Comma operator = broken design

[Timon Gehr]

On 12/08/2011 05:02 PM, Regan Heath wrote:
> 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.
>

Phobos would break, for example. And some of my code too.