[Python-Dev] yield back-and-forth?

[Edward C. Jones]

Guido van Rossum <guido at python.org> wrote:

The discussion about PEP 343 reminds me of the following. Bram Cohen
pointed out in private email that, before PEP 342, there wasn't a big
need for a shortcut to pass control to a "sub-generator" because the
following for-loop works well enough:

 def main_generator():
      ...
      for value in sub_generator():
          yield value

This is an important programming trick. It allows recursive use of 
generators for walking trees, etc. See the source code for os.walk for 
an example.