Add SCons configure checks

[senf.git] / boost_ext / boost / parameter / keyword.hpp

diff --git a/boost_ext/boost/parameter/keyword.hpp b/boost_ext/boost/parameter/keyword.hpp
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+++ b/boost_ext/boost/parameter/keyword.hpp
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+// Copyright Daniel Wallin, David Abrahams 2005. Use, modification and
+// distribution is subject to the Boost Software License, Version 1.0. (See
+// accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+
+#ifndef KEYWORD_050328_HPP
+#define KEYWORD_050328_HPP
+
+#include <boost/parameter/aux_/unwrap_cv_reference.hpp>
+#include <boost/parameter/aux_/tag.hpp>
+#include <boost/parameter/aux_/default.hpp>
+#include <boost/noncopyable.hpp>
+
+namespace boost { namespace parameter {
+
+// Instances of unique specializations of keyword<...> serve to
+// associate arguments with parameter names.  For example:
+//
+//    struct rate_;           // parameter names
+//    struct skew_;
+//    namespace
+//    {
+//      keyword<rate_> rate;  // keywords
+//      keyword<skew_> skew;
+//    }
+//
+//    ...
+//
+//    f(rate = 1, skew = 2.4);
+//
+template <class Tag>
+struct keyword : noncopyable
+{
+    template <class T>
+    typename aux::tag<Tag, T>::type
+    operator=(T& x) const
+    {
+        typedef typename aux::tag<Tag, T>::type result;
+        return result(x);
+    }
+
+    template <class Default>
+    aux::default_<Tag, Default>
+    operator|(Default& default_) const
+    {
+        return aux::default_<Tag, Default>(default_);
+    }
+
+    template <class Default>
+    aux::lazy_default<Tag, Default>
+    operator||(Default& default_) const
+    {
+        return aux::lazy_default<Tag, Default>(default_);
+    }
+
+#if !BOOST_WORKAROUND(BOOST_MSVC, < 1300)  // avoid partial ordering bugs
+    template <class T>
+    typename aux::tag<Tag, T const>::type
+    operator=(T const& x) const
+    {
+        typedef typename aux::tag<Tag, T const>::type result;
+        return result(x);
+    }
+#endif 
+
+#if !BOOST_WORKAROUND(BOOST_MSVC, < 1300)  // avoid partial ordering bugs
+    template <class Default>
+    aux::default_<Tag, const Default>
+    operator|(const Default& default_) const
+#if BOOST_WORKAROUND(BOOST_MSVC, == 1300)
+        volatile
+#endif 
+    {
+        return aux::default_<Tag, const Default>(default_);
+    }
+
+    template <class Default>
+    aux::lazy_default<Tag, Default>
+    operator||(Default const& default_) const
+#if BOOST_WORKAROUND(BOOST_MSVC, == 1300)
+        volatile
+#endif 
+    {
+        return aux::lazy_default<Tag, Default>(default_);
+    }
+#endif
+
+ public: // Insurance against ODR violations
+    
+    // People will need to define these keywords in header files.  To
+    // prevent ODR violations, it's important that the keyword used in
+    // every instantiation of a function template is the same object.
+    // We provide a reference to a common instance of each keyword
+    // object and prevent construction by users.
+    
+    static keyword<Tag>& get()
+    {
+        static keyword<Tag> result;
+        return result;
+    }
+    
+ private:
+    keyword() {}
+};
+
+// Reduces boilerplate required to declare and initialize keywords
+// without violating ODR.  Declares a keyword tag type with the given
+// name in namespace tag_namespace, and declares and initializes a
+// reference in an anonymous namespace to a singleton instance of that
+// type.
+
+#if BOOST_WORKAROUND(BOOST_MSVC, < 1300)
+
+# define BOOST_PARAMETER_KEYWORD(tag_namespace,name)                \
+    namespace tag_namespace { struct name; }                        \
+    static ::boost::parameter::keyword<tag_namespace::name>& name   \
+       = ::boost::parameter::keyword<tag_namespace::name>::get();
+
+#else
+
+#define BOOST_PARAMETER_KEYWORD(tag_namespace,name)                 \
+    namespace tag_namespace { struct name; }                        \
+    namespace                                                       \
+    {                                                               \
+       ::boost::parameter::keyword<tag_namespace::name>& name       \
+       = ::boost::parameter::keyword<tag_namespace::name>::get();   \
+    }
+
+#endif
+
+}} // namespace boost::parameter
+
+#endif // KEYWORD_050328_HPP
+