There are some lightweight ways of
handling this using roles.
Person
instanceVariables:
roles
aPerson roles add: Human new; add: Ninja
new.
There are a number of roles
implementations. One based on doesNotUnderstand which runs through the
roles collection and passes the called but not understandable message to each
instance. Some implementations will return a collection of responses if
multiple roles answer the same message, and this can get kinda tricky if you
don’t know how to watch for it. You can also define a specific
interface to your methods by specifically implementing your methods on Person to
look for a role before forwarding the method and handling the call if it does
not.
For Example:
Person >> killSilently
aPerson
hasNinjaRole ifTrue: [^self ninjaRole killSilently].
aPerson
hasHumanRole ifTrue: [^self humanRole killSilently].
aPerson
handleKillingRequestWithMoreSleepAndExercise.
Ninja >> killSilently
“walk
on rice paper leaving no trace then you will be ready”
self
doSilentKilling
Human >> killSilently
“humanity
wins”
self
tryToKill.
self
goToPoliceStation.
self
confess.
I’m not saying I like roles. I
just thought I’d mention more options.
Ron Teitelbaum
President / Principal Software Engineer
US Medical Record Specialists
Ron@xxxxxxxxxxxx
From:
beginners-bounces@xxxxxxxxxxxxxxxxxxxxxxxxxx
[mailto:beginners-bounces@xxxxxxxxxxxxxxxxxxxxxxxxxx] On Behalf Of Michael Gorsuch
Sent: Monday, November 13, 2006
3:56 PM
To: A friendly place to get
answers to even the most basic questions aboutSqueak.
Subject: Re: [Newbies] How to
squeeze Multiple Inheritance into Squeak ?
Here's an idea:
I have a Person class, but I need him to inherit traits that the Human class
has and the Ninja class has.
Is that sufficient?
On 11/13/06, Michael
Haupt <mhaupt@xxxxxxxxx>
wrote:
Hi Warakom,
On 11/13/06, Warakorn Paphrawat <warakorn_paphrawat@xxxxxxxxx>
wrote:
> Sadly enough the possibility of Multiple Inheritance in Squeak would
greatly
> benefit me in my current Squeak project ?
what exactly is the characteristic in your project that imposes this
requirement on it? Why do you need multiple inheritance? What would
you use it for?
I'd recomment looking at traits first, but without knowing what
exactly you are trying to achieve, I cannot say much more. :-)
Best,
Michael
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