discard """
  cmd: '''nim c -d:nimAllocStats --newruntime $file'''
  output: '''button
clicked!
(allocCount: 6, deallocCount: 6)'''
"""

import system / ansi_c

type
  Widget* = ref object of RootObj
    drawImpl: owned(proc (self: Widget))

  Button* = ref object of Widget
    caption: string
    onclick: owned(proc())

  Window* = ref object of Widget
    elements: seq[owned Widget]


proc newButton(caption: string; onclick: owned(proc())): owned Button =
  proc draw(self: Widget) =
    let b = Button(self)
    echo b.caption

  #result = Button(drawImpl: draw, caption: caption, onclick: onclick)
  new(result)
  result.drawImpl = draw
  result.caption = caption
  result.onclick = onclick

proc newWindow(): owned Window