[Thuban-devel] Re: RfD: Support for layer specific resources

[Bernhard Herzog]

Martin Schulze <joey at infodrom.org> writes:

> Sorry for the flood of mails.  Attached please find the test case
> and the real implementation for the Mapping class.  Hope this is
> what you want.

Almost there.

> class Mapping:

The name is a bit too generic.  Maybe ClassMapper?

>     """
>     Implements a mapping of class pairs
>     """

Actually, it's a mapping of classes (and instances thereof) to arbitrary
objects.  The renderer extensions are usually functions, for instance.

>     mapping = []

What's that for?

>     def __init__(self):
>         mapping = []
>
>     def register_class(self, key_class, client_class):
>         self.mapping.append((key_class, client_class))

I'd simply call this method "add".

>     def get_class(self, instance):
>         for key_class, client_class in self.mapping:
>             if isinstance(instance, key_class):
>                 return client_class
>         return None

And this just "get".  Makes the interface a little more like that of a
normal dict.  Also, client_class isn't restricted to classes.  It can be
an arbitrary Python object, so "obj" or "value" would be better.

>     def has_mapping(self, instance):
>         return self.get_class(instance) is not None

Maybe just "has". The dict equivalent would be "has_key" but that
doesn't fit this class all that well, though, because the instances
aren't the keys, although the behave a bit like ones.

   Bernhard

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