Org Mode: Inserting a function definition

| emacs, org, elisp

While nudging jcs to add a definition of jcs-insert-url to the blog post about Making Things Easier, I realized it might be handy to have a quick function for inserting a function definition without thinking about where it's defined. This tries to use the definition from the source, and it can fall back to using the stored function definition if necessary. There's probably a better way to do this, but this was small and fun to write. =)

Naturally, I used it to insert itself:

(defun my/org-insert-defun (function)
  "Inserts an Org source block with the definition for FUNCTION."
  (interactive (find-function-read))
  (let* ((buffer-point (condition-case nil (find-definition-noselect function nil) (error nil)))
         (new-buf (car buffer-point))
         (new-point (cdr buffer-point))
         definition)
    (if buffer-point        
      (with-current-buffer new-buf ;; Try to get original definition
        (save-excursion
          (goto-char new-point)
          (setq definition (buffer-substring-no-properties (point) (save-excursion (end-of-defun) (point))))))
      ;; Fallback: Print function definition
      (setq definition (concat (prin1-to-string (symbol-function function)) "\n")))
    (insert "#+begin_src emacs-lisp\n" definition "#+end_src\n")))
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