Question about bytecode and yield

[Daniel Brodie]

Hello,

1) I am trying to understand how yield works in a bytecode way. How
exactly does the YIELD_VALUE instruction work?
Does the function 'change' to return a generator at compile time
(which, from my understanding, not much happens at that stage in
python) or at the YIELD_VALUE bytecode?

Any pointer to documentation about this would be appriciated, I have
tried, but havn't really found anything.

2) This is the reason I am asking #1. Is it possible to, at runtime,
change the bytecode of a function so that to turn it into a generator
from a normal, average, function? Would just putting in a YIELD_VALUE
(in a sane way, obvioussly) work?

3) yield does some saving of the current frame, and so forth. Does
this happen, burried underneath, or would it be possible to do
something like that (saving the frame, local variables, etc... and
resuming it later) on my own, even as a C module.

Once again, any documentation (in CVS, or something like that) about
this would be appriciated.

Thank You,
Daniel Brodie