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

Subject: Re: [boost] [outcome] To variant, or not to variant?
From: Peter Dimov (lists_at_[hidden])
Date: 2017-06-02 14:57:15

Niall Douglas wrote:
> 3. User wants to write functional programming logic using the basic 
> vocabulary of Maybe, Either and i/o monads and basic operators of bind, 
> fmap, do etc and probably some subset or refinement of Hana for the 
> collections monads, though my GSoC student may be making the Ranges TS a 
> choice here as well later this summer.
>
> All-narrow observers make sense for this use case as the monadic operators 
> ensure your function will never be called with the wrong state.

There's no need for narrow (value) observers when using the monadic 
interface; it's all wide and since you get the value directly, you don't 
need to observe it.