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Rule written for DSL in xtext, It is not working as expected [message #1300171]

Thu, 17 April 2014 11:31

Kapil Sharma

Messages: 5
Registered: April 2014

Junior Member

I am trying -->> VL:'this is test dsl in xtext' IS ABC

TestLabelBase returns ResultExpressionRhs: 'VL:' path=stringRule;

The Rule I tried was: TestLabel returns ResultExpressionRhs: TestLabelBase ('IS' modifier=alphabateModifier)?;

alphabateModifier: (abc?='ABC' | def?='DEF' | ghi?='GHI');

It would recognize the 'IS' but not the 'ABC'.

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Re: Rule written for DSL in xtext, It is not working as expected [message #1300369 is a reply to message #1300171]

Thu, 17 April 2014 14:21

Christian Dietrich

Messages: 14664
Registered: July 2009

Senior Member

Hi,

can you please share a complete reproducable example

btw your grammar looks very complictated

Stuff:
'VL'':' label=STRING 'IS' (abc?='ABC' | def?='DEF' | ghi?='GHI');

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

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Re: Rule written for DSL in xtext, It is not working as expected [message #1300605 is a reply to message #1300369]

Thu, 17 April 2014 17:53

Kapil Sharma

Messages: 5
Registered: April 2014

Junior Member

Hi,

Thanks for your interest.

xtext rule:

TestLabelBase returns ResultExpressionRhs: 'VL:' path=stringRule;

TestLabel returns ResultExpressionRhs: TestLabelBase ('IS' modifier=alphabateModifier)?;

alphabateModifier: (abc?='ABC' | def?='DEF' | ghi?='GHI');

DSL Sample:

VL:'this is test dsl in xtext' IS ABC

Problem is :

When I want to use ABC in dsl file at the end of statement , it does not allow it.

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Re: Rule written for DSL in xtext, It is not working as expected [message #1300616 is a reply to message #1300605]

Thu, 17 April 2014 18:01

Christian Dietrich

Messages: 14664
Registered: July 2009

Senior Member

Hi, still cannot reproduce this,
please share a complete reproducable example

e.g.: what is the start (first) rule of your grammar.
if it is TestLabelBase this is your mistake

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

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Re: Rule written for DSL in xtext, It is not working as expected [message #1300639 is a reply to message #1300616]

Thu, 17 April 2014 18:21

Kapil Sharma

Messages: 5
Registered: April 2014

Junior Member

I used following import "http://www.eclipse.org/emf/2002/Ecore" as ecore in xtext.

Below is my xtext file I am using:

DSLDEMO:
(messgae+=Message)*;

Message:
element+=ResultExpression+
;

Product:
'ProductName:' name=OptEscapeString '[' group=OptQuoteString ']'
;

ResultExpression:
Product rhs=ResultExpressionRhs;

ResultExpressionRhs returns ResultExpressionRhs:
(Product | TestLabel | StringLiteral);

TestLabelBase returns ResultExpressionRhs:
'VL:' path=stringRule;

TestLabel returns ResultExpressionRhs:
TestLabelBase ('IS' modifier=alphabateModifier)?;

alphabateModifier:
(abc?='ABC' | def?='DEF' | ghi?='GHI');

StringLiteral returns ResultExpressionRhs:
value=OptEscapeString;

enum PaoParamOperator:
ASSIGN='=';

OptQuoteString:
(OptEscapeString | STRING_UNQUOTED);

OptEscapeString:
(STRING_NOESCAPE | STRING_ESCAPE);

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

terminal INT returns ecore::EInt:
'this one has been deactivated';

terminal STRING_UNQUOTED:
('a'..'z' | 'A'..'Z' | '0'..'9') ('a'..'z' | 'A'..'Z' | '0'..'9' | ' ' | '\\')+;

terminal STRING_NOESCAPE:
"'" (!("'"))* "'";

terminal STRING_ESCAPE:
'"' ('\\' ('b' | 't' | 'n' | 'f' | 'r' | 'u' | '"' | "'" | '\\') | !('\\' | '"'))* '"';

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Re: Rule written for DSL in xtext, It is not working as expected [message #1300640 is a reply to message #1300639]

Thu, 17 April 2014 18:23

Kapil Sharma

Messages: 5
Registered: April 2014

Junior Member

Hope now you will be able to understand.

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Re: Rule written for DSL in xtext, It is not working as expected [message #1300670 is a reply to message #1300639]

Thu, 17 April 2014 18:54

Christian Dietrich

Messages: 14664
Registered: July 2009

Senior Member

hi, this is still not complete . stringRule is missing.
and the info if you use terminals grammar or not.

then you have way to many terminals,
including critical ones like string unquoted.
it contains a ' ' (blank)

xtext works with lexer and parser,
the lexing is eager.

generating the grammar (asuming
TestLabelBase returns ResultExpressionRhs:
'VL:' path=STRING;)

gives a lot of ambiguity warnings

is this a existing language or a new one?

maybe you should start with an easier grammar
reusing the terminals defined in the terminal grammar

e.g:

NUMBER: INT? ('.' INT);
MY_STRING: STRING | (ID+);

stuff like 'this one has been deactivated'
is a bad idea (dont use blanks in strings)

--
Need training, onsite consulting or any other kind of help for Xtext?
Go visit http://xtext.itemis.com or send a mail to xtext at itemis dot de

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

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Re: Rule written for DSL in xtext, It is not working as expected [message #1301454 is a reply to message #1300670]

Fri, 18 April 2014 05:31

Kapil Sharma

Messages: 5
Registered: April 2014

Junior Member

Sorry my mistake stringRule must be replaced by OptEscapeString.

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Re: Rule written for DSL in xtext, It is not working as expected [message #1311169 is a reply to message #1300670]

Wed, 23 April 2014 16:42

$Ricardo \\\"CaWal\\\" Cacheta Waldemarin is currently offline$ Ricardo \\\"CaWal\\\" Cacheta Waldemarin

Messages: 29
Registered: January 2013

Junior Member

Christian Dietrich wrote on Thu, 17 April 2014 14:54

...
then you have way to many terminals,
including critical ones like string unquoted.
it contains a ' ' (blank)

(...)
xtext works with lexer and parser,
the lexing is eager.

generating the grammar (...) gives a lot of ambiguity warnings

is this a existing language or a new one?

maybe you should start with an easier grammar
reusing the terminals defined in the terminal grammar

(...)

stuff like 'this one has been deactivated'
is a bad idea (dont use blanks in strings)

Is possible to write a grammar that permits spaces in strings?

I have this problem: I need to write a grammar to load a OBO Flat File Format as an Ecore model. The OBOFFF has stanzas that are formatted as tag-value pairs that can be (or not) followed by modifiers (strings between brackets) and inline comments (string after an exclamation mark).

<tag>: <value> ['{'<modifier1>=<value1> ',' [<modifier2> '=' <value2>,...]'}'] ['!'<comment>]

The <value> part of the pair can be an ID (a unquoted string without whitespaces), a URI, a quoted string (whitespaces and escape characters allowed) or a unquoted string that should end at the end of the line or before the trailing modifiers/comment. Additionally, some values should use a combination of those strings, like:

subsetdef: GO_SLIM "GO SLIM"

I'd thought that I could write a rule to match it as

SubSetDefPair returns SubSetDefPair:
	tag='subsetdef:' WS_CHAR* subsetName=ID WS_CHAR description=QUOTED_STRING
;


terminal WS_CHAR :
	' ' | '\t' 
;
 
terminal ID  : '^'?('a'..'z'|'A'..'Z'|'_') ('a'..'z'|'A'..'Z'|'_'|'0'..'9')*;
terminal QUOTED_STRING	:
	// A String that starts and ends with double quotation marks 
	'"' ( '\

\' ('b'|'t'|'n'|'f'|'r'|'u'|'"'|"'"|'\\') | !('\\'|'"') )* '"'
;
terminal UNBOUNDED_STRING:
// a string that should end at the ending of the line or before a comment
('a'..'z'|'A'..'Z'|'_'|'0'..'9')
(('a'..'z'|'A'..'Z'|'_'|'0'..'9' | WS_CHAR)*
('a'..'z'|'A'..'Z'|'_'|'0'..'9'))?
;

[/code]

But it's not working.
I expected to match something like

subsetdef: asd "asdssd"

but it returns the following error:

Multiple markers at this line
- mismatched character '"' expecting set null
- mismatched character '<EOF>' expecting '"'

Does anyone have an idea of how I can address this issue?

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Re: Rule written for DSL in xtext, It is not working as expected [message #1311207 is a reply to message #1311169]

Wed, 23 April 2014 17:12

Christian Dietrich

Messages: 14664
Registered: July 2009

Senior Member

Hi,

just one thing: not every thing must be in the grammar. you can write semantic checks/validations in java/Xtend too

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

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Re: Rule written for DSL in xtext, It is not working as expected [message #1311267 is a reply to message #1311207]

Wed, 23 April 2014 18:00

$Ricardo \\\"CaWal\\\" Cacheta Waldemarin is currently offline$ Ricardo \\\"CaWal\\\" Cacheta Waldemarin

Messages: 29
Registered: January 2013

Junior Member

Humm... This is something I still don't understand quite well how to do (or when I should do). What's the recommended documentation (or some example) about it?

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