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How to implement generalization in XText ? [message #1722454]

Thu, 04 February 2016 17:51

Eclipse User

Hi,

Given the meta model attached below, which way of implementation is correct for the Message class.

1)
Concept:
message=Message |
attribuConc= AttributedConcept
...

OR:

2)
Concept:
name or whatever attribute

Message returns Concept:

...

So, the difference is using "return" keyword which is used for subtyping or using message inside concept. Using (1), the generated Java code creates a class concept which HAS message attribute. but using return statement (2) generate a class Message that extends Concept.

Thanks.
Parsa
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Re: How to implement generalization in XText ? [message #1722460 is a reply to message #1722454]

Thu, 04 February 2016 23:05

Eclipse User

Concept: Message | AttributedConcept;

Message: ...;

AttributedConcept: ....;

Message returns Concept:
{Message} .....

Re: How to implement generalization in XText ? [message #1722576 is a reply to message #1722460]

Fri, 05 February 2016 21:04

Eclipse User

Thanks a lot Christian for your quick reply and help.

Do you know if we have an attribute (let's say name) in Concept, and Message also inherits this "name" attribute form Concept, then from what I can see we need to declare name in the Message and not in Concept. Because concept here is just a transient element, right ? I tried having name for both Concept and for Message. In the generated ecore file it adds name attribute for both elements. However, since it is a inheritance, only Concept should have it and inherited Message can have name attribute by inheritance... What do you suggest ?

I want to end yup with generating an ecore file like below:

Concept
-name: EString

Message->Concept
-a1
-a2

So, Message still has name attribute by the definition of inheritance. Not sure, how to do in XText.

Thanks,
Bests,
Parsa

Re: How to implement generalization in XText ? [message #1722588 is a reply to message #1722576]

Sat, 06 February 2016 04:27

Eclipse User

Hi have a look in the docs. It describes how ecore is inferred. At a
certain point switching to a handwritten meta model might be better

Having the name at the parent level makes only sense if you have 2 child's.

If you have

Parent:A|B

And

A:name=ID

And

B:name=ID

Then

Parent will get the name from the inferrer

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