How to generate Java code for Xbase XExpression using JvmModelInferrer?

Question

I am trying to do the simplest example I can think of to use Xbase and the JvmModelInferrer, rather than writing a code generator. I've cut down the JVM language tutorial but I can't get correct Java code from an XExpression (or XBlockExpression). I've looked at answers like :-

How to JvmModelInferrer method body from XExpression and append boilerplate code

The specific error I am getting currently is that for an expression like 2+2, the code I generate is :-

return 2./* name is null */;

My grammar is :-

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

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

Model:
    functions+=Function*
;

Function:
    'function' name=ID 'body' exp=XBlockExpression
;

and my JvmModelInferrer is :-

    def dispatch void infer(Model element, IJvmDeclaredTypeAcceptor acceptor, boolean isPreIndexingPhase) {
        acceptor.accept(element.toClass("my.company.Functions")) [
            for (function : element.functions) {
                members += function.toMethod(function.name, typeRef(Object)) [
                    body = function.exp
                ]
            }
        ]
    }

For input :-

function TwoPlusTwo body {2+2}

The generated code is :-

package my.company;

public class Functions {
  public java.lang.Object TwoPlusTwo() {
    return 2./* name is null */;
  }
}

Am I making some completely basic error or have some fundamental misunderstanding ?

I'm using Windows 10, Eclipse 2019-12, Xtext 2.20.0, Coretto JVM

Any help would be appreciated.

are you sure your model project is a java project and has xbase.lib on classpath — Christian Dietrich, Mar 09 '20 at 09:24
That was it ! I had forgotten to add Xtend library to the build path. — guraaku, Mar 09 '20 at 12:25

score 0 · Accepted Answer · answered Mar 09 '20 at 12:31

As suggested by Christian, it needs to have the correct libraries added to the project. The Five Steps to Your JVM Language tutorial says this, I had just forgotten to do it :-

In the new workbench, create a Java project (File → New → Project… → Java Project). Xbase relies on a small runtime library on the class path. To add this, right-click on the project and go to Java Build Path → Libraries → Add Library and choose Xtend Library.

How to generate Java code for Xbase XExpression using JvmModelInferrer?

1 Answers1