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Xtext import parser rule!! [message #754385]

Wed, 02 November 2011 11:52

Mokhtar Alshubei

Messages: 121
Registered: November 2011
Location: Germany

Senior Member

Hello great people Rolling Eyes

i am a new here and working with Xtext! please help me to understand this:
Where: Xtext grammar from the demo example in the documentation (see below)
My question: how does xtext enable the import rule to exactly allow the referenced Entity to be written without its qualified name??
i'm feeling either magic or that it was meant exactly solely for that!
in the line ('extends' superType = [Entity | QualifiedName])? OK it says that the bar is for specifying the syntax of the parsed string of Entity(?) BUT HOW could it work to write:
entity Post extends my.company.common.hasAuthor {..} instead of
entity Post extends hasAuthor {..}
JUST by specifying the import statement before like this
import my.company.common.* ????????

Domainmodel:
(elements += AbstractElement)* ;
PackageDeclaration:
'package' name = QualifiedName '{'
(elements += AbstractElement)* '}'
;
AbstractElement:
PackageDeclaration | Type | Import
;
QualifiedName:
ID ('.' ID)* ;
Import:
'import' importedNamespace = QualifiedNameWithWildcard
;

QualifiedNameWithWildcard:
QualifiedName '.*'?
;
Type:
DataType | Entity
.
.
Entity:
'entity' name = ID
('extends' superType = [Entity | QualifiedName])?
'{'
(features += Feature)* '}'
;

Vielen Dank,
Mokhtar

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Re: Xtext import parser rule!! [message #754388 is a reply to message #754385]

Wed, 02 November 2011 12:02

Alexander Nittka

Messages: 1193
Registered: July 2009

Senior Member

Hi,

the short answer is: this is intended magic. The "importedNamespace" in the grammar tells Xtext to use those strings for normalising qualified names. See the documentation. You may also start digging starting at ImportNormalizer and its uses.

Alex

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Re: Xtext import parser rule!! [message #754395 is a reply to message #754388]

Wed, 02 November 2011 12:30

Mokhtar Alshubei

Messages: 121
Registered: November 2011
Location: Germany

Senior Member

Oook thank you! so 'importedNamespace' is like a keyword but i will have to provide the related parser rules as they are here? except maybe to change ID('.'ID)* to something like ID('::'ID)* ?

thank you for helping.
Mokhtar

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Re: Xtext import parser rule!! [message #754798 is a reply to message #754395]

Fri, 04 November 2011 12:18

Jan Koehnlein

Messages: 760
Registered: July 2009
Location: Hamburg

Senior Member

Yes.

Some call it magic, I call it a naming convention.

Am 02.11.11 13:30, schrieb Xtexter:
> Oook thank you! so 'importedNamespace' is like a keyword but i will have
> to provide the related parser rules as they are here? except maybe to
> change ID('.'ID)* to something like ID('::'ID)* ?
>
> thank you for helping.
> Mokhtar

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