pyode-user

[Pyode-user] subclassing ode

[Ricardo K. <ric...@gm...>]

Hi:

I want to create a subclass of ode.Body. I have written a class

class myBody(ode.Body):
    def __init__(self):
        self.world =3D ode.World()
        ode.Body.__init__(self, self.world)

...

The strange part is that when I execute the line

mb =3D myBody()

I get the error:

TypeError: function takes exactly 1 argument (0 given)

It appears as it tries to run the ode.Body.__init__ method before
calling the myBody.__init__ method. I have made some variations that
just confirm this thought.

Can anyone please tell me why this is happening, and how I can get around t=
his?

Regards,

Ricardo Kirkner

Re: [Pyode-user] subclassing ode

[Chris B. <chr...@gm...>]

On 23/01/06, Ricardo Kirkner <ric...@gm...> wrote:
> Hi:
>
> I want to create a subclass of ode.Body. I have written a class

> I get the error:
>
> TypeError: function takes exactly 1 argument (0 given)

PyODE uses Pyrex to wrap the C ODE library in python classes.

From http://www.cosc.canterbury.ac.nz/~greg/python/Pyrex/version/Doc/specia=
l_methods.html

"Keep in mind that any arguments passed to the constructor will be
passed to the __new__ method as well as the __init__ method. If you
anticipate subclassing your extension type in Python, you may find it
useful to give the __new__ method * and ** arguments so that it can
accept and ignore extra arguments. Otherwise, any Python subclass
which has an __init__ with a different signature will have to override
__new__ as well as __init__, which the writer of a Python class
wouldn't expect to have to do."

You can find the ode.Body wrapper in the pyode source at src/body.pyx