How to capture and link code comments as org agenda items?

Question

I often see or leave comments in code projects like:

//TODO more efficient hash on keys than BASE64?

Ideally, I would like to be able to highlight a comment as such and org-capture it to an org file like : code.org. The code.org file would contain an org-mode link back to the original file that it was captured in. Then I would be able to treat code.org as an agenda file.

Answer 1

A capture template can contain arbitrary elisp code using the %(...) syntax. We just need a function that takes a string (which will be the region you are capturing) and strips the comment characters. The only fussy thing is learning what the comment start character is. This function runs in the capture buffer, not the original one so we have to jump back and lookup comment-start.

(defun capture-comment-line (&optional line)
  (let ((c
        (save-excursion
          (save-window-excursion
            (switch-to-buffer (plist-get org-capture-plist :original-buffer))
          comment-start)
          )))
    (while (string-prefix-p c line)
      (setq line (string-remove-prefix c line)))
    (comment-string-strip line t t)
    )) 

Then we make a simple capture template:

(add-to-list 'org-capture-templates
       '("C" "TODO comment" entry
         (file+headline "code.org" "Tasks")
         "* %(capture-comment-line \"%i\")\n  %a"
         ))