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

[Guido van Rossum]

> > But this is the whole point of introducing a new type rather than
> > simply defining True as 1 and False as 0!
> 
> That's not how I read it: making bool a type would allow type
> checks to be done and this is a *much* more important feature
> to have than some different str(obj) output.

Depending on your POV, yes.

> There are many situations when doing RPC or interfacing with
> other systems such as databases where a type check for
> booleans is needed.

Agreed, this is a nice additional advantage.

> Currently, this can be done by simply using the already
> existing Py_True and Py_False which are exposed at
> Python level through (1==1) and (1==0) and we should not
> break this scheme. '%s' % True must continue to
> deliver '0' otherwise you'll end up breaking interfaces
> which rely on this (such as database modules).

That's a good question.  Don't databases have a separate Boolean type?
Is there really code out that relies on this?  The code would have to
assume that the boolean argument is already normalized to being
exactly 0 or 1; a generalized Python truth value wouldn't work.

I can provide a real implementation next week, and we should have
plenty of time to find out how much it breaks.

> There's also another issue here: "True" and "False"
> are English words, "0" and "1" are language neutral.

Methinks you are getting desperate for arguments here. :-)  Or should
we also remove "if" from the language?

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