Allowed characters in classnames?

[Thomas Neumann]

> Am 07.02.2012 17:23 schrieb "Thomas Neumann" <blacky+fai at fluffbunny.de>:
>> "All class names should be written in uppercase letters (execpt the
>>  class of the hostname). Do not use a dash, use an underscore."
>>
>> Which says nothing about umlauts, diacrites and other 'strange' stuff.

> Technically everything is allowed, even this is just a best practice.

This is exactly what I'm worried about. It would be a bit re-assuring to
know that restricting oneself to [a-zA-Z0-9_] is not only a sensible thing
but actually at least expected if not outright required. 'Letters' is open
for interpretation. After all "ä", "é", ô etc. are perfectly fine letters.

Sure, I can avoid defining such classnames myself. But I'm writing code
which might get used by others later on and I want to make sure it's
officially okay if I just flat out refuse to handle 'strange' classnames.
(Better to be safe then sorry and all that.)