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=0.7 required=5.0 tests=BAYES_00,INVALID_DATE, MSGID_SHORT,REPLYTO_WITHOUT_TO_CC autolearn=no autolearn_force=no version=3.4.4 Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.1 6/24/83; site mit-eddie.UUCP Path: utzoo!watmath!clyde!burl!ulysses!allegra!mit-eddie!barmar From: barmar@mit-eddie.UUCP (Barry Margolin) Newsgroups: net.arch,net.lang.ada Subject: Re: What I miss... (really C, Ada, religion) Message-ID: <74@mit-eddie.UUCP> Date: Sun, 13-Oct-85 02:28:59 EDT Article-I.D.: mit-eddi.74 Posted: Sun Oct 13 02:28:59 1985 Date-Received: Mon, 14-Oct-85 05:56:44 EDT References: <796@kuling.UUCP> <2580002@csd2.UUCP> Reply-To: barmar@mit-eddie.UUCP (Barry Margolin) Organization: MIT, Cambridge, MA Xref: watmath net.arch:1904 net.lang.ada:392 List-Id: In article <210@rtp47.UUCP> throopw@rtp47.UUCP (Wayne Throop) writes: >... So, my fuzzy answer to "What do you do in a finished >product in a high-risk environment when an unanticipated bug occurs?" is >"The best you can". Your posting made some good points, but I would like to elaborate on your simple summation. In my opinion, and I suspect also those of the designers of fancy condition-handling mechanisms, the answer is "the best that the language and architecture permit." Pascal, COBOL, and C, as far as I know, provide the programmer with very little capability to detect problems and deal with them; programs will just abort when some conditions occur, and there is nothing that can be done to automatically determine why, in order to decide what action to take. In PL/I, Ada, some BASICs, and CLU there are relatively powerful condition mechanisms, which permit the program to recognize many abnormal states. Yes, there will always be situations in which this will fail; for instance, the stack might be screwed up due to an assignment through a busted pointer. But it is best if "the best you can" translates to "detect most problems and deal with them appropriately." -- Barry Margolin ARPA: barmar@MIT-Multics UUCP: ..!genrad!mit-eddie!barmar