KEEP for multi-field value classes

[zhelenskiy]

No description provided.

[ilmirus]

Suggested change

One of other important steps of Value classes feature are Value arrays (`VArray`s) and reified classes and reified not-inline functions. They significantly extend applicability and optimizations of Value classes, **but they require MFVC to be already implemented** for that. Their importance is caused by frequent usage of containers that store and use stored values: they are currently handle value classes as boxed.

One of other important steps of Value classes feature are Value arrays (`VArray`s) and reified classes and reified not-inline functions. They significantly extend applicability and optimizations of Value classes, **but they require MFVC to be already implemented** for that. Their importance is caused by frequent usage of containers that store and use stored values: they currently handle value classes as boxed.

An example of reified class will be helpful to understand why they require MFVC.

[zhelenskiy]

I mean that impact(mfvc + varrays) > impact(mfvc) + impact(varrays) because it also includes VArray<MFVC>s. I don't know how to formulate it properly.

[soywiz]

There is another use-case I would like to share:

Here:
https://docs.korge.org/ktcc/

There I'm doing black magic tricks that are really dirty to avoid allocations, and the code looks ugly. Being able to have something like:

value class MyPointer(val buffer: Buffer, val offset: Int) {
  var x: Double get() = buffer.getDouble(0); set(value) { buffer.setDouble(0, value) }
  var y: Double get() = buffer.getDouble(8); set(value) { buffer.setDouble(8, value) }
}

That would help to have C-like pointers: an array or buffer + offset (+ maybe optionally size)