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Cross-reference: a set of constants of Enum [message #1738785]

Sun, 24 July 2016 10:42

Rotem Ge

Messages: 1
Registered: July 2016

Junior Member

Hi,
I try to write new grammar and I wrote something like Enum in Java, that enables for Var (a type in my grammar) to be a set of predefined constants.

I want it to recognize the constants that include to this Var, but I didn't find a way how to do it (although I try to read the book "Implementing Domain-Specific Languages with Xtext and Xtend", and searched a lot on the internet)

So I made a little example on the Domainmodel grammar:

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 | Var;

DataType:
'datatype' name=ID;

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

Feature:
(many?='many')? name=ID ':' type=[VarDecl |QualifiedName];

Var:
kind='Var' var=VarDecl;

VarDecl:
type=VarType name=SimpleVarID;

SimpleVarID:
ID ('[' INT ']')*;

VarType:
name='boolean'
| '{' const+=TypeConstant (',' const+=TypeConstant)* '}';

TypeConstant:
ID | INT | 'FALSE' | 'TRUE';

So, the example is:

Var {LEFT,RIGHT} move

entity C {
content: move
side: LEFT //ERROR: couldn't resolve reference to VarDecl 'LEFT'
}

I know that LEFT it's not VarDecl, it's ID, but I don't know how to do it different.
What I need to do so that LEFT would be recognize like something that include to move?
comment: in my real grammar I actually try to do move==LEFT (boolean operator) and it's not recognize LEFT as constant of move (the same error appears) .

Thanks!

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