home *** CD-ROM | disk | FTP | other *** search
- Xref: sparky comp.lang.c++:11222 comp.std.c++:892
- Newsgroups: comp.lang.c++,comp.std.c++
- Path: sparky!uunet!mcsun!Germany.EU.net!news.netmbx.de!netmbx!jrobie
- From: jrobie@netmbx.netmbx.de (Jonathan Robie)
- Subject: Re: run-time type checking (was: Re: Covariant Types in Derived Classes)
- Organization: netmbx, Berlin, Germany
- Date: Tue, 21 Jul 1992 13:53:36 GMT
- Message-ID: <78A50WF@netmbx.netmbx.de>
- References: <1992Jul20.143900.23087@merlin.hgc.edu> <1992Jul20.215058.1216@cadsun.corp.mot.com>
- Lines: 39
-
- shang@corp.mot.com (David (Lujun) Shang) writes:
-
- >In article <1992Jul20.143900.23087@merlin.hgc.edu> jcm@hgc.edu (James McKim)
- >writes:
- >> If I store a bunch of animals on the disk, I'm probably doing so
- >> because I don't expect that I will need to access features specific
- >> to a dog.
-
- >I belive many OO database users are much more critical than you.
- Absolutely! If I store an object, then I expect that I can retrieve
- that same object and have it act just exactly like the object that I
- stored--it should have the same state and behavior.
-
- After all, if I use polymorphy, then I am using the base class as an
- interface to derived classes which may not even exist at the time I
- design my interface.
-
- Take the above statement and try to apply it to a CAD system: If I
- draw a bunch of shapes on the screen, I'm probably doing so because
- I don't expect that I will need to draw things specific to a circle.
- Is this really the way we want to approach polymorphy?
-
-
- Jonathan
-
- ===========================================================================
-
- Jonathan Robie jrobie@netmbx.UUCP
- Arnold-Zweig-Str. 44 jrobie@netmbx.in-berlin.de
- O-1100 Berlin
- Deutschland Phone: +37 (2) 472 04 19 (Home, East Berlin)
- +49 (30) 342 30 66 (Work, West Berlin)
-
-
- --
- Jonathan
-
- ===========================================================================
-
-