DIP19: Remove comma operator from D and provision better syntactic support for tuples

[Andrei Alexandrescu]

On 9/24/12 4:17 AM, Don Clugston wrote:
> Regarding the comma operator: I'd love to deprecate it, but even if we
> don't, could we at least ensure that this kind of rubbish doesn't compile:
>
> void main()
> {
> int x;
> x > 0, x += 5;
> }
>
> At present, because comma expressions are expressions, not statements,
> the "x > 0" doesn't generate a "statement has no effect" error, despite
> the fact that it is meaningless and gets completely discarded.

Interesting. The comma operator is probably the only one in which an 
expression is evaluated only for the sake of its side effects. So 
eliminating the comma operator would just get rid of that case by design.

Of course, there's always the option of adding more checks or rewriting 
the comma operator from "expr1, expr2, expr3" to "{ expr1; expr2; return 
expr3; }()".


Andrei