Musings about Python syntax

[Jim Althoff]

Where can one find out more info on
"hasinterface" and "as_sequence"?

Is this a standard idiom for testing
for "sequence-ness"?

Is this different/better than something
like 

hasattr(anObject,"__get_item__")

I often want to determine whether or not
I am dealing with a sequence and would
like to use a "best practices" mechanism.

type(anObject) == type([]) or
    type(anObject) == type(())

seems too limited, BTW.

Any advice?

Thanks,

Jim


>
>    def len(obj):
>        if hasinterface(obj, as_sequence):
>            return obj.sequence_length()
>        if hasinterface(obj, as_mapping):
>            return obj.mapping_length()
>        raise TypeError, "len() of unsized object"
>
>which, for my non-purist eyes, surely looks as if
>Python treats "obj" as an arbitrary object.
>
></F>
>
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