API is not very pythonic

[lily-mara]

This is just an opinion, but all of the POVRayElement subclasses seem to have a very peacemeal API that has some strange conventions.

If I'm creating a new Camera object and I want it to be located at [0, 2, -3], and looking at [0, 1, 2], compare these methods for constructing that Camera:

# current method
c = Camera( 'location', [0, 2, -3], 'look_at', [0, 1, 2] )

# If I later want to update the properties of that Camera, I have some very confusing parsing to do:

# update c's location to [1, 2, 3]
c.args[c.args.index('location')+1] = [1, 2, 3]

Proposed API:

# current method
c = Camera( location=[0, 2, -3], look_at=[0, 1, 2] )

# If I later want to update the properties of that Camera, it's very easy:

# update c's location to [1, 2, 3]
c.location = [1, 2, 3]

The implementation for this is not much more complex than the current one:

class POVRayElement:
    def __init__(self, **kwargs):
        self.__dict__.update(kwargs)

[Zulko]

I know that it is not Pythonic at all, but your API won't work, because in POVRay the order of the arguments matters a lot. For instance this:

Sphere(xyz, radius, Texture(...), 'scale', 0.5)

Is different from this:

Sphere(xyz, radius, 'scale', 0.5, Texture(...))

In the first example the scaling applies to the texture, in the second it doesn't. You lose this flexibility if you have an argument scale=0.5 because then you can't decide of an order. And that's just one example, there are other syntaxic things that you just can't reproduce with keyword arguments.

And I am too lazy to reprogram each function to give the order in which the arguments must appear.

But it's not a big deal, to change the properties of the camera, just construct a new camera, for instance:

myscene = Scene(camera=Camera(), items=[...])
# later
myscene.camera = Camera(...)

[lily-mara]

wouldn't the scale only apply to the Texture if it was layed out like this?

sphere { xyz radius texture { scale 0.5 } }

[Zulko]

See at the end of this page. Another example which comes to mind is "translate" and "rotate", for which the order matters.

[Zulko]

So yeah this whole library is just an horrible hack. If you have other suggestions, they are welcome !