Re: [boost] [outcome] To variant, or not to variant?

Subject: Re: [boost] [outcome] To variant, or not to variant?
From: Robert Ramey (ramey_at_[hidden])
Date: 2017-06-01 14:23:08

On 6/1/17 12:22 AM, Andrzej Krzemienski via Boost wrote:
> A valid observation. In a way `expected` and `outcome` (both from
> Boost.Outcome) have different goals in mind. `expected` might in fact cover
> your case. They could be two libraries. The reason they come together is
> that they share 95% of the same implementation. 

I haven't investigated too deeply into the code so of course I didn't 
know that.  I would have "expected" that outcome, expected, et.al would 
be derived from variant which would be the shared code.  Also all the 
questions about narrow/wide interface, no empty guarantees, etc. would 
be resolved (for better or worse) in the variant library so the design, 
review, maintenance, etc. of outcome, expected et al. would be confined 
to the particular aspects of these components - thus being a more 
economic application of limited brain surface area.  Code size would be 
smaller as well.

> They differ only by
> interfaces. Two interfaces for two different problems

Right.  It's common for different 
"types/libraries/concepts/functions/etc." to factor out commonality for 
just the reasons mentioned above.

Robert Ramey