From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me X-Spam-Level: X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00 autolearn=ham autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 103376,1116ece181be1aea X-Google-Attributes: gid103376,public X-Google-ArrivalTime: 2003-09-08 07:36:02 PST Path: archiver1.google.com!news1.google.com!newsfeed.stanford.edu!logbridge.uoregon.edu!snoopy.risq.qc.ca!chi1.webusenet.com!news.webusenet.com!cyclone1.gnilink.net!spamkiller2.gnilink.net!nwrdny02.gnilink.net.POSTED!53ab2750!not-for-mail From: Ed Falis Newsgroups: comp.lang.ada Subject: Re: Is the Writing on the Wall for Ada? Message-ID: <20030908103535.29112320.falis@verizon.net> References: <3F5B8084.5080705@attbi.com> X-Newsreader: Sylpheed version 0.9.4claws (GTK+ 1.2.10; i386-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Date: Mon, 08 Sep 2003 14:36:01 GMT NNTP-Posting-Host: 151.203.77.184 X-Complaints-To: abuse@verizon.net X-Trace: nwrdny02.gnilink.net 1063031761 151.203.77.184 (Mon, 08 Sep 2003 10:36:01 EDT) NNTP-Posting-Date: Mon, 08 Sep 2003 10:36:01 EDT Xref: archiver1.google.com comp.lang.ada:42278 Date: 2003-09-08T14:36:01+00:00 List-Id: On Sun, 07 Sep 2003 19:01:48 GMT "Robert I. Eachus" wrote: > There is a proposal for Ada 200X to add interfaces to Ada. It has > been extensively worked, and will almost surely be added. > > Why? Because intefaces are different from Ada generics and solve > other problems. In particular adding interfaces to Ada allows derived > types where the type inherits one parent type and adds one or more > interfaces. > The user must then provide explicitly declared subprograms to match > any subprograms in the interfaces that are not provided by the parent > type. (In the proposal you can inherit from only interfaces as well. > But directly inheriting from only one interface is not that > interesting a case.) To get a feel for the real power of interfaces, check out "Working with Objects" by Trygve Reenskaug. This is a book from the Smalltalk community, but the concepts in it are broadly applicable. In Reenskaug's approach, interfaces are similar to the "roles" he describes. - Ed