Would it be feasible to create a compiler plugin t...

# compiler

[phldavies]

Would it be feasible to create a compiler plugin that can lift a parameter (or context-parameter) as an additional receive within the scope of a function. An example would be to have something like

context(@Receiver _: MyScope) fun doSomething() { callSomething() }

be translated to

context(_: MyScope) fun doSomething { with(contextOf<MyScope>()) { callSomething() } }

My gut says no but this would be a nice way of avoiding the need to create context parameter bridge functions.

[Youssef Shoaib [MOD]]

I believe somethiing like this is possible:

context(@Receiver _: MyScope) fun doSomething() { 
  with<MyScope>()
  callSomething()
}

Using FirExpressionResolutionExtension

[phldavies]

It looks like you found a way with wither @Youssef Shoaib [MOD] 😉

[Youssef Shoaib [MOD]]

Yep! In fact, something like this is on my radar. I wanted to add receivers from pre-existing contexts so that one can have like "mega-contexts" that automatically bring in a bunch of components.
Your use case is even easier. It turns out one can easily add arbitrary FIR before any resolution takes place using the status transformer extension. Hence, a plugin can simply add the with call based on @Receiver, and then wither takes care of adding it as a receiver

[phldavies]

Would the plugin be able to inject the wither with call for any context with a specific annotated type (to avoid bridging methods)
I.e.

@ContextAsReceiver // the annotation
interface Raise { fun raise(value: Any): Nothing }

context(_: Raise) fun doSomething { raise("hello") }

[Youssef Shoaib [MOD]]

Yeah! I think type information for parameters and such is available at that time, so you can check for annotations easily. I might whip up a prototype for you...
Only gotcha is that I haven't figured out how to do the FIR transformation properly for expression bodies with inferred return type. So currently I can't make this work:

context(_: Raise) fun doSomething() = raise("hello")

But I can make this work:

context(_: Raise) fun doSomething(): Nothing = raise("hello")

[phldavies]

I mean, for that case you'd have to specify Nothing explicitly, but I get what you mean 🙂