[Seaside-dev] basicNew

[Avi Bryant]

On Sun, Oct 5, 2008 at 3:12 AM, Julian Fitzell <jfitzell at gmail.com> wrote:

> WAPoint class>>x: xNumber y: yNumber
>  ^ self basicNew initializeWithX: xNumber y: yNumber; yourself
>
> WAPoint>>initializeWithX: xNumber y: yNumber
>  self initialize.
>  x := xNumber.
>  y := yNumber.
>
> If you really want #new to work and there are reasonable defaults, then add:
>
> WAPoint class>>new
>  ^ self x: 0 y: 0
>
> Is there a problem with this approach that I'm missing?

I think it's equivalent, and probably more Smalltalk-y.  So, the
convention becomes:

- each class has exactly one initialization method on the instance side
- if that initialization method has the same selector as its
superclass' initializer, it should call super.  Otherwise, it should
call its (inherited) superclass initializer, as you do in that
example.
- on the class side, you should have one designated constructor method
that uses #basicNew and then the designated initializer.  You only
need to reimplement this when you change the designated initializer.
- you may also have alternate constructors that simply call the
designated constructor with different parameters
- if you are changing  the designated initializer/constructor, you
must override your superclass' designated constructor to do something
appropriate (either call the designated constructor with suitable
defaults, or error if there are no defaults to use)

Julian, having gotten here, it's feeling awfully familiar - I'm pretty
sure the original conventions for Seaside code came about from exactly
the same discussion years ago, and then got lost...

Avi