1 files changed, 136 insertions, 0 deletions
diff --git a/src/boost/libs/proto/example/map_assign.cpp b/src/boost/libs/proto/example/map_assign.cpp
new file mode 100644
index 000000000..939110594
--- /dev/null
+++ b/src/boost/libs/proto/example/map_assign.cpp
@@ -0,0 +1,136 @@
+//[ MapAssign
+//  Copyright 2008 Eric Niebler. Distributed under 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)
+//
+// This is a port of map_list_of() from the Boost.Assign library.
+// It has the advantage of being more efficient at runtime by not
+// building any temporary container that requires dynamic allocation.
+
+#include <map>
+#include <string>
+#include <iostream>
+#include <boost/proto/core.hpp>
+#include <boost/proto/transform.hpp>
+#include <boost/type_traits/add_reference.hpp>
+namespace proto = boost::proto;
+using proto::_;
+
+struct map_list_of_tag
+{};
+
+// A simple callable function object that inserts a
+// (key,value) pair into a map.
+struct insert
+  : proto::callable
+{
+    template<typename Sig>
+    struct result;
+
+    template<typename This, typename Map, typename Key, typename Value>
+    struct result<This(Map, Key, Value)>
+      : boost::add_reference<Map>
+    {};
+
+    template<typename Map, typename Key, typename Value>
+    Map &operator()(Map &map, Key const &key, Value const &value) const
+    {
+        map.insert(typename Map::value_type(key, value));
+        return map;
+    }
+};
+
+// Work-arounds for Microsoft Visual C++ 7.1
+#if BOOST_WORKAROUND(BOOST_MSVC, == 1310)
+#define MapListOf(x) proto::call<MapListOf(x)>
+#define _value(x) call<proto::_value(x)>
+#endif
+
+// The grammar for valid map-list expressions, and a
+// transform that populates the map.
+struct MapListOf
+  : proto::or_<
+        proto::when<
+            // map_list_of(a,b)
+            proto::function<
+                proto::terminal<map_list_of_tag>
+              , proto::terminal<_>
+              , proto::terminal<_>
+            >
+          , insert(
+                proto::_data
+              , proto::_value(proto::_child1)
+              , proto::_value(proto::_child2)
+            )
+        >
+      , proto::when<
+            // map_list_of(a,b)(c,d)...
+            proto::function<
+                MapListOf
+              , proto::terminal<_>
+              , proto::terminal<_>
+            >
+          , insert(
+                MapListOf(proto::_child0)
+              , proto::_value(proto::_child1)
+              , proto::_value(proto::_child2)
+            )
+        >
+    >
+{};
+
+#if BOOST_WORKAROUND(BOOST_MSVC, == 1310)
+#undef MapListOf
+#undef _value
+#endif
+
+template<typename Expr>
+struct map_list_of_expr;
+
+struct map_list_of_dom
+  : proto::domain<proto::pod_generator<map_list_of_expr>, MapListOf>
+{};
+
+// An expression wrapper that provides a conversion to a
+// map that uses the MapListOf
+template<typename Expr>
+struct map_list_of_expr
+{
+    BOOST_PROTO_BASIC_EXTENDS(Expr, map_list_of_expr, map_list_of_dom)
+    BOOST_PROTO_EXTENDS_FUNCTION()
+
+    template<typename Key, typename Value, typename Cmp, typename Al>
+    operator std::map<Key, Value, Cmp, Al> () const
+    {
+        BOOST_MPL_ASSERT((proto::matches<Expr, MapListOf>));
+        std::map<Key, Value, Cmp, Al> map;
+        return MapListOf()(*this, 0, map);
+    }
+};
+
+map_list_of_expr<proto::terminal<map_list_of_tag>::type> const map_list_of = {{{}}};
+
+int main()
+{
+    // Initialize a map:
+    std::map<std::string, int> op =
+        map_list_of
+            ("<", 1)
+            ("<=",2)
+            (">", 3)
+            (">=",4)
+            ("=", 5)
+            ("<>",6)
+        ;
+
+    std::cout << "\"<\"  --> " << op["<"] << std::endl;
+    std::cout << "\"<=\" --> " << op["<="] << std::endl;
+    std::cout << "\">\"  --> " << op[">"] << std::endl;
+    std::cout << "\">=\" --> " << op[">="] << std::endl;
+    std::cout << "\"=\"  --> " << op["="] << std::endl;
+    std::cout << "\"<>\" --> " << op["<>"] << std::endl;
+
+    return 0;
+}
+//]
+