The appropriate way to set a custom font
Currently, I use the following code to achieve the custom font:

```lisp
(set-font
 (make-font
  :face (make-instance 'sketch::typeface :filename "/tmp/my-stupid-font.ttf")))
```

I basically know nothing about SDL, and know very little about Common Lisp.

And the code above used something like `sketch::typeface`, which makes me feel inelegant. Since the double colons (`::`) tell me that you do not want me to use it.

So I am wondering:

Is this the proper way to set a custom font?

If not, what should I do?

Thank you very much for creating `sketch`, I enjoyed it very much.