[Python-Dev] redefining is
ark-mlist at att.net
Fri Mar 19 17:40:57 EST 2004
> > It certainly doesn't *require* a builtin operator. I do think,
> > however, that the proposed comparison is more useful than "is" in
> > most contexts in which programmers use "is" today.
> Are you saying that most instances of "is" in current Python code
> are incorrect? If not, what do you mean by more useful?
I strongly suspect that most instances of "is" in current Python code would
not change their meaning, because most instances of "is" use either
singletons or mutable objects. However, I also think that a number of uses
of "is" that are currently incorrect, sometimes in subtle ways, would become
As things stand, I think I reluctantly agree that it's too big a change to
consider, because I can certainly imagine programs that might break.
Nevertheless, I still wish that expressions such as "x is 'foo'" did not
silently differ in outcome from one implementation to another.
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