Make 'def' and 'class' usable within expressions

[Shane Hathaway]

Thomas Heller wrote:
> Shane Hathaway <shane at zope.com> writes:
>>>    # Define an interface.
>>>    ICustomer = Interface(class):
>>>        def get_id():
>>>            """Return the customer ID"""
>>
>>Today, this would be written as:
>>
>>     class ICustomer:
>>         def get_id():
>>             """Return the customer ID"""
>>     ICustomer = Interface(ICustomer)
> 
> 
> With PEP 318 in place, it would be written as:
> 
>       class ICustomer [Interface]:
>           def get_id():
>               """Return the customer ID"""
> 
> Hm.
> 
> I like the third way best.  Why? The 'Interface(class)' idiom confuses
> me.  But maybe I'm infected by the PEP 318 virus.

What I don't like about the third alternative is the subtle distinction 
between parentheses and square brackets.  It seems like newbies would 
have a hard time with it, as would advanced programmers who are looking 
over a new code base.

Shane