On Thu, Sep 7, 2017 at 11:21 PM, Gregory Ewing <greg.ew...@canterbury.ac.nz> wrote: > Rustom Mody wrote: > >> I said: In that case please restate the definition of 'is' from the manual >> which invokes the notion of 'memory' without bringing in memory. > > > I don't know whether it's in the manual, but at least for > mutable objects, there is a way to define the notion of > "same object" that doesn't require talking about "memory": > > Two names refer to the same object if and only if mutations > made through one are visible through the other. > > Python has definite rules concerning when mutable objects > will be the same or not, and every correct implementation > must conform to them. In that sense it's a fundamental > concept that doesn't depend on implementation.
Yep. I'd call this a litmus test rather than a definition, but it's absolutely true - and it's why languages without mutable objects don't really care whether they're pass-by-X or pass-by-Y. ChrisA -- https://mail.python.org/mailman/listinfo/python-list
