Re: [boost] [C++0x] Emulation of scoped enums

Subject: Re: [boost] [C++0x] Emulation of scoped enums
From: Kjell Elster (kjell_elster_at_[hidden])
Date: 2009-03-05 10:45:37

I like it, iff you change the implementation from

#ifndef BOOST_NO_SCOPED_ENUMS
...

to

#ifdef BOOST_NO_SCOPED_ENUMS

I do have a hard time with double negations.

Kjell E

> Date: Thu, 5 Mar 2009 10:37:12 -0500
> From: bdawes_at_[hidden]
> To: boost_at_[hidden]
> Subject: [boost] [C++0x] Emulation of scoped enums
> 
> The improved type safety of the C++0x scoped enum feature is attractive, 
> so I'd like to start using it as it becomes available in compilers.
> 
> See http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2007/n2347.pdf 
> for a description. Note that the committee changed the name from 
> strongly typed enums to scoped enums.
> 
> See the attached for a boost/detail header that provides macro wrappers 
> that use scoped enums if available, otherwise fall back on C++03 
> namespaces and unscoped enums. It lets a library write:
> 
>    BOOST_SCOPED_ENUM_START(algae) { green, red, cyan };
>      BOOST_SCOPED_ENUM_END
>    ...
>    BOOST_SCOPED_ENUM(algae) sample( algae::red );
>    void func(BOOST_SCOPED_ENUM(algae));
> 
> and then a user can write:
> 
>    sample = algae::green;
>    func( algae::cyan );
> 
> Comments or suggestions appreciated,
> 
> --Beman
> 

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