# single optional param
class OptParam
	def main is shared
		x = OptParam()
		x.call = 0
		x.foo('default')
		assert x.call ==1
		x.foo('provided',10)
		assert x.call == 10

	var call =0
	
	def foo(s as String, i = nil) # optional single (dynamic) param
		#print s,i
		if s == 'default'
			assert i == nil
			i = 1
		.call = i