Just a remark about prototype language semantics

Stephane Ducasse ducasse at iam.unibe.ch
Fri Oct 23 06:51:30 UTC 1998


Hi,
I just want to have your view on the following point.  The prototype
model has some different qualities than the class model and I do not
want to dicuss this point here.

For my an object in prototype and class based language is has an
identity that refers to a Private non sharable set of data and a
sharable set of behavior (via inheirtance or delegation).

I just want to stress that what was a source of problem in some
prototype models was the sharing of value between prototypes i.e. the
fact that if I'm a prototype a that refers to my parents I shared their
slots and so if I modified one my slot my parents are modified too.

(Note that here I'm discussing if self does or not implement maps,
trait and so other implmentation techniques that are certainly
valuable.)

For me the sharing of values is not good thing, it introduce to manage
the split of object problem (see oospsla papers).

I prefer to see a prototype like an object having its private data and
sharing its behavior.

This is the semantics of Pico developed by Pr. D'hondt from VUB
http://dinf.vub.ac.be/prog/pico/


Stef





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