Re: [typecheck-users] How to accept NoneType

[shi d. <shi...@gm...>]

Sorry, I wrote my last e-mail too fast (my example is totally wrong).
My objective is to define a class where some attributes can be optionnal.
If an optionnal attribute is defined then it should be a String for example.
I would like to have something like :

String = IsOneOf(str, unicode, NoneType)
class MyClass(object):
    @accept(String, String)
    def __init__(a, b=None):
        blabla ...
but None cannot be used with the operator IsOneOf, etc.
Does it mean that with typecheck, a method or function looses its ability
to have optionnal argument ?

Thx,
Marc.


2009/1/11 shi dingan <shi...@gm...>

> Hi,
>
> I would like to define a class where an
> attribute can be None.
> For instance :
> @accept(String, String)
> class MyClass(a, b=None):
>     if b:
>         return b
>     else:
>         return a
> I didn't find a way to use typecheck on this kind
> of class. I tried to define String with
> String = IsOneOf(str, unicode, NoneType) but it does
> not work. It seems that 'None' can not
> be checked. Have you any idea ?
>
> Regards,
> Marc.
>
>