My last 2 "solutions" don't work either because for the first one I'd need a
proper nominal abstraction feature(or how to store a concept in a seq when the
elements can be different) and for the second one I'd need existential types(or
how to tell the that a seq can hold a HeterogenCell with any type parameter
when the cell's parameter type is explicitly restricted to a certain concept).
I'd an idea but it's failing for some reason:
type
Packet = ref object of RootObj
data: string
HgPackType* = concept self
pack(Packet, self)
HgCell[T, S] = object of RootObj
data: T
handler: proc(dat: T, buffer: S): void
HgPack[S] = object of RootObj
buffer: S
cells: seq[HgCell[RootObj, S]]
method pack*(p: Packet, i: int8) =
p.data &= $i
proc newHgPack*[S](): auto = HgPack[S](cells: @[])
method register*[S, T: HgPackType](msgp: HgPack[S], elem: T, handler:
proc(dat: T, b: S): void) =
msgp.add(HgCell(elem, handler))
let mp = newHgPack[Packet]()
mp.register(int8(1), proc(i: int8, buff: Packet) = buff.pack(i))
Run
