Frank Mori Hess wrote:
would be false and otherwise the composed future would not be ready yet.
Doing it the way you're proposing implies shortcutting operator&&(), which can't be implemented.
left-to right evaluation can't be short-circuited, but he's talking
Right, that's exactly my point.
about short circuiting in time, as either the lhs or rhs futures complete.
Didn't we talk about operator&&()? No 'either/or' here, only both futures. Additionally, the same comments apply as outlined below.
I'm pretty sure he's not talking about your "wait_for_all" operator&&() at all, he's talking about one with semantics closer to the "real" operator&& defined by the language.
Sure, I understand. But the issue is that these are very similar to the proposed math operators in the sense that they add semantics in terms of the future results not the futures themselves.
My main point was that such operator overloads apply to the result types and not the futures themselves, which adds unnecessary semantics and defeats separation of concerns. And, BTW, this is very much like the default conversion operator to the result type for the futures which - as most have agreed - is a bad idea.
It only appears to defeat "separation of concerns" because you're not separating your definition of the future logical operator overloads from his.
This is just wrong and I don't think I gave you any reason to assert this. Please refrain from imposing something I didn't say just for the sake of making your point.
They really are two different ideas and are not useful for the same things.
I'm perfectly aware of this. And actually I expressed exactly the same by pointing out the main difference between the two sets of operators: the logical operators I proposed are for the futures themselves while the others are related to the future results. But you're diligently ignoring my point: overloading the operators for the future results is conceptually equivalent to having a default conversion operator to the result type for the future itself! And for that reason I would not like to see something like that in the future library. OTOH, IMHO, having the logical operators alone improves code readability, simplifies the implementation (by avoiding multiple overloads for different parameter counts), allows to build more complex logical execution restrictions as (f1 || f2) && f3 (which is not possible using the proposed wait_for_all and wait_for_any), and all that without having to sacrifice any of the existing functionality.
Personally, I don't particularly want to see a future library overload any logical operators at all, or at least have the overloads sequestered in separate headers that aren't included by any of the other future library headers.
That's a matter of taste, for sure. But would you mind telling us why you don't want to have these? Your opinion sounds to be quite strong, so you must have good reasons! Regards Hartmut