[plt-scheme] "appending" to classes rather than extending

Swindle looks very interesting indeed.

Thanks for the pointers, all.

--rob


On Wed, Mar 5, 2008 at 9:17 PM, Doug Orleans <dougorleans at gmail.com> wrote:
>
> Grant Rettke writes:
>   > On Wed, Mar 5, 2008 at 9:47 PM, Doug Orleans <dougorleans at gmail.com> wrote:
>   > >  You might consider Swindle
>   >
>   > Ought one be a CLOS expert before getting started with Swindle?
>
>  Maybe if you want to do fancy things with the MOP, but otherwise it
>  should be pretty easy to pick up.  Below are some of the examples from
>  the PLT Scheme Guide chapter 13 Classes and Objects translated into
>  Swindle.
>
>  #lang swindle
>
>  (-defclass-auto-initargs- (:auto #t))
>  (-defclass-autoaccessors-naming- :slot)
>
>  (defclass <fish> () size)
>
>  (defmethod (grow (fish <fish>) (amt <number>))
>   (set! (size fish) (+ amt (size fish))))
>
>  (defmethod (eat (fish <fish>) (other-fish <fish>))
>   (grow fish (size other-fish)))
>
>  (define charlie (make <fish> :size 10)) ; this also works: (make-fish 10)
>
>  (grow charlie 6)
>  (echo (size charlie)) ; => 16
>
>  (defclass <hungry-fish> (<fish>))
>
>  (defmethod (eat-more (fish <hungry-fish>) (fish1 <fish>) (fish2 <fish>))
>   (eat fish fish1) (eat fish fish2))
>
>  (defclass <picky-fish> (<fish>))
>
>  (defmethod (grow (fish <picky-fish>) (amt <number>))
>   (call-next-method fish (* 3/4 amt)))
>
>  (define daisy (make <picky-fish> :size 20))
>
>  (eat daisy charlie)
>  (echo (size daisy)) ; => 32
>
>  (defclass <size-10-fish> (<fish>))
>
>  (defmethod (initialize (fish <size-10-fish>) initargs)
>   (call-next-method fish (list :size 10)))
>
>  (echo (size (make <size-10-fish>))) ; => 10
>
>  (defclass <default-10-fish> (<fish>))
>
>  (defmethod (initialize (fish <default-10-fish>) initargs)
>   (call-next-method fish (append initargs (list :size 10))))
>
>  (echo (size (make <default-10-fish>))) ; => 10
>  (echo (size (make <default-10-fish> :size 20))) ; => 20
>
>
>  --dougorleans at gmail.com
>
>
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