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Postings from April 2008
Jon Lang dataweaver-at-gmail.com |Perl 6| wrote: > I'm having some difficulty understanding the business with £. I > _think_ that you're saying that £ sort of acts as a prefix operator > that changes the meaning of the type with which it is associated; and > the only time that a change in meaning occurs is if the type in > question makes use of ::?CLASS or a generic parameter. > > Not only generic parameters, but overridden virtual type names too. In general, type names can be changed by derived classes just like methods. > You say that in Perl 6, a role normally treats ::?CLASS as referring > to the role. No, ::?CLASS refers to the actual class. Maybe you're confused because a footnote said to pretend it stood for the role when using the role itself as a type, because it does not exist at all. > > As for classes and roles that have generic parameters: here, you've > completely lost me. How does your proposed '£' affect such classes > and roles? > > The pointlike[::T] role has a generic parameter. The concrete class Point3D[Rat] matches "pointlike", and it figures out that to make the match work that T has to be Rat. It figures out that FoxPoint is pointlike, if it uses Num for T.Thread Previous | Thread Next