[Pitch] Reflection

[porterchild]

Excited for this! Getting KeyPaths for fields is important for our codebase, and we're currently relying on _forEachFieldWithKeyPath via @_spi(Reflection) import Swift, which is a little unfortunate. Further in the past, we did it using Mirror, which was at least equally unfortunate.
It would be great to have a proper API for this functionality!

We do need the KeyPaths to be Writable however, which isn't included in the original pitch.

But from the following I gather it would still be possible to make the KeyPaths from Field writable? Perhaps with a cast? Am I reading this correctly?

@Alejandro

@saagarjha

there is no way to fundamentally prevent the creation of a WwritableKeyPath to a mutable field in the language

Yeah, I agree with you here. I think the thing we considered was that we don't want the easy API to be able to easily vend these mutable keypaths without any way of opting in/out.