PEP 308: I liked the original proposal better

[Terry Reedy]

"Delaney, Timothy C (Timothy)" <tdelaney at avaya.com> wrote in message
news:mailman.1046059565.6975.python-list at python.org...
"class bool:

    def ifelse (self, trueresult, falseresult, callable=False):
        if self:
            if callable:
                return trueresult()
            else:
                return trueresult
        else:
            if callable:
                return falseresult()
            else:
                return falseresult

Short-circuiting and everything else required in one.
"

With the optional callable arg (which I did not notice in provious
proposals) this makes a lot of sense .... except that other forms do
not require the condition to be a boolean, so this would either
require bool(C).ifelse(x,y) or implementation as a builtin func rather
than method.  There is also extra overhead with func/method call.  If
one result is constant, and other not, forcing constant to be a
function adds a second layer of call overhead.  Still, anyone can add
function version of this to their utility package regardless of PEp
outcome.

Terry J. Reedy