[Q] new and initialize

Ned Konz ned at bike-nomad.com
Tue Apr 1 23:38:25 UTC 2003

On Tuesday 01 April 2003 03:23 pm, Brian Brown wrote:
> What is the relationship between new and initialize? I see examples
> like:
> 	var := SomeClass new initialize.
> and  also
> 	var := SomeClass new.
> Does initialize automatically get called upon object creation,

No. It is called explicitly in some classes.

> or
> is just another message that I can chose to call or not? I see
> classes both with and without initialize and I can understand there
> may be no instance setup required or maybe a superclass does it....

Tradition! In many cases, #new calls initialize.

For instance, in Morph, we see this pattern. So Morph subclass 
constructors shouldn't call initialize if they call new (because we'd 
be initializing twice).

Look at how #new is defined. In Behavior>>new we call the primitive, 
as in #basicNew.

So one idiom for new is

self basicNew initialize

which would avoid the double initialization that would occur if a 
superclass defined new to call initialize as well.

But it doesn't make any sense to have a 0-argument constructor in many 
Ned Konz

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