One thing also worth noting is that $1 is an alias to $/[1].
perl6
> my $1 = 2; say $1;
2
> my $1 = 2; say $/[1];
2
Also, $<foo> is an alias to $/<foo>. This would make them rather difficult
to use in parameters, IMO.
--
John Harrison
On Wed, Aug 18, 2010 at 3:12 AM, Moritz Lenz <mor...@faui2k3.org> wrote:
>
>
> Am 18.08.2010 01:33, schrieb Darren Duncan:
>
> David H. Adler wrote:
>>
>>> Hm. So how are valid parameter names defined? Identifiers in perl6 seem
>>> to be composed of letters, digits and underscores (and hyphens and
>>> apostrophes between letters).
>>>
>>
> That's correct.
>
>
> Are parameter names defined differently?
>>
>
> Yes and no. If you want to use the normal syntax like this:
>
> sub f(:$named-name) { ... }
>
> your indeed limited to identifiers. But with slurpy hashes you can use any
> key, really:
>
> sub f(*%h) {
> say %h{ '++' };
> }
> f(|{ '++' => 'non-identifier names work'})
>
> However this is rather clumsy, and should be reserved for interoperation
> with other languages which have different ideas of what an identifier is.
>
>
> You certainly seem to be able to declare a variable $1.
>>>
>>
> If Rakudo allows that, it's a bug. STD.pm6, Larry's Perl 6 grammar, says
> "Can't declare a numeric variable" about it.
>
>
> I believe that Perl 6 identifiers can be any string at all, but that
>> then they have to appear quoted in the general case;
>> the above
>> restriction just refers to the common case of unquoted identifiers. This
>> said, I'm not sure yet what the syntax is for quoting identifiers. --
>>
>
> This distinction is new to me. For "identifier" means what you call
> "unquoted identifier", and my reading of the synopsis so far hasn't
> contradicted that unerstanding in any way.
>
> But that's really a question of how you call stuff - your explanation is
> correct, as I demonstrated above.
>
> Cheers,
> Moritz
>
