delegators.nim

type
  VTable = object
    methodA: proc (this: MyObject; a, b: int)
    methodB: proc (this: MyObject; a, b: string)
  OtherObject = object
    fieldA: int
    fieldB: int
  MyObject = object
    vtab {.delegate(this).}: ptr VTable
    other {.delegate.}: OtherObject

var obj: MyObject
obj.methodA(3, 4)
# is rewritten to:
obj.vtab.methodA(obj, 3, 4)
# also possible:
obj.fieldA
# rewritten to:
obj.other.fieldA