onready attribute when deriving GodotClass [feature request]

[speelbarrow]

Hey folks!

GDScript has an onready annotation you can apply when declaring a variable that allows you to define how the value should be initialized when _ready is called (as opposed to init). In this library, when using the derive macro for GodotClass, the attribute #[init(default = ... )] can be used to set a default value for the struct field it tags. Would it be possible to add something like #[init(onready = ...)] for object initialization at ready time? Based on how this library currently works, this would require the tagged field to be Option<T> (so that at init time the field can be initialized in some way). Maybe the attribute could apply that Option wrapper itself?

I'm not super familiar with the internals of this library (yet), so I'm not entirely sure if this is even possible/how exactly one would go about implementing it. However, it is a feature I'd love to see implemented!

Thanks for taking the time to read this :)

[Bromeon]

Please check for existing issues: #130
But you remind me of some experiments I started a while ago, will answer there.