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: fac41,2c6139ce13be9980 X-Google-Attributes: gidfac41,public X-Google-Thread: f43e6,2c6139ce13be9980 X-Google-Attributes: gidf43e6,public X-Google-Thread: 103376,3d3f20d31be1c33a X-Google-Attributes: gid103376,public X-Google-Thread: 1108a1,2c6139ce13be9980 X-Google-Attributes: gid1108a1,public From: kennel@nospam.lyapunov.ucsd.edu (Matt Kennel (Remove 'NOSPAM' to reply)) Subject: Re: Interface/Implementation (was Re: Design by Contract) Date: 1997/09/06 Message-ID: #1/1 X-Deja-AN: 270161042 References: <340C85CE.6F42@link.com> Reply-To: kennel@NOSPAMlyapunov.ucsd.edu Organization: University of California at San Diego Newsgroups: comp.object,comp.software-eng,comp.lang.ada,comp.lang.eiffel Date: 1997-09-06T00:00:00+00:00 List-Id: On Fri, 05 Sep 1997 09:11:02 -0800, Matthew Heaney wrote: :Note that many computer scientists, among them Tony Hoare, believe that a :measurement of goodness of a language is its ability to be compiled using a :single pass. Did he say what the sign of the 'goodness delta' for a single pass was? Maybe it's negative? :-) :In that tradition, Ada was design so that it could be :compiled in a single pass. What counts as a 'pass'? :>Does the Ada95 standard impose dependency-related ordering? : :Ada was designed in the belief that the source text of a program has two :consumers: the human reader, and the Ada compiler. As such, the Ada :philosophy is that, when reading the code, one's understanding of the code :should only depend on what has come before. So yes, if there is a :dependency ordering between two subprogram bodies, then either the :dependent body must follow the other, or a specification for the body must :preceed the dependent body (subprogram specs can appear in the package :body). Wow. That is a really antideluvian mode of thought. :That there is a dependency-related ordering in Ada (both 83 and 95) is by :design; that was the precise intent of Ada's designers. This should be :regarded as a Good Thing, because it makes it easier for the human reader :to apprehend program text. Does it, really? Am I supposed to apprehend a whole program as if it were all dumped on some line printer---but as if I had never read it before, like a novel? Who would do that? Dilbert's pointy-headed-boss? :-) In real life could I even REMEMBER which identifiers were identified when? Or is this something that a computer can only remember perfectly? In real life, while I'm programming, why am I supposed to have to remember which things are "before" and "after", in some silly conflation of location in a text document with 'time'? Assuming I don't have a single source file, is this at all justifiable? -- * Matthew B. Kennel/Institute for Nonlinear Science, UCSD * * According to California Assembly Bill 3320, it is now a criminal offense * to solicit any goods or services by email to a CA resident without * providing the business's legal name and complete street address. *