In ELisp, you can skip the evaluation of a definition with the autoload cookie. The definition is evaluated only once it's used.

```
;; File foo.el

;;;###autoload
(defun foo ()
  "Doc"
  42)

(defun bar ()
  "Doc"
  43)

```

So, *if I understand correctly* the autoload functionnality is a hack to load file faster. But when I load `foo.el`, in order to skip the definition of foo the interpreter still has to read the whole form. I don't understand why it's faster.