Add std::pair tier. This is a much simplified version of boost::tie

that works only for std::pair.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@9723 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Alkis Evlogimenos 2003-11-05 05:58:26 +00:00
parent 0271345368
commit e292da29bf
2 changed files with 96 additions and 0 deletions

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@ -19,6 +19,7 @@
#include <functional>
#include "Support/iterator"
#include "boost/type_traits/transform_traits.hpp"
//===----------------------------------------------------------------------===//
// Extra additions to <functional>
@ -230,4 +231,51 @@ template <class InIt, class OutIt, class Functor>
inline OutIt mapto(InIt Begin, InIt End, OutIt Dest, Functor F) {
return copy(map_iterator(Begin, F), map_iterator(End, F), Dest);
}
//===----------------------------------------------------------------------===//
// Extra additions to <utility>
//===----------------------------------------------------------------------===//
// tie - this function ties two objects and returns a temporary object
// that is assignable from a std::pair. This can be used to make code
// more readable when using values returned from functions bundled in
// a std::pair. Since an example is worth 1000 words:
//
// typedef std::map<int, int> Int2IntMap;
//
// Int2IntMap myMap;
// Int2IntMap::iterator where;
// bool inserted;
// tie(where, inserted) = myMap.insert(std::make_pair(123,456));
//
// if (inserted)
// // do stuff
// else
// // do other stuff
namespace
{
template <typename T1, typename T2>
struct tier {
typedef typename boost::add_reference<T1>::type first_type;
typedef typename boost::add_reference<T2>::type second_type;
first_type first;
second_type second;
tier(first_type f, second_type s) : first(f), second(s) { }
tier& operator=(const std::pair<T1, T2>& p) {
first = p.first;
second = p.second;
return *this;
}
};
}
template <typename T1, typename T2>
inline tier<T1, T2> tie(T1& f, T2& s) {
return tier<T1, T2>(f, s);
}
#endif

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@ -19,6 +19,7 @@
#include <functional>
#include "Support/iterator"
#include "boost/type_traits/transform_traits.hpp"
//===----------------------------------------------------------------------===//
// Extra additions to <functional>
@ -230,4 +231,51 @@ template <class InIt, class OutIt, class Functor>
inline OutIt mapto(InIt Begin, InIt End, OutIt Dest, Functor F) {
return copy(map_iterator(Begin, F), map_iterator(End, F), Dest);
}
//===----------------------------------------------------------------------===//
// Extra additions to <utility>
//===----------------------------------------------------------------------===//
// tie - this function ties two objects and returns a temporary object
// that is assignable from a std::pair. This can be used to make code
// more readable when using values returned from functions bundled in
// a std::pair. Since an example is worth 1000 words:
//
// typedef std::map<int, int> Int2IntMap;
//
// Int2IntMap myMap;
// Int2IntMap::iterator where;
// bool inserted;
// tie(where, inserted) = myMap.insert(std::make_pair(123,456));
//
// if (inserted)
// // do stuff
// else
// // do other stuff
namespace
{
template <typename T1, typename T2>
struct tier {
typedef typename boost::add_reference<T1>::type first_type;
typedef typename boost::add_reference<T2>::type second_type;
first_type first;
second_type second;
tier(first_type f, second_type s) : first(f), second(s) { }
tier& operator=(const std::pair<T1, T2>& p) {
first = p.first;
second = p.second;
return *this;
}
};
}
template <typename T1, typename T2>
inline tier<T1, T2> tie(T1& f, T2& s) {
return tier<T1, T2>(f, s);
}
#endif