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-Thread: 103376,ec21c3c7cdc7ff3e X-Google-Attributes: gid103376,public X-Google-Language: ENGLISH,ASCII-7-bit Path: g2news1.google.com!news2.google.com!news4.google.com!newsfeed2.dallas1.level3.net!news.level3.com!newsfeed-00.mathworks.com!nntp.TheWorld.com!not-for-mail From: Robert A Duff Newsgroups: comp.lang.ada Subject: Re: Handling invalid objects Date: 20 Mar 2006 10:25:47 -0500 Organization: The World Public Access UNIX, Brookline, MA Message-ID: References: <1142279908.327131.230200@j52g2000cwj.googlegroups.com> <41LSf.4126$TK2.1805@trnddc07> NNTP-Posting-Host: shell01.theworld.com Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Trace: pcls4.std.com 1142868347 11909 192.74.137.71 (20 Mar 2006 15:25:47 GMT) X-Complaints-To: abuse@TheWorld.com NNTP-Posting-Date: Mon, 20 Mar 2006 15:25:47 +0000 (UTC) User-Agent: Gnus/5.09 (Gnus v5.9.0) Emacs/21.2 Xref: g2news1.google.com comp.lang.ada:3492 Date: 2006-03-20T10:25:47-05:00 List-Id: "Dr. Adrian Wrigley" writes: > It'd be great if the language allowed me to set and propagate > invalid values naturally! Well, it would be pretty inefficient if Booleans had an extra "invalid" value, with or without hardware support. Think about packed arrays of Boolean. Such a feature should be optional. Some languages do support such things with lighter syntax than the variant record somebody suggested earlier. - Bob