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

Le 16/05/2017 à 00:22, Peter Dimov via Boost a écrit :

Niall Douglas wrote:

...

Vicente, when he reviewed Outcome's docs, was pretty appalled at how error handling focused they are. His view is that Expected is an EITHER monad where E is exactly like T, and he was not happy that Outcome presents Expected as if it is solely for use for returning stuff from functions. No I have never said that E is like T.

And, he is right.

No, he isn't. The whole point of expected<> is that T is not like E. That's why T is _expected_, and E is _unexpected_. It's in the name.

When T is like E, you use variant. Or variant.

My own idea of expected takes one T and an arbitrary amount of Es, and while all Es are alike, T isn't.

And this aside, the general idea is to provide alternative to exceptions, which kind of implies returning stuff from functions, does it not? I agree completly.

expected is IMO the same as expected> except that it could add some syntactic sugar. I'll not be against a expected. The way either E T is used in Haskell is exactly this one. Note that with TypeClasses a type as variant can be seen in a lot of different ways. Vicente