Re: [boost] [optional] std::tr2::optional

Subject: Re: [boost] [optional] std::tr2::optional
From: Matt Chambers (matt.chambers42_at_[hidden])
Date: 2011-11-28 19:43:19

On 11/28/2011 6:05 PM, Dave Abrahams wrote:
> on Fri Nov 18 2011, paul Fultz<pfultz2-AT-yahoo.com>  wrote:
>>> I provide a list of
>>> modifications that I could think of. What is your opinion?
>> This is more of an addition to your list, but I think adding
>>
>> the | operator for getting the optional value or a default value would be nice.
>> For example:
>>
>> optional<double>  safe_sqrt(double x)
>> {
>>      if (x<  0) return none;
>>      else return sqrt(x);
>> }
>>
>> double x = safe_sqrt(4) | 0; //x = 4
>> double y = safe_sqrt(-1) | 0; //y = 0
>>
>> I dont know if this is possible for tr2, but would be really nice
>> addition in the future. Especially, since a lot of times i just
>> want a default value if the optional value doesn't exist.
> +1
+sqrt(4)