[Python-Dev] Unifying Long Integers and Integers: baseint (original) (raw)

Guido van Rossum guido at python.org
Thu Aug 12 16:44:05 CEST 2004

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/)

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