Hi,
I think i am missing something.
For example in the following code (took from the tests):
| victim virus actual |
virus := GHObjectVirus behaviour: GHGhostBehaviourStub new.
victim := 0@0 corner: 3@4.
virus infect: victim.
victim corner
The evaluation is trapped by the send:to: method in the behavior (i've
put a halt there). However if i replace the "corner" message by an
inspect of the victim, and if i evaluate "self corner", then the message
is processed without going through the send:to: method of the behavior.
It is not halted and the victim responds immediately to the message. I
have also tried to add a new method in the Rectangle class that calls
"self corner". When called in the playground, my new message is trapped
but not the "corner" sent to self.
>From what i understand it could be related to the behavior i use, but i
don't see what's missing.
Le 2016-07-28 11:35, Denis Kudriashov a écrit :
> I think I not understood second part of "self problem" in this paper. But
> self sends are covered by virus as I described.
>
> 2016-07-28 11:30 GMT+02:00 Denis Kudriashov <dionisi...@gmail.com>:
>
> Hi
>
> 2016-07-27 22:19 GMT+02:00 Steven Costiou <steven.cost...@kloum.io>:
>
> Hi,
>
> I use virus from Ghost to intercept messages sent to a given object and adapt
> methods behaviors for this particular object only. However it would seems
> that doing interception this way is subject to the "self problem" described
> in this paper from Stéphane (DUCASSE, Stéphane. Evaluating message passing
> control techniques in Smalltalk. _JOURNAL OF OBJECT ORIENTED PROGRAMMING_,
> 1999, vol. 12, p. 39-50).
>
> I understand i could do instance based adaptation using an other technique,
> but i wonder if there is any way with Ghost to deal with this "self problem"
> problem ? I think "self problem" is only related to classic proxies when
> objects stay behind them. But ObjectVirus is not proxy in this meaning. When
> you infect your object by virus it is not replaced by somebody else. It is
> same original instance but with overridden behaviour. That's why I call it
> virus without any relation to proxies.
> Any message to infected object is processed by your behaviour. All self sends
> are intercepted. But there are few exceptions:
> - special messages like ==,ifTrue/ifNil are not intercepted
> - meta messages are not intercepted. They processed by Ghost mechanics but
> they not passed to your behaviour. Meta messages defined by #currentMetaLevel
> of your behaviour. You could implement it like:
>
> YourGhostBehaviour>>currentMetaLevel
> ^GHMetaLevel empty
>
> Empty meta level means that all messages will be passed to your behaviour.
> There is also "GHMetaLevel standard" which is default one. It makes most of
> "tool messages" not interceptable. For example #printString, #class,
> #instVarAt: will be not intercepted. It's messages which are usually used by
> tools like inspector and debugger.
> Standard meta level simplifies debugging of new behaviours. If you make
> mistake somewhere standard messages will be not broken and you could debug
> error by tools.
