Re: [review][LEAF] Review of LEAF starts today : May 22 - May 31

From: Emil Dotchevski (emildotchevski_at_[hidden])
Date: 2020-05-31 18:13:27

On Sun, May 31, 2020 at 6:51 AM Bjorn Reese via Boost <boost_at_[hidden]>
wrote:
> I made a typo above. I meant to say std::get<I>.
>
> I am asking for a low-level API, not a bullet-proof API. If the latter
> is needed, then your existing pattern matching solution works just fine.
>
> The use of such a low-level API would look something like this:
>
>    leaf::context<E0, E1> ctx;
>    ctx.activate(); // I would like to avoid this though
>
>    auto ret = foo();
>    if (!ret)
>    {
>      switch (ctx.index(ret.error()))
>      {
>      case 0: // E0
>        handle_E0(ctx.get<0>(ret.error()); break;
>
>      case 1: // E1
>        handle_E1(ctx.get<1>(ret.error()); break;
>
>      default: // Unknown error type
>        panic(); break;
>      }
>    }

I think you're essentially asking for access to this function, through
slightly different interface:
https://github.com/zajo/leaf/blob/develop/include/boost/leaf/handle_error.hpp?ts=4#L236
.