Is (-1 ==True) True or False? Neither

[Terry Reedy]

Oktay Şafak wrote:

> That's what I'm trying to say: it would be more meaningful if int.__eq__ 
> did a boolean comparison when the other operand is a boolean.

For that to be done, int would have to know about its subclass, which 
generally is bad design.

> The reason is that when 
> someone writes (-1 == True) he is clearly, definitely, absolutely asking 
> for a boolean comparison, not a numerical one.

I would say that the person does not understand Python and that the code 
is probably buggy.

 > As I said before, this is  weird code;

It is a bad idea to accommodate the language and interpreter to weird 
code which should never be written.

> Well, I agree that explicit is better than implicit: when one wants to 
> use the numerical values of True or False, he should make it explicit 
> and use int(True) or int(False).

The reason to make bool a subclass of int is to avoid having to do that. 
  You do not have to like this fact of Python but it has been decided 
and will not change.

 > We never write counter += True, for example.

But you might write counter += name, where you know name is bound to a 
bool.  As I said, issubclass(bool, int) just so one would not have to 
write counter += int(name).

>> If you want to cast an object to a boolean, use bool() on it.

> Well, I can tell you in response that if you are interested in a 
> boolean's *integer* value, than make it explicit and use int(True). 

A Python bool *is* an int already: isinstance(True, int) returns True!
Adding the bool subclass around 2.3 or so was a convenience that makes 
code and output clearer, but not a necessity.  Python did fine without 
it just as many other languages do.

Terry Jan Reedy