Re: [boost] [switch_] Case Concept [ was Re: [Boost-users] formal review of Switch library...]

From: Joel de Guzman (joel_at_[hidden])
Date: 2008-01-13 01:47:47

Steven Watanabe wrote:
> AMDG
> 
> Tobias Schwinger wrote:
>> Joel de Guzman wrote:
>>   
>>>      c0, c1, ... cN          Returns a fusion sequence of Case objects
>>>     
>> seemingly equivalent to
>>
>>         (c0, c1, ... cN)
>>
>> (note: Application of comma operator ;-)).
>>
>>
>> ?! Why doesn't it just return another (compound) Case object and leave 
>> the Sequence an unspecified implementation detail...
>>   
> 
> So you want switch_ to be
> 
>   template<class R, class I, class Cases>
>   requires Case<Cases> && BuiltInIntegerOrEnum<I>
>   R switch(I i, Cases cases);
> 
> IMO, There is a very big problem here.
> Suppose that you have a fusion sequence that holds your
> cases and function objects coming from somewhere else.
> The problem of adapting it to switch_ is no easier than it
> would be with my original interface.

Oh man, either my headache is killing me, or I am currently in
dumb mode. I can't understand both Tobias and Steven. What's
a "compound Case object"?

Regards,
-- 
Joel de Guzman
http://www.boost-consulting.com
http://spirit.sf.net