Re: To :D or not to :D

On Mon, Oct 12, 2015 at 09:51:13PM +0200, Mark Overmeer wrote:
> > 	method new(MyClassHere:U: *@args) { ... }
> > 
> > in the constructor, which would be quite hostile to newbies. It's still
> > not clear to me how to avoid that.
> 
> It is also unclear to me what this means.  It is a method which requires
> and undef parameter?

Because of the second colon, it's a method accepting an undef invocant.
This is what would be needed in order for

    MyClassHere.new(...)

to work the way you expect (since MyClassHere is undefined).

> > Another concern is that if "everything" defaults to :D, then classes
> > (and other type objects) aren't really first class objects anymore,
> > which is a really neat thing to have.
> 
> Can you give me an example?  Many other languages are capable to live
> without undef and have first class type objects.  

Keep in mind that what Perl 6 calls a "type object" isn't quite the
same as class objects in other languages -- a Perl 6 typename is
really an undefined instance of a class.  In other words, the
identifiers C<Int>, C<Rat>, C<Array> etc. refer to instances of
those classes just like the literals C<3>, C<4/5>, and C<[1,2,3]> are
instances of those classes.  They share the same method spaces.

Pm