passing by refference

Fredrik Lundh fredrik at pythonware.com
Thu May 15 18:25:45 EDT 2003


Joshua Marshall wrote:

> It's only here that I disagree with you.  I consider Python values
> themselves to be object references

if you keep inventing your own terminology, you'll never win this
argument:

    http://www.python.org/doc/current/ref/objects.html

    "Objects, values and types"

    _Objects_ are Python's abstraction for data. All data in a
    Python program is represented by objects or by relations
    between objects.

    Every object has an identity, a type and a value. An object's
    _identity_ never changes once it has been created; you may
    think of it as the object's address in memory. /.../ An object's
    _type_ is also unchangeable. It determines the operations that
    an object supports (e.g., ``does it have a length?'') and also
    defines the possible values for objects of that type. /.../ The
    _value_ of some objects can change. Objects whose value can
    change are said to be _mutable_; objects whose value is un-
    changeable once they are created are called _immutable_.

(this is basically the same terminology as in the CLU papers, except
that they used the term "state" instead of Python's "value")

...so I guess what you've been saying all the time is that Python
uses call-by-identity, not call-by-state.  fair enough.

</F>








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