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copied!<p>It's not a complicated issue to make something similar to boost. Here's a class with just three functions, including the constructor, to replicate what boost did (almost).</p> <pre><code>template <typename T, typename U> class create_map { private: std::map<T, U> m_map; public: create_map(const T& key, const U& val) { m_map[key] = val; } create_map<T, U>& operator()(const T& key, const U& val) { m_map[key] = val; return *this; } operator std::map<T, U>() { return m_map; } }; </code></pre> <p>Usage:</p> <pre> std::map mymap = create_map<int, int >(1,2)(3,4)(5,6); </pre> <p>The above code works best for initialization of global variables or static members of a class which needs to be initialized and you have no idea when it gets used first but you want to assure that the values are available in it.</p> <p>If say, you've got to insert elements into an existing std::map... here's another class for you.</p> <pre><code>template <typename MapType> class map_add_values { private: MapType mMap; public: typedef typename MapType::key_type KeyType; typedef typename MapType::mapped_type MappedType; map_add_values(const KeyType& key, const MappedType& val) { mMap[key] = val; } map_add_values& operator()(const KeyType& key, const MappedType& val) { mMap[key] = val; return *this; } void to (MapType& map) { map.insert(mMap.begin(), mMap.end()); } }; </code></pre> <p>Usage:</p> <pre><code>typedef std::map<int, int> Int2IntMap; Int2IntMap testMap; map_add_values<Int2IntMap>(1,2)(3,4)(5,6).to(testMap); </code></pre> <p>See it in action with GCC 4.7.2 here: <a href="http://ideone.com/3uYJiH" rel="noreferrer">http://ideone.com/3uYJiH</a></p> <p><strong>############### EVERYTHING BELOW THIS IS OBSOLETE #################</strong></p> <p><strong>EDIT</strong>: The <code>map_add_values</code> class below, which was the original solution I had suggested, would fail when it comes to GCC 4.5+. Please look at the code above for how to <strong>add</strong> values to existing map.</p> <pre><code> template<typename T, typename U> class map_add_values { private: std::map<T,U>& m_map; public: map_add_values(std::map<T, U>& _map):m_map(_map){} map_add_values& operator()(const T& _key, const U& _val) { m_map[key] = val; return *this; } };</code></pre> <p>Usage:</p> <pre>std::map<int, int> my_map; // Later somewhere along the code map_add_values<int,int>(my_map)(1,2)(3,4)(5,6);</pre> <p>NOTE: Previously I used a <code>operator []</code> for adding the actual values. This is not possible as commented by dalle.</p> <p><strong>##################### END OF OBSOLETE SECTION #####################</strong></p>

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