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,c52c30d32b866eae X-Google-Attributes: gidfac41,public X-Google-Thread: 103376,2ea02452876a15e1 X-Google-Attributes: gid103376,public X-Google-Thread: 1108a1,c52c30d32b866eae X-Google-Attributes: gid1108a1,public From: tynor@atlanta.twr.com (Steve Tynor) Subject: Re: Real OO Date: 1996/05/15 Message-ID: #1/1 X-Deja-AN: 155048487 sender: tynor@atlanta.twr.com (Steve Tynor) references: organization: Tower Technology newsgroups: comp.lang.eiffel,comp.lang.ada,comp.object Date: 1996-05-15T00:00:00+00:00 List-Id: In article bobduff@world.std.com (Robert A Duff) writes: | In article , | Steve Tynor wrote: | >"Availablity" relates to the "export status" of each feature. If I | >write: | >[...explanation of VAPE deleted] | | Makes sense, but it doesn't answer my original question. Near the end | of 9.8, *after* the VAPE rule, there is a definition of "Availability of | an Assertion Clause" (which is not the same thing as availability of a | feature, although it's related). My question was, can a precondition | ever be "unavailable"? It seems to me that if it were, it would fail | VAPE, and therefore wouldn't be allowed in the first place. Am I | confused? No, I think you're just thinking too hard :-). The VAPE rule is a validity rule that the compiler can use as the justification for emitting an error. The "availability of an assertion clause" definition is a bit redundant, but not in contradiction. Note that the definition also applies to _postconditions_ (which VAPE does not address) so it's not entirely redundant. The VAPE rule could, I suppose, be reworded to use the definition of assertion availability: VAPE(revised): Each assertion clause in the precondition of a routine must be available to every class to which its feature is available. Same rule; just worded differently. Anyway, to answer your question: no since a precondition that is not available according to the definition implicitly violates VAPE. =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= Never express yourself more clearly than you think. -- Neils Bohr Steve Tynor Email: Steve.Tynor@atlanta.twr.com Tower Technology WWW: http://www.twr.com/