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multiple decisions warning [message #1692662]

Fri, 17 April 2015 05:39

Eclipse User

Hello,

I have two languages : Geez and Amharic
Geez is a superset of Amharic.

How can I have a rule entry for both languages in my xText grammar , which is shown below. Of course, the "Amharic" rule should be consumed in "Geez" rule. The compilation is showing me warnings. I fail to see where/why there is multiple decisions in the parsing!! (I am just strating to learn xText Rolling Eyes

)

The grammar

Language:
Geez | Amharic
;
Geez:
geez = STRING amharic = Amharic
;
Amharic:
amharic = STRING
;

The warnings:
warning(200): ../org.xtext.example.mydsl/src-gen/org/xtext/example/mydsl/parser/antlr/internal/InternalMyDsl.g:119:1: Decision can match input such as "RULE_STRING RULE_STRING" using multiple alternatives: 1, 2
As a result, alternative(s) 2 were disabled for that input
warning(200): ../org.xtext.example.mydsl.ui/src-gen/org/xtext/example/mydsl/ui/contentassist/antlr/internal/InternalMyDsl.g:176:1: Decision can match input such as "RULE_STRING RULE_STRING" using multiple alternatives: 1, 2
As a result, alternative(s) 2 were disabled for that input

Thank you.
Regards,
Nas

Re: multiple decisions warning [message #1692666 is a reply to message #1692662]

Fri, 17 April 2015 05:45

Eclipse User

Please share a complete grammar

I guess you have multiple langues elements. That makes the grammar ambigous

Re: multiple decisions warning [message #1692720 is a reply to message #1692666]

Fri, 17 April 2015 09:00

Eclipse User

Thank you Christian!

grammar org.xtext.example.langdsl.LangDsl with org.eclipse.xtext.common.Terminals

generate langDsl "http://www.xtext.org/example/langdsl/LangDsl"

LanguagesModel:
languages+=Language*;

Language:
Geez | Amharic
;

Geez:
geez = STRING amharic = Amharic
;

Amharic:
amharic = STRING
;

Regards,
Nas

Re: multiple decisions warning [message #1692721 is a reply to message #1692720]

Fri, 17 April 2015 09:02

Eclipse User

Hi yes this ambigoes.

The model "a" "b" shall this be two amharic or one geez

Re: multiple decisions warning [message #1692728 is a reply to message #1692721]

Fri, 17 April 2015 09:12

Eclipse User

I didn't get what you meant ..."a" "b"...
I should be able to delegate "Amharic" rule from "Geez"

Cheers,
Nas

Re: multiple decisions warning [message #1692731 is a reply to message #1692728]

Fri, 17 April 2015 09:18

Eclipse User

Hi,

what i want to say

consider you have the following input model

"a" "b"

This can result in two possible models

LanguagesModel [languages=[Amharic(amharic="a"),Amharic(amharic="b")]]

or

LanguagesModel [languages=[Geez(geez="a",amharic=Amharic(amharic="b"))]]

=> in One case you have one language, in the other two

[Updated on: Fri, 17 April 2015 09:24] by Moderator

Re: multiple decisions warning [message #1692737 is a reply to message #1692731]

Fri, 17 April 2015 09:32

Eclipse User

Got it!!! Tnx a lot.
Solved, of course, with minor mark at the end of the assignment, that makes the parsing unique (unambiguous).

Cheers,
Nas

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