Question

I'm using Xtext with XBase grammar.
In every generated java class I need to initialize class variable in my model inferer. This variable isn't defined in my model, but that makes no difference.
I already can generate this variable via function

element.toField("isSomethingSet", newTypeRef("boolean"))

, but I can't initialize it. I'm sure I should use toField function with additional parameter called initializer, but as this is of type Procedure1 I don't know how to use it.

Here is my slightly changed example taken from Xtext documentation. Grammar:

grammar org.xtext.example.mydsl.MyDsl with org.eclipse.xtext.xbase.Xbase
generate myDsl "http://www.xtext.org/example/mydsl/MyDsl"
Domainmodel:
  (elements += AbstractElement)*; 
AbstractElement:
   Entity;
Entity:
  'entity' name = ID ('extends' superType = JvmTypeReference)?
  '{'
    (features += Feature)*
  '}';
Feature:
  name = ID ':' type = JvmTypeReference;

ModelInferrer.xtend

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 void infer(Entity element, IJvmDeclaredTypeAcceptor acceptor,
        boolean isPrelinkingPhase) {
        acceptor.accept(element.toClass(element.fullyQualifiedName)).initializeLater     [
            documentation = element.documentation
            members += element.toField("isSomethingSet", newTypeRef("boolean"))
            for (feature : element.features) {
                members += feature.toField(feature.name, feature.type)
                members += feature.toSetter(feature.name, feature.type)
                members += feature.toGetter(feature.name, feature.type)
            }
        ]
    }
}
Was it helpful?

Solution

The procedure encapsulates the code that is required to configure the field, e.g. set the visibility, static flags, documentation or the field initializer:

element.toField("isSomethingSet", newTypeRef("boolean")) [
  initializer = '''false''' // with Xtext 2.5 or
  initializer = [ append('false') ] // prior to 2.5
]
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