Steven D'Aprano wrote:
On Sat, 04 Jul 2009 09:58:39 -0400, Dave Angel wrote:
Read his suggested approach more carefully. He's not "undoing"
anything. He's rolling back to the save-point, and then stepping
forward to the desired spot. Except for influences outside his control
(eg. file system operations), this approach has to work.
Is that anything like saying "Except for all the diseases this drug won't
cure, it cures everything"?
*wink*
<grin>
Yeah, pretty close. That's the problem with speaking in concepts,
rather than something concrete.
Somebody else brought up VM, but that has two meanings these days. The
sense I took it (with regard to save-point) was a program like VMWare,
where it virtualizes the entire machine. So any program that deals only
with the local machine will fit that approach. And yes, I know there
are subtleties beyond networks and virtual networks, like time. When
you roll the VM back, the time magically stays current. But for a
program that deals only with its own process, that tends to just look
like some other process suddenly hogged the CPU.
Now, if the snapshot is a feature of the Python VM, that's another
matter entirely.
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