Re: Perl6: What is "idfirst letter"?

[moritz]

Thanks for the question, I've tried to clarify it.

I think "idfirst" meant "a character that is allowed as the first character of an identifier", and the authoritative source in all parsing questions says that's <.alpha> (Unicode category "Letter", or the underscore).

[ikegami]

Well, in Perl5, "[" and U+0001 are allowed as the first (and only) character of an identifier, but I don't think anyone would consider them idfirst. I don't know if Perl6 has such exceptions.

[moritz]

No. There are special variables with "weird" names ($/, $!, $¢) but they aren't identifiers.

I also don't think that [ counts as an identifier character in Perl 5, because you can't write sub [ { }