Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!mcsun!ukc!dcl-cs!aber-cs!athene!pcg From: pcg@cs.aber.ac.uk (Piercarlo Grandi) Newsgroups: comp.object Subject: Re: ADT vs. Objects Message-ID: Date: 15 Nov 90 18:42:56 GMT References: <1990Nov13.212012.3662@Neon.Stanford.EDU> <3187@mrsvr.UUCP> Sender: aro@aber-cs.UUCP Organization: Coleg Prifysgol Cymru Lines: 38 Nntp-Posting-Host: teachk In-reply-to: chandra@mrsvr.UUCP's message of 14 Nov 90 16:18:52 GMT Posting-Front-End: GNU Emacs 18.55.4 of Thu Nov 23 1989 on athene (berkeley-unix) On 14 Nov 90 16:18:52 GMT, chandra@mrsvr.UUCP (B. Chandramouli) said: chandra> From article <1990Nov13.212012.3662@Neon.Stanford.EDU>, by chandra> craig@Neon.Stanford.EDU (Craig D. Chambers): craig> Inheritance of implementation seems like something that could be moved craig> out of the core language and into the programming environment, where craig> more flexible and adaptive code sharing/automatic programming could be craig> done without cramming a lot of functionality into a language craig> mechanism. If only... But we are still stuck with linkers out of the black lagoon -- oops, sorry using technology from the fifties. Sixties technology (shared libraries, dynamic link resolution) is only now becoming better known. chandra> Replacing Inheritance with Code sharing/Reuse facilities chandra> provided by the programming environment will work only for chandra> cases where you have access to the source code. I would not be so sure. Reuse is not just about reusing source. That is mandatory only for inlining. Hey, after all a linker is a great tool belonging to the programming environment that provides _implementation_ reuse. What Craig Chambers is hinting at above is clearly smarter linkers, maybe with smarter libraries, e.g. something a little better than Ada's program library facility. chandra> You need inheritance provided by the language when you want to chandra> subclass from a class that is part of a standard class library chandra> provided by a vendor for which you have only the object code chandra> and not the source. Ahem. Really? I have ever more the impression that you have a very narrow definition of code sharing and reuse. -- Piercarlo Grandi | ARPA: pcg%uk.ac.aber.cs@nsfnet-relay.ac.uk Dept of CS, UCW Aberystwyth | UUCP: ...!mcsun!ukc!aber-cs!pcg Penglais, Aberystwyth SY23 3BZ, UK | INET: pcg@cs.aber.ac.uk