Xtext: Use EClass in XExpression

debugcn Published at Dev

user2444765

I am writing on a Xtext grammar that uses XExpressions and also operates on Eclasses. Now I want to also be able to access Eclasses from the XExpression, for example I write an expression like this:

Eclass1.attribute1 = Eclass2.attribute1

I would like to know, how I can use the Eclass from within the XExpression?

Grammar

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

import "http://www.eclipse.org/emf/2002/Ecore" as ecore

generate mydsl "http://www.xtext.org/example/mydsl/Mydsl"

Model:
(operations += Operation)*;

terminal ATTR : ID ('.' ID)+;

Operation:
'operation' left=[ecore::EClass|ATTR] 'and' right=
 [ecore::EClass|ATTR] 'defined' 'as' condition=XExpression
;

Inferrer/ Infer method

def dispatch void infer(Model element, IJvmDeclaredTypeAcceptor acceptor, boolean isPreIndexingPhase) {
      acceptor.accept(element.toClass("example.mydsl")) [
        for (operation : element.operations) {
            left = operation.left
            right = operation.right
            if (left.eIsProxy()) {
                left = EcoreUtil.resolve(left, operation) as EClass
            }   
            if (right.eIsProxy()) {
                right = EcoreUtil.resolve(right, operation) as EClass
            }
            //field for right class left out, but works the same
            members += left.toField(left.name,typeRef(left.EPackage.name+"."+left.name))    
            members += operation.toMethod("conditionExpr", 
            typeRef(Void.TYPE)) [
                body = operation.condition
            ]       
        }
    ]

}

RuntimeModule

    class MyDslRuntimeModule extends AbstractMyDslRuntimeModule {

       def Class<? extends ImplicitlyImportedFeatures> bindImplicitlyImportedTypes() {
       return MyImportFeature
}

}

MyImportFeature

class MyImportFeature extends ImplicitlyImportedFeatures{
override protected getStaticImportClasses() {
    (super.getStaticImportClasses() + #[PackageFromWorkSpace]).toList
}

}

Christian Dietrich

I Am not sure if i get your question. Ususally EMF generates constants for EAttributes so if you want to access the attributes themselfs so you could either do MyDslPackage.Literals.GREETING__NAME or MyDslPackage.eINSTANCE.getGreeting_Name()

can you give some more hints on what you actually want to do

update: here is a snippet on how to get a java class from a reference to an eclass

Thingy:{
    val EClass eclazz = f.clazz
    val uri = EcorePlugin.getEPackageNsURIToGenModelLocationMap(true).get(eclazz.EPackage.nsURI)
    val rs = new ResourceSetImpl
    val r = rs.getResource(uri, true)
    r.load(null)
    val p = r.contents.head
    if (p instanceof GenModel) {
        val genClass = p.findGenClassifier(eclazz)
        if (genClass instanceof GenClass) {
            println(genClass.qualifiedInterfaceName)
            members+=f.toField(eclazz.name, genClass.qualifiedInterfaceName.typeRef)
        }
    }
}

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