"""
The duration of comparing with "is" should be the same as invoking Object.referenceEquals(). In other words, it should be no more expensive.

At least on Novell Mono 1.2.6:

Note that comparing interned strings with == is slower than calling Object.referenceEquals().
"""

class Test

	def main is shared
		Test().run

	def finish(msg as String, start as DateTime)
		duration = DateTime.now.subtract(start)
		print '[duration.totalSeconds:N4] seconds to [msg]'

	def run
		n = 20_000_000
		s1 = 'aoeu'
		s2 = 'aoeu'
		
		assert s1 is s2  # interned strings should be identical references
		
		s2 = 'asdf'

		start = DateTime.now
		for i = 0 .. n
			if s1 == s2
				print 'equal'
			if s1 == s2 # 2
				print 'equal'
			if s1 == s2
				print 'equal'
			if s1 == s2 # 4
				print 'equal'
			if s1 == s2
				print 'equal'
			if s1 == s2 # 6
				print 'equal'
			if s1 == s2
				print 'equal'
			if s1 == s2 # 8
				print 'equal'
			if s1 == s2
				print 'equal'
			if s1 == s2 # 10
				print 'equal'
		.finish('compare interned strings with ==', start)

		start = DateTime.now
		for i = 0 .. n
			if Object.referenceEquals(s1, s2)
				print 'equal'
			if Object.referenceEquals(s1, s2) # 2
				print 'equal'
			if Object.referenceEquals(s1, s2)
				print 'equal'
			if Object.referenceEquals(s1, s2) # 4
				print 'equal'
			if Object.referenceEquals(s1, s2)
				print 'equal'
			if Object.referenceEquals(s1, s2) # 6
				print 'equal'
			if Object.referenceEquals(s1, s2)
				print 'equal'
			if Object.referenceEquals(s1, s2) # 8
				print 'equal'
			if Object.referenceEquals(s1, s2)
				print 'equal'
			if Object.referenceEquals(s1, s2) # 10
				print 'equal'
		.finish('compare interned strings with Object.referenceEquals', start)

		start = DateTime.now
		for i = 0 .. n
			if s1 is s2
				print 'equal'
			if s1 is s2 # 2
				print 'equal'
			if s1 is s2
				print 'equal'
			if s1 is s2 # 4
				print 'equal'
			if s1 is s2
				print 'equal'
			if s1 is s2 # 6
				print 'equal'
			if s1 is s2
				print 'equal'
			if s1 is s2 # 8
				print 'equal'
			if s1 is s2
				print 'equal'
			if s1 is s2 # 10
				print 'equal'
		.finish('compare interned strings with "is"', start)