Json visitor and MAFileModel

>> I guess it would make sense to add these descriptions as a class
>> extension. This is one of most useful techniques of Magritte, that  
>> you
>> can attach new descriptions to any class in the system. I use this  
>> all
>> the time.
>
> I'm a bit new to Smalltalk/Squeak/Magritte terminology and I'm not
> sure what class extensions mean. May I bother you for a small example
> and a pointer for more explanations?

> >> I guess it would make sense to add these descriptions as a class
> >> extension. This is one of most useful techniques of Magritte, that
> >> you
> >> can attach new descriptions to any class in the system. I use this
> >> all
> >> the time.
> >
> > I'm a bit new to Smalltalk/Squeak/Magritte terminology and I'm not
> > sure what class extensions mean. May I bother you for a small example
> > and a pointer for more explanations?
>
> This is when you add a method to a foreign class. In your case, your
> own package adds some description methods to the foreign class
> MAFileModel. To tell Monticello that these methods belong to your code
> and not to Magritte-Core you put them into a protocol (method
> category) named *mypackagename.
>
> Does that help?
>
> Lukas
>
> --
> Lukas Renggli
> http://www.lukas-renggli.ch
>
>
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> SmallWiki, Magritte, Pier and Related Tools ...
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>

> > By the way, is there a way to add instance variable using this method?
> > I won't need them for this particular case but I can't find any
> > information about that and I'll need it for another part of the
> > application.
>
> No that is not possible, unfortunately. Most Magritte/Pier objects
> however include a property dictionary for exactly that reason.
>
> Lukas
>
> --
> Lukas Renggli
> http://www.lukas-renggli.ch
>
>
> _______________________________________________
> SmallWiki, Magritte, Pier and Related Tools ...
> https://www.iam.unibe.ch/mailman/listinfo/smallwiki
>

> > By the way, is there a way to add instance variable using this method?
> > I won't need them for this particular case but I can't find any
> > information about that and I'll need it for another part of the
> > application.
>
> No that is not possible, unfortunately. Most Magritte/Pier objects
> however include a property dictionary for exactly that reason.
>
> Lukas
>
> --
> Lukas Renggli
> http://www.lukas-renggli.ch
>
>
> _______________________________________________
> SmallWiki, Magritte, Pier and Related Tools ...
> https://www.iam.unibe.ch/mailman/listinfo/smallwiki
>

> > For most simple descriptions, streaming the value is just a matter of
> > rendering the value according to the description using the normal
> > visitor pattern. However, MAFileModel is a full-blown class and
> > doesn't have a corresponding description to guide the process.
>
> Yes, MAFileDescription is sort of a primitive type, mainly because in
> the user interface it appears as a single upload/download field.
>
> > What would be the most interesting path here: add the required
> > descriptions to the classes or just go ahead and stream the
> > attributes?
>
> I guess it would make sense to add these descriptions as a class
> extension. This is one of most useful techniques of Magritte, that you
> can attach new descriptions to any class in the system. I use this all
> the time.
>
> > It seems to me that the second options make the Json visitor to
> > tightly coupled to the MAFileModel class. On the other hand, adding
> > the descriptions may not be that interesting because it would mean
> > changing a Magritte base class.
>
> I don't know if it makes sense to add these descriptions to the core
> at the moment?
>
> Cheers,
> Lukas
>
> --
> Lukas Renggli
> http://www.lukas-renggli.ch
>
>
> _______________________________________________
> SmallWiki, Magritte, Pier and Related Tools ...
> https://www.iam.unibe.ch/mailman/listinfo/smallwiki
>

> > Altough adding descriptions would not make sense to the core, would it
> > make sense to change MAFileModel into a MAObject? That would make it
> > easier to build extensions on top of it.
>
> The idea of MAFileModel is that you can easily subclass it to provide
> your own strategy to store and retrieve the file. MAFileDescription
> takes the #kind: as an argument, so you can tell it what class to
> instantiate.
>
> Maybe you can give an example, why you need to add new values to the
> existing MAFileModel subclasses?
>
> Cheers,
> Lukas
>
> --
> Lukas Renggli
> http://www.lukas-renggli.ch
>
>
> _______________________________________________
> SmallWiki, Magritte, Pier and Related Tools ...
> https://www.iam.unibe.ch/mailman/listinfo/smallwiki
>