+class unsupported_extension: public std::runtime_error
+{
+public:
+ unsupported_extension(const std::string &w): std::runtime_error(w) { }
+ virtual ~unsupported_extension() throw() { }
+};
+
+class invalid_operation: public std::logic_error
+{
+public:
+ invalid_operation(const std::string &w): std::logic_error(w) { }
+ virtual ~invalid_operation() throw() { }
+};
+
+class stack_underflow: public std::logic_error
+{
+public:
+ stack_underflow(const std::string &w): std::logic_error(w) { }
+ virtual ~stack_underflow() throw() { }
+};
+
+class incompatible_data: public std::logic_error
+{
+public:
+ incompatible_data(const std::string &w): std::logic_error(w) { }
+ virtual ~incompatible_data() throw() { }
+};
+
+class compile_error: public std::runtime_error