Re: [Boost-users] [tuples] make_tuple_over a type-sequence

From: David Abrahams (dave_at_[hidden])
Date: 2006-03-29 09:56:15

Yuval Ronen <ronen_yuval_at_[hidden]> writes:

> EMalenfant_at_[hidden] wrote:
>> From: Yuval Ronen [mailto:ronen_yuval_at_[hidden]] 
>> 
>>>Is there a meta-function that creates a tuple type which 
>>>contains the types contained in a type-sequence? (I'm talking 
>>>about a similar thing to variant's make_variant_over).
>>>
>> 
>> 
>> We use a generator like this:
>> 
>> template<typename Typelist> 
>> struct TupleGen
>>     : boost::mpl::reverse_fold<
>>          Typelist, boost::tuples::null_type,
>> boost::tuples::cons<boost::mpl::_2, boost::mpl::_1> 
>>       >
>> {
>> };
>
> Great, thanks a lot. BTW, is there the opposite meta-function, i.e, 
> getting a typelist out of an existing tuple type?

If you use fusion, all your existing tuple types will be valid MPL
type sequences.

-- 
Dave Abrahams
Boost Consulting
www.boost-consulting.com