2011/5/2
info@tomsik.cz <info@tomsik.cz>
Thx, can you be more specific? I'm looking for reasons.
Door>>open, close (delegating to state)
OpenedDoorState>>close
ClosedDoorState>>open
delegation, empty methods, throwing exceptions, that all seems just ugly,
I don't want anybody looking in methods browser
to think that every door can be closed or opened,
because that's not right.
maybe I don't want object to become another object, maybe I just want to
change its class? (is it possible?)
Yes, you can. #check adoptInstance: or #primitiveChangeClassTo:
But again, I am not sure you need this for your example.
Did you consider traits?
Even so, I� don't think that implementing empty methods or throwing errors is that bad. In fact, it looks good for me.
�
I want empty Door class (or implementing only things possible with any door)
and subclasses representing their states.
Dne Mon, 02 May 2011 14:19:31 +0200 St�phane Ducasse <stephane.ducasse@inria.fr> napsal(a):
Do not use become: for state pattern. It is not worth.
Stef
On May 2, 2011, at 3:11 PM, info@tomsik.cz wrote:
I see that #become: is hard to follow in code (either for human or analysis tools)
I'm trying to express state-pattern:
OpenedDoor>>close
ClosedDoor>>open
And I would like to avoid this:
Door>>close
� � � �state close.
Door>>open
� � � �state open.
Because if Door cannot be opened depending on its current state, IMHO no method should be
there. Which is why become: seems as the best fit.
I would also like to know why proxy is considered better, because #messageNotUnderstood
seems pretty magic too. (except the fact that become: can crash VM)
Dne Mon, 02 May 2011 14:39:40 +0200 Mariano Martinez Peck <marianopeck@gmail.com> napsal(a):
2011/5/2 info@tomsik.cz <info@tomsik.cz>
I've heard that become: is considered to be magic
and should be avoided and replaced by either AOP or proxies,
That's "normally" true. But it depends what are you doing. For a normal app,
busieness, etc, it is not likely you will need a #become:.
However, if you are doing low level stuff, frameworks or hacky things you
may need it.
Can you tell us what are your needs and why you would like to use #become:?
or you just want to know about it?
I googled a little but I couldn't find anything more concrete.
Does anybody have any link or opinion about that?
I'd be glad to hear something more about it.
Thx
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