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Converting fragment from Antlr to Xtext [message #1765292]

Thu, 08 June 2017 08:04

Udeshika Sewwandi

Messages: 118
Registered: March 2017

Senior Member

Hi

Can I create a fragment rule for the following Antlr fragment?

SCRIPT
 : '{' SCRIPT_ATOM* '}'
 ;

 fragment SCRIPT_ATOM
  : ~[{}]
  | '"' ~["]* '"'
  | '//' ~[\r\n]*
  | SCRIPT
  ;

I could create a terminal rule as follows.

SCRIPT:
	'{' SCRIPT_ATOM* '}'
;

terminal SCRIPT_ATOM:
  ! ('{' | '}')
  | '"' (!'"')* '"'
  | '//' !('\r'|'\n')*
  //| SCRIPT
;

But SCRIPT parser rule cannot be called inside the terminal rule. What needs to be done here?
Thank you.

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Re: Converting fragment from Antlr to Xtext [message #1765298 is a reply to message #1765292]

Thu, 08 June 2017 08:50

Christian Dietrich

Messages: 14285
Registered: July 2009

Senior Member

did you consider an additional terminal aka

Scripting:
value=SCRIPT
;

terminal SCRIPT:
'{' SCRIPT_ATOM* '}'
;

terminal SCRIPT_ATOM:
! ('{' | '}')
| '"' (!'"')* '"'
| '//' !('\r'|'\n')*
| SCRIPT
;

Need professional support for Xtext, Xpand, EMF?
Go to: https://www.itemis.com/en/it-services/methods-and-tools/xtext
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Re: Converting fragment from Antlr to Xtext [message #1765302 is a reply to message #1765298]

Thu, 08 June 2017 09:25

Udeshika Sewwandi

Messages: 118
Registered: March 2017

Senior Member

The additional terminal for SCRIPT worked fine. :)

Does having cross references among the grammar rules helps in content assisting? I feel it's hard to maintain cross references in my grammar since it is a bit complex.

Thank you.

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