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multiple decisions warning [message #1692662]

Fri, 17 April 2015 09:39

naseclipse naseclipse

Messages: 14
Registered: April 2015

Junior Member

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

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

Fri, 17 April 2015 09:45

Christian Dietrich

Messages: 13882
Registered: July 2009

Senior Member

Please share a complete grammar

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

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

Fri, 17 April 2015 13:00

naseclipse naseclipse

Messages: 14
Registered: April 2015

Junior Member

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

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

Fri, 17 April 2015 13:02

Christian Dietrich

Messages: 13882
Registered: July 2009

Senior Member

Hi yes this ambigoes.

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

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

Fri, 17 April 2015 13:12

naseclipse naseclipse

Messages: 14
Registered: April 2015

Junior Member

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

Cheers,
Nas

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

Fri, 17 April 2015 13:18

Christian Dietrich

Messages: 13882
Registered: July 2009

Senior Member

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

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[Updated on: Fri, 17 April 2015 13:24]

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