Re: [pygame] When to use a constant

[Jacob Schwartz <kevlarx@netidea.com>]

   Hey,
I had a simular problem with my pygame project - and the solution I 
ended up going with was using a Vector class I wrote myself (in C).
It seemed to be the only way I could use both array index's and letters 
(.x, .y) to access vectors, and still nicely encapsulate common 
operations such as vector multiplication and normalization.

I'd be happy to share the code (.c file + .py unit test) to anyone whos 
interested.

      - Jacob

> I'm working on a simple 2D physical simulation.  The various 
> simulation objects have position and velocity attributes that store 
> the x and y components in a list.  So, to get the y component of 
> velocity for some object you do something like "sim_object.velocity[1]".
>
> Recently I've been tempted to define constants for the index values of 
> the lists, so I'd have X = 0, and Y = 1, and the code from above would 
> be "sim_object.velocity[Y]".  It would make reading the simulation 
> code somewhat easier (no more converting 0 to x and y to 1 in my head) 
> but it would add a level of indirection, which could be confusing.
>
> So, the question is, would using constants in this way be a reasonable 
> thing to do, or is it bad practice?