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From: verwer@ruuinf.cs.ruu.nl (Nico Verwer)
Newsgroups: comp.lang.pascal
Subject: Re: C Ternary Conditional Expression?
Summary: Let's have conditional expressions in Pascal
Message-ID: <1344@ruuinf.cs.ruu.nl>
Date: 26 May 89 08:37:39 GMT
References: <950025@hpclcdb.HP.COM> <6490002@hplsla.HP.COM>
Organization: Univ of Utrecht, Dept of CS
Lines: 43

In article <6490002@hplsla.HP.COM>, davidr@hplsla.HP.COM (David M. Reed) writes:
> However, C programmers have continually reminded me how "efficient" 
> code can be written in C verses Pascal, such as
> 
>     a[ (indx == last_indx) ? last_val : f(indx) ] = a [ y ];
> 
> instead of
> 
>     IF (indx = last_indx)
>        THEN temp := last_val
>        ELSE temp := f(indx);
>     a[temp] := a[y];
> 
> But that only means that you can write source code more concisely, not that
> the actual machine code is more concise (depending on the compiler, of course).
> [...]
> So why write in the terse C format? I personally think that

I think this is one of the few places where C is a "higher-level" language
than Pascal. Of course the compiler will generate code that allocates space
for a temporary variable (temp) in both cases, but why declare this variable
in your program? Personally, I would like to write the above as

      a[ IF index = last_index THEN last_val ELSE f(index) ] := a[ y ] ;

This would extend the IF-statement to conditional expressions, which in my
view is a higher-level construct than the conditional statement in Pascal,
because it allows one to write better readable code.

> All the person writing C has done, then, is to write less clear code in
> fewer lines, often making it harder to understand and maintain later (even
> by the original author, and even if well commented).  

That is why I use Pascal most of the time, that is, if I'm doing
low-level, time/space-efficient coding. When speed/memory is not
important I use prolog or some functional language, of course.

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