Customisation of Code Completion

[markusvoelter]

I am working on customizing code completion for my language. In one particular parser rule (AST type) I need to code complete a string into an external configuration (think: XML file). I got the fundamentals to work by writing my own completion provider and extending the default one. I overwrote the completeForRule method with my own logic and it basically works. One question
however:

Let's assume the completions (based on my external XML file) are ABC, AXX and DEF. If I press Ctrl-Space when the user has already written A, then I'd assume to only get ABC and AXX as proposals. Is this behavior intended to be default (ie, handled outside my completeForRule method) or should I implement this myself? If the latter, it seems that the completeForRule method doesn't get enough arguments; prefix or something is missing.

What do I do? @msujew, is your improvement of the code completion provider addressing this (@montymxb hinted at that)?

[spoenemann]

Hi Markus! AFAICT the default completion provider should take care of filtering proposals to match the current prefix:
https://github.com/langium/langium/blob/7305814026c17348df65e5d13cb9daaba8fd2437/packages/langium/src/lsp/completion/completion-provider.ts#L109

Can you confirm this from the editor behavior?

[markusvoelter]

I duplicated the DefaultCompletionProvider and adapted that filter call to also check for the e.editText.newText. Now the filtering works, but we're back to ignoring the newText upon insert (only the item label is inserted). Guess I'm missing something here ....

[markusvoelter]

Actually, this also happens if I do not adapt the filtering logic: as soon as I use code completion with a prefix, the label is used instead of the textEdit.newText.

[markusvoelter]

BTW, I can provide my project, we can also do a screenshare to explore the problem together. Might be the fastest route.

[markusvoelter]

ping, @msujew

[msujew]

@markusvoelter I've sent you a mail (@acm.org) with details for a screensharing session 👍

[goto40]

@markusvoelter Is it possible to share some snippets of your code? I am also playing with the CompletionProvider...