Re: class proposal 2

Greg Ewing wrote:
> Mark Hahn <[email protected]>:

>> I've got a two-tier class proposal that is more concrete than my old one.
>> It is mostly based on Serge's proposal but I feel Paul's thinking is
>> incorporated.  As always feel free to shoot holes in it.

> This looks interesting, but something doesn't seem quite right about
> it. If class methods are to be methods of the class in the same way
> that instance methods are methods of the instance, they should be kept
> in the instance-method-area of the class's class, not in the class.

> Classes in this proposal don't seem to have classes. In other words,
> they're not themselves objects within their own paradigm.  In this
> respect, they're more like old-style Python classes.  To a Python
> person, this will seem like a backward step.

The missing link is type. I've been pitching "right" types
since I realized how types in 1-tier system should work,
http://www.prothon.org/pipermail/prothon-user/2004-June/001805.html
later I realized the same applies to 2-tier systems.

Every class should have Type type:

class Type:
    class:
        type_ = Type
    ....

class X:
    class:
        type_ = Type
    instance:
        type = X

Besides all new class proposals break except statement, if
you try to write

except X:

it won't work because except is walking prototype chain and
the chain will lead you to X.instance_ prototype which is
not equal to X. Types solve that.

  -- Serge