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=0.2 required=5.0 tests=BAYES_00,INVALID_MSGID, REPLYTO_WITHOUT_TO_CC autolearn=no autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 103376,555956c1cdd22308 X-Google-Attributes: gid103376,public From: Mats Weber Subject: Re: Help - Constructors - ASAP. Date: 1998/07/31 Message-ID: <35C1043E.9FFB23D0@elca-matrix.ch>#1/1 X-Deja-AN: 376690239 Content-Transfer-Encoding: 7bit References: <6p75qi$rcj@news.latnet.lv> <6pi4jq$j73$1@nnrp1.dejanews.com> <6pqdr2$hn2$1@nnrp1.dejanews.com> Content-Type: text/plain; charset=us-ascii Organization: EUnet AG Mime-Version: 1.0 Reply-To: Mats.Weber@elca-matrix.ch Newsgroups: comp.lang.ada Date: 1998-07-31T00:00:00+00:00 List-Id: tedennison@my-dejanews.com wrote: > But what happens in the situation where the client (perhaps a different > developer) wants to make a child class with fields that *must* be > initialized? That seems a quite reasonable thing to do. But now the > class-wide "constructor" isn't valid anymore. It can still be called for this > new child object, but will return a garbage value. That garbage value will be a value of the parent type, and assigning it to an object of the Child type, or to an object of type Child'Class, will raise Constraint_Error, so the problem will not go undetected. If your contructors are not class-wide and not primitive, then you detect the problem at compile time. > The only way I can see around this problem is to *also* declare a primitive > constructor, and have the body of the class-wide consructor redispatch to > that. If you do that, you will run into all sorts of ambiguous call situations where you will have to qualify your expressions.