Is it impossible to attach user information to the Ast node?

[negahama]

Hello...
In my DSL, I want to infer the type of variable but I don't know how to save the type information of variables.

What I want is like this

var a = 0
var s = "s"

// instead of
var a: number = 0
var s: string = "s" 

I can infer the type of a, s by using literal 0, "s".
The problem is that I can't store the type information of variables.
Do I need to have the table to keep all variables's type?
Isn't there some more smart way?

Is it impossible to attach some user information(e.g type information) to the Ast node(a, s)?
If yes, let me know any tip to implement this feature.

Thank you in advance...

[msujew]

Hey @negahama,

we usually store this information on a DocumentCache or WorkspaceCache and simply use <AstNode, Type> for the type arguments. That way you don't need to worry about cache invalidation. See also the work in progress PR over at eclipse-langium/langium-website#241 for usage details.

[negahama]

Great... thanks a lot