Add exception_specification and unittests for it. #6

include/chaiscript/chaiscript.hpp

@@ -140,7 +140,7 @@
 ///
 /// \subsubsection addingobjects Adding Objects
 ///
-/// Named objects can be created with the #var function.
+/// Named objects can be created with the chaiscript::var function.
 /// 
 /// \code
 /// using namespace chaiscript;
@@ -300,7 +300,7 @@
 /// As much as possible, ChaiScript attempts to convert between &, *, const &, const *, boost::shared_ptr<T>,
 /// boost::shared_ptr<const T>, boost::reference_wrapper<T>, boost::reference_wrapper<const T> and value types automatically.
 ///
-/// If a var object was created in C++ from a pointer, it cannot be convered to a shared_ptr (this would add invalid reference counting).
+/// If a chaiscript::var object was created in C++ from a pointer, it cannot be convered to a shared_ptr (this would add invalid reference counting).
 /// Const may be added, but never removed. 
 ///
 /// The take away is that you can pretty much expect function calls to Just Work when you need them to.
@@ -413,6 +413,8 @@
 ///
 /// \subsection exceptions Exception Handling
 /// 
+/// \subsubsection exceptionsbasics Exception Handling Basics
+///
 /// Exceptions can be thrown in ChaiScript and caught in C++ or thrown in C++ and caught in 
 /// ChaiScript.
 ///
@@ -424,10 +426,12 @@
 /// 
 /// int main()
 /// {
+///   // Throw in C++, catch in ChaiScript
 ///   chaiscript::ChaiScript chai;
 ///   chai.add(chaiscript::fun(&throwexception), "throwexception");
 ///   chai("try { throwexception(); } catch (e) { print(e.what()); }"); // prints "err"
 /// 
+///   // Throw in ChaiScript, catch in C++
 ///   try {
 ///     chai("throw(1)");
 ///   } catch (chaiscript::Boxed_Value bv) {
@@ -436,6 +440,31 @@
 ///   }
 /// }
 /// \endcode
+/// 
+/// \subsubsection exceptionsautomatic Exception Handling Automatic Unboxing
+///
+/// As an alternative to the manual unboxing of exceptions shown above, exception specifications allow the user to tell 
+/// ChaiScript what possible exceptions are expected from the script being executed. 
+///
+/// Example:
+/// \code
+/// chaiscript::ChaiScript chai;
+///
+/// try {
+///   chai.eval("throw(runtime_error(\"error\"))", chaiscript::exception_specification<int, double, float, const std::string &, const std::exception &>());
+/// } catch (const double e) {
+/// } catch (int) {
+/// } catch (float) {
+/// } catch (const std::string &) {
+/// } catch (const std::exception &e) {
+///   // This is the one what will be called in the specific throw() above
+/// }
+/// \endcode
+///
+/// \sa chaiscript::Exception_Handler for details on automatic exception unboxing 
+/// \sa chaiscript::exception_specification
+
+
 
 /// \page LangObjectSystemRef ChaiScript Language Object Model Reference
 ///

include/chaiscript/dispatchkit/exception_specification.hpp

@@ -0,0 +1,176 @@
+// This file is distributed under the BSD License.
+// See "license.txt" for details.
+// Copyright 2009-2011, Jonathan Turner (jonathan@emptycrate.com)
+// and Jason Turner (jason@emptycrate.com)
+// http://www.chaiscript.com
+
+#ifndef CHAISCRIPT_EXCEPTION_SPECIFICATION_HPP_
+#define CHAISCRIPT_EXCEPTION_SPECIFICATION_HPP_
+
+#include "boxed_cast.hpp"
+
+namespace chaiscript
+{
+  namespace detail
+  {
+    struct Exception_Handler_Base
+    {
+      virtual void handle(const Boxed_Value &bv) = 0;
+
+      protected:
+        template<typename T>
+        void throw_type(const Boxed_Value &bv)
+        {
+          try { T t = boxed_cast<T>(bv); throw t; } catch (const exception::bad_boxed_cast &) {}
+        }
+    };
+
+    template<typename T1>
+      struct Exception_Handler_Impl1 : Exception_Handler_Base
+      {
+        virtual void handle(const Boxed_Value &bv)
+        {
+          throw_type<T1>(bv);
+        }
+      };
+    template<typename T1, typename T2>
+      struct Exception_Handler_Impl2 : Exception_Handler_Base
+      {
+        virtual void handle(const Boxed_Value &bv)
+        {
+          throw_type<T1>(bv);
+          throw_type<T2>(bv);
+        }
+      };
+
+    template<typename T1, typename T2, typename T3>
+      struct Exception_Handler_Impl3 : Exception_Handler_Base
+      {
+        virtual void handle(const Boxed_Value &bv)
+        {
+          throw_type<T1>(bv);
+          throw_type<T2>(bv);
+          throw_type<T3>(bv);
+        }
+      };
+    template<typename T1, typename T2, typename T3, typename T4>
+      struct Exception_Handler_Impl4 : Exception_Handler_Base
+      {
+        virtual void handle(const Boxed_Value &bv)
+        {
+          throw_type<T1>(bv);
+          throw_type<T2>(bv);
+          throw_type<T3>(bv);
+          throw_type<T4>(bv);
+        }
+      };
+    template<typename T1, typename T2, typename T3, typename T4, typename T5>
+      struct Exception_Handler_Impl5 : Exception_Handler_Base
+      {
+        virtual void handle(const Boxed_Value &bv)
+        {
+          throw_type<T1>(bv);
+          throw_type<T2>(bv);
+          throw_type<T3>(bv);
+          throw_type<T4>(bv);
+          throw_type<T5>(bv);
+        }
+      };
+  }
+
+  /// \brief Used in the automatic unboxing of exceptions thrown during script evaluation
+  ///
+  /// Exception specifications allow the user to tell ChaiScript what possible exceptions are expected from the script
+  /// being executed. Exception_Handler objects are created with the chaiscript::exception_specification() function.
+  ///
+  /// Example:
+  /// \code
+  /// chaiscript::ChaiScript chai;
+  ///
+  /// try {
+  ///   chai.eval("throw(runtime_error(\"error\"))", chaiscript::exception_specification<int, double, float, const std::string &, const std::exception &>());
+  /// } catch (const double e) {
+  /// } catch (int) {
+  /// } catch (float) {
+  /// } catch (const std::string &) {
+  /// } catch (const std::exception &e) {
+  ///   // This is the one what will be called in the specific throw() above
+  /// }
+  /// \endcode
+  ///
+  /// It is recommended that if catching the generic \c std::exception& type that you specifically catch
+  /// the chaiscript::exception::eval_error type, so that there is no confusion.
+  ///
+  /// \code
+  /// try {
+  ///   chai.eval("throw(runtime_error(\"error\"))", chaiscript::exception_specification<const std::exception &>());
+  /// } catch (const chaiscript::exception::eval_error &) {
+  ///   // Error in script parsing / execution
+  /// } catch (const std::exception &e) {
+  ///   // Error explicitly thrown from script
+  /// }
+  /// \endcode
+  ///
+  /// Similarly, if you are using the ChaiScript::eval form that unboxes the return value, then chaiscript::exception::bad_boxed_cast
+  /// should be handled as well.
+  /// 
+  /// \code
+  /// try {
+  ///   chai.eval<int>("1.0", chaiscript::exception_specification<const std::exception &>());
+  /// } catch (const chaiscript::exception::eval_error &) {
+  ///   // Error in script parsing / execution
+  /// } catch (const chaiscript::exception::bad_boxed_cast &) {
+  ///   // Error unboxing return value
+  /// } catch (const std::exception &e) {
+  ///   // Error explicitly thrown from script
+  /// }
+  /// \endcode
+  ///
+  /// \sa chaiscript::exception_specification for creation of chaiscript::Exception_Handler objects
+  /// \sa \ref exceptions
+  typedef boost::shared_ptr<detail::Exception_Handler_Base> Exception_Handler;
+
+  /// \brief creates a chaiscript::Exception_Handler which handles one type of exception unboxing
+  /// \sa \ref exceptions
+  template<typename T1>
+  Exception_Handler exception_specification()
+  {
+    return Exception_Handler(new detail::Exception_Handler_Impl1<T1>());
+  }
+
+  /// \brief creates a chaiscript::Exception_Handler which handles two types of exception unboxing
+  /// \sa \ref exceptions
+  template<typename T1, typename T2>
+  Exception_Handler exception_specification()
+  {
+    return Exception_Handler(new detail::Exception_Handler_Impl2<T1, T2>());
+  }
+
+  /// \brief creates a chaiscript::Exception_Handler which handles three types of exception unboxing
+  /// \sa \ref exceptions
+  template<typename T1, typename T2, typename T3>
+  Exception_Handler exception_specification()
+  {
+    return Exception_Handler(new detail::Exception_Handler_Impl3<T1, T2, T3>());
+  }
+
+  /// \brief creates a chaiscript::Exception_Handler which handles four types of exception unboxing
+  /// \sa \ref exceptions
+  template<typename T1, typename T2, typename T3, typename T4>
+  Exception_Handler exception_specification()
+  {
+    return Exception_Handler(new detail::Exception_Handler_Impl4<T1, T2, T3, T4>());
+  }
+
+  /// \brief creates a chaiscript::Exception_Handler which handles five types of exception unboxing
+  /// \sa \ref exceptions
+  template<typename T1, typename T2, typename T3, typename T4, typename T5>
+  Exception_Handler exception_specification()
+  {
+    return Exception_Handler(new detail::Exception_Handler_Impl5<T1, T2, T3, T4, T5>());
+  }
+}
+
+
+#endif
+

include/chaiscript/language/chaiscript_engine.hpp

@@ -25,6 +25,7 @@
 
 #include <chaiscript/language/chaiscript_prelude.hpp>
 #include <chaiscript/language/chaiscript_parser.hpp>
+#include "../dispatchkit/exception_specification.hpp"
 
 namespace chaiscript
 {
@@ -598,19 +599,28 @@ namespace chaiscript
     /// \brief Evaluates a string. Equivalent to ChaiScript::eval.
     ///
     /// \param[in] t_script Script to execute
+    /// \param[in] t_handler Optional Exception_Handler used for automatic unboxing of script thrown exceptions
     ///
     /// \return result of the script execution
     /// 
     /// \throw exception::eval_error In the case that evaluation fails.
-    Boxed_Value operator()(const std::string &t_script)
+    Boxed_Value operator()(const std::string &t_script, const Exception_Handler &t_handler = Exception_Handler())
     {
-      return do_eval(t_script);
+      try {
+        return do_eval(t_script);
+      } catch (Boxed_Value &bv) {
+        if (t_handler) {
+          t_handler->handle(bv);
+        }
+        throw bv;
+      }
     }
 
     /// \brief Evaluates a string and returns a typesafe result.
     ///
     /// \tparam T Type to extract from the result value of the script execution
     /// \param[in] t_input Script to execute
+    /// \param[in] t_handler Optional Exception_Handler used for automatic unboxing of script thrown exceptions
     ///
     /// \return result of the script execution
     /// 
@@ -618,41 +628,72 @@ namespace chaiscript
     /// \throw exception::bad_boxed_cast In the case that evaluation succeeds but the result value cannot be converted
     ///        to the requested type.
     template<typename T>
-    T eval(const std::string &t_input)
+    T eval(const std::string &t_input, const Exception_Handler &t_handler = Exception_Handler())
     {
-      return boxed_cast<T>(do_eval(t_input));
+      try {
+        return boxed_cast<T>(do_eval(t_input));
+      } catch (Boxed_Value &bv) {
+        if (t_handler) {
+          t_handler->handle(bv);
+        }
+        throw bv;
+      }
     }
 
     /// \brief Evaluates a string.
     ///
     /// \param[in] t_input Script to execute
+    /// \param[in] t_handler Optional Exception_Handler used for automatic unboxing of script thrown exceptions
     ///
     /// \return result of the script execution
     /// 
     /// \throw exception::eval_error In the case that evaluation fails.
-    Boxed_Value eval(const std::string &t_input)
+    Boxed_Value eval(const std::string &t_input, const Exception_Handler &t_handler = Exception_Handler())
     {
-      return do_eval(t_input);
+      try {
+        return do_eval(t_input);
+      } catch (Boxed_Value &bv) {
+        if (t_handler) {
+          t_handler->handle(bv);
+        }
+        throw bv;
+      }
     }
 
     /// \brief Loads the file specified by filename, evaluates it, and returns the result.
     /// \param[in] t_filename File to load and parse.
+    /// \param[in] t_handler Optional Exception_Handler used for automatic unboxing of script thrown exceptions
     /// \return result of the script execution
     /// \throw exception::eval_error In the case that evaluation fails.
-    Boxed_Value eval_file(const std::string &t_filename) {
-      return do_eval(load_file(t_filename), t_filename);
+    Boxed_Value eval_file(const std::string &t_filename, const Exception_Handler &t_handler = Exception_Handler()) {
+      try {
+        return do_eval(load_file(t_filename), t_filename);
+      } catch (Boxed_Value &bv) {
+        if (t_handler) {
+          t_handler->handle(bv);
+        }
+        throw bv;
+      }
     }
 
     /// \brief Loads the file specified by filename, evaluates it, and returns the typesafe result.
     /// \tparam T Type to extract from the result value of the script execution
     /// \param[in] t_filename File to load and parse.
+    /// \param[in] t_handler Optional Exception_Handler used for automatic unboxing of script thrown exceptions
     /// \return result of the script execution
     /// \throw exception::eval_error In the case that evaluation fails.
     /// \throw exception::bad_boxed_cast In the case that evaluation succeeds but the result value cannot be converted
     ///        to the requested type.
     template<typename T>
-    T eval_file(const std::string &t_filename) {
-      return boxed_cast<T>(do_eval(load_file(t_filename), t_filename));
+    T eval_file(const std::string &t_filename, const Exception_Handler &t_handler = Exception_Handler()) {
+      try {
+        return boxed_cast<T>(do_eval(load_file(t_filename), t_filename));
+      } catch (Boxed_Value &bv) {
+        if (t_handler) {
+          t_handler->handle(bv);
+        }
+        throw bv;
+      }
     }
   };
 

include/chaiscript/language/chaiscript_parser.hpp

@@ -1505,7 +1505,7 @@ namespace chaiscript
                 }
 
                 build_match(AST_NodePtr(new eval::Fun_Call_AST_Node()), prev_stack_top);
-                //FIXME: Work around for method calls until we have a better solution
+                /// \todo Work around for method calls until we have a better solution
                 if (!m_match_stack.back()->children.empty()) {
                   if (m_match_stack.back()->children[0]->identifier == AST_Node_Type::Dot_Access) {
                     AST_NodePtr dot_access = m_match_stack.back()->children[0];

unittests/eval_catch_exception_test.cpp

@@ -2,8 +2,7 @@
 
 #include <chaiscript/chaiscript.hpp>
 
-
-int main()
+int test_generic()
 {
   chaiscript::ChaiScript chai;
   
@@ -17,5 +16,107 @@ int main()
     }
   }
 
+  std::cout << "test_generic failed" << std::endl;
   return EXIT_FAILURE;
 }
+
+int test_1()
+{
+  chaiscript::ChaiScript chai;
+  
+  try {
+    chai.eval("throw(1)", chaiscript::exception_specification<int>());
+  } catch (int e) {
+    if (e == 1)
+    {
+      return EXIT_SUCCESS;
+    }
+  }
+
+  std::cout << "test_1 failed" << std::endl;
+  return EXIT_FAILURE;
+}
+
+int test_2()
+{
+  chaiscript::ChaiScript chai;
+  
+  try {
+    chai.eval("throw(1.0)", chaiscript::exception_specification<int, double>());
+  } catch (const double e) {
+    if (e == 1.0)
+    {
+      return EXIT_SUCCESS;
+    }
+  }
+
+  std::cout << "test_2 failed" << std::endl;
+  return EXIT_FAILURE;
+}
+
+int test_5()
+{
+  chaiscript::ChaiScript chai;
+
+  try {
+    chai.eval("throw(runtime_error(\"error\"))", chaiscript::exception_specification<int, double, float, const std::string &, const std::exception &>());
+  } catch (const double e) {
+    std::cout << "test_5 failed with double" << std::endl;
+    return EXIT_FAILURE;
+  } catch (int) {
+    std::cout << "test_5 failed with int" << std::endl;
+    return EXIT_FAILURE;
+  } catch (float) {
+    std::cout << "test_5 failed with float" << std::endl;
+    return EXIT_FAILURE;
+  } catch (const std::string &) {
+    std::cout << "test_5 failed with string" << std::endl;
+    return EXIT_FAILURE;
+  } catch (const std::exception &e) {
+    return EXIT_SUCCESS;
+  }
+
+  std::cout << "test_5 failed" << std::endl;
+  return EXIT_FAILURE;
+}
+
+int test_unhandled()
+{
+  chaiscript::ChaiScript chai;
+
+  try {
+    chai.eval("throw(\"error\")", chaiscript::exception_specification<int, double, float, const std::exception &>());
+  } catch (double) {
+    std::cout << "test_unhandled failed with double" << std::endl;
+    return EXIT_FAILURE;
+  } catch (int) {
+    std::cout << "test_unhandled failed with int" << std::endl;
+    return EXIT_FAILURE;
+  } catch (float) {
+    std::cout << "test_unhandled failed with float" << std::endl;
+    return EXIT_FAILURE;
+  } catch (const std::exception &e) {
+    std::cout << "test_unhandled failed with std::exception" << std::endl;
+    return EXIT_FAILURE;
+  } catch (const chaiscript::Boxed_Value &bv) {
+    return EXIT_SUCCESS;
+  }
+
+  std::cout << "test_unhandled failed" << std::endl;
+  return EXIT_FAILURE;
+}
+
+
+int main()
+{
+  if (test_generic() == EXIT_SUCCESS
+    && test_1() == EXIT_SUCCESS
+    && test_2() == EXIT_SUCCESS
+    && test_5() == EXIT_SUCCESS
+    && test_unhandled() == EXIT_SUCCESS) 
+  {
+    return EXIT_SUCCESS;
+  } else {
+    return EXIT_FAILURE;
+  }
+}