write-helm-extensions.el

write-helm-extensions.el

;; URL: http://wikemacs.org/wiki/How_to_write_helm_extensions

;;
;; A list of candidates and an action
;;

(setq some-helm-source
      '((name . "HELM at the Emacs")
        (candidates . (1 2 3 4))
        (action . (lambda (candidate)
                    (message-box "%s" candidate)))))
 
(helm :sources '(some-helm-source))

;;
;; Dynamic candidates
;;

(defun random-candidates ()
  "Return a list of 4 random numbers from 0 to 10"
  (loop for i below 4 collect (random 10)))

(setq some-helm-source
      '((name . "HELM at the Emacs")
        (candidates . random-candidates)
        (action . (lambda (candidate)
                    (message "%s" candidate)))))

(helm :sources '(some-helm-source))

;;
;; Separate candidates' sets for searching and for actions
;;

(setq data '(("John" . "john@email.com")
             ("Jim" . "jim@email.com")
             ("Jane" . "jane@email.com")
             ("Jill" . "jill@email.com")))

(setq some-helm-source
      `((name . "HELM at the Emacs")
        (candidates . ,(mapcar 'car data))
        (action . (lambda (candidate)
                    (message "%s" (cdr (assoc candidate data)))))))

(helm :sources '(some-helm-source))

(setq data '(("John" . "john@email.com")
             ("Jim" . "jim@email.com")
             ("Jane" . "jane@email.com")
             ("Jill" . "jill@email.com")))

;;
;; More than one action
;;
 
(defun open-email (candidates)
  "Compose an email to the candidates. Fill in the addresses and
move point to the subject."
  (compose-mail)
  (message-goto-to)
  (insert
   (mapconcat
    'identity
    (helm-marked-candidates)
    ","))
  (message-goto-subject))
 
(setq some-helm-source
      `((name . "HELM at the Emacs")
        (candidates . ,data)
        (action . (("show email address" . (lambda (candidate)
                                             (message-box
                                              "selected: %s"
                                              (helm-marked-candidates))))
                   ("send email" . open-email)))))
 
(helm :sources '(some-helm-source))

;;
;; Handling multiple selections
;;

(defun some-action (candidate)
  (loop for cand in (helm-marked-candidates)
        do
        (message-box "working on %s" cand)))
 
(helm :sources '(((name . "HELM")
                  (candidates . (1 2 3 4))
                  (action . (("open" . some-action))))))