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Terminal [message #1138802]

Tue, 15 October 2013 10:38

Vishal seth

Messages: 32
Registered: April 2010

Member

Hi,

While creating a rule, I am facing issue related to overlapping of terminals. In grammar below I am trying to input Reference one1.111GGG.two.three but it fails as the terminal conflicts with whole number terminal being a '.' in between.

It can however be resolved by either creating the Greeting name as a terminal rule or by changing NUM & TOKEN_STARTING_WITH_NUMBER to a non terminal rule. But converting from non terminal rule to a data type rule would have performance impact.

What should be the ideal ways to handle such use cases?

Model:
'Reference' hello=GreetingName
;

GreetingName:
ID '.' TOKEN_STARTING_WITH_NUMBER '.' ID '.' ID;

terminal ID:
'^'? ('a'..'z' | 'A'..'Z' | '_') ('a'..'z' | 'A'..'Z' | '_' | '0'..'9' | '-' | '+')*;

terminal NUM:
('0'..'9')* ('.' ('0'..'9')+)?
;

terminal TOKEN_STARTING_WITH_NUMBER:
('0'..'9')* ID;

terminal INT returns ecore::EInt:
"not to be used";

Attaching xtext file for various scenarios along with junit test case.

Regards
Vishal

Attachment: TestModelErrors.java
(Size: 0.53KB, Downloaded 112 times)
Attachment: MyDsl_datatyperule_working.xtext
(Size: 0.56KB, Downloaded 66 times)
Attachment: MyDsl_nonterminalrule_notworking.xtext
(Size: 0.55KB, Downloaded 67 times)
Attachment: MyDsl_terminal_working.xtext
(Size: 0.56KB, Downloaded 67 times)

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Re: Terminal [message #1139065 is a reply to message #1138802]

Tue, 15 October 2013 14:06

Christian Dietrich

Messages: 13661
Registered: July 2009

Senior Member

Hi,

why dont you use a datatype rule aka

TOKEN_STARTING_WITH_NUMBER:
INT? ID;

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Re: Terminal [message #1139928 is a reply to message #1139065]

Wed, 16 October 2013 03:29

Vishal seth

Messages: 32
Registered: April 2010

Member

Hi,

That's what I have done in MyDsl_datatyperule_working.xtext. My concerns for this is having a performance impact & secondly there are some other number related terminal rules, which again I have to convert into a datatype rule.

Just wanted to know what should have been the better way of handling such cases, i.e. one mentioned in MyDsl_terminal_working.xtext/ MyDsl_datatyperule_working.xtext or any other better way.

Regards
Vishal

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Re: Terminal [message #1140040 is a reply to message #1139928]

Wed, 16 October 2013 05:12

Christian Dietrich

Messages: 13661
Registered: July 2009

Senior Member

It is the property way to do (besides avoiding the use case)

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