Eclipse Community Forums: TMF (Xtext) » XText cross-reference to rule containing a cross-reference

Home » Modeling » TMF (Xtext) » XText cross-reference to rule containing a cross-reference

XText cross-reference to rule containing a cross-reference [message #1377158]

Fri, 23 May 2014 15:09

Eclipse User

The following is a simple representation of an xtext grammar with cross references.

There are two entities - a container and an object - and operations on each. I would like to be able to refer to an object either by it's own name, or qualified with the container name. I would like cross-references to be available in either case.

The grammar I have is:

Model:
    operations+=Operation*;

ContainerEntity:
    name=ID;

ObjectEntity:
    (first=[ContainerEntity] '.')? name=ID
;

Operation:
    CreateContainer | CreateObject | ContainerOp | ObjectOp
;

CreateContainer:
    'Container' container=ContainerEntity ';'
;

CreateObject:
    'Object' object=ObjectEntity ';'
;

ContainerOp:
    'ContainerOp' name=[ContainerEntity] ';'
;

ObjectOp:
    'ObjectOp' name=[ObjectEntity] ';'
;

And the editor statements are:

// Define a container and object
Container c;
Object o;

// Can define an object using container name qualifier
Object c.o2;

// Operations
ContainerOp c;
ObjectOp o;

// Cannot use object operation with container name 
ObjectOp c.o;            // ERROR: Couldn't resolve reference to ObjectEntity 'c'.

Note that it does not recognize "c" as a ContainerEntity. What can I do to make this work the way I described?

Re: XText cross-reference to rule containing a cross-reference [message #1379258 is a reply to message #1377158]

Sat, 24 May 2014 12:33

Eclipse User

Hi you have to come up with a own Customization of
DefaultDeclarativeQualifiedNameProvider and leverage NodeModelUtils
findnodesforfeature to read the cross references texr

Re: XText cross-reference to rule containing a cross-reference [message #1383995 is a reply to message #1379258]

Tue, 27 May 2014 14:11

Eclipse User

Thanks for that tip Christian.

I have since noticed that hovering on the red 'X' in the left side rather than the red underlined "c", give me this message:

Quote:

Multiple markers at this line
- Couldn't resolve reference to ObjectEntity 'c'.
- mismatched input '.' expecting ';'

I'm a little concerned the 'mismatched input' message may indicate a problem in the grammar?

I've added the following to my MyDslQualifiedNameProvider

	QualifiedName qualifiedName(ObjectEntity obj) {
		List<String> names = new ArrayList<String>();

		final EClass eClass = obj.eClass();
		final EStructuralFeature result = eClass.getEStructuralFeature("first");
		List<INode> nodes = NodeModelUtils.findNodesForFeature(obj, result);
		for (INode n : nodes) {
			System.out.println(n.getText());
                        // TODO: add ContainerEntity name to qualified name ??
		}

		names.add(obj.getName());

		QualifiedName qn = QualifiedName.create(names);
		System.out.println("QN= " + qn);
		return qn;
	}

But 'findNodesForFeature' just returns an empty list for the line 'ObjectOp c.o'. Could it be because of the 'mismatched input' message?

When called for ObjectEntity 'o2' from the line 'Object c.o2;', then 'findNodesForFeature' does return a node and node.getText() is 'c' from the ContainerEntity as expected.

So I'm still having a problem with 'ObjectOp c.o;' and getting the ContainerEntity.

[Updated on: Tue, 27 May 2014 14:23] by Moderator

Re: XText cross-reference to rule containing a cross-reference [message #1383998 is a reply to message #1383995]

Tue, 27 May 2014 14:34

Eclipse User

Hi,

i dont understand your impl. here is basically what i intended you to do

ObjectOp:
    'ObjectOp' name=[ObjectEntity|FQN] ';'
;

FQN: ID ("." ID)*;

a second problem is that xx=[YY] is short for xx=[YY|ID] which means reference an YY and parse an ID. an ID does not allow a .

=>

ObjectOp:
    'ObjectOp' name=[ObjectEntity|FQN] ';'
;

FQN: ID ("." ID)*;

then i do not understand your example model: c.o the both are not related to each other.

Re: XText cross-reference to rule containing a cross-reference [message #1384014 is a reply to message #1383998]

Tue, 27 May 2014 16:07

Eclipse User

Hi Christian,

Both code blocks in your last reply have identical content - was that supposed to be the case or did you mean to have something else in the first block?

You mentioned customizing DefaultDeclarativeQualifiedNameProvider and that's what I tried to do in MyDslQualifiedNameProvider.qualifiedName() using the NodeModelUtils.findNodesForFeature as suggested.

I don't quite follow the suggestion about FQN. If I use an FQN in the cross reference, e.g. name=[ObjectEntity|FQN], then I guess that the ObjectEntity name will contain both the ContainerEntity name and the ObjectEntity name, e.g "c.o". Then I need a way to pull this apart so that the "c" becomes a ContainerEntity name and the "o" becomes the ObjectEntity name? How would I do that?

Thanks again,

dan

Re: XText cross-reference to rule containing a cross-reference [message #1384015 is a reply to message #1384014]

Tue, 27 May 2014 16:10

Eclipse User

hmmm i was missing that one

public class MyDslQualifiedNameProvider extends
		DefaultDeclarativeQualifiedNameProvider {
	
	QualifiedName qualifiedName(ObjectEntity obj) {
		List<INode> nodes = NodeModelUtils.findNodesForFeature(obj, MyDslPackage.Literals.OBJECT_ENTITY__FIRST);
		if (nodes.size()>0) {
			return QualifiedName.create(nodes.get(0).getText().trim(), obj.getName());
		}
		return null;
	}


}

then the container should become the parent of the child and the childs name should be parentname.childname

Re: XText cross-reference to rule containing a cross-reference [message #1384017 is a reply to message #1384015]

Tue, 27 May 2014 16:13

Eclipse User

CreateContainer:
    'Container' container=ContainerEntity ';' children+= CreateObject*
;

Previous Topic:	Saving/Loading to/from BinaryResourceImpl
Next Topic:	Customization of NamesAreUniqueValidator

Goto Forum:

-=] Back to Top [=-

Current Time: Wed Jul 23 06:38:04 EDT 2025

.:: Contact :: Home ::.

Breadcrumbs

Sign up to our Newsletter