Re: [boost] Enum Conversion

Subject: Re: [boost] Enum Conversion
From: Ilya Bobyr (ilya.bobir_at_[hidden])
Date: 2012-09-03 19:01:50

On 9/2/2012 1:46 PM, Vicente J. Botet Escriba wrote:
> [...]
> I managed defining a specific opaque type, let me say MyGreek, and 
> defining implicit conversions from these types.
>
> Your example could be written as
>
> std::cout << string(MyGreek(1)) << std::endl;
> std::cout << string(MyGreek(6)) << std::endl;
> std::cout << MyGreek(Alpha) << std::endl;
> std::cout << MyGreek::Alpha << std::endl;  // using nested literal
> std::cout << string(MyGreek(Alpha)) << std::endl;
> std::cout << string(MyGreek::Alpha) << std::endl; // using nested literal
> std::cout << MyGreek(17) << std::endl;
>
>
> If think this interface corresponds more to how C++ conversions work 
> (IMO of course).
>
>
>> (Or
>> does boost even offer something like that already?)
> I don't think so. The closest could be TBoost.Enums in the sandbox, 
> but this library generates the enum and don't do the mapping.

I think that it can do both plain enums and enums that map to arbitrary 
types.  Here is an example where string are associated with enum values:

http://stackoverflow.com/a/439004

The syntax is different but the function is the same.

BOOST_ENUM_VALUES(Greek, int,
     (Alpha)(5),
     (Beta)(3),
     (Gamma)(7),
     (Delta)(1),
     (Epsilon)(6)
);

/*
class Greek {
...
typedef boost::optional<Greek> optional;
...
*/

Level::optional gammaVal = Level::get_by_name("Gamma");

-- 
Ilya Bobyr