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From: Richard D Riehle <laoxhai@ix.netcom.com>
Subject: Re: Software landmines (loops)
Date: 1998/10/03
Message-ID: <6v5sst$e22@sjx-ixn5.ix.netcom.com>#1/1
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X-NETCOM-Date: Sat Oct 03 12:11:25 PM PDT 1998
Newsgroups: comp.lang.ada
Date: 1998-10-03T12:11:25-07:00
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In article <6v4d5l$blb$1@hirame.wwa.com>,
	"Robert C. Martin" <rmartin@oma.com> wrote:

  in response to a note by John I Moore, Jr. about the do-while-do
  loop suggested by Harlan Mills,

>
>Yes, Mills did make this definition. However, I am referring to the work of
>Dijkstra in the late 60's and early 70's. Dijkstra was very clear about the
>notion of single entry and single exit within the body of a loop. I believe
>that Mills'do-while-do loop is an unauthorized addition to Dijkstra's work.

Is every pronouncement by Dijkstra the equivalent of Holy writ?  Software is
a fledgling discipline even today.  It was certainly an immature practice in
the 1960's. I seem to recall that Albert Einstein once said that we should
try to make everything as simple as possible but not  simpler.  

The notion of "single-entry/single-exit" is obsolete.  It has been for a
long time.  Instead, rational programmers understand the need for control
structures that are readable, understandable, and maintainable. This
requires them to make the code as simple as possible "but not simpler." 
Single-entry/single-exit has the disadvantage of sometimes making the code
not only as simple as possible, but also simpler.  

Perhaps we should also disallow discontinuous mathematical functions.  
 
Richard Riehle
richard@adaworks.com
http://www.adaworks.com