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Data Type Rule and EMF [message #554121]

Fri, 20 August 2010 09:02

Softwareassi

Messages: 7
Registered: August 2010

Junior Member

Hello,

I am writing my thesis about textual DSL and using Xtext 1.0 (Eclipse Helios Version) for defining my DSL. While reading the documentation I read about defining Data Type Rules and that these are special Parser Rules. The difference should be that the Parser Rule is an instance of EClass and the Data Type Rule an instance of EDataType (documentation Xtext 1.0 page 29).

So I was thinking when I define a Data Type Rule and I generate the ecore model out of it, the Data Type Rule should become a EDataType element in the model but I just got a regular EClass representation. I used the QualifiedName example from the Documentaion.

Actually my question is whether it is intended to get a EClass representation of my "QualifiedName" rule in my ecore model or should this be a EDataType representation . Or I am totaly wrong and I cannot see it this way?

This should be a Data Type Rule?

QualifiedName :
ID ('.' ID)*
;

Thanks in advance.

Sincerly
Matthias

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Re: Data Type Rule and EMF [message #554129 is a reply to message #554121]

Fri, 20 August 2010 09:32

Christian Dietrich

Messages: 14665
Registered: July 2009

Senior Member

Hi,

a DataType rule does not create a new EDataType but rather helps you to instantiate one when parsing.

QualifiedName returns ecore::EString : 
  ID ('.' ID)*
;

and with the easiest possible sample

Model: name=QualifiedName;

QualifiedName :
ID ('.' ID)*
;

I Cannot see an EClass to be produced.

Regards
Christian

Twitter : @chrdietrich
Blog : https://www.dietrich-it.de

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Re: Data Type Rule and EMF [message #554149 is a reply to message #554121]

Fri, 20 August 2010 09:41

Alexander Nittka

Messages: 1193
Registered: July 2009

Senior Member

Hi,

using

Model:
greeting=QualifiedName;
QualifiedName :
ID ('.' ID)*
;

I cannot reproduce your finding.

In the generated ecore file there is an EClass Model with an attribute
greeting of type EString. If you do not give a return type for the
datatype rule (possibly you have to provide a value converter), the type
used will be string.

Alex

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