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How to find the closest reference? [message #707916]

Tue, 02 August 2011 08:09

alex.ren2006

Messages: 46
Registered: June 2011

Member

Hi all, I am currently working on building an IDE for ATS (www.ats-lang.org). In ATS, the same name can be used for many times. For clarity of the problem, the sample grammar goes as follows:
=================================

grammar org.xtext.example.mydsl.MyDsl with org.eclipse.xtext.common.Terminals

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

Model:
	greetings+=Greeting*;
	
Greeting:
	name=ID '=' INT
	| name=ID '=' mcontent=[Greeting | ID]
	;

=================================
I also commented out the
=================================

composedCheck = "org.eclipse.xtext.validation.NamesAreUniqueValidator"

=================================
in the mwe2 file.

The corresponding source code would be like this
=================================

x = 3
x = 4
y = 4
z = x

=================================
When I Ctrl-Click on "z", it refers to the first "x", which is not what I want. Is it possible to make it jump to the second "x" which is the closest one to "z". Or is it possible to show another dialogue so that the programmer can choose? Either way is fine, any suggestion about how to do this based on Xtext is highly appreciated. Thanks a lot.

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Re: How to find the closest reference? [message #708110 is a reply to message #707916]

Tue, 02 August 2011 13:31

Alexander Nittka

Messages: 1193
Registered: July 2009

Senior Member

Hi,

as far as I know there is no hook for "linking based on user choice". The linker will grab the first object of the scope that fits the name. So what you need to do is adapt the local scope provider, creating the scope yourself.
There you have two choices: either you make sure that each name appears only once, or the closer definition is found first. For calculating the distance, navigate to the node model and extract the offset of the parser node. You will find Node(Model)Utils helpful.

Alex

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Re: How to find the closest reference? [message #708514 is a reply to message #708110]

Tue, 02 August 2011 22:28

alex.ren2006

Messages: 46
Registered: June 2011

Member

Thank you very much for your advice. I am now reading the ImportedNamespaceAwareLocalSpaceProvider. I think the easy way is to imitate it and then write my own CustomImportedNamespaceAwareLocalSpaceProvider. I am still a newbie to Xtext. Please correct if I am wrong. In the function
============================

protected IScope getLocalElementsScope(IScope parent, final EObject context,
			final EReference reference) {

=============================
I see the code
=============================

ISelectable allDescriptions = getAllDescriptions(context.eResource());

=============================
Does this "allDescriptions" contain all the nodes to create the scope?

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