Wrong linking / references

[grafandreas]

Creating a language with the small grammar below results in the following unexpected behaviour:

The references in line Stage: Are not actually navigable references in the generated VSCode editor
The name=ID in Microaction: will actually result in a navigable reference in VSCode editor, but it will not navigate to any definition.

grammar CorePerfDsl

entry CorePerfModel_sec :  (mad=Microaction_def | stdef=Stage_def)* ;

Stage_def : 'Stagxe' (st+=Stage | '{' st+=Stage (',' st+=Stage)* '}');

Stage : name=ID '(' microactions+=[Microaction] (',' microactions+=[Microaction])* ')';

//////////////////////////// MICROACTION ////////////////////////////

Microaction_def : 'Microaction' (ma+=Microaction | '{' ma+=Microaction (',' ma+=Microaction)* '}');

Microaction : name=ID '(' ')';

terminal KEYWORD_ALL  : '[ALL]' ;
terminal KEYWORD_REST : '[?]' ;

hidden terminal WS: /\s+/;
terminal ID: /[_a-zA-Z][\w_]*/;
terminal INT returns number: /[0-9]+/;
terminal STRING: /"(\\.|[^"\\])*"|'(\\.|[^'\\])*'/;

hidden terminal ML_COMMENT: /\/\*[\s\S]*?\*\//;
hidden terminal SL_COMMENT: /\/\/[^\n\r]*/;

[msujew]

Hey @grafandreas, I've converted this issue into a discussion, as you're not encountering a bug.

will actually result in a navigable reference in VSCode editor, but it will not navigate to any definition.

So it's a navigatable reference, but it doesn't navigate? That sounds like an oxymoron :D

Anyway, first off there's a major issue (and the latest versions of Langium should warn you about that) in your entry rule. Parsing multiple Microaction_def or Stage_def will override existing elements. You should use += instead of = there if you want to use *.

Then there's the issue of linking: Langium doesn't magically know how all references are supposed to be linked. Instead, it features a relatively simplistic default mechanism (local scopes) that can be customized/extended to support your language. See our scoping guide.

[grafandreas]

@msujew It is a navigable reference in the grammar, but it is not reflected in the editor.

Maybe I am to Xtext influenced, I was assuming that the default scoping picks up matching elements in a file (as local scope)?

[msujew]

Langium's default scoping uses local scopes as well. However, as Microaction instances are defined in the scope of a Microaction_def, it won't be available outside of that. That is the definition of a local scope. By default, elements are only available if they are a sibling, a parent, or a sibling of a parent (recursively). To adjust how the scoping is done, see the scoping guide posted above.