"clipka" <nomail@nomail> wrote:
> "Trevor G Quayle" <Tin### [at] hotmailcom> wrote:
> > Perhaps the easiest and most universal solution to implement would be to add a
> > global "loop_limit" variable that would set the maximum number of loops allowed
> > (similar to max_trace value).  POV would then only need to keep track of the
> > number of iterations the current loop has gone through and kick it out when it
> > reaches the limit, rather than tracking any number of variables.
>
> That sounds like an option.
>
> I'm not sure though whether it would be superior to just waiting for the user to
> decide that it was about time for the parsing to finish.
>

It would give the user the advantage of pointing out the offending loop.

>
> > I would
> > expect that POV would also report an error (without aborting) to the message
> > window that a loop was terminated with the line number for debugging purposes.
>
> I disagree. Just dropping out of a loop before all conditions have been
> established that might be presumed by the following code may mess up, and in
> some cases (software using #write) actually have the potential to mess up data.
>
>
> Maybe just printing a debug info but continuing with the loop would be the most
> sensible thing to do; if the user finds that it doesn't make sense to keep the
> loop going, he can abort the render anytime.
>

This is true assuming that the user does not want an infinite loop situation at
all.

There are circumstances where the user may want the loop to continue until it
reaches an assumed infinite loop and then jump the loop and get on with the
render.
For example, the non-intersecting spheres in a box scenerio I described before.
The user may want as many spheres as possible to fit in the box, but does not
really know the practical limit.  (I know this scenario could be handled with a
large for loop or by other means, but it is meant as a simple demonstration of
an intended situation)


>
> > The one disadvantage to this is that it would be globaL and apply to all loops
> > within the scene.
>
> I don't see a problem with that. Of couse you could specify a max iteration
> thing per loop, but then again that would be quite redundant in the cases it's
> most needed.

I agree it wouldn't likely be a problem in most circumstances.

-tgq

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