[Bf-python] Re: Python Ipocurve/CurNurb module changes

[Ken Hughes]

Stephen Swaney wrote:
> On Tue, Jun 21, 2005 at 01:36:29PM -0700, Ken Hughes wrote:
> 
>>>Since the control points are an attribute of a curve, we should change
>>>the BezTriple impl. to hold a pointer to the parent curve and an index
>>>into the control point array.  This way we can throw an exception when
>>>the control point array has changed too radically.  I know this is not
>>>a pythonic as we would like, but given that we are wrapping an array
>>>contained in an object, I believe it is a reasonable compromise.  This
>>>behavior will need to be explicitly documented.  This change affects
>>>iterators.
>>
>>My idea goes the other way; the curve hold pointers to its child bezTriple.
>>Changes to the curve are propagated down to them; deletion of points is
>>handled by NULLing the bezTriple's pointer.  Each bezTriple only has to
>>check "if (!self->bezt)" to throw an exception.
> 
> The thing we are wrapping here is an array contained inside a blender
> object, not an independent object.  If we were doing a clean
> implementation, I would agree completely.

I'm about to start pulling out my code and starting to think about your
way.  Can you define "changed too radically"?  Only thing I can think
of is a BezTriple sees its index is greater than the curve's list length.

[Aside #1: Again, in defense of my approach (as in "elaborate on
implementation") it disadvantages are it has a speed penalty when points
are added or removed from the curve (but only then), and it incurs extra
storage (unused pointers).  Advantage is no segfaults.]

Ken