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=-1.3 required=5.0 tests=BAYES_00,INVALID_MSGID autolearn=no autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: fac41,2c6139ce13be9980 X-Google-Attributes: gidfac41,public X-Google-Thread: 103376,3d3f20d31be1c33a X-Google-Attributes: gid103376,public X-Google-Thread: 1108a1,2c6139ce13be9980 X-Google-Attributes: gid1108a1,public X-Google-Thread: f43e6,2c6139ce13be9980 X-Google-Attributes: gidf43e6,public From: Matt Austern Subject: Re: Safety-critical development in Ada and Eiffel Date: 1997/08/14 Message-ID: #1/1 X-Deja-AN: 264194612 References: <33E9ADE9.4709@flash.net> <33F133D7.71AC@erols.com> <33F25933.7F83@flash.net> <33F27B5C.6A3C@erols.com> Organization: SGI Newsgroups: comp.object,comp.software-eng,comp.lang.ada,comp.lang.eiffel Date: 1997-08-14T00:00:00+00:00 List-Id: Ted Velkoff writes: > Meanwhile at home I write software in Eiffel, where assertions are built > into the language. In Eiffel, all I do is Step 1: write the > pre/post-conditions and invariants. I don't need to do Step 2 (keep > spec and body in synch) since in Eiffel, the spec (properly speaking, > the short form) is automatically generated by tools. Step 3, (coding > the assertion tests, handling failures, providing useful diagnostics) is > provided automatically by the environment. Furthermore, the three flaws > are eliminated: 1) with a compile-time switch I can turn off monitoring > (I don't have to go through and "comment out" reams of code); 2) it's > easy to monitor post-conditions, since this is provided by the tools > (caveat - this is useful for testing and integration; postcondition > monitoring necessarily incurs a performance penalty); 3) mentioned > above, there is no spec/body redundancy to be managed by the programmer. Have preconditions and postconditions been extended in recent versions of Eiffel? I haven't yet read the second editon of Eiffel: The Language yet, and I haven't used Eiffel for a year or so. When I last did, though, there were a number of restrictions on them. I note that, because of those restrictions, many of the interesting preconditions and postconditions in ETL itself were written as comments rather than as executable code.