Comma operator = broken design

[Regan Heath]

On Thu, 08 Dec 2011 12:17:20 -0000, so <so at so.so> wrote:

> On Thu, 08 Dec 2011 11:17:48 +0200, Dejan Lekic <dejan.lekic at gmail.com>  
> wrote:
>
>>
>>>
>>> Why is this operator still kept around?
>>
>> No offense, but I find it strange/funny that you even ask why! :)
>>
>> Have you never used comma in for loops???
>>
>
> Not sure if it is that relevant for D, but good point.
>
> for(auto i=beg(), e=end(); i!=e; ++i)
> for(auto i, j, k;; ++i, ++k)
> ...

It's kinda amusing that this thread appeared just as we had a case of this  
here at work.  The developer accidentally coded something like...

if (function(..), FALSE)
{
}

Accidentally adding the ", FALSE" /after/ the ) instead of as a new  
parameter to the function.

(note; This was in C++ with default parameter values so the function can  
in fact take 1-4 args).

When I pointed this out, he said "how does that even compile" and was  
completely unaware of the existence of the comma operator, nor (once I  
explained it) did he realise it was in any way related to the comma used  
in for loops.  People simply don't think of them as being the same thing  
at all.  Instead, people learn the comma syntax as a special  
characteristic of the for loop, and use it nowhere else.

I think the comma operator is of little benefit (except where used in a  
for loop) and it is a source of bugs and we'd be better off without it.   
Even if it means porting C/C++ requires modification, or existing D (I  
doubt very much of it) breaks.

R

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