Arnaud Delobelle wrote:
// What is passed to foo below is obviously not a 'variable
// reference' as the argument is not a variable.
foo(a[3]); // Now a[3] == 7
foo(b.i); // Now b.i == 7
Yes, it is. By "variable" I mean what C calls an lvalue,
i.e. something you can assign to.
I'm not sure that your definition of 'call by value' is widely
accepted. If it was, then this thread wouldn't exist.
It seems to be accepted by the Java and VB community,
judging by what they refer to as call-by-value in those
languages.
You won't necessarily find it written down anywhere in
the exact words I used. I have reverse-engineered it
from the characteristics of a wide variety of languages
that use the term call-by-value to describe one of their
parameter passing mechanisms. Think of it as a theory
that fits the observed linguistic facts.
(CBV) An evaluation strategy where arguments are evaluated before
the function or procedure is entered. Only the values of the
arguments are passed and changes to the arguments within the called
procedure have no effect on the actual arguments as seen by the
caller.
That hinges on what exactly is meant by "changes to
the arguments". In Python it can only mean assigning
directly to the bare name -- anything else isn't
changing the argument itself, but something else to
which the argument refers.
--
Greg
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