Hi dennis
two points:
- aClass new returns an instance of that class
- super represents the receiver of the message but the lookup of the
method in the superclass
of the class that contains the super call. Once the method is found
it is applied to the original receiver.
So now
Monster class>> new
^ super new initialize
is executed when you do Monster new
what is the receiver of the message new => Monster.
So super new is looked up in the super class of Monster and once
found applied on
Monster, then point 1 makes that you get back an instance of the
receiver of the message new.
Stef
On 13 oct. 06, at 15:57, dennis petrocelli wrote:
Greetings smalltalkers,
I'm a newbie trying to get my head around inheritance. I'm puzzled
by the following example. It seems to do what I mean, but not what
I type ;) This is a good thing, but I'd get further if I
understood the semantics a bit better.
from http://www.cosc.canterbury.ac.nz/wolfgang.kreutzer/cosc205/
smalltalk1.html
Class: Monster
Superclass: Object
Category: Sesame Street
Instance variables: colour tummy
initialization
initialize
self colour: #green.
self tummy: Bag new
"There is only a single class method and no class variables."
creation
new
^ super new initialize
What I don't understand is this: Monster new returns an instance
of Monster, what you'd want it to. But Monster new executes "^
super new" which to my mind should return an instance of Object,
not Monster. Just to confuse myself further, I typed:
Monster superclass new
and got an Object. It seems to me that "super new" and "superclass
new" should do the same thing.
Any points to clarify my confusion would be greatly appreciated.
Thanks,
Dennis Petrocelli
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