>>> class Foo:
... counter = 0
... def GetTick():
... yield 0
... if --counter < 0:
... print "Hello"
...
>>> f = Foo()
Foo
>>> join(f.GetTick(), '')
>>> join(f.GetTick(), '')
System.InvalidProgramException: Common Language Runtime detected an invalid prog
ram.
at CompilerGenerated.GetTick___generator1_Enumerator.MoveNext()
at Boo.Lang.Builtins.join(IEnumerable enumerable, String separator) in c:\pro
jects\boo\src\Boo.Lang\Builtins.cs:line 76
at Input3Module.Main(String[] argv)
>>>