[Patch] First bits of the algo merge

[Howard Hinnant]

On Dec 15, 2005, at 5:04 AM, Paolo Carlini wrote:

> Indeed, there is a whole series of functions, those that you pointed
> out, which have got a very strong (too strong)
> _SameTypeConcept<_ValueType1, _ValueType2> in the predicated  
> version of
> the algorithm (e.g., includes, set_*, etc.). Because of that, I  
> believe
> _LessThanComparableConcept<_ValueType1> is currently equivalent to  
> what
> you are suggesting.
>
> Therefore, the real question is: shall we remove
> _SameTypeConcept<_ValueType1, _ValueType2> from the predicated  
> version,
> in those cases? Let's reach an agreement about that and let's go ahead
> with this part of the work!

Ah, good point.

I'm concentrating on set_difference here (predicated version):

How 'bout:

       __glibcxx_function_requires 
(_InputIteratorConcept<_InputIterator1>)
       __glibcxx_function_requires 
(_InputIteratorConcept<_InputIterator2>)
       __glibcxx_function_requires 
(_OutputIteratorConcept<_OutputIterator,
	    typename iterator_traits<_InputIterator1>::value_type>)
       __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
	    typename iterator_traits<_InputIterator1>::value_type,
	    typename iterator_traits<_InputIterator2>::value_type>)
       __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
	    typename iterator_traits<_InputIterator2>::value_type,
	    typename iterator_traits<_InputIterator1>::value_type>)
       __glibcxx_requires_sorted_pred(__first1, __last1, __comp);
       __glibcxx_requires_sorted_pred(__first2, __last2, __comp);

I've removed _SameTypeConcept, and added the reverse  
_BinaryPredicateConcept (which could be made neater with typedefs).   
I think all of the set_* animals need that binary predicate both ways.

-Howard