how to refer inner cross reference

[zrwsmd]

FunctionBlock:
'FUNCTION_BLOCK' name=Identifier
(methods+=Methods)*
'END_FUNCTION_BLOCK'
;

Methods:
'METHOD' name=Identifier
'END_METHOD'
;

if i want to refer function method name at below rule ,how should i refer it

aa:
fbMethodName=[FunctionBlock:?]

[cdietrich]

depends on your usecase? your impl of the scoping etc

fbMethodName=[FunctionBlock:Identifier]

or

QualifiedName: Identifier ("." Identifier)*;
...
fbMethodName=[FunctionBlock:QualifiedName]

[zrwsmd]

I don't know how to write without thinking

[cdietrich]

maybe this terribly old example gives some idea
https://github.com/cdietrich/CoreDsl-Langium/blob/127dba30229639066022327d79f6a590ece9532e/src/language-server/core-dsl-scope-computation.ts#L30

[zrwsmd]

thanks a lot,actually ,i am confused about langium lifecycle,the offical document is a bit difficult to understand

[cdietrich]

the concept for if there is a reference someRef=[Xxxxxx] and you write Yyyyyyy
and langium tries to figure out what Xxxxxxx instance Yyyyyyy is is called scoping
and implemented in the scope provider.

maybe https://eclipse.dev/Xtext/documentation/303_runtime_concepts.html#scoping also gives some inspiration

[zrwsmd]

thanks a lot

[msujew]

Hey @zrwsmd, I would recommend taking a look at this scoping guide. That is probably what you're looking for.

[msujew]

The StreamScope is an implementation of the Scope interface. The global scope is just an instance of the Scope interface that represents all globally available objects.

[zrwsmd]

in which condition should i override DefaultScopeProvider&getScope,
in which condition should i override DefaultScopeProvider&getGlobalScope,

[msujew]

You want to override getScope in case you want to adjust how a specific reference is resolved. getGlobalScope should be overriden to determine which elements are available for referencing on a global level.

[zrwsmd]

can you please describe it in a more concise and understandable way or list a simple example to describe it ,a little abstract

[msujew]

Every concise way of explaining how scopes work will be pretty abstract. If you want a better understanding of how scoping works, I would recommend to read a book on Xtext. The authors explain scoping pretty in depth. See Markus Völter's DSL Engineering. Starting at page 230, he explains how scoping and linking in Xtext work. These mechanism are very similar to how they work in Langium.