[Python-Dev] PEP 285: Adding a bool type

[Andrew Koenig]

Guido> Another argument for deriving bool from int: implementation
Guido> inheritance.  A bool must behave just like an int, and this is
Guido> most easily accomplished this way: the bool type doesn't have
Guido> implementations for most operations: it inherits them from the
Guido> int type, which find a bool acceptable where an int is
Guido> required.

Liskov substitutibility would seem to suggest deriving int from bool,
not the other way around.  That is: If I have a program that uses bool
values, I can change it so that it uses int values without affecting
the behavior of the program.  The reverse is not true.

I wonder if this is the circle-ellipse problem over again?

-- 
Andrew Koenig, ark@research.att.com, http://www.research.att.com/info/ark