Delete Ast Element in Custom Action: How to determine the position until where to delete the text

[goto40]

I use langium 2.1.3

• I have a custom action (like in https://github.com/eclipse-langium/langium/blob/main/packages/langium/src/grammar/lsp/grammar-code-actions.ts) to delete an unused part of my model.
• If I delete the text from range: diagnostic.range.start .. diagnostic.range.end I do not delete the model text as expected, because I want to delete the model text until the next model element starts.

Not

my-model-element1
my-model-element2-to-be-deleted // delete this with my action!
my-model-element1

-->

my-model-element1
 // delete this with my action!
my-model-element1

But

my-model-element1
my-model-element2-to-be-deleted // delete this with my action!
my-model-element1

-->

my-model-element1
my-model-element1

How did I solve this: I determine the "end position" to be deleted by calling getNextNode(myModelElementToBeDeleted.$cstNode, false)?.range.start

It works.

Is this the way it is intended to do this?

[msujew]

Hey @goto40,

since you want to delete all text from one AST node until the next node, it seems reasonable to use getNextNode. You shouldn't run into any issues with that such as unintentionally deleting more code than intended. We use getNextNode for some custom CST validations in our own projects quite regularly.

If I delete the text from range: diagnostic.range.start .. diagnostic.range.end I do not delete the model text as expected, because I want to delete the model text until the next model element starts.

What is "expected" in this regard would be up for discussion. Since the diagnostic is only applied to the actual model text (but not the whole line), it will only delete what actually belongs to the model. As the comment does not belong to it, it will stay right where it is. I would say that this is the expected behavior for this functionality.

[goto40]

Thank you. The comment is deleted in my case... I thought the "false" argument passed to getNextNode was ment for that...