Re: [F-Script-talk] newbie questions

[Philippe M. <pm...@ac...>]

Le 19 juin 06 =E0 16:25, Rainer Keller a =E9crit :

> Hi all,
>
> I just found F-Script a few days ago and was going through the
> tutorials and reading up what I could find. I also tried looking at
> the list archives, but I get an error when I do that:
> "Private archive file not found"

Yes, the mailing list has recently suffered several problems =20
following a change of the underlying system. SourceForge, which is =20
operating the mailing list, has been made aware of the problem with =20
the archive and it should be fixed very soon now.

> I did subscribe to the list and confirmed, so I think I am properly
> registered.
>
> Now what I wanted to search for was creating classes, having an image
> and a changes file.
>
> For creating classes at least for debugging and experimentation (aka
> hacking ;) I thought it should be possible to create an Objective-C
> class for the "Metaclass". Well, I am probably misunderstanding the
> Metaclass concept still, but this is what I was thinking of:
> Just a class with one member that has 2 NSDictionaries, one for the
> members and one for the methods. make sure that it catches all
> unknown methods which get sent to it and then looks them up in your
> dictionary. Would that be possible?

Yes. Actually the KFDecorator module adopts this kind of approach =20
(see http://homepage.mac.com/kenferry/software.html#KFDecorator).

Note that F-Script also has a built-in experimental support for =20
creating classes (this functionality is implemented in the JGType =20
class). It uses the Objective-C runtime functions in order to create =20
"real" Objective-C classes on the fly. Here is a basic example where =20
we create a new subclass of NSObject, named MyClass, with three =20
instance variables named a, b and c, and define a simple method named =20=

method1:

 > NSObject subclass:'MyClass' instanceVariableNames:'a b c'
MyClass

 > MyClass
MyClass

 > MyClass setFSBlock:[:self :_cmd| 'Method ' ++ _cmd ++ ' called on =20
' ++ self printString] asInstanceMethod:#method1

 > myInstance :=3D MyClass alloc init

 > myInstance method1
'Method method1 called on <MyClass: 0x4bb69c0>'

There are several limitations in the current implementation: no =20
direct access to instances variables (you have to use KVC), no =20
support for calling super etc.

> For having an image and a changes file there might be a conflict if
> multiple interpreters are running, at least you would need to find
> some logic, which I could probably look up in other Smalltalks.

The saveSpace and loadSpace methods of the class System let you save =20
or load an entire workspace. Not really the same as an image, though.

Best,

Philippe

> I thought somebody probably had these ideas and wishes before, but
> didn't see anything on the website and had no luck with the list
> archive. Could someone kindly give me a few pointers where to look or
> point out why this is silly/won't work?
>
> Best regards!
> Rainer Keller