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From: gwyn@BRL.ARPA (VLD/VMB)
Newsgroups: net.lang.c
Subject: Re:  break, continue, return, goto
Message-ID: <3242@brl-tgr.ARPA>
Date: Fri, 15-Nov-85 02:25:56 EST
Article-I.D.: brl-tgr.3242
Posted: Fri Nov 15 02:25:56 1985
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Just a note on the nondeterministic "if" (a.k.a. Dijkstra's
guarded command construct):  The selected case need NOT be
picked "at random".  The choice need not even be "fair"
in a statistical sense, for most uses of this construct.
The implementation can e.g. always pick the first true
case; however, the programmer is not allowed to make use
of this implementation detail.  The claim that such a
language differs from what is needed in a "real language"
needs some substantiation.  Since this newsgroup is for
C, however, further dialogue on this should be conducted
elsewhere.  (By the way, Dijkstra's "A Discipline of
Programming" is a real classic.  A funny thing is, he
claims that his discipline results in correct programs,
but there are at least three known bugs in his examples.)

David Gries wrote a textbook on the same subject which
is probably more accessible to most programmers.  I think
it was entitled "The Science of Computer Programming".  I
hope more people study this subject, so I will have fewer
bugs to deal with in the future.