class OptCtor
	def main is shared
		x = OptCtor()
		assert x.x == 'default'

		x1 = OptCtor('foo')
		assert x1.x == 'foo'

	var x = ''
	
	cue init(s as String = 'default')	
		base.init
		.x = s
		print 'OptCtor [.x]'