Article View: comp.lang.java
Article #326Re: Will Java kill C++?
From: Graham Perkins
Date: Fri, 19 Apr 1996 15:35
Date: Fri, 19 Apr 1996 15:35
26 lines
1896 bytes
1896 bytes
Matthias Blume wrote: > > You understood me right -- I do not believe in OOP, and I won't defend > it. However, there is a middle ground, which is called `subtyping'. > Genuine subtyping is not middle ground, but an extreme. A type denotes a set of items. A subtype denotes a subset of those items. A subtype cannot be used as a polymorphic stand-in in a programming scenario unless all the operators of the main type are defined on the subset, and the subset is closed with respect to those operations. Trivially, NATURAL cannot be considered a subtype of INTEGER, nor FLOAT a subtype of DOUBLE. More importantly, most subclassing you find in yer average Smalltalk, C++, Eiffel, Java etc library is not genuine subtyping. IMHO Matthias is being a little too idealistic. Formal strictness is useful and generally not practised as wide as it should but software development also require pragmatism, and relaxing the notion of "subtype" yields a great deal of productivity potential without damaging static correctness too much. -- person: Graham Perkins paper: School of Computing voice: +44 (0)1908 834936 De Montfort University dots: +44 (0)1908 834948 Milton Keynes MK7 6HP bits: grp@dmu.ac.uk United Kingdom
Technical Details
Message-ID:
<3177B2BC.482B@dmu.ac.uk>Path:
arc1-ca.pugleaf.net!yama.mcc.ac.uk!dmu!usenetReferences:
<BLUME.96Apr16103345@zayin.cs.princeton.edu> <4l3vu1$imr@newsbf02.news.aol.com> <BLUME.96Apr18104240@zayin.cs.princeton.edu>Show Full Headers
Complete Article Headers
Path: arc1-ca.pugleaf.net!yama.mcc.ac.uk!dmu!usenet From: Graham Perkins <grp@dmu.ac.uk> Newsgroups: comp.lang.java,comp.lang.c++,comp.lang.smalltalk Subject: Re: Will Java kill C++? Date: Fri, 19 Apr 1996 16:35:24 +0100 Organization: De Montfort University Message-ID: <3177B2BC.482B@dmu.ac.uk> References: <BLUME.96Apr16103345@zayin.cs.princeton.edu> <4l3vu1$imr@newsbf02.news.aol.com> <BLUME.96Apr18104240@zayin.cs.princeton.edu> NNTP-Posting-Host: mkcsst22.mk.dmu.ac.uk Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Mailer: Mozilla 2.0 (Win16; I)