Re: [pygame] immutable vectors in math package

[Lorenz Quack <don@xxxxxxxxxxxxxxxxx>]

Hi Christopher,

good question.
Currently the Vector types are implemented in a C-extension and I'm not sure how to subclass from a pure python object 
in C. I'm sure it's possible just that I've never done it before.
But I am afraid that you would have to go through the Python API to access any attributes from the C side which would 
have a negative impact on performance.
Another alternative would be to implement the whole thing in pure python, which certainly is a possibility. Just one 
that I didn't pursue.

Cheers,
Lorenz


On 30/10/14 01:14, Christopher Night wrote:
> I have not used either the original API nor yours, so this suggestion may be off base, but if they're going to be
> immutable, why not subclass collections.namedtuple("Vector2", "x y"), and get a few handy methods defined for free?
>
> -Christopher
>
> On Wed Oct 29 2014 at 7:41:54 PM Greg Ewing <greg.ewing@xxxxxxxxxxxxxxxx <mailto:greg.ewing@xxxxxxxxxxxxxxxx>> wrote:
>
>     Lorenz Quack wrote:
>
>      >  * you cannot access the components x/y/z directly...
>       > use ... new accessor methods x()/y()/z()
>
>     Is this change really necessary? It will be a big backward
>     step for code readability.
>
>     There shouldn't be any reason you can't provide read-only
>     access using attribute notation.
>
>     --
>     Greg