class Button

	sig ClickHandler(sender as Object, args as EventArgs)

	event _click as ClickHandler

	def addClickHandler(clickhdlr as ClickHandler)
		listen _click, clickhdlr
		
	def _onMouseClick
		# pretend it's always in our bounds and we're enabled
		raise _click, EventArgs()

	def receiveMouseClick
		_onMouseClick


class Program

	shared

		var _didClick = false
		
		def main
			butt = Button()
			butt.addClickHandler(ref .handleClick)
			assert not _didClick
			butt.receiveMouseClick
			assert _didClick

		def handleClick(sender as Object, args as EventArgs)
			_didClick = true