[Python-ideas] Yielding through context managers

[Jan Kaliszewski]

> >class cd(object):
> >     def __init__(self, path):
> >         self.inner_path = path
> >
> >     def __enter__(self):
> >         self.outer_path = os.getcwd()
> >         os.chdir(self.inner_path)
> >
> >     def __exit__(self, exc_type, exc_val, exc_tb):
> >         os.chdir(self.outer_path)
> >
> >     def __yield__(self):
> >         self.inner_path = os.getcwd()
> >         os.chdir(self.outer_path)
> >
> >     def __send__(self):
> >         self.outer_path = os.getcwd()
> >         os.chdir(self.inner_path)
[snip]
> >def my_generator(path):
> >     with cd(path):
> >         yield do_something()
> >         do_something_else()

Interesting idea, though doing this with present Python does not seem to
be very painful:

    class cd(object):

        def __init__(self, path):
            self.inner_path = path

        def __enter__(self):
            self.outer_path = os.getcwd()
            os.chdir(self.inner_path)
            return self

        def __exit__(self, exc_type, exc_val, exc_tb):
            os.chdir(self.outer_path)

    def my_generator(path):
        with cd(path) as context:
            output = do_something()
            with cd(context.outer_path):
                yield output
            ...

Cheers.
*j