Path: utzoo!attcan!uunet!cs.utexas.edu!milano!cadillac!vaughan@mcc.com
From: vaughan@mcc.com (Paul Vaughan)
Newsgroups: comp.lang.c++
Subject: Re: Arguments to Overloaded Operators
Message-ID: <1100@cadillac.CAD.MCC.COM>
Date: 8 Jun 89 16:13:00 GMT
References: <11032@orstcs.CS.ORST.EDU>
Sender: news@cadillac.CAD.MCC.COM
Reply-To: vaughan@mcc.com (Paul Vaughan)
Organization: MCC VLSI CAD Program
Lines: 22
In-reply-to: budd@mist.CS.ORST.EDU (Tim Budd)

Two questions:
1)
Has anyone considered overloaded functions/operators that are selected
not only by a match of parameter types, but also according to the
return type needed in the context?  That is, have multiple
definitions for the same function name with differing return types.
Forgive me if this has been beaten to death before.

2)
In LISP Flavors and CLOS, there has been a movement away from "message
passing" to generic functions.  Using what is called multiple argument
dispatch in CLOS, you get something like overloaded virtual functions.
The functions can be "virtual" on each argument.
One of the big advantages is that the distinction between member
functions and other functions (overloaded or not) goes away.  You no
longer have a special syntax for member function invocation, pointers
to member functions, or any of that, and it becomes almost transparent
whether a data object is implemented as a class or not.  Is anyone
considering a similar movement for C++?

 Paul Vaughan, MCC CAD Program | ARPA: vaughan@mcc.com | Phone: [512] 338-3639
 Box 200195, Austin, TX 78720  | UUCP: ...!cs.utexas.edu!milano!cadillac!vaughan