Another newbie question

[Paul Rubin]

aleax at mail.comcast.net (Alex Martelli) writes:
> > I could imagine using Python's built-in complex numbers to represent
> > 2D points.  They're immutable, last I checked.  I don't see a big
> > conflict.
> 
> No big conflict at all -- as I recall, last I checked, computation on
> complex numbers was optimized enough to make them an excellent choice
> for 2D points' internal representations.  I suspect you wouldn't want to
> *expose* them as such (e.g. by inheriting) but rather wrap them, because
> referring to the .real and .imag "coordinates" of a point (rather than
> .x and .y) IS rather weird.  Wrapping would also leave you the choice of
> making 2D coordinates a class with mutable instances, if you wish,
> reducing the choice of a complex rather than two reals to a "mere
> implementation detail";-).

Right, you could use properties to make point.x get the real part of
an internal complex number.  But now you're back to point.x being an
accessor function; you've just set things up so you can call it
without parentheses, like in Perl.  E.g.

    a = point.x
    b = point.x
    assert (a is b)    # can fail

for that matter

    assert (point.x is point.x) 

can fail.  These attributes aren't "member variables" any more.