[Tutor] recursive generator

[Stefan Behnel]

Steven D'Aprano, 07.03.2010 14:27:
> On Sun, 7 Mar 2010 11:58:05 pm spir wrote:
>>      def __iter__(self):
>>          ''' Iteration on (key,value) pairs. '''
>>          print '*',
>>          if self.holdsEntry:
>>              yield (self.key,self.value)
>>          for child in self.children:
>>              print "<",
>>              child.__iter__()
>>              print ">",
>>          raise StopIteration
>
>
> __iter__ should be an ordinary function, not a generator. Something like
> this should work:
>
> # Untested.
>      def __iter__(self):
>          ''' Iteration on (key,value) pairs. '''
>          def inner():
>              print '*',  # Side effects bad...
>              if self.holdsEntry:
>                  yield (self.key,self.value)
>              for child in self.children:
>                  print "<",
>                  child.__iter__()
>                  print ">",
>              raise StopIteration
>          return inner()

That's just an unnecessarily redundant variation on the above. It's 
perfectly ok if __iter__() is a generator method.

Stefan