Re: [boost] PR: Remove safe_bool idiom from boost.tribool

Subject: Re: [boost] PR: Remove safe_bool idiom from boost.tribool
From: Robert Ramey (ramey_at_[hidden])
Date: 2018-05-22 04:47:18

On 5/21/18 6:02 PM, Peter Dimov via Boost wrote:
> Robert Ramey wrote:
> 
>> > I'm strongly opposed to downgrading from safe_bool to implicit bool.
>>
>> I made my argument why this is good idea.  What's wrong with my argument?
> 
> Defining a conversion to bool enables unwanted operations such as
> 
>  Â Â  tribool b1, b2;
> 
>  Â Â  b1 < b2;
>  Â Â  b1 + b2;
>  Â Â  b1 + 5;
>  Â Â  b1 * 2;
> 
> That's the whole point of "safe bool", to avoid those.

Right.

But - Since the have been prohibited by the current safe_bool, there are 
none in current code. So the change won't break anything.

Finally.  I believe that these are compile time errors in C++17.  So 
safe_bool isn't needed to prevent them anymore anyway.

Robert Ramey

> 
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