Re: [boost] [signals2] Test failure in C++11 (trivial fix for incorrect usage of boost::optional)

Subject: Re: [boost] [signals2] Test failure in C++11 (trivial fix for incorrect usage of boost::optional)
From: Peter Dimov (lists_at_[hidden])
Date: 2014-02-28 11:26:58

Frank Mori Hess wrote:
> Nothing is a problem once you get used to it.  I apologize for using a
> bit of hyperbole, let me try again.  I consider the following obvious:
> given two expressions like "!x" and "x==false" we have:
>
> desirable behavior: they both compile and mean the same thing.
> neutral behavior: only one compiles.
> undesirable behavior: they both compile and mean completely different 
> things.

This is obviously a matter of stylistic preference, but still, mine runs 
contrary to yours. x == false is an anti-pattern and should never be 
preferred to !x, even when x is bool; similarly, x == true is an 
anti-pattern and should never be preferred to plain x. Boolean logic doesn't 
have ==. Nobody prefers ( x == y ) == false to !( x == y ) or x != y, let 
alone ( x == y ) == true to x == y.

And when our original x is not bool but, say, a pointer, x == false is just 
silly, even though it works.