Re: [BLACKBOX] Seasons Greetings from Linuxland

From: [at]} <Chris>
Date: Wed, 22 Dec 2010 09:15:20 +1030

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>-----Original Message-----
>From: BlackBox [mailto:BLACKBOX{([at]})nowhere.xy
>Bernhard Treutwein
>Sent: Wednesday, 22 December 2010 7:16 AM
>To: BLACKBOX{([at]})nowhere.xy
>Subject: Re: [BLACKBOX] Seasons Greetings from Linuxland
>
>but (I guess) it would be easier to program a safe system in a
>safe language than in an unsafe language like C (the holy gnu) ...
>

I believe so - C just gives you so many different wonderful ways to shoot
yourself in the foot. A few days ago a C programmer was complaining in
another group that the following "does not work, gives unexpected results":

  digdata[digNr] = (bitdata[bitNr++] * 8) + (bitdata[bitNr++] * 4) +
(bitdata[bitNr++] * 2) + (bitdata[bitNr++]);

That reminded me of something Wirth said in his paper "Good Ideas, Through
the Looking Glass" which can be downloaded from:

http://www.inf.ethz.ch/personal/wirth/index.html

-----------------------------------

"The ugliness of a construct usually appears in combination with other
language features. In C, we may write, for example, x+++++y, a riddle rather
than an expression, and a challenge for a sophisticated parser! Guess what?
Is its value is equal to ++x+++y+1? Or is the following correct?

  x+++++y+1==++x+++y

  x+++y++==x+++++y+1

One is tempted to postulate a new algebra! It is indeed absolutely
surprising with which eqanimity this notational monster was accepted by the
world-wide programmer's community"

-----------------------------------

He also has something to say about the use of typecasts (a.k.a. 'loopholes')
in the same paper ...

Regards,
Chris

Chris Burrows
CFB Software
http://www.cfbsoftware.com

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Received on Tue Dec 21 2010 - 23:45:20 UTC