[Python-Dev] Unifying Long Integers and Integers: baseint

[Guido van Rossum]

> This is why "integer" is a better name than "baseinteger".
> For now it can be the common supertype of int and long.
> In the future, it can be the name of the single integer
> type.

No, that will be int, of course!

Like 'basestring', 'baseinteger' is intentionally cumbersome, because
it is only the base class of all *built-in* integral types.  Note that
UserString is *not* subclassing basestring, and likewise if you wrote
an integer-like class from scratch it should not inherit from
baseinteger.  Code testing for these types is interested in knowing
whether something is a member of one of the *built-in* types, which is
often needed because other built-in operations (e.g. many extension
modules) only handle the built-in types.

If you want to test for integer-like or string-like behavior, you
won't be able to use isinstance(), but instead you'll have to check
for the presence of certain methods.

I know this is not easy in the case of integers, but I don't want to
start requiring inheritance from a marker base type now.  Python is
built on duck typing.  (Google for it.)

--Guido van Rossum (home page: http://www.python.org/~guido/)