[Seaside-dev] basicNew

[Randal L. Schwartz]

>>>>> "Julian" == Julian Fitzell <jfitzell at gmail.com> writes:

Julian> Seaside-Core-pmm.267.mcz
Julian> - use #new instead of #basicNew for WACallbackRegistry, using
Julian> #basicNew has already lead to interesing bugs in other places

Julian> I always thought the pattern was:

Julian> Foo class>>bar: param
Julian>   ^ self basicNew initializeWithBar: param

Foo> initializeWithBar: param
Julian>   self initialize.
Julian>   bar := param

Julian> I guess calling new instead of basicNew and not call #initialize from
Julian> #initializeWithBar: also works, but means you don't have control over
Julian> when (or if) #initialize gets called.  I have to admit that the whole
Julian> initialization pattern feels a bit ugly both ways though. Is this the
Julian> preferred pattern throughout now?

The Squeak way has been to have something equivalent to:

    Class class >> new
        ^self basicNew initialize.
    Class >> initialize
        ^self.

So for specialization in initialization, you add:

    MyClass >> initialize
        super initialize.
        [stuff here].
        ^self.

As in, it's important for initialize to always call super, and also to always
return self, and return a sane object that might only need some additional
settings.

And for specialized constructors, you add:

    MyClass class >> on: anObject
        ^self new on: anObject; yourself.
    MyClass >> on: anObject
        [stuff here].

This is the Squeak pattern as I understand it, and since Seaside is sourced in
Squeak, this is the pattern that has been established for specialization in
Seaside items.

-- 
Randal L. Schwartz - Stonehenge Consulting Services, Inc. - +1 503 777 0095
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