Re: [gmf-dev] GMF "philosophical" question

[Alex Shatalin <shatalin@xxxxxxxxx>]

Hi!

I answered this question in GMF newsgroup.

______________
Alex Shatalin

On 09.10.2009, at 11:58, Hristina Moneva <xmoneva@xxxxxxxxx> wrote:

> Hallo, all!
>
> I already posted this in the newsgroup, but I am not convinces that  
> there is better place... I think my question belongs more here.
> Anyway, any ideas are welcome...
>
> Set-up:
> The model used in the experiment is as follows:
>
> Root<>---0..1->Block-----
> ........................|_0..*__|
>
> (later modified like this: add containment)
> Root<>---0..1->Block<>--
> .........................|_0..*__|
>
>
> Where, Root represents the diagram element (the canvas) and the Block
> represents a tree-like structure.
>
> Small experiment:
> Step1: Using GMF, the set-up is modeled in ecore and then all the  
> steps
> performed till achieving diagram editor, which allows graphical  
> modeling of
> directed acyclic graphs using our simple DSL.
> Step2: Change the ecore model as shown in the set-up (change the
> self-reference of the Block to containment). DO NOT regenerate the  
> diagram
> editor (only the model) and run. It does not crash! It works! But  
> the graph
> is not graph any more....
>
> Philosophical question:
> Directed acyclic graph (you can use the DSL above). Always  
> (intuitive for
> the user) it is presented as nodes and edges and it is a tree-like
> structure. For example:
> .........................Node4
> ............Node2<
> Node1< .............Node5
> ............\
> ..............Node3
> There are two implementations possible. 1. Using containment. 2. Using
> references.
>
> Now the question. Based on the experiment, GMF does not allow to  
> choose the
> implementation, if you have preference (fixed) graphical  
> representation. My
> humble opinion is that in MVC, the model and the view are decoupled  
> via the
> controller. So that the model structure and semantics in independent  
> from
> the view representation and semantics.
>
> Small example why I may have preference to one of the approaches  
> (case 1):
> the model represents DSL. The DSL is containing the structure and the
> semantics of the domain. If my domain is "car", I expect that my car
> contains 4 wheels and 3/5 doors, etc. But the view may be still  
> graph-like
> structure.
>
> So, am I wrong (missing something) in applying GMF? Is there really  
> such
> assumption while generating the view? Can I overcome it still using  
> GMF or I
> have to use separately EMF and GEF?
> Best regards,
> Hristina
>
> --
> XpucmuHa MOHEBA / Hristina MONEVA
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