Eclipse Community Forums: TMF (Xtext) » Disambiguate between reference and ValidID

Help

Home

Home » Modeling » TMF (Xtext) » Disambiguate between reference and ValidID

Show: Today's Messages :: Show Polls :: Message Navigator

Disambiguate between reference and ValidID [message #1731570]

Fri, 06 May 2016 22:05

Larry LeBron

Messages: 124
Registered: October 2015

Senior Member

I have a point in my grammar where I would like to handle either a ValidID or a cross-reference.

However, this creates an ambiguity, as the cross-reference also relies on the RULE_ID.

Is there a good solution to this, other than inserting some kind of special token?

Here's a simple example grammar to illustrate:

Declaration:
   name=ID
;

Reference:
   IDReference | DeclarationReference
;

IDReference:
   idRef = ValidID ';'
;

DeclarationReference:
   declRef = [Declaration] ';'
;

I could just use the ValidID rule, and then internally check if such an ID matches a known declaration. If that's the best option, can do, though it'll mean losing the inherent benefits of the cross-reference system.

Report message to a moderator

Re: Disambiguate between reference and ValidID [message #1731577 is a reply to message #1731570]

Sat, 07 May 2016 05:03

Christian Dietrich

Messages: 13193
Registered: July 2009

Senior Member

In case you dont know it. [Type] is Short for [Type|ID] so an ID will be used. Of Course you can change this to whatever you like e.g [Type|YourID] with YourID being a Terminal Or a datatype rule

Need professional support for Xtext, Xpand, EMF?
Go to: https://www.itemis.com/en/xtext/
Twitter : @chrdietrich
Blog : https://www.dietrich-it.de

Report message to a moderator