passing by refference

[Aahz]

In article <873cjfbrxd.fsf at charter.net>,
Doug Quale  <quale1 at charter.net> wrote:
>
>Argument passing in Java and C are no different from Python.  

At the technical level, that's correct, provided you define "argument"
correctly.  But because assignment does different things in Python, too
many Java/C programmers get confused with Python's semantics.

In C, you have this:

    myStruct a, b;
    a.x = 1;
    b = a;
    a.x = 2;
    print ("%d\n", b.x);

There's simply nowhere in Python that assignment performs a value copy
that way.  Using "value" to describe both the references to objects and
to the objects themselves is too confusing.  Therefore "call-by-value"
is confusing and should be avoided when discussing Python.
-- 
Aahz (aahz at pythoncraft.com)           <*>         http://www.pythoncraft.com/

"In many ways, it's a dull language, borrowing solid old concepts from
many other languages & styles:  boring syntax, unsurprising semantics,
few automatic coercions, etc etc.  But that's one of the things I like
about it."  --Tim Peters on Python, 16 Sep 93