Re: [boost] [review] Review of Outcome v2 (Fri-19-Jan to Sun-28-Jan, 2018)

2018-02-08 18:56 GMT+01:00 Nevin Liber via Boost :

On Mon, Feb 5, 2018 at 6:00 PM, Rob Stewart via Boost < boost@lists.boost.org

...

wrote:

...

I think the library could, at least, assert in debug builds when a result or outcome is not inspected.

That can be problematic. Suppose you have one that isn't inspected (because the library you are calling uses outcome for return values) and an exception is thrown (say, from a different library). Is it incorrect to not have inspected it? http://lists.boost.org/mailman/listinfo.cgi/boost

Another such case that does not involve exceptions. Suppose I have a function template that can convert any T to any U, such as lexical_cast but with different interface: ``` template auto convert(T const& v) noexcept(false) -> result ``` This function still throws exceptions upon resource shortage but signals failure through `result<>` if a given value of type `T` cannot be represented in type `U`. When, at some place, I use it to convert from `int` to `string`, I know that for this combination of T and U the function cannot fail to find representation, so it is correct for me not to check for failure: ``` string s = convert<string>(-123).assume_value(); ``` Would a run-time check be able to keep silent in the case like that? Regards, &rzej;