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Error in creating fragment for STRING [message #1799725]

Wed, 12 December 2018 22:09

Eclipse User

Hi,
I have the below code for a DSL that I'm building using Xtext in Eclipse (I'm converting a .g4 file to Xetxt: -

Domainmodel:
	elements+=projection_name elements+=projection_component elements+=layer_specification
	elements+=description
;

projection_name
   : keywords+=KEYWORD_projection model_name+=projection_name_model_name punctuations+=SEMICOLON
   ;

projection_name_model_name
   : identifiers+=identifier2
   ;


projection_component
   : keywords+=KEYWORD_component component_name+=projection_component_component_name punctuations+=SEMICOLON
   ;

projection_component_component_name
   : identifier+=identifier2
   ;


layer_specification
   : keywords+=KEYWORD_layer layer_name+=layer_specification_layer_name punctuations+=SEMICOLON
   ;

layer_specification_layer_name
   : identifier+=identifier2
   ;


description
   : keywords+=KEYWORD_description string+=STRING punctuations+=SEMICOLON
   ;

KEYWORD_component
   : ( key='component' )
 
   ;


KEYWORD_description
   : ( key='description' )
 
   ;

KEYWORD_layer
   : ( key='layer' )
 
   ;

KEYWORD_projection
   : ( key='projection' )
 
   ;


fragment STRING
   : '"' ( ('\\'|'"') | ('\\'|'"'))* '"'
 
   ;

SEMICOLON
   : symbol=';'
 
   ;


identifier2
   : IDENTIFIER
   ;

projectionmainidentifier
   : IDENTIFIER
   ;

offlineexpressionidentifier
   : IDENTIFIER
   | KEYWORD_description
   | KEYWORD_projection
   ;

IDENTIFIER
   : name=ID
 
   ;

Everything is fine except for the 'fragment STRING' definition. The word 'STRING' gets underlined in red and states "A datatype rule cannot override a terminal rule."

Could you please tell me how this should be corrected?
Regards.

[Updated on: Wed, 12 December 2018 22:30] by Moderator

Re: Error in creating fragment for STRING [message #1799728 is a reply to message #1799725]

Wed, 12 December 2018 23:04

Eclipse User

@Override 
terminal STRING
   : '"' ( ('\\'|'"') | ('\\'|'"'))* '"'
 
   ;

Re: Error in creating fragment for STRING [message #1799735 is a reply to message #1799728]

Thu, 13 December 2018 03:12

Eclipse User

Thank you Karsten. After implementing the syntax you suggested, the artifacts are generated without errors. But when I try to type the syntax 'description' in runtime, I get the error that I have attached with this reply.
Could you kindly help me overcome this error?

Attachment: STRINGERROR.png
(Size: 8.80KB, Downloaded 79 times)

Re: Error in creating fragment for STRING [message #1799738 is a reply to message #1799735]

Thu, 13 December 2018 03:17

Eclipse User

the fragment misses a NOT i think (have a look at the string rule in the superclass)
(i dont understand what your intention with that rule is)

[Updated on: Thu, 13 December 2018 03:19] by Moderator

Re: Error in creating fragment for STRING [message #1799740 is a reply to message #1799735]

Thu, 13 December 2018 03:24

Eclipse User

@Override 
terminal STRING
   : '"' ( '\\' . | !('\\'|'"') )* '"' 
   ;

Re: Error in creating fragment for STRING [message #1799744 is a reply to message #1799740]

Thu, 13 December 2018 03:58

Eclipse User

Thank you Karsten and Christian! It is working fine now.

Re: Error in creating fragment for STRING [message #1799745 is a reply to message #1799744]

Thu, 13 December 2018 04:00

Eclipse User

How can I find the definitions provided by Default in Xtext. e.g: the default definition given for STRING ?

Re: Error in creating fragment for STRING [message #1799746 is a reply to message #1799745]

Thu, 13 December 2018 04:03

Eclipse User

simply klick on the default terminal grammar name in the top

Re: Error in creating fragment for STRING [message #1799747 is a reply to message #1799746]

Thu, 13 December 2018 04:11

Eclipse User

I tried this. But when I click on 'terminal STRING', what I get is:

TerminalRule STRING

ALERT_LINE_COMMENT : ( '//!' ('\r'|'\n')* ) ; QUESTION_LINE_COMMENT : ( '//?' ('\r'|'\n')* ) ; GOOD_LINE_COMMENT : ( '//=' ('\r'|'\n')* ) ; CHARACTER : ('\'') ('\'') ('\'') ; terminal TIME : ( ('0'..'9')+ ':' ('0'..'9')+ ) ;

This is, surprisingly, the syntax definitions (that are commented) I have mentioned above the terminal STRING rule!
The other thing I realized was that, when I removed the comments from the above said definitions, the default STRING is given just as 'TerminalRule STRING'. So I guess the definition I'm getting must be wrong, because whatever I put as comments above the terminal rule, will be displayed as its definition. Could you please help me with this problem?

[Updated on: Thu, 13 December 2018 04:21] by Moderator

Re: Error in creating fragment for STRING [message #1799753 is a reply to message #1799747]

Thu, 13 December 2018 04:42

Eclipse User

noooooooooo
i means this line:
!!!!!!!
grammar org.xtext.example.mydsl.MyDsl with org.eclipse.xtext.common.Terminals
!!!!!!!!!!

Re: Error in creating fragment for STRING [message #1799759 is a reply to message #1799753]

Thu, 13 December 2018 05:17

Eclipse User

Do you mean the Rules listed down in the outline tab, as in the attached pictire below?