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cross references and the next rule without keyword [message #1012999]

Fri, 22 February 2013 15:37

Fy Za

Messages: 245
Registered: March 2010

Senior Member

Dear All,
In My grammar,
I have these rules

Transition:
	('from' initial+=InitialState)* 
         action=StatementSequence	
;

InitialState:
	origin=[StateDeclaration] (read ?= '?')?
;
StatementSequence returns Statement:
	Statement ({StatementSequence.statements+=current} ';' statements+=Statement)*
;

Statement:
        
	NullStatement //start with 'null'
	| ToStatement //start with 'to'
	| PatternStatement

So, I have a problem when the First statement is a PatternStatement because it doesn't start with a keywork
for example:
Example 1

from a b c 
to x

No problem

Example 2

from a b c 
null

No problem

but
Example 3

from a b c 
x := y

here, there is a problem. the x variable is considered as a [StateDeclaration]
the error is Couldn't resolve reference to StateDeclaration 'x'.

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Re: cross references and the next rule without keyword [message #1013007 is a reply to message #1012999]

Fri, 22 February 2013 15:48

Christian Dietrich

Messages: 14665
Registered: July 2009

Senior Member

How does PatternStatement look like?

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

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Re: cross references and the next rule without keyword [message #1013010 is a reply to message #1013007]

Fri, 22 February 2013 15:50

Fy Za

Messages: 245
Registered: March 2010

Senior Member

It looks to
var=[Variable] ':=' exp=Expression

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Re: cross references and the next rule without keyword [message #1013016 is a reply to message #1013010]

Fri, 22 February 2013 16:05

Christian Dietrich

Messages: 14665
Registered: July 2009

Senior Member

Hmmm,

i do not really get your problem
(besides this little typo???)

Transition:
	'from'( initial+=InitialState)* 
         action=StatementSequence	
;

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

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Re: cross references and the next rule without keyword [message #1013019 is a reply to message #1013016]

Fri, 22 February 2013 16:09

Fy Za

Messages: 245
Registered: March 2010

Senior Member

Ohhh
I am Sorry.
This is the transition rule

Transition:
	'from'( initial+=InitialState)* 
         action=StatementSequence	
;

but with this also, I have the same problem

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Re: cross references and the next rule without keyword [message #1013024 is a reply to message #1013019]

Fri, 22 February 2013 16:13

Christian Dietrich

Messages: 14665
Registered: July 2009

Senior Member

then there must be something else in your grammar here is my test


Model:
	states+=StateDeclaration*
	vars+=Variable*
	trans+=Transition
;

StateDeclaration:
	"state" name=ID
;

Variable:
	"var" name=ID
;

Transition:
	'from'( initial+=InitialState)* 
         action=StatementSequence	
;

InitialState:
	origin=[StateDeclaration] (read ?= '?')?
;
StatementSequence returns Statement:
	Statement ({StatementSequence.statements+=current} ';' statements+=Statement)*
;

Statement:
        
	NullStatement //start with 'null'
	| ToStatement //start with 'to'
	| PatternStatement ;
	
	NullStatement:
		{NullStatement}'null'
	;
	
	ToStatement:
	{ToStatement}	'to'
	;
	PatternStatement:
		var=[Variable] ':=' exp=ID
	;

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

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