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,FREEMAIL_FROM autolearn=ham autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 103376,309015504ed37ff0 X-Google-Attributes: gid103376,public X-Google-ArrivalTime: 2003-09-29 20:11:03 PST Path: news1.google.com!newsfeed.stanford.edu!headwall.stanford.edu!newshub.sdsu.edu!elnk-nf2-pas!newsfeed.earthlink.net!wn14feed!wn13feed!wn11feed!worldnet.att.net!204.127.198.203!attbi_feed3!attbi_feed4!attbi.com!rwcrnsc51.ops.asp.att.net.POSTED!not-for-mail Message-ID: <3F78F430.1070909@comcast.net> From: "Robert I. Eachus" User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:1.0.2) Gecko/20021120 Netscape/7.01 X-Accept-Language: en-us, en MIME-Version: 1.0 Newsgroups: comp.lang.ada Subject: Re: Usage of Interfaces with Ada 95 References: <1064595326.831730@master.nyc.kbcfp.com> <4nii41-067.ln1@boavista.snafu.de> <3F7726E4.6040402@comcast.net> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit NNTP-Posting-Host: 24.34.139.183 X-Complaints-To: abuse@comcast.net X-Trace: rwcrnsc51.ops.asp.att.net 1064891462 24.34.139.183 (Tue, 30 Sep 2003 03:11:02 GMT) NNTP-Posting-Date: Tue, 30 Sep 2003 03:11:02 GMT Organization: Comcast Online Date: Tue, 30 Sep 2003 03:11:02 GMT Xref: news1.google.com comp.lang.ada:282 Date: 2003-09-30T03:11:02+00:00 List-Id: Hyman Rosen wrote: > Me too. How unfortunate that in Ada, to get abilities similar > to C++'s constructors, destructors, and assignment operator > you must inherit from a common base class! Nope! Mix-ins to the rescue. You can mix a component of a type derived from Controlled (or Limited Controlled) into an uncontrolled type. In fact, the base type doesn't even need to be tagged. Access discriminants can be used to allow the operations of the controlled component to access the entire record. (But if you use this style you will find that the access discriminants are not often needed.) -- Robert I. Eachus "Quality is the Buddha. Quality is scientific reality. Quality is the goal of Art. It remains to work these concepts into a practical, down-to-earth context, and for this there is nothing more practical or down-to-earth than what I have been talking about all along...the repair of an old motorcycle." -- from Zen and the Art of Motorcycle Maintenance by Robert Pirsig