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Xtext Symbol [message #1746112]

Sat, 22 October 2016 06:23

Yves LEDUC

Messages: 56
Registered: May 2015

Member

Eclipse Xtext concept symbol
Is there documentation on the notion of symbol?
That is to say where I found this:

Name returns Symbol:
ValidID
;

Ref:
{SymbolRef} symbol=[Symbol]
;

how is he using?
Is it possible to extend this to:
SymbolVar
SymbolConst
SymbolData
SymbolModule
...
besides Symbol so as to select the symbols used.

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Re: Xtext Symbol [message #1746113 is a reply to message #1746112]

Sat, 22 October 2016 06:29

Christian Dietrich

Messages: 14500
Registered: July 2009

Senior Member

Hi can you please explain what you mean.

In Xtext you have edobjects

Thing: ... someattr=ID ...

And Cross references

ThingReferecigObject: ... ref=[Thing] ...

To be able to reference a thing it needs a attribute named name

name=ID

So please explain your question. From an model perspective
If you can't from a grammar perspective

Or give it a name through IQualifedNameProvide

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Re: Xtext Symbol [message #1746158 is a reply to message #1746113]

Mon, 24 October 2016 08:32

Jan Koehnlein

Messages: 760
Registered: July 2009
Location: Hamburg

Senior Member

There is no built-in notion of a Symbol. In Xtext, rules create instances of a class model when they are processing the text. The example says that the rule Name returns an instance of the class Symbol when it matches. The definition of classes like Symbol are, depending on the model definition in your grammar, either derived from the grammar or imported from an existing Ecore model.

You can build any kind of inheritance hierarchy in the Ecore model, e.g. by defining

Symbol:
   SymbolVar | SymbolConst | SymbolData | SymbolModule;

You will make SymbolVar etc. inherit from Symbol, even if you never call the rule explicitly. Common features, e.g. a String attribute called name will be uplifted to the super class.
A cross-reference to a Symbol, as in you Ref rule, can then point to any subclass of Symbol. For the details of the linking and the special meaning of an attribute called name, please read the docs.

Have a look at the Grammar section of Xtext documentation for details on the Ecore model / Xtext relationship.

---
Get professional support from the Xtext committers at www.typefox.io

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Re: Xtext Symbol [message #1751486 is a reply to message #1746158]

Tue, 10 January 2017 17:14

Yves LEDUC

Messages: 56
Registered: May 2015

Member

For example to do this

grammar fr.infoly.eclipse.xtext.crossreferencescoping.Algo with org.eclipse.xtext.common.Terminals

generate algo "http://www.infoly.fr/eclipse/xtext/crossreferencescoping/Algo"
/*
Algo: // Un Algo se compose de :
varglobales+=VarDecls // Déclarations de varaibles globales
modules+=Module*; // De modules

VarDecls: {VarDecls} 'Variable:' variables+=VarDecl*;
VarDecl: name=VarName;
VarName: name=ID;
VarRef: ref=[VarName];

Module:
'Module' name=ID '(' ')'
varglocales+=VarDecl*
'Début'
statements+=Statement*
'Fin'
;

Statement: var = VarRef;
*/

// Avec Symbol
Algo: // Un Algo se compose de :
varglobales+=VarDecls // Déclarations de varaibles globales
modules+=Module*; // De modules

VarDecls: {VarDecls} 'Variable:' variables+=VarDecl*;
VarDecl: name=VarName;
VarName returns SymbolVar: name=ID;
VarRef: {SymbolVarRef} symbol=[SymbolVar];

Module returns SymbolModule:
'Module' name=ID '(' ')'
varglocales+=VarDecl*
'Début'
statements+=Statement*
'Fin'
;

ModuleRef: {SymbolModuleRef} symbol=[SymbolModule];

Symbol: SymbolModule | SymbolVar ;

Statement: statement=[Symbol];
// or
//Statement: StatementCall | StatementVar;
//StatementCall: cal = ModuleRef;
//StatementVar: var = VarRef;

But it does not work

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Re: Xtext Symbol [message #1751493 is a reply to message #1751486]

Tue, 10 January 2017 18:39

Christian Dietrich

Messages: 14500
Registered: July 2009

Senior Member

Hi, can you please share a test model as well? the following grammar works fine for me

Algo: // Un Algo se compose de :
varglobales+=VarDecls // Déclarations de varaibles globales
modules+=Module*; // De modules

VarDecls: {VarDecls} 'Variable:' variables+=VarDecl*;
VarDecl: name=VarName;
VarName returns SymbolVar: name=ID;
VarRef: {SymbolVarRef} symbol=[SymbolVar];

Module returns SymbolModule:
'Module' name=ID '(' ')'
varglocales+=VarDecl*
'Début'
statements+=Statement*
'Fin'
;

Statement: StatementVar;
StatementVar: var = VarRef;

with this model/test

@RunWith(XtextRunner)
@InjectWith(MyDslInjectorProvider)
class MyDslParsingTest{

	@Inject
	ParseHelper<Algo> parseHelper

	@Test 
	def void loadModel() {
		val result = parseHelper.parse('''
			Variable: a b c
			Module m1 ()
			m1a m1b m1c
			Début
			a
			m1a
			Fin
			Module m2 ()
			m2a m2b m2c
			Début
			b
			m2b
			Fin
		''')
		Assert.assertNotNull(result)
		EcoreUtil2.resolveAll(result)
		println(result.eResource.errors)
	}

}

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Re: Xtext Symbol [message #1751537 is a reply to message #1746112]

Wed, 11 January 2017 10:01

Yves LEDUC

Messages: 56
Registered: May 2015

Member

I do not understand everything works fine now?
Even this with the module calls in addition:

Variable:
gvar1 // Déclaration var globale 1
gvar2 // Déclaration var globale 2

// Module 1
Module mod1( )
Variable:
lvar11 // Déclaration dans module 1 var locale 1
lvar12 // Déclaration dans module 1 var locale 2
Début
mod2()
gvar1 // Référence à la var globale 1
gvar2 // Référence à la var globale 2
lvar11 // Référence à la var locale 1 du module 1
lvar12 // Référence à la var locale 2 du module 1
Fin

Thank you very much for your help
Yves
// Module 2
Module mod2( )
Variable:
lvar21 // Déclaration dans module 2 var locale 1
lvar22 // Déclaration dans module 2 var locale 2
Début

gvar1 // Référence à la var globale 1
gvar2 // Référence à la var globale 2
lvar21 // Référence à la var locale 1 du module 2
lvar22 // Référence à la var locale 2 du module 2
mod1( )
Fin

With this grammar :

grammar fr.infoly.eclipse.xtext.crossreferencescoping.Algo with org.eclipse.xtext.common.Terminals

generate algo "http://www.infoly.fr/eclipse/xtext/crossreferencescoping/Algo"

/*
* ALGORITHME
*/
Algo: // Un Algo se compose de :
varglobales=VarDecls // Déclarations de varaibles globales
modules+=Module*; // De modules

VarDecls: {VarDecls} 'Variable:' variables+=VarDecl*;
VarDecl: name=VarName;
VarName returns SymbolVar: name=ID;
VarRef: {SymbolVarRef} symbol=[SymbolVar];

Module returns SymbolModule:
'Module' name=ID '(' ')'
varglocales=VarDecls
'Début'
statements+=Statement*
'Fin'
;

ModuleRef: ref=[SymbolModule];

Statement: StatementVar | StatementCall;
StatementVar: var = VarRef;
StatementCall: call = ModuleRef '(' ')';

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