Eclipse Community Forums: TMF (Xtext) » Xtext returns statement

Help

Home

Home » Modeling » TMF (Xtext) » Xtext returns statement(Xtext returns statement)

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

Xtext returns statement [message #1732058]

Thu, 12 May 2016 10:28

RamaRao Nandamuri

Messages: 120
Registered: April 2016

Senior Member

Model: {Model} NL* statements+=Statement*;

If {Model} is not there then I am getting error like

The rule 'Model' may be consumed without object
instantiation. Add an action to ensure object creation, e.g.
'{Model}'.
Why it is can explain?

Statement returns Statement: If|Switch;

What is returns Statement do here?

Can anybody tell me?

Report message to a moderator

Re: Xtext returns statement [message #1732059 is a reply to message #1732058]

Thu, 12 May 2016 10:42

Christian Dietrich

Messages: 14665
Registered: July 2009

Senior Member

the returns statement tells which is the returntype. e.g. you could have 2 different rules returning the same return type.

with an unassigend action you can do two things

- force the creation of a subtype

e.g

Parent: {Subtype1} "st1" name=ID | {Subtype2} "st2" name=ID;

or force the creation of an eobject even if no attributes are assigned (xtext by default creates object only if the have at least one assignment

StringType: {StringType}"string";

in your case

Statement returns Statement: If|Switch;

the returns Statement is not necessary

Twitter : @chrdietrich
Blog : https://www.dietrich-it.de

Report message to a moderator