building embedded classes as in C/C++

[Markus Stenberg]

Andy Beall <beall at psych.ucsb.edu> writes:
> I'd like to build an embedded structure (Python class) much like I do in
> C if possible.  When I do the following, multiple instances of my final
> class overwrite each others sub-class values!

You did not pay attention, however; you set _class_wide_ variables, global
to all instances (pos, ang). Thus, the behavior was to be expected.

Try this instead:

class Object:
	def __init__(self):
		self.pos = Point()
		self.ang = Point()

> 
> -------------------------------------------------------------------------
> class Point:
> 	x = 0
> 	y = 0
> 	z = 0
> 
> class Object:
> 	pos = Point()
> 	ang = Point()
> 
> 
> obj1 = Object()
> obj2 = Object()
> 
> obj1.ang.x = 123
> 
> print obj2.ang.x    <<-- AND I FIND IT CONTAINS OBJ1's X VALUE
> -------------------------------------------------------------------------
> 
> 
> 
> In C, this would be:
> 
> -------------------------------------------------------------------------
> typedef struct Point {
> 	float  x;
> 	float  y;
> 	float  z;
> } Point;
> 
> typedef struct Object {
> 	Point  pos;
> 	Point  ang;
> } Object;
> 
> Object obj1;
> Object obj2;
> 
> obj1.ang.x = 123;
> printf("%f", obj2.ang.x);   <<-- AND NOW THE VALUES IN OBJ1 AND OBJ2 
> 				 WILL NOT BE RELATED (OBJ2 WILL JUST 
> 				 CONTAIN GARGAGE AT THIS POINT).
> -------------------------------------------------------------------------

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