From: Xavier Noria <fxn@...>
Date: 2007-09-30T02:39:11+09:00
Subject: Re: a different type of reference (shocked)

On Sep 29, 2007, at 4:59 PM, Robert Dober wrote:

> You are however wrong IMHO when looking at the problem from the
> callees side, there is only one parameter which is @_. You have
> accessed it in your example and when assigning to it the assignment is
> not propagated to the actual parameters, that  is clearly *not* call
> by reference behavior.
> or is my knowledge outdated maybe (I have learnt that 25years ago).

Note that's your own interpretation, which does not coincide with the  
semantics of Perl. In Perl @_ is not an argument, it is the mean by  
which a function receives its arguments (versus named parameters).  
That's the role of @_.

Since in Perl the arguments are the elements of @_, the fact that  
assigning to $_[0] changes the value in the caller's shows Perl is  
pass-by-reference. I explained a bit what happens under the hood to  
depict aliases are actually passed through the stack. But to justify  
pass-by-reference (eg in the Camel Book) you don't refer to the  
implementation, you assert it does because of the way it works,  
because of the semantics.

-- fxn