Life vests, condoms, and parachutes also not 100 percent safe. However, jump without a parachute is not the same as equipped.
Your argument is the same, as argument against free software like: "if we do not have 100 percent warranty that free software doesn't contain backdoors, then it is better to use proprietary software in terms of backdoors."
Which is wrong, obviously.
Sincerely,
Norayr
----- Original message -----
> "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!
>
> Wirth's line x+++++y won't compile with the only C compiler I have
> available at the moment.
>
> When
> z = 0;
> x = 1;
> y = 1;
>
> The expressions
>
> z = x++ + y++;
> z = x++ + ++y; Wirth's example
> z = ++x + y++;
> z = ++x + ++y;
>
> yield values of 2, 3, 3, 4 respectively.
>
> As Chris Burrow' said, "C just gives you so many different wonderful
> ways to shoot yourself in the foot". C programmers are not obliged to
> write code like this. They are free to spread the code over several
> lines. They choose not to do so preferring to rely on 'C idioms'.
>
> The problem is that in order to understand what the programmer intended
> the result of this expression should be, the reader has to evaluate the
> expression according to the precedence rules for operators in C. All
> this to save two Linefeeds, two characters and two semicolons.
>
> Pascal/Modula/Oberon programmers are not entirely free of this approach.
>
> The code
>
> PROCEDURE IsDigit(ch: CHAR): BOOLEAN;
> BEGIN
> RETURN (ch <= '9') & (ch >= '0')
> END IsDigit;
>
> is regarded as good 'style'.
>
> Yet it suffers from the same problem as the C code above. To understand
> what the programmer intended the reader has to evaluate what follows the
> RETURN.
>
> The code
>
> PROCEDURE IsDigit(ch: CHAR): BOOLEAN;
> VAR
> b: BOOLEAN;
> BEGIN
> b := FALSE;
> IF (ch >= '0') & (ch <='9') THEN
> b := TRUE;
> END;
> RETURN b;
> END IsDigit;
>
> is regarded as bad 'style', but the intention of the programmer is
> more easily understood.
>
> It is an article of faith for 'Oberoners' that Wirthian languages are
> superior to 'C' type languages and that their use makes it easier to
> write bug free code.
>
> Look at http://acm.uva.es/problemset/statsjudge2.php for some empirical
> evidence about this.
>
> The lines starting AC (Accepted, right answer, correctly presented), PE
> (Presentation error) and WA (Wrong answer) are the ones to pay attention
> to.
>
> More details of the nature of the programs and the meaning of the other
> codes at the start of a line can be found at
> http://www.cs.sunysb.edu/~skiena/392/ and the links provided. There are
> some pdf files of lectures which can be downloaded; 'Week 1' has some
> details.
>
> The kinds of programs upon which these results are based do not cover
> the full spectrum of programs that Wirth had in mind in designing Modula
> 2 and Oberon. Nonetheless the results are interesting and the sample
> size is so large that the sampling error is likely to be very small.
>
> Les May
>
>
> ----
> To unsubscribe, send a message with body "SIGNOFF BLACKBOX" to
> LISTSERV{([at]})nowhere.xy---- To unsubscribe, send a message with body "SIGNOFF BLACKBOX" to LISTSERV{([at]})nowhere.xy
Received on Mon Dec 27 2010 - 16:35:06 UTC