not to do what you describe “Write a short Swift function that calls StoreKit, and call that from objC”. Maybe you know about some documentation describing how to do this?
Just write a swift function (you’ve already done that, or start again with hello_world) and look at the generated bridging header; that will show the syntax of the objC call. (With some obfuscation probably).
Things to note:
There is the @objc annotation.
async functions need the withCompletionHndler stuff mentioned earlier.
I recall having to write a class with a single static method, rather than a function. I don’t recall the details.
Topic:
App & System Services
SubTopic:
StoreKit