[news.eclipse.epsilon] Re: Help on the steps to follow for a model compo

[Dimitris Kolovos <dskolovos@xxxxxxxxx>]

Hi Juan-Pedro,

ECL is used in order to establish a match trace (i.e. the 
correspondences on which EML can then merge the models). Since you 
already have an intermediate model, you can use ECL to "transform" it to 
a match trace.

So if your metamodels are:

-- A.emf --

class A {
  attr String name;
}

-- B.emf --

class B {
  ref A a;
  attr String annotation;
}

-- C.emf --

class C {
  attr String name;
}

your ECL comparison will look something like this:

rule AB
  match a : AModel!A
  with b : BModel!B {

  compare {
    return b.a = a;
  }
}

and your EML merging will look like this:

rule AB2C
  merge a : AModel!A
  with b : BModel!B
  into c : CModel!C {

  c.name = a.name + '_' b.annotation;
}

Hope this helps. If not, please let me know.

Cheers,
Dimitris

Juan Pedro Silva wrote:
> Hi everybody.
> I'm taking my first steps with Epsilon (EML mostly), and I'm trying to 
> compose Model A (from Metamodel A) and Model B (from Metamodel B) into 
> Model C (from Metamodel C). Two inputs, one output, three different 
> metamodels.
> I have already defined the metamodels, the emfatic file with the 
> relationships between the input metamodels, and generated the 
> correspondent ecore model. I also created a ".modelink" indicating the 
> elements I want to combine (merge).
> Now I'm wondering how to continue.
>
> To launch a model merge I need the ".eml" that tells epsilon the source 
> (base), the aspect, and the target.
> I guess I can add the ".modelink" (actually, the model with the 
> relationships resulting from it) as input, and according to the 
> relationships modeled in it make the ".eml" merge elements from A with 
> elements from B into C. Am I right?.
>
> However, I'm not  sure on what to do with the ".ecl" matching.
> Do I have to make rules for matching elements in Model A with elements 
> in Model B?, or for matching elements in Model A with elements in Model 
> C, and then rules for matching elements in Model B with elements in 
> Model C?.
>
> Which is the correct strategy to make such a composition?.
> Thanks in advance.
> Regards,
>             Juan Pedro