grammar: difference between rule, token and regex

[Rene Hangstrup Møller]

Hi

I am toying around with Parrot and the compiler tools. The documenation 
of Perl 6 grammars that I have been able to find only describe rule. But 
the grammars in Parrot 0.4.4 for punie and APL use rule, token and regex 
elements.

Can someone please clarify the difference between these three types, and 
when you should use one or the other?

Kind Regards
Rene H. Møller