[kuschku]

> The IDE/Editor just sends the position inside a document which needs to be completed and the language server responds with all possible suggestions. There's absolutely no need to store an AST in the editor for that. The AST can stay in the language server for that. It's the same for references to types, refactoring commands, etc. Yes, if someone needs some non-standard "data stream analysis" the command and results for that might not yet be standardized in LSP - but they could be added if it's worth it for the users. And I guess one can also have non-standardized optional extension APIs between a language server and an editor. In the end it's the same: The editor asks the language server (which has full access to AST): Give me "a graph of where the variable comes from, and how it's transformed", and the language server responds in a well-defined way which the editor just needs to render.

That would be pretty stupid, though, as every language server would duplicate a massive amount of code.

[wtetzner]

And if you put the logic in the IDE, then every IDE has to duplicate the functionality for every language.

It seems like the language implementation is the right place to put logic that requires information about how the language works.

[teacup50]

To implement a proper IDE, you're going to have to "duplicate" that logic anyway.