Re: [boost] [optional] Counterintuitive comparators

From: Fernando Cacciola (fernando_cacciola_at_[hidden])
Date: 2006-10-23 14:33:34

Richard Smith wrote:
> I was recently bitten by bug in some code using
> boost::optional.  A simple test case is:
> 
>   #include <boost/optional.hpp>
>   #include <cassert>
> 
>   int main() {
>     boost::optional<int> i = 0;
>     assert( i == 0 );
>   }
> 
> Somebody had written code like this, presumably assuming the
> second argument to the comparison operator would convert
> implicitly to a boost::optional<int> and the code would
> behave as if it read:
> 
>   assert( i && i.get() == 0 );
> 
OK, deep comparison operators have been requested before, but all this 
time I remained unconvinced there were really needed, until now.

As you said, optional<> provides value-based semantics in other places, 
so given the kind of bug you discovered, I think is time to add these too.

Best

Fernando Cacciola