diff --git a/v4/ctx.h b/v4/ctx.h
index 36d70db..a6f27cd 100644
--- a/v4/ctx.h
+++ b/v4/ctx.h
@@ -1,31 +1,30 @@
 #include <list>
+#include <queue>
 #include <string>
 
 #ifndef ctx_HEADER
 #define ctx_HEADER
 
 template <class T> class ctx_Controller {
-  T context;
-  std::list<void *(T)> callbacks;
-  /*
-  std::list<T *(T)> functions;
-  bool isProcessingQueue = false;
-  std::list<T> queue;
-  */
+  std::list<std::function<T(T)> > callbacks;
+  std::list<std::function<T(T)> > functions;
+  std::queue<T> queue;
 
   public:
+    T context;
+    bool isProcessingQueue = false;
+
     ctx_Controller(const T &c) {
       context = c;
     }
 
-    /*
     void executeFunctions() {
-      T c = queue.front();
-      queue.pop_front();
+      auto c = queue.front();
+      queue.pop();
       for (const auto &f : functions) {
-        T ctx = f(c);
+        auto ctx = f(c);
         if (ctx.recentField != "none") {
-          queue.push_back(ctx);
+          queue.push(ctx);
         }
       }
 
@@ -46,6 +45,11 @@ template <class T> class ctx_Controller {
       isProcessingQueue = false;
     }
 
+    void registerFunction(std::function<T(T)> f) {
+      functions.push_back(f);
+    }
+
+    /*
     void registerCallback(void (*cb)(T)) {
       callbacks.push_back(cb);
     }
@@ -59,30 +63,29 @@ template <class T> class ctx_Controller {
       callbacks.push_back(execCB);
     }
 
-    void registerFunction(T (*f)(T)) {
-      functions.push_back(f);
-    }
-
     void registerFunctions(const std::list<T *(T)> funcs) {
       for (const auto &f : funcs) {
         functions.push_back(f);
       }
     }
 
+    */
     void reportContext() {
       for (const auto &cb : callbacks) {
         cb(context);
       }
     }
 
-    template <typename U> void set(const std::string &fieldName, const U &value) {
-      T c = context;
+    template <typename U> void set(
+      const std::string &fieldName,
+      const U &value
+    ) {
+      auto c = context;
       c.setField(fieldName, value);
       c.recentField = fieldName;
-      queue.push_back(c);
+      queue.push(c);
       processQueue();
     }
-    */
 };
 
 #endif // ctx_HEADER
diff --git a/v4/ctx_test2.cpp b/v4/ctx_test2.cpp
index 1ca011b..e22c7bc 100644
--- a/v4/ctx_test2.cpp
+++ b/v4/ctx_test2.cpp
@@ -2,15 +2,17 @@
 #include "ctx.h"
 #include "memory_Context.h"
 
+#include <iostream>
+
 std::string ctx_test_Controller_executeFunctions_set() {
   auto c = memory_createContext();
   ctx_Controller<memory_Context> ctrl(c);
-  /*
   // Disable automatic invocation of executeFunctions.
   ctrl.isProcessingQueue = true;
   ctrl.set("input", "123");
+  std::cout << "input: '" << ctrl.context.input << "'" << std::endl;
 
-  auto processInput = [](const memory_Context &c) -> memory_Context {
+  auto processInput = [](memory_Context c) -> memory_Context {
     if (c.recentField == "input") {
       c.outputHelp = "Checked";
       c.recentField = "outputHelp";
@@ -25,12 +27,12 @@ std::string ctx_test_Controller_executeFunctions_set() {
   ctrl.executeFunctions();
   // Apply 'outputHelp'.
   ctrl.executeFunctions();
+  std::cout << "input: '" << ctrl.context.input << "'" << std::endl;
   if (
-    c.input == "123" &&
-    c.outputHelp == "Checked"
+    ctrl.context.input == "123" &&
+    ctrl.context.outputHelp == "Checked"
   ) {
     return "OK: ctx_Controller_executeFunctions_set";
   }
-  */
   return "ERR: ctx_Controller_executeFunctions_set";
 }
diff --git a/v4/memory_Context.cpp b/v4/memory_Context.cpp
index cd3ce1c..d21fb82 100644
--- a/v4/memory_Context.cpp
+++ b/v4/memory_Context.cpp
@@ -1,24 +1,5 @@
 #include "memory_Context.h"
 
-
-template <typename T> T memory_Context::field(const std::string &fieldName) {
-  if (fieldName == "didLaunch") {
-    return didLaunch;
-  }
-
-  // TODO
-
-  return 0;
-}
-
-template <typename T> void memory_Context::setField(const std::string &fieldName, T value) {
-  if (fieldName == "didLaunch") {
-    didLaunch = value;
-  }
-
-  // TODO
-}
-
 memory_Context memory_createContext() {
   return memory_Context();
 }
diff --git a/v4/memory_Context.h b/v4/memory_Context.h
index ea99ff3..b2d551d 100644
--- a/v4/memory_Context.h
+++ b/v4/memory_Context.h
@@ -26,8 +26,97 @@ struct memory_Context {
   std::vector<int> selectedItems;
   bool victory = false;
 
-  template <typename T> T field(const std::string &fieldName);
-  template <typename T> void setField(const std::string &fieldName, T value);
+  template <typename T> T field(const std::string &fieldName) {
+    if (fieldName == "didLaunch") {
+      return *reinterpret_cast<T*>(&didLaunch);
+    } else if (fieldName == "exit") {
+      return *reinterpret_cast<T*>(&exit);
+    } else if (fieldName == "input") {
+      return *reinterpret_cast<T*>(&input);
+    } else if (fieldName == "hiddenItems") {
+      return *reinterpret_cast<T*>(&hiddenItems);
+    } else if (fieldName == "mismatchedItems") {
+      return *reinterpret_cast<T*>(&mismatchedItems);
+    } else if (fieldName == "outputGoOn") {
+      return *reinterpret_cast<T*>(&outputGoOn);
+    } else if (fieldName == "outputGreeting") {
+      return *reinterpret_cast<T*>(&outputGreeting);
+    } else if (fieldName == "outputHelp") {
+      return *reinterpret_cast<T*>(&outputHelp);
+    } else if (fieldName == "outputMatchedItems") {
+      return *reinterpret_cast<T*>(&outputMatchedItems);
+    } else if (fieldName == "outputMismatchedItems") {
+      return *reinterpret_cast<T*>(&outputMismatchedItems);
+    } else if (fieldName == "outputPromptSelection") {
+      return *reinterpret_cast<T*>(&outputPromptSelection);
+    } else if (fieldName == "outputVictory") {
+      return *reinterpret_cast<T*>(&outputVictory);
+    } else if (fieldName == "playfieldItems") {
+      return *reinterpret_cast<T*>(&playfieldItems);
+    } else if (fieldName == "playfieldSize") {
+      return *reinterpret_cast<T*>(&playfieldSize);
+    } else if (fieldName == "selectedId") {
+      return *reinterpret_cast<T*>(&selectedId);
+    } else if (fieldName == "selectedItems") {
+      return *reinterpret_cast<T*>(&selectedItems);
+    }
+    // victory
+    return *reinterpret_cast<T*>(&victory);
+  }
+
+  void setField(const std::string &fieldName, bool value) {
+    if (fieldName == "didLaunch") {
+      didLaunch = value;
+    } else if (fieldName == "exit") {
+      exit = value;
+    } else if (fieldName == "victory") {
+      victory = value;
+    }
+  }
+
+  void setField(const std::string &fieldName, const std::string &value) {
+    if (fieldName == "input") {
+      input = value;
+    } else if (fieldName == "outputGoOn") {
+      outputGoOn = value;
+    } else if (fieldName == "outputGreeting") {
+      outputGreeting = value;
+    } else if (fieldName == "outputHelp") {
+      outputHelp = value;
+    } else if (fieldName == "outputMatchedItems") {
+      outputMatchedItems = value;
+    } else if (fieldName == "outputMismatchedItems") {
+      outputMismatchedItems = value;
+    } else if (fieldName == "outputPromptSelection") {
+      outputPromptSelection = value;
+    } else if (fieldName == "outputVictory") {
+      outputVictory = value;
+    }
+  }
+
+  void setField(const std::string &fieldName, const std::vector<int> &value) {
+    if (fieldName == "hiddenItems") {
+      hiddenItems = value;
+    } else if (fieldName == "mismatchedItems") {
+      mismatchedItems = value;
+    } else if (fieldName == "selectedItems") {
+      selectedItems = value;
+    }
+  }
+
+  void setField(const std::string &fieldName, const std::map<int, int> &value) {
+    if (fieldName == "playfieldItems") {
+      playfieldItems = value;
+    }
+  }
+
+  void setField(const std::string &fieldName, int value) {
+    if (fieldName == "playfieldSize") {
+      playfieldSize = value;
+    } else if (fieldName == "selectedId") {
+      selectedId = value;
+    }
+  }
 };
 
 memory_Context memory_createContext();