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: 103376,37e6dbf5e31f6da0 X-Google-Attributes: gid103376,public X-Google-Thread: 1108a1,37e6dbf5e31f6da0 X-Google-Attributes: gid1108a1,public X-Google-Thread: f43e6,37e6dbf5e31f6da0 X-Google-Attributes: gidf43e6,public X-Google-Thread: ff6c8,37e6dbf5e31f6da0 X-Google-Attributes: gidff6c8,public X-Google-Thread: 10db24,37e6dbf5e31f6da0 X-Google-Attributes: gid10db24,public From: "Norman H. Cohen" Subject: Re: Software Engineering News Brief Date: 1996/11/11 Message-ID: <32877082.1A29@watson.ibm.com>#1/1 X-Deja-AN: 195815257 references: <55nqea$32a@news2.delphi.com> <3280BAFA.1B2F@email.mot.com> <563tle$cu7$1@shade.twinsun.com> content-type: text/plain; charset=us-ascii organization: IBM Thomas J. Watson Research Center mime-version: 1.0 reply-to: ncohen@watson.ibm.com newsgroups: comp.lang.ada,comp.sw.components,comp.object,comp.software-eng,comp.edu x-mailer: Mozilla 3.0 (Win95; I) Date: 1996-11-11T00:00:00+00:00 List-Id: Paul Eggert wrote (about the range of years 1901 to 2099): > Actually, many kinds of applications require support for dates outside > that range; it was shortsighted of the Ada standard-writers to prohibit > implementations from having better standard date support than that. But if some implementations have better "standard date support" than others, it's no longer "standard", is it? The predefined Calendar package has a type for representing times and dates in the range 1901 to 2099, but an implementation can provide a nonstandard package that supports a different range, as long as the implementation ALSO provides the standard package. Similarly, a programmer can easily write hiw own package supporting a different range. The intended use of the package Calendar, reflected in its design, is the manipulation of dates and times during and near to the execution of the program, most obviously to query the current time or to establish the time at which some action should be performed. (Ada programs that use package Calendar construct dates prior to the advent of Ada are quite rare. The example of such a program on page 88 of Ada as a Second Language is intended to be facetious, as is made clear by the text introducing it.) The predefined package Calendar was not designed for calendrical calculations such as determining the day of the week on which November 11 occurred in the year 1376, and does not provide facilities that would be particularly helpful in making such calculations. If you were writing an application that required such calculations, you would probably write your own, quite different, package. -- Norman H. Cohen mailto:ncohen@watson.ibm.com http://www.research.ibm.com/people/n/ncohen