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how to create an external cross-reference in the AST [message #1823441]

Thu, 26 March 2020 18:50

L R

Messages: 12
Registered: July 2019

Junior Member

I am attempting to create a model using the model factory. I can create cross-references that link within the AST, but I can not discern how to create an external cross-reference. As an example, using the 15-minute tutorial grammar (https://www.eclipse.org/Xtext/documentation/102_domainmodelwalkthrough.html).

I want to create the following model using the model factory:

entity Test {
	f1 : String
}

In this example "String" is a cross-reference to the datatypes.dmodel. I can create the rest of the model using the following code:

Domainmodel dm = DomainmodelFactory.eINSTANCE.createDomainmodel();
Entity en = DomainmodelFactory.eINSTANCE.createEntity();
dm.getElements().add(en);
en.setName("Test");
Feature fea = DomainmodelFactory.eINSTANCE.createFeature();
en.getFeatures().add(fea);
fea.setName("f1");

The only remaining step is to set fea Type to something using fea.setType(). Ideally, I could create some object, set its name to "String", and then use it for the assignment.

I could envision a process where I search the global scope and find the dataype String in file datatypes.dmodel. This seems like a lot of work to do to just resolve this external cross reference.

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Re: how to create an external cross-reference in the AST [message #1823443 is a reply to message #1823441]

Thu, 26 March 2020 18:56

Christian Dietrich

Messages: 14665
Registered: July 2009

Senior Member

Hi,

do you run in eclipse or standalone? who run the code above?
is there another file with the String already existing?
if you use a resourceset with all resources in standalone mode,
and a resourceset created with IResourceSetProvider.get(iproject) in eclipse and give the resource an uri in that project
then you should be able to ask the scope provider for a (Data)type with the name String

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

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Re: how to create an external cross-reference in the AST [message #1823444 is a reply to message #1823443]

Thu, 26 March 2020 19:07

L R

Messages: 12
Registered: July 2019

Junior Member

This code would be used as part of a translation from one grammar to another. In this example, String would exist in the datatypes.dmodel file. However, I would not always expect for that file to have been created. (I might be able to constrain that, but would prefer not to.).

Do you know of an example someplace showing how to query the scope provider?

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Re: how to create an external cross-reference in the AST [message #1823445 is a reply to message #1823444]

Thu, 26 March 2020 19:10

Christian Dietrich

Messages: 14665
Registered: July 2009

Senior Member

so you want to transform both at once?
then you have to use
org.eclipse.xtext.ui.resource.LiveScopeResourceSetInitializer
in eclipse

section on create methods
in https://www.eclipse.org/xtend/documentation/202_xtend_classes_members.html#methods

might also be helpful

you can simply call scopeProvider.getScope(contextObject, Reference)
with context object the objectz holding the reference
and Reference = MyDslPackage.Literals.HOLDINGTYPE_REFERENCENAME

and the call scope.getSingleElement(QualifiedName)

note:
the contextObject needs to be part of the
eresource in the resourceset
at this point in time

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

[Updated on: Thu, 26 March 2020 19:17]

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