I see questions on SO every so often about overloading the comma operator in C++ (mainly unrelated to the overloading itself, but things like the notion of sequence points), and it makes me wonder:
When should you overload the comma? What are some examples of its practical uses?
I just can't think of any examples off the top of my head where I've seen or needed to something like
foo, bar;
in real-world code, so I'm curious as to when (if ever) this is actually used.
Let's change the emphasis a bit to:
When should you overload the comma?
The answer: Never.
The exception: If you're doing template metaprogramming, operator,
has a special place at the very bottom of the operator precedence list, which can come in handy for constructing SFINAE-guards, etc.
The only two practical uses I've seen of overloading operator,
are both in Boost: