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: 103376,66752102482bbdca X-Google-Attributes: gid103376,public From: "Robert I. Eachus" Subject: Re: Required Metrics Date: 2000/05/18 Message-ID: <39233EC6.C4738579@earthlink.net>#1/1 X-Deja-AN: 624779827 Content-Transfer-Encoding: 7bit References: <5DDO4.2237$wb7.194854@news.flash.net> <8ek4ea$5ta$1@nnrp1.deja.com> <8es65n$5hn$1@nnrp1.deja.com> <%MoQ4.7915$wb7.556168@news.flash.net> <8eulom$u8m$1@nnrp1.deja.com> <3914F1DC.A5EE1751@earthlink.net> <8f3tfl$d32$1@nnrp1.deja.com> X-Accept-Language: en,pdf Content-Type: text/plain; charset=us-ascii X-Complaints-To: abuse@earthlink.net X-Trace: newsread2.prod.itd.earthlink.net 958611072 63.24.60.10 (Wed, 17 May 2000 17:51:12 PDT) Organization: The MITRE Corporation MIME-Version: 1.0 NNTP-Posting-Date: Wed, 17 May 2000 17:51:12 PDT Newsgroups: comp.lang.ada Date: 2000-05-18T00:00:00+00:00 List-Id: Robert Dewar wrote: > Not till the ARG ruled clearly on this issue, and the AVO > backed it up with the tests (which as I mention above, I > helped write), in ACVC version 1.10, did a proper set of > tests get written. I have no disagreement with what Robert Dwer wrote here (hmmm enthusiastically agree? applaud wildly?). However, the Chapter 13 tests which RBKD wrote had less effect on Ada 95 than he and others including myself hoped, for several reasons. First, by the time some of these were required by the ACVC vendors were all working on Ada 9X compilers and were unwilling to make fundamental changes not required by Ada 9X. Second, the conformance rules were changed to allow compilers not to comply with up to ten tests, as long as the intent was to correct these in the next validated version. In practice, since most new tests in 1.10 and after were chapter 13 tests, it allowed vendors to be much more agressive in stating that "this cannot be 'simply' implemented in this compiler." Of course, in many cases this was exactly right--it was the tests that would have required major compiler changes that didn't get made. Finally, since many of the Chapter 13 tests were, in effect, pushed back by challenges to later ACVC versions, some of these tests were never effectively required. Since the design of Ada 9X started well before ACVC 1.10 affected production compilers, the experience of users during the early phases of the Ada 9X development process was with compilers that in some cases did not take representation clauses, etc. seriously. So as Robert Dewar points out, while the requirements in Ada 95 are much more clearly spelled out, they are definitely a subset of what was finally required in Ada 83. (Fortunately, the marketplace has tended to require this 'additional' support in any case. I hope 'de facto' becomes 'de jure' with the next Ada standard... > Interesting -- I had COMPLETELY forgotten this > statement in the standard. It is of course an exact codification > of some of the things that Bob Duff and I have argued. In > particular, it provides an absolutely CLEAR basis for Bob Duff's > observation that the behavior of the delivered binary compiler > code, and the behavior of code generated by this compiler > constitute documentation in the sense of the RM. > > So the RM *did* try to define what documentation meant, and > came up with something about as far from what Ken has in mind > as one can imagine. Yes, the intent was to prevent documentation requirements from limiting actual implementations. In Ada 83, the ACVC tests effectively required every Ada compiler to implement a "usable" maximum input line length. And the blasted ACVC tests checked that the compiler DID NOT accept longer lines, whle requiring that you accept an identifier that was the same length as a line. So you had to set an arbitrary maximum line length and enforce it even if in the absence of the ACVC test the limit would only be imposed by memory size or file characteristics. In Ada 95 the requirement concerning line length is in RM 2.2(15): "...The maximum supported line length and lexical element length are implementation defined." (The minimum for each is 200 characters.)