Re: [boost] [outcome] outcome without empty state?

Let me just recall her the suggestion from Peter made in the other thread. Mybe have two types: `expected` does not have the empty state or default constructor -- it is used as function's return type `prepare_expected` is either T or E or Empty -- you use it inside function to build expected:

``` expected f() { prepare_expected ans; // populate (or not) ans return ans; // in this conversion you can do all sorts of checks } ```

When it comes to converting from `prepare_expected` to `expected`, you have plenty of choices: require manual conversion, narrow-contract to be checked, a defensive if and throw... I am just not sure if performance can be negatively impacted with this.

I originally considered this design for Outcome's API. I ended up rejecting it because it's superfluous if you have correctly designed your expected/outcome/whatever in the first place. Niall -- ned Productions Limited Consulting http://www.nedproductions.biz/ http://ie.linkedin.com/in/nialldouglas/