C++ Expected converted to idiomatic D

[Paul Backus]

On Thursday, 16 August 2018 at 20:37:33 UTC, Per Nordlöw wrote:
> In
>
> https://www.youtube.com/watch?v=nVzgkepAg5Y
>
> Andrei describes his proposal for STL `Expected` planned to be 
> included in C++20.
>
> Have anybody converted the C++ proposal to idiomatic D, yet?
>
> Hopefully without the pointer-legacy which unfortunately was 
> allowed into `std:optional`.
>
> Andrei claims we should it as return types for non-throwing 
> variants of parse() and to() in the works at
>
> https://github.com/dlang/phobos/pull/6665

I've got a basic version up and running:

https://github.com/pbackus/expected