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discard """
cmd: '''nim c --newruntime $file'''
errormsg: "'=copy' is not available for type <owned Button>; requires a copy because it's not the last read of ':envAlt.b1'; routine: main"
line: 48
"""
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)
proc newWindow(): owned Window =
proc draw(self: Widget) =
let w = Window(self)
for e in w.elements:
if not e.drawImpl.isNil: e.drawImpl(e)
result = Window(drawImpl: draw, elements: @[])
proc draw(w: Widget) =
if not w.drawImpl.isNil: w.drawImpl(w)
proc add*(w: Window; elem: owned Widget) =
w.elements.add elem
proc main =
var w = newWindow()
var b = newButton("button", nil)
b.onclick = proc () =
b.caption = "clicked!"
w.add b
w.draw()
# simulate button click:
b.onclick()
w.draw()
main()
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