## Finding emails from tags from org-contacts database

| categories: org-mode | tags: | View Comments

Org-mode has a contacts manager called org-contacts. If you set it up, you can use it to insert email addresses using a tag in message-mode. Out of the box though, it only works on one tag. You cannot do something like +group-phd to get entries tagged group but not tagged phd. Here we develop a function to do that for us.

We could use the org-files and map the headings to do this, but org-contacts has already done this and has a database we can use instead. We get the database from org-contacts-filter. Here is the first entry.

(car (org-contacts-filter))


(Chris Jones #<marker at 1 in contacts.org> ((FILE . c:/Users/jkitchin/Dropbox/org-mode/contacts.org) (TAGS . :co2:) (ALLTAGS . :co2:) (BLOCKED . ) (COMPANY . Georgia Tech, Chemical Engineering) (EMAIL . Christopher.Jones@chbe.gatech.edu) (CATEGORY . contacts)))

It looks like we have (name marker (cons cells)) for each entry. We can get the tags associated with that entry like this.

We can get the tags for an entry with this code:

(let ((entry (car (org-contacts-filter))))
(cdr (assoc "TAGS" (nth 2 entry))))

:co2:


We will use some code for org tags. Notably, from a tags expression, we can automatically generate code that tells us if we have a match. Here we generate the code to test for a match on "+co2-group".

(let ((todo-only nil))
(cdr (org-make-tags-matcher "+co2-group")))


(and (progn (setq org-cached-props nil) (and (not (member group tags-list)) (member co2 tags-list))) t)

Note we will have to bind tags-list before we eval this.

So to use it, we need to split the tags from an org-contacts entry into a list of strings. It appears each entry just has the tag string, so we split the substring (skipping first and last characters) by ":" to get the list. We do that here, and test if a list of tags containing "co2" is matched by the expression "co2-junior".

(let* ((tags-list (split-string (substring ":co2:" 1 -1) ":"))
(todo-only nil))
(eval (cdr (org-make-tags-matcher "co2-junior"))))

t


It is. So, now we just need to loop through the database, and collect entries that match.

(defun insert-emails-from-tags (tag-expression)
"insert emails from org-contacts that match the tags expression. For example:
group-phd will match entries tagged with group but not with phd."
(interactive "sTags: ")
(insert
(mapconcat 'identity
(loop for contact in (org-contacts-filter)
for contact-name = (car contact)
for email = (org-contacts-strip-link (car (org-contacts-split-property
(or
(cdr (assoc-string org-contacts-email-property
""))))
for tags = (cdr (assoc "TAGS" (nth 2 contact)))
for tags-list = (if tags
(split-string (substring (cdr (assoc "TAGS" (nth 2 contact))) 1 -1) ":")
'())
if (let ((todo-only nil))
(eval (cdr (org-make-tags-matcher tag-expression))))

collect (org-contacts-format-email contact-name email))
",")))


This is not quite completion in message-mode, but it is good enough. You put your cursor in the To field, and run that command, enter the tag expression, and you will get your emails!