// See http://www.boost.org/libs/utility/operators.htm for documentation.
// Revision History
+// 07 Aug 08 Added "euclidean" spelling. (Daniel Frey)
+// 03 Apr 08 Make sure "convertible to bool" is sufficient
+// for T::operator<, etc. (Daniel Frey)
+// 24 May 07 Changed empty_base to depend on T, see
+// http://svn.boost.org/trac/boost/ticket/979
// 21 Oct 02 Modified implementation of operators to allow compilers with a
// correct named return value optimization (NRVO) to produce optimal
// code. (Daniel Frey)
namespace boost {
namespace detail {
+template <typename T> class empty_base {
+
// Helmut Zeisel, empty base class optimization bug with GCC 3.0.0
#if defined(__GNUC__) && __GNUC__==3 && __GNUC_MINOR__==0 && __GNU_PATCHLEVEL__==0
-class empty_base {
bool dummy;
-};
-#else
-class empty_base {};
#endif
+};
+
} // namespace detail
} // namespace boost
// Note that friend functions defined in a class are implicitly inline.
// See the C++ std, 11.4 [class.friend] paragraph 5
-template <class T, class U, class B = ::boost::detail::empty_base>
+template <class T, class U, class B = ::boost::detail::empty_base<T> >
struct less_than_comparable2 : B
{
- friend bool operator<=(const T& x, const U& y) { return !(x > y); }
- friend bool operator>=(const T& x, const U& y) { return !(x < y); }
+ friend bool operator<=(const T& x, const U& y) { return !static_cast<bool>(x > y); }
+ friend bool operator>=(const T& x, const U& y) { return !static_cast<bool>(x < y); }
friend bool operator>(const U& x, const T& y) { return y < x; }
friend bool operator<(const U& x, const T& y) { return y > x; }
- friend bool operator<=(const U& x, const T& y) { return !(y < x); }
- friend bool operator>=(const U& x, const T& y) { return !(y > x); }
+ friend bool operator<=(const U& x, const T& y) { return !static_cast<bool>(y < x); }
+ friend bool operator>=(const U& x, const T& y) { return !static_cast<bool>(y > x); }
};
-template <class T, class B = ::boost::detail::empty_base>
+template <class T, class B = ::boost::detail::empty_base<T> >
struct less_than_comparable1 : B
{
friend bool operator>(const T& x, const T& y) { return y < x; }
- friend bool operator<=(const T& x, const T& y) { return !(y < x); }
- friend bool operator>=(const T& x, const T& y) { return !(x < y); }
+ friend bool operator<=(const T& x, const T& y) { return !static_cast<bool>(y < x); }
+ friend bool operator>=(const T& x, const T& y) { return !static_cast<bool>(x < y); }
};
-template <class T, class U, class B = ::boost::detail::empty_base>
+template <class T, class U, class B = ::boost::detail::empty_base<T> >
struct equality_comparable2 : B
{
friend bool operator==(const U& y, const T& x) { return x == y; }
- friend bool operator!=(const U& y, const T& x) { return !(x == y); }
- friend bool operator!=(const T& y, const U& x) { return !(y == x); }
+ friend bool operator!=(const U& y, const T& x) { return !static_cast<bool>(x == y); }
+ friend bool operator!=(const T& y, const U& x) { return !static_cast<bool>(y == x); }
};
-template <class T, class B = ::boost::detail::empty_base>
+template <class T, class B = ::boost::detail::empty_base<T> >
struct equality_comparable1 : B
{
- friend bool operator!=(const T& x, const T& y) { return !(x == y); }
+ friend bool operator!=(const T& x, const T& y) { return !static_cast<bool>(x == y); }
};
// A macro which produces "name_2left" from "name".
// implementation available.
#define BOOST_BINARY_OPERATOR_COMMUTATIVE( NAME, OP ) \
-template <class T, class U, class B = ::boost::detail::empty_base> \
+template <class T, class U, class B = ::boost::detail::empty_base<T> > \
struct NAME##2 : B \
{ \
friend T operator OP( const T& lhs, const U& rhs ) \
{ T nrv( rhs ); nrv OP##= lhs; return nrv; } \
}; \
\
-template <class T, class B = ::boost::detail::empty_base> \
+template <class T, class B = ::boost::detail::empty_base<T> > \
struct NAME##1 : B \
{ \
friend T operator OP( const T& lhs, const T& rhs ) \
{ T nrv( lhs ); nrv OP##= rhs; return nrv; } \
};
-#define BOOST_BINARY_OPERATOR_NON_COMMUTATIVE( NAME, OP ) \
-template <class T, class U, class B = ::boost::detail::empty_base> \
-struct NAME##2 : B \
-{ \
- friend T operator OP( const T& lhs, const U& rhs ) \
- { T nrv( lhs ); nrv OP##= rhs; return nrv; } \
-}; \
- \
-template <class T, class U, class B = ::boost::detail::empty_base> \
-struct BOOST_OPERATOR2_LEFT(NAME) : B \
-{ \
- friend T operator OP( const U& lhs, const T& rhs ) \
- { T nrv( lhs ); nrv OP##= rhs; return nrv; } \
-}; \
- \
-template <class T, class B = ::boost::detail::empty_base> \
-struct NAME##1 : B \
-{ \
- friend T operator OP( const T& lhs, const T& rhs ) \
- { T nrv( lhs ); nrv OP##= rhs; return nrv; } \
+#define BOOST_BINARY_OPERATOR_NON_COMMUTATIVE( NAME, OP ) \
+template <class T, class U, class B = ::boost::detail::empty_base<T> > \
+struct NAME##2 : B \
+{ \
+ friend T operator OP( const T& lhs, const U& rhs ) \
+ { T nrv( lhs ); nrv OP##= rhs; return nrv; } \
+}; \
+ \
+template <class T, class U, class B = ::boost::detail::empty_base<T> > \
+struct BOOST_OPERATOR2_LEFT(NAME) : B \
+{ \
+ friend T operator OP( const U& lhs, const T& rhs ) \
+ { T nrv( lhs ); nrv OP##= rhs; return nrv; } \
+}; \
+ \
+template <class T, class B = ::boost::detail::empty_base<T> > \
+struct NAME##1 : B \
+{ \
+ friend T operator OP( const T& lhs, const T& rhs ) \
+ { T nrv( lhs ); nrv OP##= rhs; return nrv; } \
};
#else // defined(BOOST_HAS_NRVO) || defined(BOOST_FORCE_SYMMETRIC_OPERATORS)
// BOOST_OPERATOR2_LEFT(NAME) only looks cool, but doesn't provide
// optimization opportunities to the compiler :)
-#define BOOST_BINARY_OPERATOR_COMMUTATIVE( NAME, OP ) \
-template <class T, class U, class B = ::boost::detail::empty_base> \
-struct NAME##2 : B \
-{ \
- friend T operator OP( T lhs, const U& rhs ) { return lhs OP##= rhs; } \
- friend T operator OP( const U& lhs, T rhs ) { return rhs OP##= lhs; } \
-}; \
- \
-template <class T, class B = ::boost::detail::empty_base> \
-struct NAME##1 : B \
-{ \
- friend T operator OP( T lhs, const T& rhs ) { return lhs OP##= rhs; } \
+#define BOOST_BINARY_OPERATOR_COMMUTATIVE( NAME, OP ) \
+template <class T, class U, class B = ::boost::detail::empty_base<T> > \
+struct NAME##2 : B \
+{ \
+ friend T operator OP( T lhs, const U& rhs ) { return lhs OP##= rhs; } \
+ friend T operator OP( const U& lhs, T rhs ) { return rhs OP##= lhs; } \
+}; \
+ \
+template <class T, class B = ::boost::detail::empty_base<T> > \
+struct NAME##1 : B \
+{ \
+ friend T operator OP( T lhs, const T& rhs ) { return lhs OP##= rhs; } \
};
#define BOOST_BINARY_OPERATOR_NON_COMMUTATIVE( NAME, OP ) \
-template <class T, class U, class B = ::boost::detail::empty_base> \
+template <class T, class U, class B = ::boost::detail::empty_base<T> > \
struct NAME##2 : B \
{ \
friend T operator OP( T lhs, const U& rhs ) { return lhs OP##= rhs; } \
}; \
\
-template <class T, class U, class B = ::boost::detail::empty_base> \
+template <class T, class U, class B = ::boost::detail::empty_base<T> > \
struct BOOST_OPERATOR2_LEFT(NAME) : B \
{ \
friend T operator OP( const U& lhs, const T& rhs ) \
{ return T( lhs ) OP##= rhs; } \
}; \
\
-template <class T, class B = ::boost::detail::empty_base> \
+template <class T, class B = ::boost::detail::empty_base<T> > \
struct NAME##1 : B \
{ \
friend T operator OP( T lhs, const T& rhs ) { return lhs OP##= rhs; } \
// incrementable and decrementable contributed by Jeremy Siek
-template <class T, class B = ::boost::detail::empty_base>
+template <class T, class B = ::boost::detail::empty_base<T> >
struct incrementable : B
{
friend T operator++(T& x, int)
typedef T incrementable_type;
};
-template <class T, class B = ::boost::detail::empty_base>
+template <class T, class B = ::boost::detail::empty_base<T> >
struct decrementable : B
{
friend T operator--(T& x, int)
// Iterator operator classes (contributed by Jeremy Siek) ------------------//
-template <class T, class P, class B = ::boost::detail::empty_base>
+template <class T, class P, class B = ::boost::detail::empty_base<T> >
struct dereferenceable : B
{
P operator->() const
}
};
-template <class T, class I, class R, class B = ::boost::detail::empty_base>
+template <class T, class I, class R, class B = ::boost::detail::empty_base<T> >
struct indexable : B
{
R operator[](I n) const
#if defined(BOOST_HAS_NRVO) || defined(BOOST_FORCE_SYMMETRIC_OPERATORS)
#define BOOST_BINARY_OPERATOR( NAME, OP ) \
-template <class T, class U, class B = ::boost::detail::empty_base> \
+template <class T, class U, class B = ::boost::detail::empty_base<T> > \
struct NAME##2 : B \
{ \
friend T operator OP( const T& lhs, const U& rhs ) \
{ T nrv( lhs ); nrv OP##= rhs; return nrv; } \
}; \
\
-template <class T, class B = ::boost::detail::empty_base> \
+template <class T, class B = ::boost::detail::empty_base<T> > \
struct NAME##1 : B \
{ \
friend T operator OP( const T& lhs, const T& rhs ) \
#else // defined(BOOST_HAS_NRVO) || defined(BOOST_FORCE_SYMMETRIC_OPERATORS)
#define BOOST_BINARY_OPERATOR( NAME, OP ) \
-template <class T, class U, class B = ::boost::detail::empty_base> \
+template <class T, class U, class B = ::boost::detail::empty_base<T> > \
struct NAME##2 : B \
{ \
friend T operator OP( T lhs, const U& rhs ) { return lhs OP##= rhs; } \
}; \
\
-template <class T, class B = ::boost::detail::empty_base> \
+template <class T, class B = ::boost::detail::empty_base<T> > \
struct NAME##1 : B \
{ \
friend T operator OP( T lhs, const T& rhs ) { return lhs OP##= rhs; } \
#undef BOOST_BINARY_OPERATOR
-template <class T, class U, class B = ::boost::detail::empty_base>
+template <class T, class U, class B = ::boost::detail::empty_base<T> >
struct equivalent2 : B
{
friend bool operator==(const T& x, const U& y)
{
- return !(x < y) && !(x > y);
+ return !static_cast<bool>(x < y) && !static_cast<bool>(x > y);
}
};
-template <class T, class B = ::boost::detail::empty_base>
+template <class T, class B = ::boost::detail::empty_base<T> >
struct equivalent1 : B
{
friend bool operator==(const T&x, const T&y)
{
- return !(x < y) && !(y < x);
+ return !static_cast<bool>(x < y) && !static_cast<bool>(y < x);
}
};
-template <class T, class U, class B = ::boost::detail::empty_base>
+template <class T, class U, class B = ::boost::detail::empty_base<T> >
struct partially_ordered2 : B
{
friend bool operator<=(const T& x, const U& y)
- { return (x < y) || (x == y); }
+ { return static_cast<bool>(x < y) || static_cast<bool>(x == y); }
friend bool operator>=(const T& x, const U& y)
- { return (x > y) || (x == y); }
+ { return static_cast<bool>(x > y) || static_cast<bool>(x == y); }
friend bool operator>(const U& x, const T& y)
{ return y < x; }
friend bool operator<(const U& x, const T& y)
{ return y > x; }
friend bool operator<=(const U& x, const T& y)
- { return (y > x) || (y == x); }
+ { return static_cast<bool>(y > x) || static_cast<bool>(y == x); }
friend bool operator>=(const U& x, const T& y)
- { return (y < x) || (y == x); }
+ { return static_cast<bool>(y < x) || static_cast<bool>(y == x); }
};
-template <class T, class B = ::boost::detail::empty_base>
+template <class T, class B = ::boost::detail::empty_base<T> >
struct partially_ordered1 : B
{
friend bool operator>(const T& x, const T& y)
{ return y < x; }
friend bool operator<=(const T& x, const T& y)
- { return (x < y) || (x == y); }
+ { return static_cast<bool>(x < y) || static_cast<bool>(x == y); }
friend bool operator>=(const T& x, const T& y)
- { return (y < x) || (x == y); }
+ { return static_cast<bool>(y < x) || static_cast<bool>(x == y); }
};
// Combined operator classes (contributed by Daryle Walker) ----------------//
-template <class T, class U, class B = ::boost::detail::empty_base>
+template <class T, class U, class B = ::boost::detail::empty_base<T> >
struct totally_ordered2
: less_than_comparable2<T, U
, equality_comparable2<T, U, B
> > {};
-template <class T, class B = ::boost::detail::empty_base>
+template <class T, class B = ::boost::detail::empty_base<T> >
struct totally_ordered1
: less_than_comparable1<T
, equality_comparable1<T, B
> > {};
-template <class T, class U, class B = ::boost::detail::empty_base>
+template <class T, class U, class B = ::boost::detail::empty_base<T> >
struct additive2
: addable2<T, U
, subtractable2<T, U, B
> > {};
-template <class T, class B = ::boost::detail::empty_base>
+template <class T, class B = ::boost::detail::empty_base<T> >
struct additive1
: addable1<T
, subtractable1<T, B
> > {};
-template <class T, class U, class B = ::boost::detail::empty_base>
+template <class T, class U, class B = ::boost::detail::empty_base<T> >
struct multiplicative2
: multipliable2<T, U
, dividable2<T, U, B
> > {};
-template <class T, class B = ::boost::detail::empty_base>
+template <class T, class B = ::boost::detail::empty_base<T> >
struct multiplicative1
: multipliable1<T
, dividable1<T, B
> > {};
-template <class T, class U, class B = ::boost::detail::empty_base>
+template <class T, class U, class B = ::boost::detail::empty_base<T> >
struct integer_multiplicative2
: multiplicative2<T, U
, modable2<T, U, B
> > {};
-template <class T, class B = ::boost::detail::empty_base>
+template <class T, class B = ::boost::detail::empty_base<T> >
struct integer_multiplicative1
: multiplicative1<T
, modable1<T, B
> > {};
-template <class T, class U, class B = ::boost::detail::empty_base>
+template <class T, class U, class B = ::boost::detail::empty_base<T> >
struct arithmetic2
: additive2<T, U
, multiplicative2<T, U, B
> > {};
-template <class T, class B = ::boost::detail::empty_base>
+template <class T, class B = ::boost::detail::empty_base<T> >
struct arithmetic1
: additive1<T
, multiplicative1<T, B
> > {};
-template <class T, class U, class B = ::boost::detail::empty_base>
+template <class T, class U, class B = ::boost::detail::empty_base<T> >
struct integer_arithmetic2
: additive2<T, U
, integer_multiplicative2<T, U, B
> > {};
-template <class T, class B = ::boost::detail::empty_base>
+template <class T, class B = ::boost::detail::empty_base<T> >
struct integer_arithmetic1
: additive1<T
, integer_multiplicative1<T, B
> > {};
-template <class T, class U, class B = ::boost::detail::empty_base>
+template <class T, class U, class B = ::boost::detail::empty_base<T> >
struct bitwise2
: xorable2<T, U
, andable2<T, U
, orable2<T, U, B
> > > {};
-template <class T, class B = ::boost::detail::empty_base>
+template <class T, class B = ::boost::detail::empty_base<T> >
struct bitwise1
: xorable1<T
, andable1<T
, orable1<T, B
> > > {};
-template <class T, class B = ::boost::detail::empty_base>
+template <class T, class B = ::boost::detail::empty_base<T> >
struct unit_steppable
: incrementable<T
, decrementable<T, B
> > {};
-template <class T, class U, class B = ::boost::detail::empty_base>
+template <class T, class U, class B = ::boost::detail::empty_base<T> >
struct shiftable2
: left_shiftable2<T, U
, right_shiftable2<T, U, B
> > {};
-template <class T, class B = ::boost::detail::empty_base>
+template <class T, class B = ::boost::detail::empty_base<T> >
struct shiftable1
: left_shiftable1<T
, right_shiftable1<T, B
> > {};
-template <class T, class U, class B = ::boost::detail::empty_base>
+template <class T, class U, class B = ::boost::detail::empty_base<T> >
struct ring_operators2
: additive2<T, U
, subtractable2_left<T, U
, multipliable2<T, U, B
> > > {};
-template <class T, class B = ::boost::detail::empty_base>
+template <class T, class B = ::boost::detail::empty_base<T> >
struct ring_operators1
: additive1<T
, multipliable1<T, B
> > {};
-template <class T, class U, class B = ::boost::detail::empty_base>
+template <class T, class U, class B = ::boost::detail::empty_base<T> >
struct ordered_ring_operators2
: ring_operators2<T, U
, totally_ordered2<T, U, B
> > {};
-template <class T, class B = ::boost::detail::empty_base>
+template <class T, class B = ::boost::detail::empty_base<T> >
struct ordered_ring_operators1
: ring_operators1<T
, totally_ordered1<T, B
> > {};
-template <class T, class U, class B = ::boost::detail::empty_base>
+template <class T, class U, class B = ::boost::detail::empty_base<T> >
struct field_operators2
: ring_operators2<T, U
, dividable2<T, U
, dividable2_left<T, U, B
> > > {};
-template <class T, class B = ::boost::detail::empty_base>
+template <class T, class B = ::boost::detail::empty_base<T> >
struct field_operators1
: ring_operators1<T
, dividable1<T, B
> > {};
-template <class T, class U, class B = ::boost::detail::empty_base>
+template <class T, class U, class B = ::boost::detail::empty_base<T> >
struct ordered_field_operators2
: field_operators2<T, U
, totally_ordered2<T, U, B
> > {};
-template <class T, class B = ::boost::detail::empty_base>
+template <class T, class B = ::boost::detail::empty_base<T> >
struct ordered_field_operators1
: field_operators1<T
, totally_ordered1<T, B
> > {};
-template <class T, class U, class B = ::boost::detail::empty_base>
+template <class T, class U, class B = ::boost::detail::empty_base<T> >
struct euclidian_ring_operators2
: ring_operators2<T, U
, dividable2<T, U
, modable2_left<T, U, B
> > > > > {};
-template <class T, class B = ::boost::detail::empty_base>
+template <class T, class B = ::boost::detail::empty_base<T> >
struct euclidian_ring_operators1
: ring_operators1<T
, dividable1<T
, modable1<T, B
> > > {};
-template <class T, class U, class B = ::boost::detail::empty_base>
+template <class T, class U, class B = ::boost::detail::empty_base<T> >
struct ordered_euclidian_ring_operators2
: totally_ordered2<T, U
, euclidian_ring_operators2<T, U, B
> > {};
-template <class T, class B = ::boost::detail::empty_base>
+template <class T, class B = ::boost::detail::empty_base<T> >
struct ordered_euclidian_ring_operators1
: totally_ordered1<T
, euclidian_ring_operators1<T, B
> > {};
-
-template <class T, class P, class B = ::boost::detail::empty_base>
+
+template <class T, class U, class B = ::boost::detail::empty_base<T> >
+struct euclidean_ring_operators2
+ : ring_operators2<T, U
+ , dividable2<T, U
+ , dividable2_left<T, U
+ , modable2<T, U
+ , modable2_left<T, U, B
+ > > > > > {};
+
+template <class T, class B = ::boost::detail::empty_base<T> >
+struct euclidean_ring_operators1
+ : ring_operators1<T
+ , dividable1<T
+ , modable1<T, B
+ > > > {};
+
+template <class T, class U, class B = ::boost::detail::empty_base<T> >
+struct ordered_euclidean_ring_operators2
+ : totally_ordered2<T, U
+ , euclidean_ring_operators2<T, U, B
+ > > {};
+
+template <class T, class B = ::boost::detail::empty_base<T> >
+struct ordered_euclidean_ring_operators1
+ : totally_ordered1<T
+ , euclidean_ring_operators1<T, B
+ > > {};
+
+template <class T, class P, class B = ::boost::detail::empty_base<T> >
struct input_iteratable
: equality_comparable1<T
, incrementable<T
, dereferenceable<T, P, B
> > > {};
-template <class T, class B = ::boost::detail::empty_base>
+template <class T, class B = ::boost::detail::empty_base<T> >
struct output_iteratable
: incrementable<T, B
> {};
-template <class T, class P, class B = ::boost::detail::empty_base>
+template <class T, class P, class B = ::boost::detail::empty_base<T> >
struct forward_iteratable
: input_iteratable<T, P, B
> {};
-template <class T, class P, class B = ::boost::detail::empty_base>
+template <class T, class P, class B = ::boost::detail::empty_base<T> >
struct bidirectional_iteratable
: forward_iteratable<T, P
, decrementable<T, B
// which is an indirect base class of bidirectional_iterable,
// random_access_iteratable must not be derived from totally_ordered1
// but from less_than_comparable1 only. (Helmut Zeisel, 02-Dec-2001)
-template <class T, class P, class D, class R, class B = ::boost::detail::empty_base>
+template <class T, class P, class D, class R, class B = ::boost::detail::empty_base<T> >
struct random_access_iteratable
: bidirectional_iteratable<T, P
, less_than_comparable1<T
// Otherwise, because a Borland C++ 5.5 bug prevents a using declaration
// from working, we are forced to use inheritance for that compiler.
-# define BOOST_IMPORT_TEMPLATE4(template_name) \
- template <class T, class U, class V, class W, class B = ::boost::detail::empty_base> \
+# define BOOST_IMPORT_TEMPLATE4(template_name) \
+ template <class T, class U, class V, class W, class B = ::boost::detail::empty_base<T> > \
struct template_name : ::template_name<T, U, V, W, B> {};
-# define BOOST_IMPORT_TEMPLATE3(template_name) \
- template <class T, class U, class V, class B = ::boost::detail::empty_base> \
+# define BOOST_IMPORT_TEMPLATE3(template_name) \
+ template <class T, class U, class V, class B = ::boost::detail::empty_base<T> > \
struct template_name : ::template_name<T, U, V, B> {};
-# define BOOST_IMPORT_TEMPLATE2(template_name) \
- template <class T, class U, class B = ::boost::detail::empty_base> \
+# define BOOST_IMPORT_TEMPLATE2(template_name) \
+ template <class T, class U, class B = ::boost::detail::empty_base<T> > \
struct template_name : ::template_name<T, U, B> {};
-# define BOOST_IMPORT_TEMPLATE1(template_name) \
- template <class T, class B = ::boost::detail::empty_base> \
+# define BOOST_IMPORT_TEMPLATE1(template_name) \
+ template <class T, class B = ::boost::detail::empty_base<T> > \
struct template_name : ::template_name<T, B> {};
# endif // BOOST_NO_USING_TEMPLATE
# define BOOST_OPERATOR_TEMPLATE(template_name) \
template <class T \
,class U = T \
- ,class B = ::boost::detail::empty_base \
+ ,class B = ::boost::detail::empty_base<T> \
,class O = typename is_chained_base<U>::value \
> \
struct template_name : template_name##2<T, U, B> {}; \
// In this case we can only assume that template_name<> is equivalent to the
// more commonly needed template_name1<> form.
# define BOOST_OPERATOR_TEMPLATE(template_name) \
- template <class T, class B = ::boost::detail::empty_base> \
+ template <class T, class B = ::boost::detail::empty_base<T> > \
struct template_name : template_name##1<T, B> {};
#endif // BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
BOOST_OPERATOR_TEMPLATE(ordered_field_operators)
BOOST_OPERATOR_TEMPLATE(euclidian_ring_operators)
BOOST_OPERATOR_TEMPLATE(ordered_euclidian_ring_operators)
+BOOST_OPERATOR_TEMPLATE(euclidean_ring_operators)
+BOOST_OPERATOR_TEMPLATE(ordered_euclidean_ring_operators)
BOOST_OPERATOR_TEMPLATE2(input_iteratable)
BOOST_OPERATOR_TEMPLATE1(output_iteratable)
BOOST_OPERATOR_TEMPLATE2(forward_iteratable)