self-insert-command source code?

[Marcin Borkowski]

To my disappointment, I've just found out that self-insert-command is
written in C and not in Elisp.  I don't speak C very well (and don't
have the sources for Emacs installed (yet)), so could anyone shed some
light on these two questions (just in some spare time – it's not that I
/need/ it now).

1. Why is that so?  Since this is an interactive function, performance
should not be the issue.

2. What it might look like /if/ it was written in Elisp?

TIA,

-- 
Marcin Borkowski
http://octd.wmi.amu.edu.pl/en/Marcin_Borkowski
Faculty of Mathematics and Computer Science
Adam Mickiewicz University