Re: [boost] [outcome] success-or-failure objects

Subject: Re: [boost] [outcome] success-or-failure objects
From: Gavin Lambert (gavinl_at_[hidden])
Date: 2018-01-23 22:40:13

On 24/01/2018 11:13, Emil Dotchevski wrote:
>> There's a sizeable number of people who are very keen on doing so. Hence
>> std::logic_error and family i.e. WG21 historically has agreed.
> 
> It is unreasonable to think that a program that has just encountered a
> logic error can recover gracefully from it any more it can do so from a
> crash. Try to recover, and you might make things worse, possibly much worse.

Not necessarily.  It depends on how well-partitioned things are and how 
far-reaching the side effects executed thus far affect other things.

For an example, think of a web browser.  At some point it parses some 
malformed HTML and sets a property local to the page to null.  At some 
later point something accesses that property without checking for null 
first.  This is a logic error, but it's a completely benign and 
recoverable one (at least on platforms where memory around null is 
guaranteed to be invalid).  The browser can recover simply by aborting 
the load/render of that page and showing an error, without affecting any 
other pages or crashing the browser itself.

Other similar cases exist, where a data structure might be left in an 
undefined but still destructible state, but it doesn't matter because 
the error recovery process will just destroy that structure anyway.