[Python-3000] Types and classes

[Benjamin Peterson]

On Wed, Apr 2, 2008 at 5:20 PM, Guido van Rossum <guido at python.org> wrote:

> On Wed, Apr 2, 2008 at 3:03 PM, Amaury Forgeot d'Arc <amauryfa at gmail.com>
> wrote:
> >  On Wed, Apr 2, 2008 at 11:57 PM, Paul Prescod <paul at prescod.net> wrote:
> >  >  But does anyone else find it odd that the types of some things are
> >  >  classes and the classes of some things are types?
> >  >
> >  >  >>> type(socket.socket())
> >  >  <class 'socket.socket'>
> >  >  >>> type("abc")
> >  >  <type 'str'>
> >  >  >>> socket.socket().__class__
> >  >  <class 'socket.socket'>
> >  >  >>> "abc".__class__
> >  >  <type 'str'>
> >  >
> >  >  In a recent talk I could only explain this as a historical quirk. As
> I
> >  >  understand, it is now possible to make types that behave basically
> >  >  exactly like classes and classes that behave exactly like types. Is
> >  >  there any important difference between them anymore?
> >
> >  I can find one difference:
> >  - types are written in C
> >  - classes are written in Python
> >
> >  and there is a difference in behaviour:
> >  most types don't have a writable __dict__, and you cannot add members.
> >  classes are more flexible.
>
> That's more correctly described as the difference between built-in
> types/classes and user-defined types/classes.
>
> I think it's still just a historical quirk; maybe we should bite the
> bullet and fix this in py3k. (Still, 'type' and 'class' will both be
> part of the language, one as a built-in function and metaclass, the
> other as a keyword.)

Especially because of that I think we should change. list, dict, and set
aren't metaclasses, so it would make since to fix it.

>
>
> --
> --Guido van Rossum (home page: http://www.python.org/~guido/<http://www.python.org/%7Eguido/>
> )
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-- 
Cheers,
Benjamin Peterson
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