[Newbies] invoking a *class* method from a workspace
bert at freudenbergs.de
Sat May 26 16:40:45 UTC 2007
On May 26, 2007, at 18:32 , mstram wrote:
> Well obviously I need to a lot more reading and experimenting with
> even if "class" methods are "regular" methods, there is something
> with them as far as :
> 1) the syntax to access them ("fire" .. "call" .. "invoke" ???
> what is the
> traditional term ? )
There is no special syntax. The only difference is the receiver.
Either you send a message to an instance of a class or or the class
itself (which, as mentioned before, is a regular object).
> 2) At least one difference I've found is that I when tried to create a
> "class" method that accessed an instance variable,
Instance variables are private, they can only be accessed by the
object itself. So from the class object you cannot access instance
variables of one of its instances.
> Squeak warned that the variable didn't exist and asked if I wante
> to create it (is this a bug?) ...
> even though it was "declared" in the class definition.
> But Squeak says that 'ivar1' is undeclared and asks if I want to
> declare it.
> It accepts it being declared as an instance variable (even though
> it already
> was according to the class definition ... (is this a bug?).
No, what you did there is you defined 'ivar1' as an instance variable
of the class object itself, not for instances of your class. It will
be listed in the browser when you switch to the class side
definition. This feature is very rarely used.
- Bert -
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