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Postings from May 2008
On 2008 May 3, at 6:25, Richard Hainsworth wrote: > - if u want to add a role to an existing object, perl wraps the > object into a class, adds the role, reinstantiates the object. As I understand it, Perl inserts a new anonymous class as the object's parent, and adds the role to that. The object isn't reinstantiated or otherwise modified, just reparented. As for the assertion in the subject: one could conceptually see a class being composed of a "role part" and a "class part". Using the object as a role would invoke only the "role part". (I would prefer some kind of indication that this is intended, e.g. a cast or maybe an adverb selecting the role.) > It seems to me that the jargon of 'inheritance' normally applied to > a relation between objects and classes is misplaced in perl6. It is > rather classes 'inherit' roles (like animals inherit genes from > parents). Objects emerge as You're just using the wrong model, I think. You need to look at the Smalltalk/OREXX/Ruby mixin model, in which you can mix new parents into individual objects; not the C++/Java model where an object has a fixed class that defines its "shape" and any inheritance must be done as part of that class or its superclasses. -- brandon s. allbery [solaris,freebsd,perl,pugs,haskell] allbery@kf8nh.com system administrator [openafs,heimdal,too many hats] allbery@ece.cmu.edu electrical and computer engineering, carnegie mellon university KF8NHThread Previous | Thread Next