Re: [boost] [variant2] Review of Variant2 started today : April 1 - April 10

Andrey Semashev wrote:

...

Also, IMHO, it's better to have libraries more focused and fine grained. Why not have `expected` as a separate library?

expected is basically a variant, with a slightly different interface.

To expand on that a bit... to implement expected you need an underlying variant. You can either implement your own ad-hoc one, which is a duplication of work; or you could use an existing variant, but then you inherit its properties and have to reflect those in the specification of `expected`. For instance, if the variant can be valueless, you need to figure out what to do in `expected` when it gets into that state. For those reasons, it makes most sense to develop `variant` and `expected` in parallel, as parts of the same library.