Re: [Visualpython-users] Backwards-compatibility problems in Visual 5

[Roberto A. M. <rha...@ho...>]

> After some discussion with David Scherer, we're convinced that
> scene.objects should indeed remain a tuple in Visual 5.0, not a list. As
> he says, "Lists are mutable, so the user can try to do things like del
> scene.objects[2] and won't get any error message or indication that they
> are not doing the right thing. IMO error checking is MORE important than
> backward compatibility: hardly anyone will remember Visual 3 in a year,
> but people will make the same errors forever."

I agree with most of the previous paragraph.


> But I also have a question about the example code you show.
>
> m.pick is the object picked, so you already know the object. What value
> is there in knowing the sequence position of this object in
> scene.objects, where the order of the objects is not relevant?
>

It is relevant, as long as the sequence itself is relevant.

Let's say that I'm taking GPS readings at regular intervals, marking a  
route, then i draw those points in VPython, in the very same order they  
where taken.

There are two ways I would like to access those points and getting any  
associated info to them: either merely pointing-and-clicking, Or navigate  
across the points sequence using keys defined as "Next" or "Previous". In  
the last case, since those points belong to a route, it is desirable to  
jump from point to point in the original order, either backwards or  
forward.

Best regard,

Roberto.

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