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: 103376,80bc3e0698be468f X-Google-Attributes: gid103376,public X-Google-Language: ENGLISH,ASCII-7-bit Path: g2news1.google.com!postnews.google.com!z14g2000cwz.googlegroups.com!not-for-mail From: "jimmaureenrogers@worldnet.att.net" Newsgroups: comp.lang.ada Subject: Re: Type safety on wikipedia Date: 26 Jan 2006 05:53:28 -0800 Organization: http://groups.google.com Message-ID: <1138283608.433842.76060@z14g2000cwz.googlegroups.com> References: <1138260496.230283.147640@g43g2000cwa.googlegroups.com> NNTP-Posting-Host: 69.170.89.0 Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" X-Trace: posting.google.com 1138283614 28967 127.0.0.1 (26 Jan 2006 13:53:34 GMT) X-Complaints-To: groups-abuse@google.com NNTP-Posting-Date: Thu, 26 Jan 2006 13:53:34 +0000 (UTC) User-Agent: G2/0.2 X-HTTP-UserAgent: Mozilla/5.0 (Windows; U; Windows NT 5.1; rv:1.7.3) Gecko/20040913 Firefox/0.10,gzip(gfe),gzip(gfe) Complaints-To: groups-abuse@google.com Injection-Info: z14g2000cwz.googlegroups.com; posting-host=69.170.89.0; posting-account=SqOfxAwAAAAkL81YAPGH1JdBwpUXw9ZG Xref: g2news1.google.com comp.lang.ada:2647 Date: 2006-01-26T05:53:28-08:00 List-Id: "The appropriate formalization of this slogan depends on the style of formal semantics used for a particular language. In the context of denotational semantics, type safety means that the meaning (or the value) of an expression that is well-typed, say with type t, is a bona fide member of the set corresponding to t." Even with unchecked conversion Ada has the 'Valid attribute, allowing the programmer to determine if the result of an unchecked conversion is a valid value. I do not see how Unchecked_Deallocation interferes with type safety. Ada access types are typed. There is no Ada equivalent to a C void*. An Ada access type cannot be made to point to an object of some foreign type. For instance, type Integer_Access is access Integer; An instance of Integer_Access cannot reference a task, or a real number, or some record type. Garbage collection cannot improve type safety in Ada or any other language. It can only automate the process of deallocating dynamically allocated objects. Jim Rogers