I found some very odd behaviour in Python's very basic types

[Terry Reedy]

On 3/10/2011 12:47 AM, Sunjay Varma wrote:
> For some reason, sub-classing and overwriting a built-in type does not
> change the behavior of the literal. Logically speaking, overwriting a
> name, such as str, should delete the basic str type, and replace it
> with the new class or object put in its place.

No, that is fundamentally wrong. Rebinding a name in a particular 
namespace only deletes the association in that namespace.

Built-in classes are just that. You cannot get rid of them. They are 
used in the operation of the interpreter.

> For some reason though,
> even though the interpreter says that str == type("hello"),
> overwriting the str name changes nothing in the literal.

Right. By design. String and number literals are always string and 
number literals.

> Is this a bug?

No.

-- 
Terry Jan Reedy