Wiki

Changes between Version 3 and Version 4 of Listen

Listen

v3	v4
64	64	{{{
65	65	#!cobra
66		# Todo example using closure/anonymous method
	66	# The event handler method can also be declared using a closure if that's desirable
	67	listen g.actionEvent, do(source as Object, args as EventArgs)
	68	print 'Event received from [source]'
	69
	70	# Heres an example wrt GTK# declaring an eventhandler for an Application exit button
	71	# the indented code on the lines following the do( is the closure code
	72	listen button.clicked, do(sender, args as EventArgs)
	73	print 'Quitting'
	74	Application.quit
67	75	}}}
68	76
…	…
72	80	method invocation.[[BR]]
73	81	In practice this means that most listen statements will have their second
74		argument as a method name prefixed with '''ref'''.
	82	argument as a method name prefixed with '''ref'''.[[BR]]
	83	You need the '''ref''' keyword to specify a reference to a named method so that it is not invoked. [[BR]]
	84	A closure (using '''do''') is itself referring to code (rather than invoking it) so
	85	you never need both '''ref''' and '''do''' at the same time.