+
+class unknown_keyword: public std::runtime_error
+{
+public:
+ unknown_keyword(const std::string &);
+ virtual ~unknown_keyword() throw() { }
+};
+
+
+class invalid_signature: public std::runtime_error
+{
+public:
+ invalid_signature(const std::string &, const std::string &);
+ virtual ~invalid_signature() throw() { }
+};
+
+
+class no_collection: public std::runtime_error
+{
+public:
+ no_collection(const std::type_info &);
+};
+