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From: wrl@apple.com (Wayne Loofbourrow)
Newsgroups: comp.lang.c++
Subject: Proposed extension ++@ , @++
Message-ID: <4684@internal.Apple.COM>
Date: 11 Oct 89 23:27:34 GMT
Sender: usenet@Apple.COM
Organization: Apple Computer, Inc.
Lines: 45

The following is a proposed extension to operator overloading of 
operator++ and operator-- :

In current C++, it is possible to overload operator ++.  However, it is 
not possible to make a distinction between prefix and postfix usage.
This leads to an inability to create user-defined types that
behave just like built in types.

How about allowing declarations of the form:

class complex
{
    // ...
public:
    // ...
    complex operator ++@ ();  // prefix ++ operator
    complex operator @++ ();  // postfix ++ operator
};

complex complex::operator ++@()
{
    *this = *this + 1;
    return *this;
}

complex complex::operator @++()
{
    complex c = *this;
    *this = *this + 1;
    return c;
}

For compatibility with current C++, defining the operator++ function would 
be equivalent to defining both operator ++@ and operator @++ identically.
This should allow all current C++ code to work just fine and also
allow further discrimination when it is desired.

The same extension would apply to operator-- .

What do people think?

Wayne Loofbourrow
Advanced Technology Group
Apple Computer, Inc.
Internet: wrl@apple.com