Eclipse Community Forums: TMF (Xtext) » Unexpected behavior on linkage between Xtext resource and inferred JVM type

Home » Modeling » TMF (Xtext) » Unexpected behavior on linkage between Xtext resource and inferred JVM type(My DSL inferres two JVM types from a grammar element. Xtext only recognizes one of them)

Show: Today's Messages :: Show Polls :: Message Navigator

Unexpected behavior on linkage between Xtext resource and inferred JVM type [message #1771309]

Wed, 23 August 2017 21:20

Miguel Jimenez

Messages: 40
Registered: July 2015

Member

Hi,

I'm generating two Java classes (Entity.java & EntityEntity.java) from a grammar element (Entity). These are the grammar definition and the JVM model inferrer:

grammar org.xtext.example.mydsl.MyDsl with org.eclipse.xtext.xbase.Xbase
generate myDsl "http://www.xtext.org/example/mydsl/MyDsl"

DomainModel:
	importSection=XImportSection?
	elements+=AbstractElement*;
	
AbstractElement:
	PackageDeclaration | Entity;

PackageDeclaration:
	'package' name=QualifiedName '{'
		elements+=AbstractElement*
	'}';

Entity:
	'entity' name=ValidID body=XBlockExpression;

package org.xtext.example.mydsl.jvmmodel

import com.google.inject.Inject
import org.eclipse.xtext.naming.IQualifiedNameProvider
import org.eclipse.xtext.xbase.jvmmodel.AbstractModelInferrer
import org.eclipse.xtext.xbase.jvmmodel.IJvmDeclaredTypeAcceptor
import org.eclipse.xtext.xbase.jvmmodel.JvmTypesBuilder
import org.xtext.example.mydsl.myDsl.Entity

class MyDslJvmModelInferrer extends AbstractModelInferrer {

	@Inject extension JvmTypesBuilder
	@Inject extension IQualifiedNameProvider

	def dispatch infer(Entity entity,
		extension IJvmDeclaredTypeAcceptor acceptor, boolean prelinkingPhase) {
		accept(entity.toClass('''hard.coded.Entity«entity.name»'''))
		accept(entity.toClass( entity.fullyQualifiedName )) [
			documentation = entity.documentation
			members += entity.toMethod("body", typeRef(void)) [
				body = entity.body
			]
		]
	}
}

These are two example files:

test1.mydsl

package foo {
	entity Computer {
	}
}

test2.mydsl

package hello {
	entity Laptop {
		println(new EntityComputer())
	}
}

if I change the constructor call to "new Entity()", Xtext does not find the class and I need to import it. Why does that happen, and how can I fix it? (i.e., I do not want to import the class, just like when I instantiate "EntityComputer").

Thank you.
Miguel

Report message to a moderator

Re: Unexpected behavior on linkage between Xtext resource and inferred JVM type [message #1771321 is a reply to message #1771309]

Thu, 24 August 2017 04:22

Christian Dietrich

Messages: 14285
Registered: July 2009

Senior Member

Hi,

i dont understand.
you dont inferr a class called entity.
you inferr stuff to a hardcode package and stuff to the package declared.

so what should "new Entity()" call to?

Need professional support for Xtext, Xpand, EMF?
Go to: https://www.itemis.com/en/it-services/methods-and-tools/xtext
Twitter : @chrdietrich
Blog : https://www.dietrich-it.de

Report message to a moderator

Re: Unexpected behavior on linkage between Xtext resource and inferred JVM type [message #1771322 is a reply to message #1771321]

Thu, 24 August 2017 05:03

Miguel Jimenez

Messages: 40
Registered: July 2015

Member

Hi,
I made a mistake in the question. I mean "new Computer()". Here is the complete explanation:

The two examples I posted generate four Java classes: hello.Laptop, hard.coded.EntityLaptop, foo.Computer, and hard.coded.EntityComputer.
In test2.mydsl, I have "println(new EntityComputer())". In that case, Xtext has no problem finding the class hard.coded.EntityComputer without adding an import to the File.
If I change that statement to "println(new Computer())", Xtext cannot find the class foo.Computer and I have to import it, even though both classes are inferred from the same model.

Report message to a moderator

Re: Unexpected behavior on linkage between Xtext resource and inferred JVM type [message #1771323 is a reply to message #1771322]

Thu, 24 August 2017 05:42

Christian Dietrich

Messages: 14285
Registered: July 2009

Senior Member

But new computer is in a different package?!?

Need professional support for Xtext, Xpand, EMF?
Go to: https://www.itemis.com/en/it-services/methods-and-tools/xtext
Twitter : @chrdietrich
Blog : https://www.dietrich-it.de

Report message to a moderator

Re: Unexpected behavior on linkage between Xtext resource and inferred JVM type [message #1771326 is a reply to message #1771323]

Thu, 24 August 2017 06:26

Miguel Jimenez

Messages: 40
Registered: July 2015

Member

Both classes are instantiated from a different package (the class calling the constructor is hello.Laptop):

hard.coded.EntityComputer
foo.Computer

Isn't that the same case? If it requires to import classes that are in different packages, why is "new EntityComputer" working?

Report message to a moderator

Re: Unexpected behavior on linkage between Xtext resource and inferred JVM type [message #1771327 is a reply to message #1771326]

Thu, 24 August 2017 06:35

Christian Dietrich

Messages: 14285
Registered: July 2009

Senior Member

no, the hard coded package is known to both (since you inferrer a class inside hard.coded for both entities.

Need professional support for Xtext, Xpand, EMF?
Go to: https://www.itemis.com/en/it-services/methods-and-tools/xtext
Twitter : @chrdietrich
Blog : https://www.dietrich-it.de

Report message to a moderator

Re: Unexpected behavior on linkage between Xtext resource and inferred JVM type [message #1771333 is a reply to message #1771327]

Thu, 24 August 2017 07:26

Miguel Jimenez

Messages: 40
Registered: July 2015

Member

Is there a way to avoid importing the class?

Report message to a moderator

Re: Unexpected behavior on linkage between Xtext resource and inferred JVM type [message #1771336 is a reply to message #1771333]

Thu, 24 August 2017 07:54

Christian Dietrich

Messages: 14285
Registered: July 2009

Senior Member

i dont understand. if you have

package X {
entity Entity
}

package X2 {
entity Entity
}

whichone should be picked?

Need professional support for Xtext, Xpand, EMF?
Go to: https://www.itemis.com/en/it-services/methods-and-tools/xtext
Twitter : @chrdietrich
Blog : https://www.dietrich-it.de

Report message to a moderator

Re: Unexpected behavior on linkage between Xtext resource and inferred JVM type [message #1771341 is a reply to message #1771336]

Thu, 24 August 2017 08:32

Miguel Jimenez

Messages: 40
Registered: July 2015

Member

You're right about that. The reason I'm trying to avoid the Java import is because in the actual language
I already have a cross reference to the model (used for other things). Something like this:

include X.Entity // a cross reference
package X2 {
    entity SomeEntity {
        new Entity() // I don't want to have both include and import
    }
}

In that case, is it possible to use that cross reference to make the inferred type known?
I tried inserting an empty method returning the included type just to insert the Java import in the inferred class but it sill requires the import in the model.

Report message to a moderator

Re: Unexpected behavior on linkage between Xtext resource and inferred JVM type [message #1771343 is a reply to message #1771341]

Thu, 24 August 2017 08:37

Christian Dietrich

Messages: 14285
Registered: July 2009

Senior Member

Have a look at the ximportsection*scopeprovider class

Need professional support for Xtext, Xpand, EMF?
Go to: https://www.itemis.com/en/it-services/methods-and-tools/xtext
Twitter : @chrdietrich
Blog : https://www.dietrich-it.de

Report message to a moderator

Re: Unexpected behavior on linkage between Xtext resource and inferred JVM type [message #1771411 is a reply to message #1771343]

Thu, 24 August 2017 19:41

Miguel Jimenez

Messages: 40
Registered: July 2015

Member

Thank you Christian.
I'm posting the solution in case it's useful to anyone:

MyDsl.xtext

grammar org.xtext.example.mydsl.MyDsl with org.eclipse.xtext.xbase.Xbase

generate myDsl "http://www.xtext.org/example/mydsl/MyDsl"

DomainModel:
	extensions=ExtensionSection?
	importSection=XImportSection?
	elements+=AbstractElement*;

ExtensionSection:
	declarations+=IncludeDeclaration+;

IncludeDeclaration:
	'includes' entity=[Entity|QualifiedName];

AbstractElement:
	PackageDeclaration | Entity;

PackageDeclaration:
	'package' name=QualifiedName '{'
	elements+=AbstractElement*
	'}';

Entity:
	'entity' name=ValidID body=XBlockExpression;

MyDslJvmModelInferrer.xtend

package org.xtext.example.mydsl.jvmmodel

import com.google.common.collect.Lists
import com.google.inject.Inject
import org.eclipse.xtext.naming.IQualifiedNameProvider
import org.eclipse.xtext.xbase.jvmmodel.AbstractModelInferrer
import org.eclipse.xtext.xbase.jvmmodel.IJvmDeclaredTypeAcceptor
import org.eclipse.xtext.xbase.jvmmodel.JvmTypesBuilder
import org.xtext.example.mydsl.myDsl.DomainModel
import org.xtext.example.mydsl.myDsl.Entity
import org.xtext.example.mydsl.myDsl.PackageDeclaration

class MyDslJvmModelInferrer extends AbstractModelInferrer {

	@Inject extension JvmTypesBuilder
	@Inject extension IQualifiedNameProvider

	def dispatch infer(DomainModel model,
		extension IJvmDeclaredTypeAcceptor acceptor, boolean prelinkingPhase) {
		if (prelinkingPhase)
			return
		val entities = model.elements.filter(Entity) + model.elements.filter(PackageDeclaration).entities
		entities.forEach[entity|
			accept(entity.toClass(entity.fullyQualifiedName)) [
				documentation = entity.documentation
				members += entity.toMethod("body", typeRef(void)) [
					body = entity.body
				]
			]
		]
	}

	def Iterable<Entity> entities(Iterable<PackageDeclaration> packages) {
		val entities = Lists.newArrayList
		packages.forEach[^package|
			entities.addAll(^package.elements.filter(Entity))
			entities.addAll(^package.elements.filter(PackageDeclaration).entities)
		]
		entities
	}
}

MyDslImportSectionNamespaceScopeProvider.xtend

package org.xtext.example.mydsl.scoping

import com.google.common.collect.Lists
import com.google.inject.Inject
import java.util.Collections
import java.util.List
import org.eclipse.emf.ecore.EObject
import org.eclipse.xtext.naming.IQualifiedNameProvider
import org.eclipse.xtext.scoping.impl.ImportNormalizer
import org.eclipse.xtext.xbase.XConstructorCall
import org.eclipse.xtext.xbase.scoping.XImportSectionNamespaceScopeProvider
import org.xtext.example.mydsl.myDsl.DomainModel
import org.xtext.example.mydsl.myDsl.ExtensionSection

// With a little help from https://stackoverflow.com/a/28027025/738968
class MyDslImportSectionNamespaceScopeProvider extends XImportSectionNamespaceScopeProvider {

	@Inject extension IQualifiedNameProvider

	override List<ImportNormalizer> internalGetImportedNamespaceResolvers(EObject context, boolean ignoreCase) {
		switch(context) {
			XConstructorCall: {
				val container = context.model as DomainModel
				if (container.extensions != null)
					container.extensions.provideImportNormalizerList(ignoreCase)
				else
					Collections.emptyList
			}
			default:
				super.internalGetImportedNamespaceResolvers(context, ignoreCase)
		}
	}

	/*
	 * Iterates upwards through the AST until a DomainModel is found.
	 */
	def EObject model(EObject o) {
        switch (o) {
            DomainModel: o
            default: o.eContainer.model
        }
    }

	/*
	 * Creates the list of all imports of an ExtensionSection. This implementation is similar to 
	 * getImportedNamespaceResolvers(XImportSection, boolean)
	 */
	def List<ImportNormalizer> provideImportNormalizerList(ExtensionSection extensionSection, boolean ignoreCase) {
        val List<ImportNormalizer> result = Lists.newArrayList
        extensionSection.declarations.forEach[includeDecl|
        	result.add(
        		includeDecl.entity
        			.fullyQualifiedName
        			.toString
        			.createImportedNamespaceResolver(ignoreCase)
        	)
        ]
        result
    }

}

MyDslRuntimeModule.xtend

package org.xtext.example.mydsl

import com.google.inject.Binder
import com.google.inject.name.Names
import org.eclipse.xtext.scoping.IScopeProvider
import org.eclipse.xtext.scoping.impl.AbstractDeclarativeScopeProvider
import org.xtext.example.mydsl.scoping.MyDslImportSectionNamespaceScopeProvider

class MyDslRuntimeModule extends AbstractMyDslRuntimeModule {

	override void configureIScopeProviderDelegate(Binder binder) {
		binder.bind(IScopeProvider)
			.annotatedWith(Names.named(AbstractDeclarativeScopeProvider.NAMED_DELEGATE))
			.to(MyDslImportSectionNamespaceScopeProvider);
	}

}

And the example code:
test.mydsl

includes foo.Computer

package hello {
	entity Laptop {
		println(new Computer)
	}
}

test2.mydsl

package foo {
	entity Computer {
		
	}
}

Report message to a moderator

Previous Topic:	Reference ecore model from other ecore model?
Next Topic:	"Xtext validation" task causing Eclipse to collapse

Goto Forum:

-=] Back to Top [=-

[ Syndicate this forum (XML) ] [

]

Current Time: Sat Jul 02 16:50:42 GMT 2022

.:: Contact :: Home ::.

Breadcrumbs

Sign up to our Newsletter