[support] getting the underscore to be unusable in user names

[Earnie Boyd]

Quoting Cog Rusty <cog.rusty at gmail.com>:

>
>>   if (ereg("[^\x80-\xF7 [:alnum:]@_.-]", $name)) return t('The username
>> contains an illegal character.');
>>
>> seems to be disallowing @, underscore, period and hyphen...or is it allowing
>> them? Regular expressions were never my forte!
>

I don't think it is coded correctly.  The range is 128-247 decimal 
which in my day indicated control characters.  So if $name contains 
these or a space or alphanumeric or an @ or an _ or ANY CHARACTER (. is 
a regular expression meta character meaning any character) or a - then 
it will return the text message that username is invalid.

You need to character escape the period to make it useful.  Maybe change it to
ereg("[\^\x80-\xF7 @_\.\-]", $name) would be useful.

>
> Neither mine. I think that one says that names can't begin (^) with
> these characters. In the absence of better advice, I would change

In researching I could only find ^ outside of the [] and I'm guessing 
the range is limited to the first character of $name since it is inside 
the [].

> something that I understand, for example I would copy and adapt the if
> (strpos($name, '  ') !== FALSE) line which checks for double spaces.
>

But you take away the fun of parsing the expression manually to 
understand it. ;D.  Joking aside, regular expressions are very useful 
for this type of parsing.  I was looking for a good tutorial on 
extended regular expression patterns but didn't come up with one.

Earnie -- http://for-my-kids.com/