Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!radar!cadillac!vaughan From: vaughan@puma.cad.mcc.com (Paul Vaughan) Newsgroups: comp.std.c++ Subject: Re: type/member tags (was Re: asking an object for its type) Message-ID: Date: 28 Feb 91 16:38:49 GMT References: <27C95D3A.1715@tct.uucp> <27CC322C.510C@tct.uucp> Sender: news@cadillac.CAD.MCC.COM Organization: MCC CAD Program, Austin, Texas Lines: 31 In-reply-to: chip@tct.uucp's message of 27 Feb 91 22:26:51 GMT I work on an application that has objects that know their type (implementation based on the NIHCL approach). This application also has many classes which do not have type information. I see this as an expression of the flexibility of C++--if you need type information, you can program it, otherwise you're not burdened with its overhead. However my attitude about this is not inflexible. I believe it would make sense to include type related functions for classes which have virtual functions as a standard part of the language. Overhead could be restricted to a per class basis, rather than a per object basis. Certain limitations, such as casting down from a virtual base class, could then be overcome. Compatibility with C would not be affected. Compatibility with existing code would be minimally affected. I believe that the need for this sort of information on objects that have virtual functions is pervasive enough to warrant this minimal overhead. I believe that compiler supported implementations could be substantially better than user programmed implementations. While I don't have any good suggestions for how this might be supported syntactically, I believe that a reasonable solution can be found. In short, I believe that it makes sense to recognize "classes with virtual functions" as an important concept worthy of a name and special functionality. -- 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 ---------------------------------------------------------------------------------- I spent from $3 to $10 today to pay interest on the national debt. How about you? ----------------------------------------------------------------------------------