yield: implementation details and other technica

[David Mertz, Ph.D.]

    I have a technical problem for which grabbing the context of a
    generator and *throwing* it up the stack would be preferable to the
    current implementation...  What I want is a giant coroutine between
    a bunch of objects and a master scheduler that I control....For one,
    certain high level methods are called that imply a yield in a higher
    context.

"Raymond Hettinger" <vze4rx4y at verizon.net> wrote previously:
|Joe, try looking at:
|http://gnosis.cx/publish/programming/charming_python_b7.txt
|The article shows how to use generators with a master scheduler.  His
|example shows how to implement co-routines, but it is general purpose.
|Used this way, the scheduler has the ability to resume any process,
|in effect deciding the current continuation.

The article Raymond suggest is indeed probably the most on topic.  It
also follows on a related one.  The HTML versions of both are at:

    http://gnosis.cx/publish/programming/charming_python_b5.html
    http://gnosis.cx/publish/programming/charming_python_b7.html

Moreover, for some more fleshed out examples of scheduling generators,
take a look at the SimPy project.  The authors of that use a bit of the
framework I suggested in those articles, but in a much more fleshed out
form.  The also handle some data passing in a nice way.  But it's not
hard to yield some "cargo" along with a state target, in any case.

One thing I regret in my first article on this is that I used string
names for targets rather than the callable objects themselves.  I think
the latter article fixed that, and I believe SimPy does to.

Generators are even more cool that you might think at first brush.

Yours, David...

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