_letter.pdf

org-irc.el

@@ -28,10 +28,8 @@
 ;; Link to an IRC session. Only ERC has been implemented at the
 ;; moment.
 ;;
-;; Place org-irc.el in your load path and add this to your
-;; .emacs:
-;;
-;; (require 'org-irc)
+;; Please configure the variable `org-default-extensions' to ensure that
+;; this extension will be loaded.
 ;;
 ;; Please note that at the moment only ERC is supported. Other clients
 ;; shouldn't be diffficult to add though.
@@ -51,6 +49,8 @@
 ;;
 ;;; Code:
 
+(require 'org-irc)
+
 (defvar org-irc-client 'erc
   "The IRC client to act on")
 (defvar org-irc-link-to-logs nil

org.el

@@ -151,6 +151,32 @@ With prefix arg HERE, insert it at point."
   :group 'hypermedia
   :group 'calendar)
 
+(defcustom org-load-hook '(org-load-default-extensions)
+  "Hook that is run after org.el has been loaded.
+This happens also after `org' has been provided, so
+requiring something in this hook that does a (require 'org) is ok."
+  :group 'org
+  :type 'hook)
+
+(defcustom org-default-extensions '(org-irc)
+  "Extensions that should always be loaded together with org.el
+If the description starts with <A>, this means the extension
+will be autoloaded when needed, to preloading is not necessary."
+  :group 'org
+  :type
+  '(set :greedy t
+	(const :tag "    Mouse support (org-mouse.el)" org-mouse)
+	(const :tag "<A> Publishing (org-publish.el)" org-publish)
+	(const :tag "<A> LaTeX export (org-export-latex.el)" org-export-latex)
+	(const :tag "    IRC/ERC links (org-irc.el)" org-irc)
+	(const :tag "    Apple Mail message links under OS X (org-mac-message.el)" org-mac-message)
+))
+
+(defun org-load-default-extensions ()
+  "Load all extensions that are listed in `org-default-extensions'."
+  (mapc 'require org-default-extensions))
+	  
+
 ;; FIXME: Needs a separate group...
 (defcustom org-completion-fallback-command 'hippie-expand
   "The expansion command called by \\[org-complete] in normal context.
@@ -12006,7 +12032,6 @@ For links to usenet articles, arg negates `org-usenet-links-prefer-google'.
 For file links, arg negates `org-context-in-file-links'."
   (interactive "P")
   (setq org-store-link-plist nil)  ; reset
-  (require 'org-irc)
   (let (link cpltxt desc description search txt)
     (cond