Path: utzoo!utgpu!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!mailrus!ames!haven!uvaarpa!babbage!mac3n
From: mac3n@babbage.acc.virginia.edu (Alex Colvin)
Newsgroups: comp.lang.c++
Subject: Re: Improved switch statement
Summary: wirth / dijkstra / parnas
Message-ID: <480@babbage.acc.virginia.edu>
Date: 3 Jan 89 14:02:00 GMT
References: <1031@uqvax.decnet.uq.oz> <901@husc6.harvard.edu> <17966@glacier.STANFORD.EDU>
Organization: University of Virginia
Lines: 15

>      Djykstra looked at this issue some years ago, and came up with
> the notion of "guarded commands".  See his "Algorithms + Data Structures
> = Programs".

Actually, A+D=P is Wirth. "Discipline of Programming" is Dijkstra's guarded
command book.

I believe the switch statement with case labels is Hoare's, as an
alternative to the Algolish label array.

Parnas combined the IF and DO guarded command sets into a IT statement that
required explicit looping or exit.

As to switch, if I'd wanted a long chain of tests, I could have written it
that way myself.