inherits.nim

import strutils, unicode

type
  Component = ref object of RootObj
  CPosition = ref object of Component
    x, y: int
  CVelocity = ref object of Component
    dx, dy: int
  CRune = ref object of Component
    rune: Rune

  Entity = object
    position: CPosition
    velocity: CVelocity
    rune: CRune

proc `$`[T](v: ref T): string = $(v[])

var e = Entity(
  position: CPosition(x:100, y:50),
  velocity: CVelocity(dx:1, dy:2),
  rune: CRune(rune: toRunes("@")[0]))

if e.position != nil:
  echo "e has a position!"

# gameplay code - has reference to a relevant entity...
var
  pos = e.position
  rune = e.rune
echo "Rendering $1 at $2, $3".format(rune.rune, pos.x, pos.y)