wow - i got that wrong. check this example from the reference
http://docs.racket-lang.org/reference/createclass.html#(form._((lib._racket/private/class-internal..rkt)._augment)) #lang racket (define buzzer% (class object% (super-new) (define/pubment (buzz) (displayln "bzzzt") (inner (void) buzz)))) (define loud-buzzer% (class buzzer% (super-new) (define (buzz) (displayln "BZZZZZZZZZT")) (augment buzz))) (send (new buzzer%) buzz) ;bzzzt (send (new loud-buzzer%) buzz) ;bzzzt ;BZZZZZZZZZT s. On Mon, Sep 24, 2012 at 8:15 AM, Stephen De Gabrielle < stephen.degabrie...@acm.org> wrote: > The way I read it was the new function gets called instead of inner; > > #lang racket > > (define a% > (class object% > (super-new) > (define/pubment (hello) > (printf "Hello ") > (inner 0) > (printf "!~n ")))) > > > (define b% > (class a% > (super-new) > (define/augment (hello greg) > ;Call super here? > (printf " ~a ~n" greg)))) > > (send (new b%) hello "Bob") > -> Hello Bob! > > Is this right? > > Cheers, > Stephen > > > > On Monday, September 24, 2012, Gregory Woodhouse wrote: > >> I am trying to understand how augmentable methods (as described in >> section 13.5 of The Guide) work. >> >> Between the extremes of allowing arbitrary overriding and disallowing >> overriding entirely, the class system also supports Beta-style >> augmentable methods [Goldberg04]. A method declared with pubment is like >> public, but the method cannot be overridden in subclasses; it can be >> augmented only. A pubment method must explicitly invoke an augmentation >> (if any) using inner; a subclass augments the method using augment, >> instead of override. >> >> >> From this I conclude that if, for example, I have a class a% and a >> subclass b% and I want to augment a method of a% in b% I need to call inner >> in the definition of the method in a%, not b%. Something like this >> >> #lang racket >> >> (define a% >> (class object% >> (super-new) >> (define/pubment (hello) >> (printf "Hello~n") >> (inner 0)))) >> >> (define b% >> (class a% >> (super-new) >> (define/augment (hello) >> ;Call super here? >> (printf ", world!~n")))) >> >> >> but this gives me an error (not really a surprise). My assumption is that >> super should be used in the subclass when overriding a method, but if a >> method is to be augmented any potential code in an augmenting class should >> be invoked from the superclass and super is not used in the subclass. >> Obviously, I'm missing something. >> > > > -- > > -- > Stephen De Gabrielle > stephen.degabrie...@acm.org > Telephone +44 (0)20 85670911 > Mobile +44 (0)79 85189045 > http://www.degabrielle.name/stephen > ---- > Professor: Oh God! I clicked without reading! > Cubert: And I slightly modified something I own! > Professor: We're monsters! > > -- -- Stephen De Gabrielle stephen.degabrie...@acm.org Telephone +44 (0)20 85670911 Mobile +44 (0)79 85189045 http://www.degabrielle.name/stephen ---- Professor: Oh God! I clicked without reading! Cubert: And I slightly modified something I own! Professor: We're monsters!
____________________ Racket Users list: http://lists.racket-lang.org/users
