Auto complete recent comint messages.

org-babel-history.el

(defmacro my-save-excursion (&rest forms)
  `(let* ((oldp (point))
          (oldbuff (current-buffer))
          (retval (progn ,@forms)))

     (unless (eq (current-buffer) oldbuff) (switch-to-buffer oldbuff))
     (goto-char oldp)
     etval))

(defun my-helm-comint-input-ring-action (candidate)
  "Default action for comint history."
  (with-helm-current-buffer
    (insert candidate)))

(defvar my-helm-source-comint-input-ring
  '((name . "Comint history")
    (candidates . (lambda ()
                    (with-helm-current-buffer
                      (ring-elements comint-input-ring))))
    (action . my-helm-comint-input-ring-action))
  "Source that provide helm completion against `comint-input-ring'.")

(defun maybe-switch-to-org ()
  (when (and org-src-mode org-src--beg-marker)
    (let ((my-marker org-src--beg-marker))
      ;; (goto-char org-src--beg-marker) didn't work :(
      (switch-to-buffer
       (marker-buffer my-marker))
      (goto-char
       (marker-position my-marker)))))

(defun my-comint-anywhere ()
  (interactive)
  (progn
    (my-save-excursion
     (maybe-switch-to-org)
     (switch-to-buffer (org-babel-initiate-session))
     (setq my-comint-input-ring comint-input-ring))
    (message "Restored!")
    (setq comint-input-ring my-comint-input-ring)
    (helm :sources 'my-helm-source-comint-input-ring
          :buffer "*helm comint history*")))

(global-set-key (kbd "C-S-r") #'my-comint-anywhere)
(global-set-key (kbd "C-R") #'my-comint-anywhere)
(define-key comint-mode-map (kbd "C-R") #'helm-comint-input-ring)
(define-key comint-mode-map (kbd "C-S-r") #'helm-comint-input-ring)