[EMAIL PROTECTED] wrote:

>Petr Krenzelok wrote:
>  
>
>>That's the first thing someone will have to explain me - why naked-objects or RFM 
>uses blocks and name value pairs? Is there any advantage?
>>    
>>
>
>Yes! :)
>
>Because one can alter the block at runtime! For example, adding more fields or 
>removing them. That allows customising each record.
>
You can do so with object too. Object = template you load from your 
repository. If you want to extend, you can extend the class (block of 
set-word and value pairs), and instantiate the object (load block into 
context) once again :-)

>>2) As you can see, I need some relations - each building has its rooms, - typical 
>parent child relationship. That relationship can be expressed in RFM, if I understand 
>it correctly, but what if child can have its own child relationships etc.?
>>    
>>
>
>I'm working on that kind of thing, with bidirectional links expressed as containment. 
>Something like:
>
>[Teacher "A. Teacher" Room []] ; Last block contains next block:
>[Room "K5" Teacher []] ; Last block contains first block.
>  
>
Uh, I didn't mean something like that, but well, I don't understand 
above anyway :-) Seems like some of never ending recursion :-) What I 
also don't like about RFM so far is - that it stores field names with 
each record, which I see as redundant, unless it has its own purpose I 
can be not aware of. (e.g. that each record can have variable set of fields)

>>3) Can objects be extended in the real time by adding another attribute? 
>>    
>>
>No! And if another object points to the object, you're going to have problems. That's 
>because the other object will hang on to the orignal, when you change it.
>  
>
I meant something bit different - not real rebol objects, but e.g. 
earlier mentined accommodation class. System admin (not necessarily 
rebol programmer) can say to himself one day - hey, this hotel has 
cinema inside. Where should I put that? So he goes to "object" 
repository, selects hotel class, and adds/describes "attribute" (field) 
of 'cinema-inside? type e.g. That was what I meant by ability to extend 
"object" during the system life-time ...Of course there can be 
consequences to it, like such field not existing in former records - so 
ti may cause some difficulcy to query engine e.g.

-perk-

>
>Andrew Martin
>
>  
>



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