Re: What I miss... (really C, Ada, religion)

[barmar@mit-eddie.UUCP (Barry Margolin)]

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