Welcome to Squeak!

On Monday 28 June 2004 6:38 pm, Steve Greenberg wrote:

> I'm trying to do the simplest thing, but there is clearly some basic
> concept that I'm missing here.  I'm running Squeak 3.6.

Note that Squeak 3.7 has an important change: there is a default call to 
#initialize in the definition of #new up in Behavior.

So you will not often want to write this kind of code any more (as it's 
redundant):

	MyClass class >> new
		^super basicNew initialize

> In short, I have ClassA and ClassB, which is a subclass of Class A.
> Each class has one variable, and when I create the class I'd like to
> see the initialization methods run on both classes.

Are you talking about class initialization (like when you load it into a new 
image) or instance initialization (like when you make a new object of your 
class)? We have both flavors, since classes are also objects.

> When I execute:
>
>     b _ ClassB new initialize
>
> I expected that both classes would be initialized.  What actually
> happens is that only ClassB is initialized.

I hope that your new object ("b") is what's getting initialized, *not* the 
class.

What should happen, given your code, is:

	ClassB class >> new
		ClassA class >> new
			Object class >> new
				Object class >> basicNew
			ClassB>> initialize
		ClassB>> initialize

That is, ClassB>>initialize gets called twice, and the ClassA>>initialize gets 
called not at all.

> Object subclass: #ClassA
> 	instanceVariableNames: 'anIntA '
> 	classVariableNames: ''
> 	poolDictionaries: ''
> 	category: 'SEG'
>
> initialize
> 	anIntA _ 1.
>
> new
> 	^ super new initialize

This isn't really a safe scheme; if you later make a new superclass for ClassA 
that *itself* calls initialize, you'll get it called again. Better probably 
to say
	^super basicNew initialize

and to make your initialize method call *its* superclass:

	initialize
		super initialize.
		anIntA _ 1.

> -------
>
> ClassA subclass: #ClassB
> 	instanceVariableNames: 'anIntB '
> 	classVariableNames: ''
> 	poolDictionaries: ''
> 	category: 'SEG'
>
> initialize
> 	anIntB _ 1

If you want the superclass initialize method to be called, you should also do 
it here:

	initialize
		super initialize.
		anIntB _ 1

> new
> 	^ super new initialize

ClassB class>>new isn't needed (it's a duplicate of its parent's definition). 
And in fact it's causing ClassB>>initialize to be called twice.

-- 
Ned Konz
http://bike-nomad.com/squeak/