Add the ability to save and restore the state of local variables #25

CMakeLists.txt

@@ -196,6 +196,10 @@ if(BUILD_TESTING)
     target_link_libraries(expected_eval_errors_test ${LIBS})
     add_test(NAME Expected_Eval_Errors_Test COMMAND expected_eval_errors_test)
 
+    add_executable(set_state_test unittests/set_state_test.cpp)
+    target_link_libraries(set_state_test ${LIBS})
+    add_test(NAME Set_State_Test COMMAND set_state_test)
+
     if (MULTITHREAD_SUPPORT_ENABLED)
       add_executable(multithreaded_test unittests/multithreaded_test.cpp)
       target_link_libraries(multithreaded_test ${LIBS})

include/chaiscript/chaiscript.hpp

@@ -140,7 +140,10 @@
 ///
 /// \subsubsection addingobjects Adding Objects
 ///
-/// Named objects can be created with the chaiscript::var function.
+/// Named objects can be created with the chaiscript::var function. Note: adding a object
+/// adds it to the current thread scope, not to a global scope. If you have multiple 
+/// threads that need to access the same variables you will need to add them
+/// separately for each thread, from the thread itself.
 /// 
 /// \code
 /// using namespace chaiscript;

include/chaiscript/dispatchkit/dispatchkit.hpp

@@ -666,6 +666,27 @@ namespace chaiscript
           return functions.find(name) != functions.end();
         }
 
+        /// \returns All values in the local thread state, added through the add() function
+        std::map<std::string, Boxed_Value> get_locals() const
+        {
+          StackData &stack = get_stack_data();
+          Scope &scope = stack.front();
+          return scope;
+        }
+
+        /// \brief Sets all of the locals for the current thread state.
+        ///
+        /// \param[in] t_locals The map<name, value> set of variables to replace the current state with
+        ///
+        /// Any existing locals are removed and the given set of variables is added
+        void set_locals(const std::map<std::string, Boxed_Value> &t_locals)
+        {
+          StackData &stack = get_stack_data();
+          Scope &scope = stack.front();
+          scope = t_locals;
+        }
+
+
 
         ///
         /// Get a map of all objects that can be seen from the current scope in a scripting context

include/chaiscript/language/chaiscript_engine.hpp

@@ -456,8 +456,12 @@ namespace chaiscript
       std::set<std::string> active_loaded_modules;
     };
 
-    /// \brief Returns a state object that represents the current state of the system
+    /// \brief Returns a state object that represents the current state of the global system
-    /// \return Current state of the system
+    ///
+    /// The global system includes the reserved words, global const objects, functions and types.
+    /// local variables are thread specific and not included.
+    ///
+    /// \return Current state of the global system
     ///
     /// \b Example:
     ///
@@ -478,6 +482,10 @@ namespace chaiscript
     }
 
     /// \brief Sets the state of the system
+    ///
+    /// The global system includes the reserved words, global objects, functions and types.
+    /// local variables are thread specific and not included.
+    ///
     /// \param[in] t_state New state to set
     ///
     /// \b Example:
@@ -497,7 +505,23 @@ namespace chaiscript
       m_engine.set_state(t_state.engine_state);
     }
 
-    /// \brief Adds a type, function or object to ChaiScript
+    /// \returns All values in the local thread state, added through the add() function
+    std::map<std::string, Boxed_Value> get_locals() const
+    {
+      return m_engine.get_locals();
+    }
+
+    /// \brief Sets all of the locals for the current thread state.
+    ///
+    /// \param[in] t_locals The map<name, value> set of variables to replace the current state with
+    ///
+    /// Any existing locals are removed and the given set of variables is added
+    void set_locals(const std::map<std::string, Boxed_Value> &t_locals)
+    {
+      m_engine.set_locals(t_locals);
+    }
+
+    /// \brief Adds a type, function or object to ChaiScript. Objects are added to the local thread state.
     /// \param[in] t_t Item to add
     /// \param[in] t_name Name of item to add
     /// \returns Reference to current ChaiScript object

unittests/set_state_test.cpp

@@ -0,0 +1,61 @@
+#include <chaiscript/chaiscript.hpp>
+
+
+int myfun()
+{
+  return 2;
+}
+
+int main()
+{
+
+  chaiscript::ChaiScript chai;
+
+  // save the initial state of globals and locals
+  chaiscript::ChaiScript::State firststate = chai.get_state();
+  std::map<std::string, chaiscript::Boxed_Value> locals = chai.get_locals();
+  
+  // add some new globals and locals
+  chai.add(chaiscript::var(1), "i");
+
+  chai.add(chaiscript::fun(&myfun), "myfun");
+
+
+  bool didcall = chai.eval<int>("myfun()") == 2;
+
+  bool hadi = chai.eval<int>("i") == 1;
+
+  chai.set_state(firststate);
+
+  // set state should have reverted the state of the functions and dropped
+  // the 'myfun'
+  bool didnotcall = false;
+
+  try {
+    chai.eval<int>("myfun()");
+  } catch (const chaiscript::exception::eval_error &) {
+    didnotcall = true;
+  }
+
+  // set state should not affect the local variables
+  bool stillhasid = chai.eval<int>("i") == 1;
+
+  // After resetting the locals we expect the 'i' to be gone
+  chai.set_locals(locals);
+
+
+  bool nolongerhasid = false;
+
+  try {
+    chai.eval<int>("i");
+  } catch (const chaiscript::exception::eval_error &) {
+    nolongerhasid = true;
+  }
+
+  if (didcall && hadi && didnotcall && stillhasid && nolongerhasid)
+  {
+    return EXIT_SUCCESS;
+  } else {
+    return EXIT_FAILURE;
+  }
+}