Re: [boost] [review] Review of Outcome (starts Fri-19-May)

Vicente J. Botet Escriba wrote:

Le 15/05/2017 à 01:35, Peter Dimov via Boost a écrit :

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Niall Douglas wrote:

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The major refinement of outcome<T>, result<T> and option<T> over expected is that you **never** get undefined behaviour when using their observers like you do with expected. So when you call .error() for example, you always get well defined semantics and behaviours.

I fully agree with this design decision of yours, by the way. In fact I consider that a defect in expected<>.

Why? We have *e that is narrow and value() that is wide.

I don't like undefined behavior (except when I like it). An accessor that gives you the error without checking first would supposedly save a branch, which I wouldn't consider an acceptable tradeoff even if it did indeed save a branch; but in practice, in correct code the check would already have been made and the compiler would be able to see that. And yes, I don't like *e either.