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 classes.