73 files changed, 1135 insertions, 1795 deletions

diff --git a/.gitmodules b/.gitmodules
index 74cf7bbe4..aa4d2b067 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -9,7 +9,7 @@
 	url = https://github.com/cuberite/ChatLog.git
 [submodule "lib/mbedtls"]
 	path = lib/mbedtls
-	url = https://github.com/ARMmbed/mbedtls.git
+	url = https://github.com/cuberite/polarssl.git
 	ignore = dirty
 [submodule "lib/SQLiteCpp"]
 	path = lib/SQLiteCpp
diff --git a/Server/Plugins/Core b/Server/Plugins/Core
-Subproject c0509526be5569bbc52bbcd3d64c256b834c451
+Subproject 842accabb13d626364e558a34aa5922dbea4efd
diff --git a/src/Bindings/LuaState.cpp b/src/Bindings/LuaState.cpp
index 7bd4becb6..57c420795 100644
--- a/src/Bindings/LuaState.cpp
+++ b/src/Bindings/LuaState.cpp
@@ -1,4 +1,4 @@
-
+
 // LuaState.cpp
 
 // Implements the cLuaState class representing the wrapper over lua_State *, provides associated helper functions
diff --git a/src/Bindings/LuaState.h b/src/Bindings/LuaState.h
index 98f1cbc28..2e82c6994 100644
--- a/src/Bindings/LuaState.h
+++ b/src/Bindings/LuaState.h
@@ -1,4 +1,4 @@
-
+
 // LuaState.h
 
 // Declares the cLuaState class representing the wrapper over lua_State *, provides associated helper functions
diff --git a/src/Bindings/LuaWindow.cpp b/src/Bindings/LuaWindow.cpp
index 2802c69db..ae390e576 100644
--- a/src/Bindings/LuaWindow.cpp
+++ b/src/Bindings/LuaWindow.cpp
@@ -54,22 +54,15 @@ cLuaWindow::~cLuaWindow()
 	m_Contents.RemoveListener(*this);
 
 	// Close open lua window from players, to avoid dangling pointers
-	class cPlayerCallback : public cPlayerListCallback
-	{
-		virtual bool Item(cPlayer * a_Player)
+	cRoot::Get()->ForEachPlayer([this](cPlayer & a_Player)
 		{
-			if (a_Player->GetWindow() == m_LuaWindow)
+			if (a_Player.GetWindow() == this)
 			{
-				a_Player->CloseWindow(false);
+				a_Player.CloseWindow(false);
 			}
 			return false;
 		}
-		cLuaWindow * m_LuaWindow;
-	public:
-		cPlayerCallback(cLuaWindow & a_LuaWindow) { m_LuaWindow = &a_LuaWindow; }
-	} PlayerCallback(*this);
-
-	cRoot::Get()->ForEachPlayer(PlayerCallback);
+	);
 
 	// Must delete slot areas now, because they are referencing this->m_Contents and would try to access it in cWindow's
 	// destructor, when the member is already gone.
diff --git a/src/Bindings/LuaWindow.h b/src/Bindings/LuaWindow.h
index 8f3349d00..31891c7a3 100644
--- a/src/Bindings/LuaWindow.h
+++ b/src/Bindings/LuaWindow.h
@@ -1,4 +1,4 @@
-
+
 // LuaWindow.h
 
 // Declares the cLuaWindow class representing a virtual window that plugins may create and open for the player
@@ -9,13 +9,14 @@
 
 #pragma once
 
+#include <functional>
 #include "LuaState.h"
 #include "../UI/Window.h"
 #include "../ItemGrid.h"
 
 
 class cPlayer;
-typedef cItemCallback<cPlayer> cPlayerListCallback;
+using cPlayerListCallback = std::function<bool(cPlayer &)>;
 
 
 /** A window that has been created by a Lua plugin and is handled entirely by that plugin
diff --git a/src/Bindings/ManualBindings.cpp b/src/Bindings/ManualBindings.cpp
index 38dc2cf83..5f8a3507d 100644
--- a/src/Bindings/ManualBindings.cpp
+++ b/src/Bindings/ManualBindings.cpp
@@ -1483,44 +1483,29 @@ static int tolua_cPluginManager_CallPlugin(lua_State * tolua_S)
 	}
 
 	// Call the destination plugin using a plugin callback:
-	class cCallback :
-		public cPluginManager::cPluginCallback
-	{
-	public:
-		int m_NumReturns;
-
-		cCallback(const AString & a_FunctionName, cLuaState & a_SrcLuaState) :
-			m_NumReturns(0),
-			m_FunctionName(a_FunctionName),
-			m_SrcLuaState(a_SrcLuaState)
+	int NumReturns = 0;
+	auto PluginCallback = [&](cPlugin & a_Plugin)
 		{
-		}
-	protected:
-		const AString & m_FunctionName;
-		cLuaState & m_SrcLuaState;
-
-		virtual bool Item(cPlugin * a_Plugin) override
-		{
-			if (!a_Plugin->IsLoaded())
+			if (!a_Plugin.IsLoaded())
 			{
 				return false;
 			}
-			m_NumReturns = static_cast<cPluginLua *>(a_Plugin)->CallFunctionFromForeignState(
-				m_FunctionName, m_SrcLuaState, 4, lua_gettop(m_SrcLuaState)
+			NumReturns = static_cast<cPluginLua &>(a_Plugin).CallFunctionFromForeignState(
+				FunctionName, L, 4, lua_gettop(L)
 			);
 			return true;
-		}
-	} Callback(FunctionName, L);
-	if (!cPluginManager::Get()->DoWithPlugin(PluginName, Callback))
+		};
+
+	if (!cPluginManager::Get()->DoWithPlugin(PluginName, PluginCallback))
 	{
 		return 0;
 	}
-	if (Callback.m_NumReturns < 0)
+	if (NumReturns < 0)
 	{
 		// The call has failed, there are zero return values. Do NOT return negative number (Lua considers that a "yield")
 		return 0;
 	}
-	return Callback.m_NumReturns;
+	return NumReturns;
 }
 
 
@@ -3243,42 +3228,29 @@ static int tolua_cRoot_DoWithPlayerByUUID(lua_State * tolua_S)
 		return 0;
 	}
 
-	class cCallback :
-		public cPlayerListCallback
-	{
-	public:
-		cCallback(cLuaState & a_LuaState) :
-			m_LuaState(a_LuaState)
-		{
-		}
-
-		virtual bool Item(cPlayer * a_Player) override
-		{
-			bool ret = false;
-			m_LuaState.Call(m_FnRef, a_Player, cLuaState::Return, ret);
-			return ret;
-		}
-
-		cLuaState & m_LuaState;
-		cLuaState::cRef m_FnRef;
-	} Callback(L);
-
 	// Get parameters:
 	cRoot * Self;
 	cUUID PlayerUUID;
-	L.GetStackValues(1, Self, PlayerUUID, Callback.m_FnRef);
+	cLuaState::cRef FnRef;
+	L.GetStackValues(1, Self, PlayerUUID, FnRef);
 
 	if (PlayerUUID.IsNil())
 	{
 		return L.ApiParamError("Expected a non-nil UUID for parameter #1");
 	}
-	if (!Callback.m_FnRef.IsValid())
+	if (!FnRef.IsValid())
 	{
 		return L.ApiParamError("Expected a valid callback function for parameter #2");
 	}
 
 	// Call the function:
-	bool res = Self->DoWithPlayerByUUID(PlayerUUID, Callback);
+	bool res = Self->DoWithPlayerByUUID(PlayerUUID, [&](cPlayer & a_Player)
+		{
+			bool ret = false;
+			L.Call(FnRef, &a_Player, cLuaState::Return, ret);
+			return ret;
+		}
+	);
 
 	// Push the result as the return value:
 	L.Push(res);
diff --git a/src/Bindings/ManualBindings.h b/src/Bindings/ManualBindings.h
index dc9d9462f..64a44a240 100644
--- a/src/Bindings/ManualBindings.h
+++ b/src/Bindings/ManualBindings.h
@@ -1,4 +1,4 @@
-
+
 // ManualBindings.h
 
 // Declares the cManualBindings class used as a namespace for functions exported to the Lua API manually
@@ -57,7 +57,7 @@ public:
 	template <
 		class Ty1,
 		class Ty2,
-		bool (Ty1::*DoWithFn)(const AString &, cItemCallback<Ty2> &)
+		bool (Ty1::*DoWithFn)(const AString &, const std::function<bool(Ty2 &)> &)
 	>
 	static int DoWith(lua_State * tolua_S)
 	{
@@ -89,28 +89,14 @@ public:
 			return lua_do_error(tolua_S, "Error in function call '#funcname#': Expected a valid callback function for parameter #2");
 		}
 
-		class cLuaCallback : public cItemCallback<Ty2>
-		{
-		public:
-			cLuaCallback(cLuaState & a_LuaState, cLuaState::cRef & a_FnRef):
-				m_LuaState(a_LuaState),
-				m_FnRef(a_FnRef)
-			{
-			}
-
-		private:
-			virtual bool Item(Ty2 * a_Item) override
+		// Call the DoWith function:
+		bool res = (Self->*DoWithFn)(ItemName, [&](Ty2 & a_Item)
 			{
 				bool ret = false;
-				m_LuaState.Call(m_FnRef, a_Item, cLuaState::Return, ret);
+				L.Call(FnRef, &a_Item, cLuaState::Return, ret);
 				return ret;
 			}
-			cLuaState & m_LuaState;
-			cLuaState::cRef & m_FnRef;
-		} Callback(L, FnRef);
-
-		// Call the DoWith function:
-		bool res = (Self->*DoWithFn)(ItemName, Callback);
+		);
 
 		// Push the result as the return value:
 		L.Push(res);
@@ -125,7 +111,7 @@ public:
 	template <
 		class Ty1,
 		class Ty2,
-		bool (Ty1::*DoWithFn)(const AString &, cItemCallback<Ty2> &)
+		bool (Ty1::*DoWithFn)(const AString &, const std::function<bool(Ty2 &)> &)
 	>
 	static int StaticDoWith(lua_State * tolua_S)
 	{
@@ -152,28 +138,14 @@ public:
 			return lua_do_error(tolua_S, "Error in function call '#funcname#': Expected a valid callback function for parameter #2");
 		}
 
-		class cLuaCallback : public cItemCallback<Ty2>
-		{
-		public:
-			cLuaCallback(cLuaState & a_LuaState, cLuaState::cRef & a_FnRef):
-				m_LuaState(a_LuaState),
-				m_FnRef(a_FnRef)
-			{
-			}
-
-		private:
-			virtual bool Item(Ty2 * a_Item) override
+		// Call the DoWith function:
+		bool res = (Ty1::Get()->*DoWithFn)(ItemName, [&](Ty2 & a_Item)
 			{
 				bool ret = false;
-				m_LuaState.Call(m_FnRef, a_Item, cLuaState::Return, ret);
+				L.Call(FnRef, &a_Item, cLuaState::Return, ret);
 				return ret;
 			}
-			cLuaState & m_LuaState;
-			cLuaState::cRef & m_FnRef;
-		} Callback(L, FnRef);
-
-		// Call the DoWith function:
-		bool res = (Ty1::Get()->*DoWithFn)(ItemName, Callback);
+		);
 
 		// Push the result as the return value:
 		L.Push(res);
@@ -187,7 +159,7 @@ public:
 	template <
 		class Ty1,
 		class Ty2,
-		bool (Ty1::*DoWithFn)(UInt32, cItemCallback<Ty2> &)
+		bool (Ty1::*DoWithFn)(UInt32, const std::function<bool(Ty2 &)> &)
 	>
 	static int DoWithID(lua_State * tolua_S)
 	{
@@ -215,28 +187,14 @@ public:
 			return lua_do_error(tolua_S, "Error in function call '#funcname#': Expected a valid callback function for parameter #2");
 		}
 
-		class cLuaCallback : public cItemCallback<Ty2>
-		{
-		public:
-			cLuaCallback(cLuaState & a_LuaState, cLuaState::cRef & a_FnRef):
-				m_LuaState(a_LuaState),
-				m_FnRef(a_FnRef)
-			{
-			}
-
-		private:
-			virtual bool Item(Ty2 * a_Item) override
+		// Call the DoWith function:
+		bool res = (Self->*DoWithFn)(ItemID, [&](Ty2 & a_Item)
 			{
 				bool ret = false;
-				m_LuaState.Call(m_FnRef, a_Item, cLuaState::Return, ret);
+				L.Call(FnRef, &a_Item, cLuaState::Return, ret);
 				return ret;
 			}
-			cLuaState & m_LuaState;
-			cLuaState::cRef & m_FnRef;
-		} Callback(L, FnRef);
-
-		// Call the DoWith function:
-		bool res = (Self->*DoWithFn)(ItemID, Callback);
+		);
 
 		// Push the result as the return value:
 		L.Push(res);
@@ -251,7 +209,7 @@ public:
 	template <
 		class SELF,
 		class ITEM,
-		bool (SELF::*DoWithFn)(int, int, int, cItemCallback<ITEM> &)
+		bool (SELF::*DoWithFn)(int, int, int, const std::function<bool(ITEM &)> &)
 	>
 	static int DoWithXYZ(lua_State * tolua_S)
 	{
@@ -282,28 +240,14 @@ public:
 			return lua_do_error(tolua_S, "Error in function call '#funcname#': Expected a valid callback function for parameter #5");
 		}
 
-		class cLuaCallback : public cItemCallback<ITEM>
-		{
-		public:
-			cLuaCallback(cLuaState & a_LuaState, cLuaState::cRef & a_FnRef):
-				m_LuaState(a_LuaState),
-				m_FnRef(a_FnRef)
-			{
-			}
-
-		private:
-			virtual bool Item(ITEM * a_Item) override
+		// Call the DoWith function:
+		bool res = (Self->*DoWithFn)(BlockX, BlockY, BlockZ, [&](ITEM & a_Item)
 			{
 				bool ret = false;
-				m_LuaState.Call(m_FnRef, a_Item, cLuaState::Return, ret);
+				L.Call(FnRef, &a_Item, cLuaState::Return, ret);
 				return ret;
 			}
-			cLuaState & m_LuaState;
-			cLuaState::cRef & m_FnRef;
-		} Callback(L, FnRef);
-
-		// Call the DoWith function:
-		bool res = (Self->*DoWithFn)(BlockX, BlockY, BlockZ, Callback);
+		);
 
 		// Push the result as the return value:
 		L.Push(res);
@@ -318,7 +262,7 @@ public:
 	template <
 		class SELF,
 		class ITEM,
-		bool (SELF::*DoWithFn)(int, int, int, cItemCallback<ITEM> &),
+		bool (SELF::*DoWithFn)(int, int, int, const std::function<bool(ITEM &)> &),
 		bool (SELF::*CoordCheckFn)(int, int, int) const
 	>
 	static int DoWithXYZ(lua_State * tolua_S)
@@ -356,28 +300,14 @@ public:
 			).c_str());
 		}
 
-		class cLuaCallback : public cItemCallback<ITEM>
-		{
-		public:
-			cLuaCallback(cLuaState & a_LuaState, cLuaState::cRef & a_FnRef):
-				m_LuaState(a_LuaState),
-				m_FnRef(a_FnRef)
-			{
-			}
-
-		private:
-			virtual bool Item(ITEM * a_Item) override
+		// Call the DoWith function:
+		bool res = (Self->*DoWithFn)(BlockX, BlockY, BlockZ, [&](ITEM & a_Item)
 			{
 				bool ret = false;
-				m_LuaState.Call(m_FnRef, a_Item, cLuaState::Return, ret);
+				L.Call(FnRef, &a_Item, cLuaState::Return, ret);
 				return ret;
 			}
-			cLuaState & m_LuaState;
-			cLuaState::cRef & m_FnRef;
-		} Callback(L, FnRef);
-
-		// Call the DoWith function:
-		bool res = (Self->*DoWithFn)(BlockX, BlockY, BlockZ, Callback);
+		);
 
 		// Push the result as the return value:
 		L.Push(res);
@@ -391,7 +321,7 @@ public:
 	template <
 		class Ty1,
 		class Ty2,
-		bool (Ty1::*ForEachFn)(int, int, cItemCallback<Ty2> &)
+		bool (Ty1::*ForEachFn)(int, int, const std::function<bool(Ty2 &)> &)
 	>
 	static int ForEachInChunk(lua_State * tolua_S)
 	{
@@ -421,28 +351,14 @@ public:
 			return lua_do_error(tolua_S, "Error in function call '#funcname#': Expected a valid callback function for parameter #4");
 		}
 
-		class cLuaCallback : public cItemCallback<Ty2>
-		{
-		public:
-			cLuaCallback(cLuaState & a_LuaState, cLuaState::cRef & a_FnRef):
-				m_LuaState(a_LuaState),
-				m_FnRef(a_FnRef)
-			{
-			}
-
-		private:
-			virtual bool Item(Ty2 * a_Item) override
+		// Call the DoWith function:
+		bool res = (Self->*ForEachFn)(ChunkX, ChunkZ, [&](Ty2 & a_Item)
 			{
 				bool ret = false;
-				m_LuaState.Call(m_FnRef, a_Item, cLuaState::Return, ret);
+				L.Call(FnRef, &a_Item, cLuaState::Return, ret);
 				return ret;
 			}
-			cLuaState & m_LuaState;
-			cLuaState::cRef & m_FnRef;
-		} Callback(L, FnRef);
-
-		// Call the DoWith function:
-		bool res = (Self->*ForEachFn)(ChunkX, ChunkZ, Callback);
+		);
 
 		// Push the result as the return value:
 		L.Push(res);
@@ -456,7 +372,7 @@ public:
 	template <
 		class Ty1,
 		class Ty2,
-		bool (Ty1::*ForEachFn)(const cBoundingBox &, cItemCallback<Ty2> &)
+		bool (Ty1::*ForEachFn)(const cBoundingBox &, const std::function<bool(Ty2 &)> &)
 	>
 	static int ForEachInBox(lua_State * tolua_S)
 	{
@@ -488,36 +404,19 @@ public:
 			return lua_do_error(tolua_S, "Error in function call '#funcname#': Expected a valid callback function for parameter #2");
 		}
 
-		// Callback wrapper for the Lua function:
-		class cLuaCallback : public cItemCallback<Ty2>
-		{
-		public:
-			cLuaCallback(cLuaState & a_LuaState, cLuaState::cRef & a_FuncRef) :
-				m_LuaState(a_LuaState),
-				m_FnRef(a_FuncRef)
+		bool res = (Self->*ForEachFn)(*Box, [&](Ty2 & a_Item)
 			{
-			}
-
-		private:
-			cLuaState & m_LuaState;
-			cLuaState::cRef & m_FnRef;
-
-			// cItemCallback<Ty2> overrides:
-			virtual bool Item(Ty2 * a_Item) override
-			{
-				bool res = false;
-				if (!m_LuaState.Call(m_FnRef, a_Item, cLuaState::Return, res))
+				bool ret = false;
+				if (!L.Call(FnRef, &a_Item, cLuaState::Return, ret))
 				{
 					LOGWARNING("Failed to call Lua callback");
-					m_LuaState.LogStackTrace();
+					L.LogStackTrace();
 					return true;  // Abort enumeration
 				}
 
-				return res;
+				return ret;
 			}
-		} Callback(L, FnRef);
-
-		bool res = (Self->*ForEachFn)(*Box, Callback);
+		);
 
 		// Push the result as the return value:
 		L.Push(res);
@@ -531,7 +430,7 @@ public:
 	template <
 		class Ty1,
 		class Ty2,
-		bool (Ty1::*ForEachFn)(cItemCallback<Ty2> &)
+		bool (Ty1::*ForEachFn)(const std::function<bool(Ty2 &)> &)
 	>
 	static int ForEach(lua_State * tolua_S)
 	{
@@ -558,29 +457,14 @@ public:
 			return lua_do_error(tolua_S, "Error in function call '#funcname#': Expected a valid callback function for parameter #1");
 		}
 
-		class cLuaCallback : public cItemCallback<Ty2>
-		{
-		public:
-			cLuaCallback(cLuaState & a_LuaState, cLuaState::cRef & a_FnRef):
-				m_LuaState(a_LuaState),
-				m_FnRef(a_FnRef)
-			{
-			}
-
-		private:
-			cLuaState & m_LuaState;
-			cLuaState::cRef & m_FnRef;
-
-			virtual bool Item(Ty2 * a_Item) override
+		// Call the enumeration:
+		bool res = (Self->*ForEachFn)([&](Ty2 & a_Item)
 			{
-				bool res = false;  // By default continue the enumeration
-				m_LuaState.Call(m_FnRef, a_Item, cLuaState::Return, res);
-				return res;
+				bool ret = false;  // By default continue the enumeration
+				L.Call(FnRef, &a_Item, cLuaState::Return, ret);
+				return ret;
 			}
-		} Callback(L, FnRef);
-
-		// Call the enumeration:
-		bool res = (Self->*ForEachFn)(Callback);
+		);
 
 		// Push the return value:
 		L.Push(res);
@@ -595,7 +479,7 @@ public:
 	template <
 		class Ty1,
 		class Ty2,
-		bool (Ty1::*ForEachFn)(cItemCallback<Ty2> &)
+		bool (Ty1::*ForEachFn)(const std::function<bool(Ty2 &)> &)
 	>
 	static int StaticForEach(lua_State * tolua_S)
 	{
@@ -616,29 +500,14 @@ public:
 			return lua_do_error(tolua_S, "Error in function call '#funcname#': Expected a valid callback function for parameter #1");
 		}
 
-		class cLuaCallback : public cItemCallback<Ty2>
-		{
-		public:
-			cLuaCallback(cLuaState & a_LuaState, cLuaState::cRef & a_FnRef):
-				m_LuaState(a_LuaState),
-				m_FnRef(a_FnRef)
-			{
-			}
-
-		private:
-			cLuaState & m_LuaState;
-			cLuaState::cRef & m_FnRef;
-
-			virtual bool Item(Ty2 * a_Item) override
+		// Call the enumeration:
+		bool res = (Ty1::Get()->*ForEachFn)([&](Ty2 & a_Item)
 			{
-				bool res = false;  // By default continue the enumeration
-				m_LuaState.Call(m_FnRef, a_Item, cLuaState::Return, res);
-				return res;
+				bool ret = false;  // By default continue the enumeration
+				L.Call(FnRef, &a_Item, cLuaState::Return, ret);
+				return ret;
 			}
-		} Callback(L, FnRef);
-
-		// Call the enumeration:
-		bool res = (Ty1::Get()->*ForEachFn)(Callback);
+		);
 
 		// Push the return value:
 		L.Push(res);
diff --git a/src/Bindings/ManualBindings_World.cpp b/src/Bindings/ManualBindings_World.cpp
index 10b5daf1e..826439e3f 100644
--- a/src/Bindings/ManualBindings_World.cpp
+++ b/src/Bindings/ManualBindings_World.cpp
@@ -1,4 +1,4 @@
-
+
 // ManualBindings_World.cpp
 
 // Implements the manual Lua API bindings for the cWorld class
@@ -237,10 +237,10 @@ static int tolua_cWorld_DoWithPlayerByUUID(lua_State * tolua_S)
 	}
 
 	// Call the function:
-	bool res = Self->DoWithPlayerByUUID(PlayerUUID, [&](cPlayer * a_Player)
+	bool res = Self->DoWithPlayerByUUID(PlayerUUID, [&](cPlayer & a_Player)
 		{
 			bool ret = false;
-			L.Call(FnRef, a_Player, cLuaState::Return, ret);
+			L.Call(FnRef, &a_Player, cLuaState::Return, ret);
 			return ret;
 		}
 	);
diff --git a/src/Bindings/PluginManager.cpp b/src/Bindings/PluginManager.cpp
index 7c4712f0f..1b3736e3c 100644
--- a/src/Bindings/PluginManager.cpp
+++ b/src/Bindings/PluginManager.cpp
@@ -1,4 +1,4 @@
-
+
 #include "Globals.h"  // NOTE: MSVC stupidness requires this to be the same across all modules
 
 #include "PluginManager.h"
@@ -1993,14 +1993,14 @@ bool cPluginManager::IsValidHookType(int a_HookType)
 
 
 
-bool cPluginManager::DoWithPlugin(const AString & a_PluginName, cPluginCallback & a_Callback)
+bool cPluginManager::DoWithPlugin(const AString & a_PluginName, const cPluginCallback & a_Callback)
 {
 	// TODO: Implement locking for plugins
 	for (auto & plugin: m_Plugins)
 	{
 		if (plugin->GetName() == a_PluginName)
 		{
-			return a_Callback.Item(plugin.get());
+			return a_Callback(*plugin);
 		}
 	}
 	return false;
@@ -2010,12 +2010,12 @@ bool cPluginManager::DoWithPlugin(const AString & a_PluginName, cPluginCallback
 
 
 
-bool cPluginManager::ForEachPlugin(cPluginCallback & a_Callback)
+bool cPluginManager::ForEachPlugin(const cPluginCallback & a_Callback)
 {
 	// TODO: Implement locking for plugins
 	for (auto & plugin: m_Plugins)
 	{
-		if (a_Callback.Item(plugin.get()))
+		if (a_Callback(*plugin))
 		{
 			return false;
 		}
diff --git a/src/Bindings/PluginManager.h b/src/Bindings/PluginManager.h
index 66f7d290a..4de4bdeae 100644
--- a/src/Bindings/PluginManager.h
+++ b/src/Bindings/PluginManager.h
@@ -1,8 +1,9 @@
-
+
 #pragma once
 
 
 #include "Defines.h"
+#include <functional>
 
 
 
@@ -194,7 +195,7 @@ public:
 
 
 	/** The interface used for enumerating and extern-calling plugins */
-	typedef cItemCallback<cPlugin> cPluginCallback;
+	using cPluginCallback = std::function<bool(cPlugin &)>;
 
 	typedef std::list<cPlugin *> PluginList;
 
@@ -372,18 +373,18 @@ public:
 
 	/** Calls the specified callback with the plugin object of the specified plugin.
 	Returns false if plugin not found, otherwise returns the value that the callback has returned. */
-	bool DoWithPlugin(const AString & a_PluginName, cPluginCallback & a_Callback);
+	bool DoWithPlugin(const AString & a_PluginName, const cPluginCallback & a_Callback);
 
 	/** Calls the specified callback for each plugin in m_Plugins.
 	Returns true if all plugins have been reported, false if the callback has aborted the enumeration by returning true. */
-	bool ForEachPlugin(cPluginCallback & a_Callback);
+	bool ForEachPlugin(const cPluginCallback & a_Callback);
 
 	/** Returns the name of the folder (cPlugin::GetFolderName()) from which the specified plugin was loaded. */
 	AString GetPluginFolderName(const AString & a_PluginName);  // tolua_export
 
 	/** Returns the path where individual plugins' folders are expected.
 	The path doesn't end in a slash. */
-	static AString GetPluginsPath(void) { return FILE_IO_PREFIX + AString("Plugins"); }  // tolua_export
+	static AString GetPluginsPath(void) { return FILE_IO_PREFIX "Plugins"; }  // tolua_export
 
 private:
 	friend class cRoot;
diff --git a/src/BlockArea.cpp b/src/BlockArea.cpp
index 667a231a4..755d98583 100644
--- a/src/BlockArea.cpp
+++ b/src/BlockArea.cpp
@@ -1,4 +1,4 @@
-
+
 // BlockArea.cpp
 
 // NOTE: compile.sh checks for this file in order to determine if this is the Cuberite folder.
@@ -2239,7 +2239,7 @@ int cBlockArea::MakeIndex(int a_RelX, int a_RelY, int a_RelZ) const
 
 
 
-bool cBlockArea::DoWithBlockEntityRelAt(int a_RelX, int a_RelY, int a_RelZ, cItemCallback<cBlockEntity> & a_Callback)
+bool cBlockArea::DoWithBlockEntityRelAt(int a_RelX, int a_RelY, int a_RelZ, const cBlockEntityCallback & a_Callback)
 {
 	ASSERT(IsValidRelCoords(a_RelX, a_RelY, a_RelZ));
 	if (!HasBlockEntities())
@@ -2252,14 +2252,14 @@ bool cBlockArea::DoWithBlockEntityRelAt(int a_RelX, int a_RelY, int a_RelZ, cIte
 	{
 		return false;
 	}
-	return a_Callback.Item(itr->second);
+	return a_Callback(*itr->second);
 }
 
 
 
 
 
-bool cBlockArea::DoWithBlockEntityAt(int a_BlockX, int a_BlockY, int a_BlockZ, cItemCallback<cBlockEntity> & a_Callback)
+bool cBlockArea::DoWithBlockEntityAt(int a_BlockX, int a_BlockY, int a_BlockZ, const cBlockEntityCallback & a_Callback)
 {
 	return DoWithBlockEntityRelAt(a_BlockX - m_Origin.x, a_BlockY - m_Origin.y, a_BlockZ - m_Origin.z, a_Callback);
 }
@@ -2268,7 +2268,7 @@ bool cBlockArea::DoWithBlockEntityAt(int a_BlockX, int a_BlockY, int a_BlockZ, c
 
 
 
-bool cBlockArea::ForEachBlockEntity(cItemCallback<cBlockEntity> & a_Callback)
+bool cBlockArea::ForEachBlockEntity(const cBlockEntityCallback & a_Callback)
 {
 	if (!HasBlockEntities())
 	{
@@ -2276,7 +2276,7 @@ bool cBlockArea::ForEachBlockEntity(cItemCallback<cBlockEntity> & a_Callback)
 	}
 	for (auto & keyPair: *m_BlockEntities)
 	{
-		if (a_Callback.Item(keyPair.second))
+		if (a_Callback(*keyPair.second))
 		{
 			return false;
 		}
diff --git a/src/BlockArea.h b/src/BlockArea.h
index 2e35b9436..e7080ed88 100644
--- a/src/BlockArea.h
+++ b/src/BlockArea.h
@@ -1,4 +1,4 @@
-
+
 // BlockArea.h
 
 // Interfaces to the cBlockArea object representing an area of block data that can be queried from cWorld and then accessed again without further queries
@@ -17,13 +17,14 @@
 #include "ForEachChunkProvider.h"
 #include "ChunkDataCallback.h"
 #include "Cuboid.h"
+#include <functional>
 
 
 
 
 // fwd:
 class cCuboid;
-
+using cBlockEntityCallback = std::function<bool(cBlockEntity &)>;
 
 
 
@@ -376,18 +377,18 @@ public:
 	/** Calls the callback for the block entity at the specified coords.
 	Returns false if there is no block entity at those coords, or the block area doesn't have baBlockEntities.
 	Returns the value that the callback has returned if there is a block entity. */
-	bool DoWithBlockEntityRelAt(int a_RelX, int a_RelY, int a_RelZ, cItemCallback<cBlockEntity> & a_Callback);
+	bool DoWithBlockEntityRelAt(int a_RelX, int a_RelY, int a_RelZ, const cBlockEntityCallback & a_Callback);
 
 	/** Calls the callback for the block entity at the specified coords.
 	Returns false if there is no block entity at those coords.
 	Returns the value that the callback has returned if there is a block entity. */
-	bool DoWithBlockEntityAt   (int a_BlockX, int a_BlockY, int a_BlockZ, cItemCallback<cBlockEntity> & a_Callback);
+	bool DoWithBlockEntityAt   (int a_BlockX, int a_BlockY, int a_BlockZ, const cBlockEntityCallback & a_Callback);
 
 	/** Calls the callback for all the block entities.
 	If the callback returns true, aborts the enumeration and returns false.
 	If the callback returns true, continues with the next BE.
 	Returns true if all block entities have been enumerated (including the case when there is none or the area is without baBlockEntities). */
-	bool ForEachBlockEntity(cItemCallback<cBlockEntity> & a_Callback);
+	bool ForEachBlockEntity(const cBlockEntityCallback & a_Callback);
 
 	/** Direct read-only access to block entities. */
 	const cBlockEntities & GetBlockEntities(void) const { ASSERT(HasBlockEntities()); return *m_BlockEntities; }
diff --git a/src/BlockEntities/BeaconEntity.cpp b/src/BlockEntities/BeaconEntity.cpp
index a98547ba7..1d088a56f 100644
--- a/src/BlockEntities/BeaconEntity.cpp
+++ b/src/BlockEntities/BeaconEntity.cpp
@@ -1,4 +1,4 @@
-
+
 #include "Globals.h"  // NOTE: MSVC stupidness requires this to be the same across all modules
 
 #include "BeaconEntity.h"
@@ -195,33 +195,21 @@ void cBeaconEntity::UpdateBeacon(void)
 			GetWindow()->SetProperty(0, m_BeaconLevel);
 		}
 
-		class cPlayerCallback :
-			public cPlayerListCallback
-		{
-		public:
-			cPlayerCallback(Vector3d a_Position):
-				m_Position(a_Position)
+		Vector3d BeaconPosition(m_PosX, m_PosY, m_PosZ);
+		GetWorld()->ForEachPlayer([=](cPlayer & a_Player)
 			{
-			}
-
-			virtual bool Item(cPlayer * a_Player)
-			{
-				Vector3d Distance = m_Position - a_Player->GetPosition();
+				Vector3d Distance = BeaconPosition - a_Player.GetPosition();
 				if (
 					(std::abs(Distance.y) <= 14) &&
 					(std::abs(Distance.x) <= 20) &&
 					(std::abs(Distance.z) <= 20)
 				)
 				{
-					a_Player->AwardAchievement(eStatistic::achFullBeacon);
+					a_Player.AwardAchievement(eStatistic::achFullBeacon);
 				}
 				return false;
 			}
-
-		private:
-			Vector3d m_Position;
-		} PlayerCallback(Vector3d(m_PosX, m_PosY, m_PosZ));
-		GetWorld()->ForEachPlayer(PlayerCallback);
+		);
 	}
 }
 
@@ -249,46 +237,28 @@ void cBeaconEntity::GiveEffects(void)
 		SecondaryEffect = m_SecondaryEffect;
 	}
 
-	class cPlayerCallback : public cPlayerListCallback
-	{
-		int m_Radius;
-		Vector3d m_Position;
-		cEntityEffect::eType m_PrimaryEffect, m_SecondaryEffect;
-		short m_EffectLevel;
-
-		virtual bool Item(cPlayer * a_Player)
+	Vector3d BeaconPosition(m_PosX, m_PosY, m_PosZ);
+	GetWorld()->ForEachPlayer([=](cPlayer & a_Player)
 		{
-			Vector3d PlayerPosition = Vector3d(a_Player->GetPosition());
-			if (PlayerPosition.y > m_Position.y)
+			auto PlayerPosition = a_Player.GetPosition();
+			if (PlayerPosition.y > BeaconPosition.y)
 			{
-				PlayerPosition.y = m_Position.y;
+				PlayerPosition.y = BeaconPosition.y;
 			}
 
 			// TODO: Vanilla minecraft uses an AABB check instead of a radius one
-			if ((PlayerPosition - m_Position).Length() <= m_Radius)
+			if ((PlayerPosition - BeaconPosition).Length() <= Radius)
 			{
-				a_Player->AddEntityEffect(m_PrimaryEffect, 180, m_EffectLevel);
+				a_Player.AddEntityEffect(m_PrimaryEffect, 180, EffectLevel);
 
 				if (m_SecondaryEffect != cEntityEffect::effNoEffect)
 				{
-					a_Player->AddEntityEffect(m_SecondaryEffect, 180, 0);
+					a_Player.AddEntityEffect(m_SecondaryEffect, 180, 0);
 				}
 			}
 			return false;
 		}
-
-	public:
-		cPlayerCallback(int a_Radius, Vector3d a_Position, cEntityEffect::eType a_PrimaryEffect, cEntityEffect::eType a_SecondaryEffect, short a_EffectLevel):
-			m_Radius(a_Radius),
-			m_Position(a_Position),
-			m_PrimaryEffect(a_PrimaryEffect),
-			m_SecondaryEffect(a_SecondaryEffect),
-			m_EffectLevel(a_EffectLevel)
-		{
-		}
-
-	} PlayerCallback(Radius, Vector3d(m_PosX, m_PosY, m_PosZ), m_PrimaryEffect, SecondaryEffect, EffectLevel);
-	GetWorld()->ForEachPlayer(PlayerCallback);
+	);
 }
 
 
diff --git a/src/BlockEntities/ChestEntity.cpp b/src/BlockEntities/ChestEntity.cpp
index a8f5b7242..5e8b29a45 100644
--- a/src/BlockEntities/ChestEntity.cpp
+++ b/src/BlockEntities/ChestEntity.cpp
@@ -138,33 +138,18 @@ bool cChestEntity::UsedBy(cPlayer * a_Player)
 void cChestEntity::ScanNeighbours()
 {
 	// Callback for finding neighbouring chest:
-	class cFindNeighbour :
-		public cChestCallback
+	auto FindNeighbour = [this](cChestEntity & a_Chest)
 	{
-	public:
-		cChestEntity * m_Neighbour;
-		BLOCKTYPE      m_ChestType;
-
-		cFindNeighbour(BLOCKTYPE a_ChestType) :
-			m_Neighbour(nullptr),
-			m_ChestType(a_ChestType)
+		if (a_Chest.GetBlockType() != m_BlockType)
 		{
+			// Neighboring block is not the same type of chest
+			return true;
 		}
-
-		virtual bool Item(cChestEntity * a_Chest) override
-		{
-			if (a_Chest->GetBlockType() != m_ChestType)
-			{
-				// Neighboring block is not the same type of chest
-				return true;
-			}
-			m_Neighbour = a_Chest;
-			return false;
-		}
+		m_Neighbour = &a_Chest;
+		return false;
 	};
 
 	// Scan horizontally adjacent blocks for any neighbouring chest of the same type:
-	cFindNeighbour FindNeighbour(m_BlockType);
 	if (
 		m_World->DoWithChestAt(m_PosX - 1, m_PosY, m_PosZ,     FindNeighbour) ||
 		m_World->DoWithChestAt(m_PosX + 1, m_PosY, m_PosZ,     FindNeighbour) ||
@@ -172,7 +157,6 @@ void cChestEntity::ScanNeighbours()
 		m_World->DoWithChestAt(m_PosX,     m_PosY, m_PosZ + 1, FindNeighbour)
 	)
 	{
-		m_Neighbour = FindNeighbour.m_Neighbour;
 		m_Neighbour->m_Neighbour = this;
 		// Force neighbour's window shut. Does Mojang server do this or should a double window open?
 		m_Neighbour->DestroyWindow();
diff --git a/src/BlockEntities/HopperEntity.cpp b/src/BlockEntities/HopperEntity.cpp
index 0467685af..2fac188b1 100644
--- a/src/BlockEntities/HopperEntity.cpp
+++ b/src/BlockEntities/HopperEntity.cpp
@@ -193,8 +193,7 @@ bool cHopperEntity::MovePickupsIn(cChunk & a_Chunk, Int64 a_CurrentTick)
 {
 	UNUSED(a_CurrentTick);
 
-	class cHopperPickupSearchCallback :
-		public cEntityCallback
+	class cHopperPickupSearchCallback
 	{
 	public:
 		cHopperPickupSearchCallback(const Vector3i & a_Pos, cItemGrid & a_Contents) :
@@ -204,22 +203,20 @@ bool cHopperEntity::MovePickupsIn(cChunk & a_Chunk, Int64 a_CurrentTick)
 		{
 		}
 
-		virtual bool Item(cEntity * a_Entity) override
+		bool operator () (cEntity & a_Entity)
 		{
-			ASSERT(a_Entity != nullptr);
-
-			if (!a_Entity->IsPickup())
+			if (!a_Entity.IsPickup())
 			{
 				return false;
 			}
 
-			Vector3f EntityPos = a_Entity->GetPosition();
+			Vector3f EntityPos = a_Entity.GetPosition();
 			Vector3f BlockPos(m_Pos.x + 0.5f, static_cast<float>(m_Pos.y) + 1, m_Pos.z + 0.5f);  // One block above hopper, and search from center outwards
 			double Distance = (EntityPos - BlockPos).Length();
 
 			if (Distance < 0.5)
 			{
-				if (TrySuckPickupIn(static_cast<cPickup *>(a_Entity)))
+				if (TrySuckPickupIn(static_cast<cPickup &>(a_Entity)))
 				{
 					return false;
 				}
@@ -228,9 +225,9 @@ bool cHopperEntity::MovePickupsIn(cChunk & a_Chunk, Int64 a_CurrentTick)
 			return false;
 		}
 
-		bool TrySuckPickupIn(cPickup * a_Pickup)
+		bool TrySuckPickupIn(cPickup & a_Pickup)
 		{
-			cItem & Item = a_Pickup->GetItem();
+			cItem & Item = a_Pickup.GetItem();
 
 			for (int i = 0; i < ContentsWidth * ContentsHeight; i++)
 			{
@@ -238,7 +235,7 @@ bool cHopperEntity::MovePickupsIn(cChunk & a_Chunk, Int64 a_CurrentTick)
 				{
 					m_bFoundPickupsAbove = true;
 					m_Contents.SetSlot(i, Item);
-					a_Pickup->Destroy();  // Kill pickup
+					a_Pickup.Destroy();  // Kill pickup
 
 					return true;
 				}
@@ -252,7 +249,7 @@ bool cHopperEntity::MovePickupsIn(cChunk & a_Chunk, Int64 a_CurrentTick)
 
 					if (Item.IsEmpty())
 					{
-						a_Pickup->Destroy();  // Kill pickup if all items were added
+						a_Pickup.Destroy();  // Kill pickup if all items were added
 					}
 					return true;
 				}
diff --git a/src/BlockEntities/MobSpawnerEntity.cpp b/src/BlockEntities/MobSpawnerEntity.cpp
index 5246ae6ca..8a4cc4d38 100644
--- a/src/BlockEntities/MobSpawnerEntity.cpp
+++ b/src/BlockEntities/MobSpawnerEntity.cpp
@@ -1,4 +1,4 @@
-
+
 #include "Globals.h"  // NOTE: MSVC stupidness requires this to be the same across all modules
 
 #include "MobSpawnerEntity.h"
@@ -138,47 +138,36 @@ void cMobSpawnerEntity::SpawnEntity(void)
 		return;
 	}
 
-	class cCallback : public cChunkCallback
-	{
-	public:
-		cCallback(int a_RelX, int a_RelY, int a_RelZ, eMonsterType a_MobType, int a_NearbyEntitiesNum) :
-			m_RelX(a_RelX),
-			m_RelY(a_RelY),
-			m_RelZ(a_RelZ),
-			m_MobType(a_MobType),
-			m_NearbyEntitiesNum(a_NearbyEntitiesNum)
-		{
-		}
-
-		virtual bool Item(cChunk * a_Chunk)
+	auto MobType = m_Entity;
+	bool EntitiesSpawned = m_World->DoWithChunk(GetChunkX(), GetChunkZ(), [&](cChunk & a_Chunk)
 		{
 			auto & Random = GetRandomProvider();
 
-			bool EntitiesSpawned = false;
+			bool HaveSpawnedEntity = false;
 			for (size_t i = 0; i < 4; i++)
 			{
-				if (m_NearbyEntitiesNum >= 6)
+				if (NearbyEntities >= 6)
 				{
 					break;
 				}
 
 				int RelX = m_RelX + static_cast<int>((Random.RandReal<double>() - Random.RandReal<double>()) * 4.0);
-				int RelY = m_RelY + Random.RandInt(-1, 1);
+				int RelY = m_PosY + Random.RandInt(-1, 1);
 				int RelZ = m_RelZ + static_cast<int>((Random.RandReal<double>() - Random.RandReal<double>()) * 4.0);
 
-				cChunk * Chunk = a_Chunk->GetRelNeighborChunkAdjustCoords(RelX, RelZ);
+				cChunk * Chunk = a_Chunk.GetRelNeighborChunkAdjustCoords(RelX, RelZ);
 				if ((Chunk == nullptr) || !Chunk->IsValid())
 				{
 					continue;
 				}
 				EMCSBiome Biome = Chunk->GetBiomeAt(RelX, RelZ);
 
-				if (cMobSpawner::CanSpawnHere(Chunk, RelX, RelY, RelZ, m_MobType, Biome))
+				if (cMobSpawner::CanSpawnHere(Chunk, RelX, RelY, RelZ, MobType, Biome))
 				{
 					double PosX = Chunk->GetPosX() * cChunkDef::Width + RelX;
 					double PosZ = Chunk->GetPosZ() * cChunkDef::Width + RelZ;
 
-					auto Monster = cMonster::NewMonsterFromType(m_MobType);
+					auto Monster = cMonster::NewMonsterFromType(MobType);
 					if (Monster == nullptr)
 					{
 						continue;
@@ -188,7 +177,7 @@ void cMobSpawnerEntity::SpawnEntity(void)
 					Monster->SetYaw(Random.RandReal(360.0f));
 					if (Chunk->GetWorld()->SpawnMobFinalize(std::move(Monster)) != cEntity::INVALID_ID)
 					{
-						EntitiesSpawned = true;
+						HaveSpawnedEntity = true;
 						Chunk->BroadcastSoundParticleEffect(
 							EffectID::PARTICLE_MOBSPAWN,
 							static_cast<int>(PosX * 8.0),
@@ -196,19 +185,15 @@ void cMobSpawnerEntity::SpawnEntity(void)
 							static_cast<int>(PosZ * 8.0),
 							0
 						);
-						m_NearbyEntitiesNum++;
+						NearbyEntities++;
 					}
 				}
 			}
 			return EntitiesSpawned;
 		}
-	protected:
-		int m_RelX, m_RelY, m_RelZ;
-		eMonsterType m_MobType;
-		int m_NearbyEntitiesNum;
-	} Callback(m_RelX, m_PosY, m_RelZ, m_Entity, NearbyEntities);
+	);
 
-	if (m_World->DoWithChunk(GetChunkX(), GetChunkZ(), Callback))
+	if (EntitiesSpawned)
 	{
 		ResetTimer();
 	}
diff --git a/src/Blocks/BlockBed.cpp b/src/Blocks/BlockBed.cpp
index 77572a254..0032ec079 100644
--- a/src/Blocks/BlockBed.cpp
+++ b/src/Blocks/BlockBed.cpp
@@ -1,12 +1,12 @@
-
+
 // BlockBed.cpp
 
 #include "Globals.h"
 #include "BlockBed.h"
 
 #include "BroadcastInterface.h"
-#include "Entities/../World.h"
 #include "Entities/Player.h"
+#include "../World.h"
 #include "../BoundingBox.h"
 #include "../Mobs/Monster.h"
 #include "../BlockEntities/BedEntity.h"
@@ -53,66 +53,6 @@ void cBlockBedHandler::OnDestroyed(cChunkInterface & a_ChunkInterface, cWorldInt
 
 
 
-class cFindMobs :
-	public cEntityCallback
-{
-	virtual bool Item(cEntity * a_Entity) override
-	{
-		return (
-			(a_Entity->GetEntityType() == cEntity::etMonster) &&
-			(static_cast<cMonster*>(a_Entity)->GetMobFamily() == cMonster::mfHostile)
-		);
-	}
-};
-
-
-
-
-
-class cTimeFastForwardTester :
-	public cPlayerListCallback
-{
-	virtual bool Item(cPlayer * a_Player) override
-	{
-		if (!a_Player->IsInBed())
-		{
-			return true;
-		}
-
-		return false;
-	}
-};
-
-
-
-
-
-class cPlayerBedStateUnsetter :
-	public cPlayerListCallback
-{
-public:
-	cPlayerBedStateUnsetter(Vector3i a_Position, cChunkInterface & a_ChunkInterface) :
-		m_Position(a_Position),
-		m_ChunkInterface(a_ChunkInterface)
-	{
-	}
-
-	virtual bool Item(cPlayer * a_Player) override
-	{
-		cBlockBedHandler::SetBedOccupationState(m_ChunkInterface, a_Player->GetLastBedPos(), false);
-		a_Player->SetIsInBed(false);
-		return false;
-	}
-
-private:
-	Vector3i m_Position;
-	cChunkInterface & m_ChunkInterface;
-};
-
-
-
-
-
 bool cBlockBedHandler::OnUse(cChunkInterface & a_ChunkInterface, cWorldInterface & a_WorldInterface, cPlayer & a_Player, int a_BlockX, int a_BlockY, int a_BlockZ, eBlockFace a_BlockFace, int a_CursorX, int a_CursorY, int a_CursorZ)
 {
 	if (a_WorldInterface.GetDimension() != dimOverworld)
@@ -133,7 +73,14 @@ bool cBlockBedHandler::OnUse(cChunkInterface & a_ChunkInterface, cWorldInterface
 		}
 		else
 		{
-			cFindMobs FindMobs;
+			auto FindMobs = [](cEntity & a_Entity)
+			{
+				return (
+					(a_Entity.GetEntityType() == cEntity::etMonster) &&
+					(static_cast<cMonster&>(a_Entity).GetMobFamily() == cMonster::mfHostile)
+				);
+			};
+
 			if (!a_Player.GetWorld()->ForEachEntityInBox(cBoundingBox(a_Player.GetPosition() - Vector3i(0, 5, 0), 8, 10), FindMobs))
 			{
 				a_Player.SendMessageFailure("You may not rest now, there are monsters nearby");
@@ -164,11 +111,24 @@ bool cBlockBedHandler::OnUse(cChunkInterface & a_ChunkInterface, cWorldInterface
 				a_Player.SetIsInBed(true);
 				a_Player.SendMessageSuccess("Home position set successfully");
 
-				cTimeFastForwardTester Tester;
-				if (a_WorldInterface.ForEachPlayer(Tester))
+				auto TimeFastForwardTester = [](cPlayer & a_OtherPlayer)
 				{
-					cPlayerBedStateUnsetter Unsetter(Vector3i(a_BlockX + PillowDirection.x, a_BlockY, a_BlockZ + PillowDirection.z), a_ChunkInterface);
-					a_WorldInterface.ForEachPlayer(Unsetter);
+					if (!a_OtherPlayer.IsInBed())
+					{
+						return true;
+					}
+					return false;
+				};
+
+				if (a_WorldInterface.ForEachPlayer(TimeFastForwardTester))
+				{
+					a_WorldInterface.ForEachPlayer([&](cPlayer & a_OtherPlayer)
+						{
+							cBlockBedHandler::SetBedOccupationState(a_ChunkInterface, a_OtherPlayer.GetLastBedPos(), false);
+							a_OtherPlayer.SetIsInBed(false);
+							return false;
+						}
+					);
 					a_WorldInterface.SetTimeOfDay(0);
 					a_ChunkInterface.SetBlockMeta(a_BlockX, a_BlockY, a_BlockZ, Meta & 0x0b);  // Clear the "occupied" bit of the bed's block
 				}
@@ -184,25 +144,12 @@ bool cBlockBedHandler::OnUse(cChunkInterface & a_ChunkInterface, cWorldInterface
 
 void cBlockBedHandler::OnPlacedByPlayer(cChunkInterface & a_ChunkInterface, cWorldInterface & a_WorldInterface, cPlayer & a_Player, const sSetBlock & a_BlockChange)
 {
-	class cBedColor :
-		public cBedCallback
-	{
-	public:
-		short m_Color;
-
-		cBedColor(short a_Color) :
-			m_Color(a_Color)
+	a_Player.GetWorld()->DoWithBedAt(a_BlockChange.GetX(), a_BlockChange.GetY(), a_BlockChange.GetZ(), [&](cBedEntity & a_Bed)
 		{
-		}
-
-		virtual bool Item(cBedEntity * a_Bed) override
-		{
-			a_Bed->SetColor(m_Color);
+			a_Bed.SetColor(a_Player.GetEquippedItem().m_ItemDamage);
 			return true;
 		}
-	};
-	cBedColor BedCallback(a_Player.GetEquippedItem().m_ItemDamage);
-	a_Player.GetWorld()->DoWithBedAt(a_BlockChange.GetX(), a_BlockChange.GetY(), a_BlockChange.GetZ(), BedCallback);
+	);
 }
 
 
@@ -211,19 +158,12 @@ void cBlockBedHandler::OnPlacedByPlayer(cChunkInterface & a_ChunkInterface, cWor
 
 void cBlockBedHandler::ConvertToPickups(cWorldInterface & a_WorldInterface, cItems & a_Pickups, NIBBLETYPE a_BlockMeta, int a_BlockX, int a_BlockY, int a_BlockZ)
 {
-	class cBedColor :
-		public cBedCallback
-	{
-	public:
-		short m_Color = E_META_WOOL_RED;
-
-		virtual bool Item(cBedEntity * a_Bed) override
+	short Color = E_META_WOOL_RED;
+	a_WorldInterface.DoWithBedAt(a_BlockX, a_BlockY, a_BlockZ, [&](cBedEntity & a_Bed)
 		{
-			m_Color = a_Bed->GetColor();
+			Color = a_Bed.GetColor();
 			return true;
 		}
-	};
-	cBedColor BedCallback;
-	a_WorldInterface.DoWithBedAt(a_BlockX, a_BlockY, a_BlockZ, BedCallback);
-	a_Pickups.Add(cItem(E_ITEM_BED, 1, BedCallback.m_Color));
+	);
+	a_Pickups.Add(cItem(E_ITEM_BED, 1, Color));
 }
diff --git a/src/Blocks/BlockEnderchest.h b/src/Blocks/BlockEnderchest.h
index 7ce162cd5..8fd5c2a89 100644
--- a/src/Blocks/BlockEnderchest.h
+++ b/src/Blocks/BlockEnderchest.h
@@ -18,7 +18,6 @@ public:
 
 	virtual void ConvertToPickups(cItems & a_Pickups, NIBBLETYPE a_BlockMeta) override
 	{
-		// todo: Drop Ender Chest if using silk touch pickaxe
 		a_Pickups.push_back(cItem(E_BLOCK_OBSIDIAN, 8, 0));
 	}
 
diff --git a/src/Blocks/BlockHandler.cpp b/src/Blocks/BlockHandler.cpp
index 76cfc763f..41b9780ac 100644
--- a/src/Blocks/BlockHandler.cpp
+++ b/src/Blocks/BlockHandler.cpp
@@ -525,6 +525,12 @@ void cBlockHandler::DropBlock(cChunkInterface & a_ChunkInterface, cWorldInterfac
 					// Need to access the bed entity to get the color for the item damage
 					ConvertToPickups(a_WorldInterface, Pickups, Meta, a_BlockX, a_BlockY, a_BlockZ);
 				}
+				case E_BLOCK_ENDER_CHEST:
+				{
+					// Reset meta to 0
+					Pickups.Add(m_BlockType, 1, 0);
+					break;
+				}
 				default: Pickups.Add(m_BlockType, 1, Meta); break;
 			}
 		}
diff --git a/src/Blocks/BlockMobHead.h b/src/Blocks/BlockMobHead.h
index 30aba2491..764cd7f65 100644
--- a/src/Blocks/BlockMobHead.h
+++ b/src/Blocks/BlockMobHead.h
@@ -30,36 +30,32 @@ public:
 			return;
 		}
 
-		class cCallback : public cBlockEntityCallback
-		{
-			virtual bool Item(cBlockEntity * a_BlockEntity)
+		a_WorldInterface.DoWithBlockEntityAt(a_BlockX, a_BlockY, a_BlockZ, [](cBlockEntity & a_BlockEntity)
 			{
-				if (a_BlockEntity->GetBlockType() != E_BLOCK_HEAD)
+				if (a_BlockEntity.GetBlockType() != E_BLOCK_HEAD)
 				{
 					return false;
 				}
-				cMobHeadEntity * MobHeadEntity = static_cast<cMobHeadEntity*>(a_BlockEntity);
+				auto & MobHeadEntity = static_cast<cMobHeadEntity&>(a_BlockEntity);
 
 				cItems Pickups;
-				Pickups.Add(E_ITEM_HEAD, 1, static_cast<short>(MobHeadEntity->GetType()));
+				Pickups.Add(E_ITEM_HEAD, 1, static_cast<short>(MobHeadEntity.GetType()));
 				auto & r1 = GetRandomProvider();
 
 				// Mid-block position first
 				double MicroX, MicroY, MicroZ;
-				MicroX = MobHeadEntity->GetPosX() + 0.5;
-				MicroY = MobHeadEntity->GetPosY() + 0.5;
-				MicroZ = MobHeadEntity->GetPosZ() + 0.5;
+				MicroX = MobHeadEntity.GetPosX() + 0.5;
+				MicroY = MobHeadEntity.GetPosY() + 0.5;
+				MicroZ = MobHeadEntity.GetPosZ() + 0.5;
 
 				// Add random offset second
 				MicroX += r1.RandReal<double>(-0.5, 0.5);
 				MicroZ += r1.RandReal<double>(-0.5, 0.5);
 
-				MobHeadEntity->GetWorld()->SpawnItemPickups(Pickups, MicroX, MicroY, MicroZ);
+				MobHeadEntity.GetWorld()->SpawnItemPickups(Pickups, MicroX, MicroY, MicroZ);
 				return false;
 			}
-		} Callback;
-
-		a_WorldInterface.DoWithBlockEntityAt(a_BlockX, a_BlockY, a_BlockZ, Callback);
+		);
 	}
 
 	virtual ColourID GetMapBaseColourID(NIBBLETYPE a_Meta) override
diff --git a/src/Blocks/WorldInterface.h b/src/Blocks/WorldInterface.h
index 524e8d642..4c1f6ddc8 100644
--- a/src/Blocks/WorldInterface.h
+++ b/src/Blocks/WorldInterface.h
@@ -1,15 +1,18 @@
-
+
 #pragma once
 
-
+#include <functional>
 #include "../Mobs/MonsterTypes.h"
 
-
-typedef cItemCallback<cBlockEntity> cBlockEntityCallback;
+class cBedEntity;
+class cBlockEntity;
 class cBroadcastInterface;
 class cItems;
 class cPlayer;
 
+using cBedCallback         = std::function<bool(cBedEntity   &)>;
+using cBlockEntityCallback = std::function<bool(cBlockEntity &)>;
+using cPlayerListCallback  = std::function<bool(cPlayer      &)>;
 
 
 
@@ -28,7 +31,10 @@ public:
 
 	virtual void DoExplosionAt(double a_ExplosionSize, double a_BlockX, double a_BlockY, double a_BlockZ, bool a_CanCauseFire, eExplosionSource a_Source, void * a_SourceData) = 0;
 
-	virtual bool DoWithBedAt(int a_BlockX, int a_BlockY, int a_BlockZ, cBedCallback & a_Callback) = 0;
+	virtual bool DoWithBedAt(int a_BlockX, int a_BlockY, int a_BlockZ, const cBedCallback & a_Callback) = 0;
+
+	/** Calls the callback for the block entity at the specified coords; returns false if there's no block entity at those coords, true if found */
+	virtual bool DoWithBlockEntityAt(int a_BlockX, int a_BlockY, int a_BlockZ, const cBlockEntityCallback & a_Callback) = 0;
 
 	/** Spawns item pickups for each item in the list. May compress pickups if too many entities: */
 	virtual void SpawnItemPickups(const cItems & a_Pickups, double a_BlockX, double a_BlockY, double a_BlockZ, double a_FlyAwaySpeed = 1.0, bool IsPlayerCreated = false) = 0;
@@ -46,19 +52,16 @@ public:
 	Returns the UniqueID of the spawned experience orb, or cEntity::INVALID_ID on failure. */
 	virtual UInt32 SpawnExperienceOrb(double a_X, double a_Y, double a_Z, int a_Reward) = 0;
 
-	/** Calls the callback for the block entity at the specified coords; returns false if there's no block entity at those coords, true if found */
-	virtual bool DoWithBlockEntityAt(int a_BlockX, int a_BlockY, int a_BlockZ, cBlockEntityCallback & a_Callback) = 0;
-
 	/** Sends the block on those coords to the player */
 	virtual void SendBlockTo(int a_BlockX, int a_BlockY, int a_BlockZ, cPlayer & a_Player) = 0;
 
 	/** Calls the callback for each player in the list; returns true if all players processed, false if the callback aborted by returning true */
-	virtual bool ForEachPlayer(cItemCallback<cPlayer> & a_Callback) = 0;
+	virtual bool ForEachPlayer(const cPlayerListCallback & a_Callback) = 0;
 
 	/** Calls the callback for each entity that has a nonempty intersection with the specified boundingbox.
 	Returns true if all entities processed, false if the callback aborted by returning true.
 	If any chunk in the box is missing, ignores the entities in that chunk silently. */
-	virtual bool ForEachEntityInBox(const cBoundingBox & a_Box, cEntityCallback & a_Callback) = 0;
+	virtual bool ForEachEntityInBox(const cBoundingBox & a_Box, const cEntityCallback & a_Callback) = 0;
 
 	virtual void SetTimeOfDay(int a_TimeOfDay) = 0;
 
diff --git a/src/Chunk.cpp b/src/Chunk.cpp
index 78a8461d3..3a81b9ed1 100644
--- a/src/Chunk.cpp
+++ b/src/Chunk.cpp
@@ -1,4 +1,4 @@
-
+
 #include "Globals.h"  // NOTE: MSVC stupidness requires this to be the same across all modules
 
 #ifndef _WIN32
@@ -2114,17 +2114,12 @@ bool cChunk::HasEntity(UInt32 a_EntityID)
 
 
 
-bool cChunk::ForEachEntity(cEntityCallback & a_Callback)
+bool cChunk::ForEachEntity(const cEntityCallback & a_Callback)
 {
 	// The entity list is locked by the parent chunkmap's CS
-	for (auto itr = m_Entities.begin(), itr2 = itr; itr != m_Entities.end(); itr = itr2)
+	for (const auto & Entity : m_Entities)
 	{
-		++itr2;
-		if (!(*itr)->IsTicking())
-		{
-			continue;
-		}
-		if (a_Callback.Item(itr->get()))
+		if (Entity->IsTicking() && a_Callback(*Entity))
 		{
 			return false;
 		}
@@ -2136,23 +2131,22 @@ bool cChunk::ForEachEntity(cEntityCallback & a_Callback)
 
 
 
-bool cChunk::ForEachEntityInBox(const cBoundingBox & a_Box, cEntityCallback & a_Callback)
+bool cChunk::ForEachEntityInBox(const cBoundingBox & a_Box, const cEntityCallback & a_Callback)
 {
 	// The entity list is locked by the parent chunkmap's CS
-	for (auto itr = m_Entities.begin(), itr2 = itr; itr != m_Entities.end(); itr = itr2)
+	for (const auto & Entity : m_Entities)
 	{
-		++itr2;
-		if (!(*itr)->IsTicking())
+		if (!Entity->IsTicking())
 		{
 			continue;
 		}
-		cBoundingBox EntBox((*itr)->GetPosition(), (*itr)->GetWidth() / 2, (*itr)->GetHeight());
+		cBoundingBox EntBox(Entity->GetPosition(), Entity->GetWidth() / 2, Entity->GetHeight());
 		if (!EntBox.DoesIntersect(a_Box))
 		{
 			// The entity is not in the specified box
 			continue;
 		}
-		if (a_Callback.Item(itr->get()))
+		if (a_Callback(*Entity))
 		{
 			return false;
 		}
@@ -2164,23 +2158,14 @@ bool cChunk::ForEachEntityInBox(const cBoundingBox & a_Box, cEntityCallback & a_
 
 
 
-bool cChunk::DoWithEntityByID(UInt32 a_EntityID, cEntityCallback & a_Callback, bool & a_CallbackResult)
-{
-	return DoWithEntityByID(a_EntityID, std::bind(&cEntityCallback::Item, &a_Callback, std::placeholders::_1), a_CallbackResult);
-}
-
-
-
-
-
-bool cChunk::DoWithEntityByID(UInt32 a_EntityID, cLambdaEntityCallback a_Callback, bool & a_CallbackResult)
+bool cChunk::DoWithEntityByID(UInt32 a_EntityID, const cEntityCallback & a_Callback, bool & a_CallbackResult)
 {
 	// The entity list is locked by the parent chunkmap's CS
 	for (const auto & Entity : m_Entities)
 	{
 		if ((Entity->GetUniqueID() == a_EntityID) && (Entity->IsTicking()))
 		{
-			a_CallbackResult = a_Callback(Entity.get());
+			a_CallbackResult = a_Callback(*Entity);
 			return true;
 		}
 	}  // for itr - m_Entitites[]
@@ -2192,7 +2177,7 @@ bool cChunk::DoWithEntityByID(UInt32 a_EntityID, cLambdaEntityCallback a_Callbac
 
 
 template <class tyEntity, BLOCKTYPE... tBlocktype>
-bool cChunk::GenericForEachBlockEntity(cItemCallback<tyEntity>& a_Callback)
+bool cChunk::GenericForEachBlockEntity(const std::function<bool(tyEntity &)> & a_Callback)
 {
 	// The blockentity list is locked by the parent chunkmap's CS
 	for (auto & KeyPair : m_BlockEntities)
@@ -2203,7 +2188,7 @@ bool cChunk::GenericForEachBlockEntity(cItemCallback<tyEntity>& a_Callback)
 			(IsOneOf<tBlocktype...>(Block->GetBlockType()))
 		)
 		{
-			if (a_Callback.Item(static_cast<tyEntity *>(Block)))
+			if (a_Callback(*static_cast<tyEntity *>(Block)))
 			{
 				return false;
 			}
@@ -2216,7 +2201,7 @@ bool cChunk::GenericForEachBlockEntity(cItemCallback<tyEntity>& a_Callback)
 
 
 
-bool cChunk::ForEachBlockEntity(cBlockEntityCallback & a_Callback)
+bool cChunk::ForEachBlockEntity(const cBlockEntityCallback & a_Callback)
 {
 	return GenericForEachBlockEntity<cBlockEntity>(a_Callback);
 }
@@ -2225,7 +2210,7 @@ bool cChunk::ForEachBlockEntity(cBlockEntityCallback & a_Callback)
 
 
 
-bool cChunk::ForEachBrewingstand(cBrewingstandCallback & a_Callback)
+bool cChunk::ForEachBrewingstand(const cBrewingstandCallback & a_Callback)
 {
 	return GenericForEachBlockEntity<cBrewingstandEntity,
 		E_BLOCK_BREWING_STAND
@@ -2236,7 +2221,7 @@ bool cChunk::ForEachBrewingstand(cBrewingstandCallback & a_Callback)
 
 
 
-bool cChunk::ForEachChest(cChestCallback & a_Callback)
+bool cChunk::ForEachChest(const cChestCallback & a_Callback)
 {
 	return GenericForEachBlockEntity<cChestEntity,
 		E_BLOCK_CHEST
@@ -2247,7 +2232,7 @@ bool cChunk::ForEachChest(cChestCallback & a_Callback)
 
 
 
-bool cChunk::ForEachDispenser(cDispenserCallback & a_Callback)
+bool cChunk::ForEachDispenser(const cDispenserCallback & a_Callback)
 {
 	return GenericForEachBlockEntity<cDispenserEntity,
 		E_BLOCK_DISPENSER
@@ -2258,7 +2243,7 @@ bool cChunk::ForEachDispenser(cDispenserCallback & a_Callback)
 
 
 
-bool cChunk::ForEachDropper(cDropperCallback & a_Callback)
+bool cChunk::ForEachDropper(const cDropperCallback & a_Callback)
 {
 	return GenericForEachBlockEntity<cDropperEntity,
 		E_BLOCK_DROPPER
@@ -2269,7 +2254,7 @@ bool cChunk::ForEachDropper(cDropperCallback & a_Callback)
 
 
 
-bool cChunk::ForEachDropSpenser(cDropSpenserCallback & a_Callback)
+bool cChunk::ForEachDropSpenser(const cDropSpenserCallback & a_Callback)
 {
 	return GenericForEachBlockEntity<cDropSpenserEntity,
 		E_BLOCK_DISPENSER,
@@ -2281,7 +2266,7 @@ bool cChunk::ForEachDropSpenser(cDropSpenserCallback & a_Callback)
 
 
 
-bool cChunk::ForEachFurnace(cFurnaceCallback & a_Callback)
+bool cChunk::ForEachFurnace(const cFurnaceCallback & a_Callback)
 {
 	return GenericForEachBlockEntity<cFurnaceEntity,
 		E_BLOCK_FURNACE,
@@ -2294,7 +2279,7 @@ bool cChunk::ForEachFurnace(cFurnaceCallback & a_Callback)
 
 
 template <class tyEntity, BLOCKTYPE... tBlocktype>
-bool cChunk::GenericDoWithBlockEntityAt(int a_BlockX, int a_BlockY, int a_BlockZ, cItemCallback<tyEntity>& a_Callback)
+bool cChunk::GenericDoWithBlockEntityAt(int a_BlockX, int a_BlockY, int a_BlockZ, const std::function<bool(tyEntity &)> & a_Callback)
 {
 	// The blockentity list is locked by the parent chunkmap's CS
 	cBlockEntity * Block = GetBlockEntity(a_BlockX, a_BlockY, a_BlockZ);
@@ -2309,14 +2294,14 @@ bool cChunk::GenericDoWithBlockEntityAt(int a_BlockX, int a_BlockY, int a_BlockZ
 	{
 		return false;  // Not any of the given tBlocktypes
 	}
-	return !a_Callback.Item(static_cast<tyEntity *>(Block));
+	return !a_Callback(*static_cast<tyEntity *>(Block));
 }
 
 
 
 
 
-bool cChunk::DoWithBlockEntityAt(int a_BlockX, int a_BlockY, int a_BlockZ, cBlockEntityCallback & a_Callback)
+bool cChunk::DoWithBlockEntityAt(int a_BlockX, int a_BlockY, int a_BlockZ, const cBlockEntityCallback & a_Callback)
 {
 	return GenericDoWithBlockEntityAt<cBlockEntity>(a_BlockX, a_BlockY, a_BlockZ, a_Callback);
 }
@@ -2324,7 +2309,7 @@ bool cChunk::DoWithBlockEntityAt(int a_BlockX, int a_BlockY, int a_BlockZ, cBloc
 
 
 
-bool cChunk::DoWithBeaconAt(int a_BlockX, int a_BlockY, int a_BlockZ, cBeaconCallback & a_Callback)
+bool cChunk::DoWithBeaconAt(int a_BlockX, int a_BlockY, int a_BlockZ, const cBeaconCallback & a_Callback)
 {
 	return GenericDoWithBlockEntityAt<cBeaconEntity,
 		E_BLOCK_BEACON
@@ -2334,7 +2319,7 @@ bool cChunk::DoWithBeaconAt(int a_BlockX, int a_BlockY, int a_BlockZ, cBeaconCal
 
 
 
-bool cChunk::DoWithBedAt(int a_BlockX, int a_BlockY, int a_BlockZ, cBedCallback & a_Callback)
+bool cChunk::DoWithBedAt(int a_BlockX, int a_BlockY, int a_BlockZ, const cBedCallback & a_Callback)
 {
 	return GenericDoWithBlockEntityAt<cBedEntity,
 		E_BLOCK_BED
@@ -2344,7 +2329,7 @@ bool cChunk::DoWithBedAt(int a_BlockX, int a_BlockY, int a_BlockZ, cBedCallback
 
 
 
-bool cChunk::DoWithBrewingstandAt(int a_BlockX, int a_BlockY, int a_BlockZ, cBrewingstandCallback & a_Callback)
+bool cChunk::DoWithBrewingstandAt(int a_BlockX, int a_BlockY, int a_BlockZ, const cBrewingstandCallback & a_Callback)
 {
 	return GenericDoWithBlockEntityAt<cBrewingstandEntity,
 		E_BLOCK_BREWING_STAND
@@ -2355,7 +2340,7 @@ bool cChunk::DoWithBrewingstandAt(int a_BlockX, int a_BlockY, int a_BlockZ, cBre
 
 
 
-bool cChunk::DoWithChestAt(int a_BlockX, int a_BlockY, int a_BlockZ, cChestCallback & a_Callback)
+bool cChunk::DoWithChestAt(int a_BlockX, int a_BlockY, int a_BlockZ, const cChestCallback & a_Callback)
 {
 	return GenericDoWithBlockEntityAt<cChestEntity,
 		E_BLOCK_CHEST,
@@ -2367,7 +2352,7 @@ bool cChunk::DoWithChestAt(int a_BlockX, int a_BlockY, int a_BlockZ, cChestCallb
 
 
 
-bool cChunk::DoWithDispenserAt(int a_BlockX, int a_BlockY, int a_BlockZ, cDispenserCallback & a_Callback)
+bool cChunk::DoWithDispenserAt(int a_BlockX, int a_BlockY, int a_BlockZ, const cDispenserCallback & a_Callback)
 {
 	return GenericDoWithBlockEntityAt<cDispenserEntity,
 		E_BLOCK_DISPENSER
@@ -2378,7 +2363,7 @@ bool cChunk::DoWithDispenserAt(int a_BlockX, int a_BlockY, int a_BlockZ, cDispen
 
 
 
-bool cChunk::DoWithDropperAt(int a_BlockX, int a_BlockY, int a_BlockZ, cDropperCallback & a_Callback)
+bool cChunk::DoWithDropperAt(int a_BlockX, int a_BlockY, int a_BlockZ, const cDropperCallback & a_Callback)
 {
 	return GenericDoWithBlockEntityAt<cDropperEntity,
 		E_BLOCK_DROPPER
@@ -2389,7 +2374,7 @@ bool cChunk::DoWithDropperAt(int a_BlockX, int a_BlockY, int a_BlockZ, cDropperC
 
 
 
-bool cChunk::DoWithDropSpenserAt(int a_BlockX, int a_BlockY, int a_BlockZ, cDropSpenserCallback & a_Callback)
+bool cChunk::DoWithDropSpenserAt(int a_BlockX, int a_BlockY, int a_BlockZ, const cDropSpenserCallback & a_Callback)
 {
 	return GenericDoWithBlockEntityAt<cDropSpenserEntity,
 		E_BLOCK_DISPENSER,
@@ -2401,7 +2386,7 @@ bool cChunk::DoWithDropSpenserAt(int a_BlockX, int a_BlockY, int a_BlockZ, cDrop
 
 
 
-bool cChunk::DoWithFurnaceAt(int a_BlockX, int a_BlockY, int a_BlockZ, cFurnaceCallback & a_Callback)
+bool cChunk::DoWithFurnaceAt(int a_BlockX, int a_BlockY, int a_BlockZ, const cFurnaceCallback & a_Callback)
 {
 	return GenericDoWithBlockEntityAt<cFurnaceEntity,
 		E_BLOCK_FURNACE,
@@ -2413,7 +2398,7 @@ bool cChunk::DoWithFurnaceAt(int a_BlockX, int a_BlockY, int a_BlockZ, cFurnaceC
 
 
 
-bool cChunk::DoWithNoteBlockAt(int a_BlockX, int a_BlockY, int a_BlockZ, cNoteBlockCallback & a_Callback)
+bool cChunk::DoWithNoteBlockAt(int a_BlockX, int a_BlockY, int a_BlockZ, const cNoteBlockCallback & a_Callback)
 {
 	return GenericDoWithBlockEntityAt<cNoteEntity,
 		E_BLOCK_NOTE_BLOCK
@@ -2424,7 +2409,7 @@ bool cChunk::DoWithNoteBlockAt(int a_BlockX, int a_BlockY, int a_BlockZ, cNoteBl
 
 
 
-bool cChunk::DoWithCommandBlockAt(int a_BlockX, int a_BlockY, int a_BlockZ, cCommandBlockCallback & a_Callback)
+bool cChunk::DoWithCommandBlockAt(int a_BlockX, int a_BlockY, int a_BlockZ, const cCommandBlockCallback & a_Callback)
 {
 	return GenericDoWithBlockEntityAt<cCommandBlockEntity,
 		E_BLOCK_COMMAND_BLOCK
@@ -2435,7 +2420,7 @@ bool cChunk::DoWithCommandBlockAt(int a_BlockX, int a_BlockY, int a_BlockZ, cCom
 
 
 
-bool cChunk::DoWithMobHeadAt(int a_BlockX, int a_BlockY, int a_BlockZ, cMobHeadCallback & a_Callback)
+bool cChunk::DoWithMobHeadAt(int a_BlockX, int a_BlockY, int a_BlockZ, const cMobHeadCallback & a_Callback)
 {
 	return GenericDoWithBlockEntityAt<cMobHeadEntity,
 		E_BLOCK_HEAD
@@ -2446,7 +2431,7 @@ bool cChunk::DoWithMobHeadAt(int a_BlockX, int a_BlockY, int a_BlockZ, cMobHeadC
 
 
 
-bool cChunk::DoWithFlowerPotAt(int a_BlockX, int a_BlockY, int a_BlockZ, cFlowerPotCallback & a_Callback)
+bool cChunk::DoWithFlowerPotAt(int a_BlockX, int a_BlockY, int a_BlockZ, const cFlowerPotCallback & a_Callback)
 {
 	return GenericDoWithBlockEntityAt<cFlowerPotEntity,
 		E_BLOCK_FLOWER_POT
diff --git a/src/Chunk.h b/src/Chunk.h
index c5e252114..2523f2e5c 100644
--- a/src/Chunk.h
+++ b/src/Chunk.h
@@ -1,4 +1,4 @@
-
+
 #pragma once
 
 #include "Entities/Entity.h"
@@ -37,18 +37,7 @@ class cMobCensus;
 class cMobSpawner;
 class cSetChunkData;
 
-typedef std::list<cClientHandle *>         cClientHandleList;
-typedef cItemCallback<cEntity>             cEntityCallback;
-typedef cItemCallback<cBeaconEntity>       cBeaconCallback;
-typedef cItemCallback<cBedEntity>          cBedCallback;
-typedef cItemCallback<cBrewingstandEntity> cBrewingstandCallback;
-typedef cItemCallback<cChestEntity>        cChestCallback;
-typedef cItemCallback<cDispenserEntity>    cDispenserCallback;
-typedef cItemCallback<cFurnaceEntity>      cFurnaceCallback;
-typedef cItemCallback<cNoteEntity>         cNoteBlockCallback;
-typedef cItemCallback<cCommandBlockEntity> cCommandBlockCallback;
-typedef cItemCallback<cMobHeadEntity>      cMobHeadCallback;
-typedef cItemCallback<cFlowerPotEntity>    cFlowerPotCallback;
+typedef std::list<cClientHandle *>                cClientHandleList;
 
 // A convenience macro for calling GetChunkAndRelByAbsolute.
 #define PREPARE_REL_AND_CHUNK(Position, OriginalChunk) cChunk * Chunk; Vector3i Rel; bool RelSuccess = (OriginalChunk).GetChunkAndRelByAbsolute(Position, &Chunk, Rel);
@@ -258,87 +247,86 @@ public:
 	bool HasEntity(UInt32 a_EntityID);
 
 	/** Calls the callback for each entity; returns true if all entities processed, false if the callback aborted by returning true */
-	bool ForEachEntity(cEntityCallback & a_Callback);  // Lua-accessible
+	bool ForEachEntity(const cEntityCallback & a_Callback);  // Lua-accessible
 
 	/** Calls the callback for each entity that has a nonempty intersection with the specified boundingbox.
 	Returns true if all entities processed, false if the callback aborted by returning true. */
-	bool ForEachEntityInBox(const cBoundingBox & a_Box, cEntityCallback & a_Callback);  // Lua-accessible
+	bool ForEachEntityInBox(const cBoundingBox & a_Box, const cEntityCallback & a_Callback);  // Lua-accessible
 
 	/** Calls the callback if the entity with the specified ID is found, with the entity object as the callback param. Returns true if entity found. */
-	bool DoWithEntityByID(UInt32 a_EntityID, cEntityCallback & a_Callback, bool & a_CallbackResult);  // Lua-accessible
-	bool DoWithEntityByID(UInt32 a_EntityID, cLambdaEntityCallback a_Callback, bool & a_CallbackResult);  // Lambda version
+	bool DoWithEntityByID(UInt32 a_EntityID, const cEntityCallback & a_Callback, bool & a_CallbackResult);  // Lua-accessible
 
 	/** Calls the callback for each tyEntity; returns true if all block entities processed, false if the callback aborted by returning true
 	tBlocktypes are all blocktypes convertible to tyEntity which are to be called. If no block type is given the callback is called for every block entity
 	Accessible only from within Chunk.cpp */
 	template <class tyEntity, BLOCKTYPE... tBlocktype>
-	bool GenericForEachBlockEntity(cItemCallback<tyEntity>& a_Callback);
+	bool GenericForEachBlockEntity(const std::function<bool(tyEntity &)> & a_Callback);
 
 	/** Calls the callback for each block entity; returns true if all block entities processed, false if the callback aborted by returning true */
-	bool ForEachBlockEntity(cBlockEntityCallback & a_Callback);  // Lua-accessible
+	bool ForEachBlockEntity(const cBlockEntityCallback & a_Callback);  // Lua-accessible
 
 	/** Calls the callback for each brewingstand; returns true if all brewingstands processed, false if the callback aborted by returning true */
-	bool ForEachBrewingstand(cBrewingstandCallback & a_Callback);  // Lua-accessible
+	bool ForEachBrewingstand(const cBrewingstandCallback & a_Callback);  // Lua-accessible
 
 	/** Calls the callback for each chest; returns true if all chests processed, false if the callback aborted by returning true */
-	bool ForEachChest(cChestCallback & a_Callback);  // Lua-accessible
+	bool ForEachChest(const cChestCallback & a_Callback);  // Lua-accessible
 
 	/** Calls the callback for each dispenser; returns true if all dispensers processed, false if the callback aborted by returning true */
-	bool ForEachDispenser(cDispenserCallback & a_Callback);
+	bool ForEachDispenser(const cDispenserCallback & a_Callback);
 
 	/** Calls the callback for each dropper; returns true if all droppers processed, false if the callback aborted by returning true */
-	bool ForEachDropper(cDropperCallback & a_Callback);
+	bool ForEachDropper(const cDropperCallback & a_Callback);
 
 	/** Calls the callback for each dropspenser; returns true if all dropspensers processed, false if the callback aborted by returning true */
-	bool ForEachDropSpenser(cDropSpenserCallback & a_Callback);
+	bool ForEachDropSpenser(const cDropSpenserCallback & a_Callback);
 
 	/** Calls the callback for each furnace; returns true if all furnaces processed, false if the callback aborted by returning true */
-	bool ForEachFurnace(cFurnaceCallback & a_Callback);  // Lua-accessible
+	bool ForEachFurnace(const cFurnaceCallback & a_Callback);  // Lua-accessible
 
 	/** Calls the callback for the tyEntity at the specified coords; returns false if there's no such block entity at those coords, true if found
 	tBlocktype is a list of the blocktypes to be called. If no BLOCKTYPE template arguments are given the callback is called for any block entity
 	Accessible only from within Chunk.cpp */
 	template <class tyEntity, BLOCKTYPE... tBlocktype>
-	bool GenericDoWithBlockEntityAt(int a_BlockX, int a_BlockY, int a_BlockZ, cItemCallback<tyEntity>& a_Callback);
+	bool GenericDoWithBlockEntityAt(int a_BlockX, int a_BlockY, int a_BlockZ, const std::function<bool(tyEntity &)> & a_Callback);
 
 	/** Calls the callback for the block entity at the specified coords; returns false if there's no block entity at those coords, true if found */
-	bool DoWithBlockEntityAt(int a_BlockX, int a_BlockY, int a_BlockZ, cBlockEntityCallback & a_Callback);  // Lua-acessible
+	bool DoWithBlockEntityAt(int a_BlockX, int a_BlockY, int a_BlockZ, const cBlockEntityCallback & a_Callback);  // Lua-acessible
 
 	/** Calls the callback for the beacon at the specified coords; returns false if there's no beacon at those coords, true if found */
-	bool DoWithBeaconAt(int a_BlockX, int a_BlockY, int a_BlockZ, cBeaconCallback & a_Callback);  // Lua-acessible
+	bool DoWithBeaconAt(int a_BlockX, int a_BlockY, int a_BlockZ, const cBeaconCallback & a_Callback);  // Lua-acessible
 
 	/** Calls the callback for the brewingstand at the specified coords; returns false if there's no brewingstand at those coords, true if found */
-	bool DoWithBrewingstandAt(int a_BlockX, int a_BlockY, int a_BlockZ, cBrewingstandCallback & a_Callback);  // Lua-acessible
+	bool DoWithBrewingstandAt(int a_BlockX, int a_BlockY, int a_BlockZ, const cBrewingstandCallback & a_Callback);  // Lua-acessible
 
 	/** Calls the callback for the bed at the specified coords; returns false if there's no bed at those coords, true if found */
-	bool DoWithBedAt(int a_BlockX, int a_BlockY, int a_BlockZ, cBedCallback & a_Callback);  // Lua-acessible
+	bool DoWithBedAt(int a_BlockX, int a_BlockY, int a_BlockZ, const cBedCallback & a_Callback);  // Lua-acessible
 
 	/** Calls the callback for the chest at the specified coords; returns false if there's no chest at those coords, true if found */
-	bool DoWithChestAt(int a_BlockX, int a_BlockY, int a_BlockZ, cChestCallback & a_Callback);  // Lua-acessible
+	bool DoWithChestAt(int a_BlockX, int a_BlockY, int a_BlockZ, const cChestCallback & a_Callback);  // Lua-acessible
 
 	/** Calls the callback for the dispenser at the specified coords; returns false if there's no dispenser at those coords or callback returns true, returns true if found */
-	bool DoWithDispenserAt(int a_BlockX, int a_BlockY, int a_BlockZ, cDispenserCallback & a_Callback);
+	bool DoWithDispenserAt(int a_BlockX, int a_BlockY, int a_BlockZ, const cDispenserCallback & a_Callback);
 
 	/** Calls the callback for the dispenser at the specified coords; returns false if there's no dropper at those coords or callback returns true, returns true if found */
-	bool DoWithDropperAt(int a_BlockX, int a_BlockY, int a_BlockZ, cDropperCallback & a_Callback);
+	bool DoWithDropperAt(int a_BlockX, int a_BlockY, int a_BlockZ, const cDropperCallback & a_Callback);
 
 	/** Calls the callback for the dispenser at the specified coords; returns false if there's no dropspenser at those coords or callback returns true, returns true if found */
-	bool DoWithDropSpenserAt(int a_BlockX, int a_BlockY, int a_BlockZ, cDropSpenserCallback & a_Callback);
+	bool DoWithDropSpenserAt(int a_BlockX, int a_BlockY, int a_BlockZ, const cDropSpenserCallback & a_Callback);
 
 	/** Calls the callback for the furnace at the specified coords; returns false if there's no furnace at those coords or callback returns true, returns true if found */
-	bool DoWithFurnaceAt(int a_BlockX, int a_BlockY, int a_BlockZ, cFurnaceCallback & a_Callback);  // Lua-accessible
+	bool DoWithFurnaceAt(int a_BlockX, int a_BlockY, int a_BlockZ, const cFurnaceCallback & a_Callback);  // Lua-accessible
 
 	/** Calls the callback for the noteblock at the specified coords; returns false if there's no noteblock at those coords or callback returns true, returns true if found */
-	bool DoWithNoteBlockAt(int a_BlockX, int a_BlockY, int a_BlockZ, cNoteBlockCallback & a_Callback);
+	bool DoWithNoteBlockAt(int a_BlockX, int a_BlockY, int a_BlockZ, const cNoteBlockCallback & a_Callback);
 
 	/** Calls the callback for the command block at the specified coords; returns false if there's no command block at those coords or callback returns true, returns true if found */
-	bool DoWithCommandBlockAt(int a_BlockX, int a_BlockY, int a_BlockZ, cCommandBlockCallback & a_Callback);
+	bool DoWithCommandBlockAt(int a_BlockX, int a_BlockY, int a_BlockZ, const cCommandBlockCallback & a_Callback);
 
 	/** Calls the callback for the mob head block at the specified coords; returns false if there's no mob head block at those coords or callback returns true, returns true if found */
-	bool DoWithMobHeadAt(int a_BlockX, int a_BlockY, int a_BlockZ, cMobHeadCallback & a_Callback);
+	bool DoWithMobHeadAt(int a_BlockX, int a_BlockY, int a_BlockZ, const cMobHeadCallback & a_Callback);
 
 	/** Calls the callback for the flower pot at the specified coords; returns false if there's no flower pot at those coords or callback returns true, returns true if found */
-	bool DoWithFlowerPotAt(int a_BlockX, int a_BlockY, int a_BlockZ, cFlowerPotCallback & a_Callback);
+	bool DoWithFlowerPotAt(int a_BlockX, int a_BlockY, int a_BlockZ, const cFlowerPotCallback & a_Callback);
 
 	/** Retrieves the test on the sign at the specified coords; returns false if there's no sign at those coords, true if found */
 	bool GetSignLines (int a_BlockX, int a_BlockY, int a_BlockZ, AString & a_Line1, AString & a_Line2, AString & a_Line3, AString & a_Line4);  // Lua-accessible
diff --git a/src/ChunkMap.cpp b/src/ChunkMap.cpp
index 6afce338d..524d5b2ff 100644
--- a/src/ChunkMap.cpp
+++ b/src/ChunkMap.cpp
@@ -1,4 +1,4 @@
-
+
 #include "Globals.h"  // NOTE: MSVC stupidness requires this to be the same across all modules
 
 #include "ChunkMap.h"
@@ -731,7 +731,7 @@ bool cChunkMap::UseBlockEntity(cPlayer * a_Player, int a_BlockX, int a_BlockY, i
 
 
 
-bool cChunkMap::DoWithChunk(int a_ChunkX, int a_ChunkZ, cChunkCallback & a_Callback)
+bool cChunkMap::DoWithChunk(int a_ChunkX, int a_ChunkZ, const cChunkCallback & a_Callback)
 {
 	cCSLock Lock(m_CSChunks);
 	cChunkPtr Chunk = GetChunkNoLoad(a_ChunkX, a_ChunkZ);
@@ -739,30 +739,15 @@ bool cChunkMap::DoWithChunk(int a_ChunkX, int a_ChunkZ, cChunkCallback & a_Callb
 	{
 		return false;
 	}
-	return a_Callback.Item(Chunk);
+	return a_Callback(*Chunk);
 }
 
 
-bool cChunkMap::DoWithChunkAt(Vector3i a_BlockPos, std::function<bool(cChunk &)> a_Callback)
+bool cChunkMap::DoWithChunkAt(Vector3i a_BlockPos, const cChunkCallback & a_Callback)
 {
 	int ChunkX, ChunkZ;
 	cChunkDef::BlockToChunk(a_BlockPos.x, a_BlockPos.z, ChunkX, ChunkZ);
-	struct cCallBackWrapper : cChunkCallback
-	{
-		cCallBackWrapper(std::function<bool(cChunk &)> a_InnerCallback) :
-			m_Callback(a_InnerCallback)
-		{
-		}
-
-		virtual bool Item(cChunk * a_Chunk)
-		{
-			return m_Callback(*a_Chunk);
-		}
-
-	private:
-		std::function<bool(cChunk &)> m_Callback;
-	} callback(a_Callback);
-	return DoWithChunk(ChunkX, ChunkZ, callback);
+	return DoWithChunk(ChunkX, ChunkZ, a_Callback);
 }
 
 
@@ -1598,7 +1583,7 @@ OwnedEntity cChunkMap::RemoveEntity(cEntity & a_Entity)
 
 
 
-bool cChunkMap::ForEachEntity(cEntityCallback & a_Callback)
+bool cChunkMap::ForEachEntity(const cEntityCallback & a_Callback)
 {
 	cCSLock Lock(m_CSChunks);
 	for (const auto & Chunk : m_Chunks)
@@ -1615,7 +1600,7 @@ bool cChunkMap::ForEachEntity(cEntityCallback & a_Callback)
 
 
 
-bool cChunkMap::ForEachEntityInChunk(int a_ChunkX, int a_ChunkZ, cEntityCallback & a_Callback)
+bool cChunkMap::ForEachEntityInChunk(int a_ChunkX, int a_ChunkZ, const cEntityCallback & a_Callback)
 {
 	cCSLock Lock(m_CSChunks);
 	cChunkPtr Chunk = GetChunkNoGen(a_ChunkX, a_ChunkZ);
@@ -1630,7 +1615,7 @@ bool cChunkMap::ForEachEntityInChunk(int a_ChunkX, int a_ChunkZ, cEntityCallback
 
 
 
-bool cChunkMap::ForEachEntityInBox(const cBoundingBox & a_Box, cEntityCallback & a_Callback)
+bool cChunkMap::ForEachEntityInBox(const cBoundingBox & a_Box, const cEntityCallback & a_Callback)
 {
 	// Calculate the chunk range for the box:
 	int MinChunkX = FloorC(a_Box.GetMinX() / cChunkDef::Width);
@@ -1792,60 +1777,41 @@ void cChunkMap::DoExplosionAt(double a_ExplosionSize, double a_BlockX, double a_
 		area.Write(*m_World, bx - ExplosionSizeInt, MinY, bz - ExplosionSizeInt);
 	}
 
-	class cTNTDamageCallback :
-		public cEntityCallback
-	{
-	public:
-		cTNTDamageCallback(cBoundingBox & a_CBBBTNT, Vector3d a_CBExplosionPos, int a_CBExplosionSize) :
-			m_bbTNT(a_CBBBTNT),
-			m_ExplosionPos(a_CBExplosionPos),
-			m_ExplosionSize(a_CBExplosionSize)
-		{
-		}
+	Vector3d ExplosionPos{ a_BlockX, a_BlockY, a_BlockZ };
+	cBoundingBox bbTNT(ExplosionPos, 0.5, 1);
+	bbTNT.Expand(ExplosionSizeInt * 2, ExplosionSizeInt * 2, ExplosionSizeInt * 2);
 
-		virtual bool Item(cEntity * a_Entity) override
+	ForEachEntity([&](cEntity & a_Entity)
 		{
-			if (a_Entity->IsPickup() && (a_Entity->GetTicksAlive() < 20))
+			if (a_Entity.IsPickup() && (a_Entity.GetTicksAlive() < 20))
 			{
 				// If pickup age is smaller than one second, it is invincible (so we don't kill pickups that were just spawned)
 				return false;
 			}
 
-			Vector3d DistanceFromExplosion = a_Entity->GetPosition() - m_ExplosionPos;
+			Vector3d DistanceFromExplosion = a_Entity.GetPosition() - ExplosionPos;
 
-			if (!a_Entity->IsTNT() && !a_Entity->IsFallingBlock())  // Don't apply damage to other TNT entities and falling blocks, they should be invincible
+			if (!a_Entity.IsTNT() && !a_Entity.IsFallingBlock())  // Don't apply damage to other TNT entities and falling blocks, they should be invincible
 			{
-				cBoundingBox bbEntity(a_Entity->GetPosition(), a_Entity->GetWidth() / 2, a_Entity->GetHeight());
+				cBoundingBox bbEntity(a_Entity.GetPosition(), a_Entity.GetWidth() / 2, a_Entity.GetHeight());
 
-				if (!m_bbTNT.IsInside(bbEntity))  // If bbEntity is inside bbTNT, not vice versa!
+				if (!bbTNT.IsInside(bbEntity))  // If bbEntity is inside bbTNT, not vice versa!
 				{
 					return false;
 				}
 
 				// Ensure that the damage dealt is inversely proportional to the distance to the TNT centre - the closer a player is, the harder they are hit
-				a_Entity->TakeDamage(dtExplosion, nullptr, static_cast<int>((1 / DistanceFromExplosion.Length()) * 6 * m_ExplosionSize), 0);
+				a_Entity.TakeDamage(dtExplosion, nullptr, static_cast<int>((1 / DistanceFromExplosion.Length()) * 6 * ExplosionSizeInt), 0);
 			}
 
 			// Apply force to entities around the explosion - code modified from World.cpp DoExplosionAt()
 			DistanceFromExplosion.Normalize();
-			DistanceFromExplosion *= m_ExplosionSize * m_ExplosionSize;
-			a_Entity->AddSpeed(DistanceFromExplosion);
+			DistanceFromExplosion *= ExplosionSizeInt * ExplosionSizeInt;
+			a_Entity.AddSpeed(DistanceFromExplosion);
 
 			return false;
 		}
-
-	protected:
-		cBoundingBox & m_bbTNT;
-		Vector3d m_ExplosionPos;
-		int m_ExplosionSize;
-	};
-
-	cBoundingBox bbTNT(Vector3d(a_BlockX, a_BlockY, a_BlockZ), 0.5, 1);
-	bbTNT.Expand(ExplosionSizeInt * 2, ExplosionSizeInt * 2, ExplosionSizeInt * 2);
-
-
-	cTNTDamageCallback TNTDamageCallback(bbTNT, Vector3d(a_BlockX, a_BlockY, a_BlockZ), ExplosionSizeInt);
-	ForEachEntity(TNTDamageCallback);
+	);
 
 	// Wake up all simulators for the area, so that water and lava flows and sand falls into the blasted holes (FS #391):
 	m_World->GetSimulatorManager()->WakeUpArea(cCuboid(
@@ -1858,16 +1824,7 @@ void cChunkMap::DoExplosionAt(double a_ExplosionSize, double a_BlockX, double a_
 
 
 
-bool cChunkMap::DoWithEntityByID(UInt32 a_UniqueID, cEntityCallback & a_Callback)
-{
-	return DoWithEntityByID(a_UniqueID, std::bind(&cEntityCallback::Item, &a_Callback, std::placeholders::_1));
-}
-
-
-
-
-
-bool cChunkMap::DoWithEntityByID(UInt32 a_UniqueID, cLambdaEntityCallback a_Callback)
+bool cChunkMap::DoWithEntityByID(UInt32 a_UniqueID, const cEntityCallback & a_Callback)
 {
 	cCSLock Lock(m_CSChunks);
 	bool res = false;
@@ -1885,7 +1842,7 @@ bool cChunkMap::DoWithEntityByID(UInt32 a_UniqueID, cLambdaEntityCallback a_Call
 
 
 
-bool cChunkMap::ForEachBlockEntityInChunk(int a_ChunkX, int a_ChunkZ, cBlockEntityCallback & a_Callback)
+bool cChunkMap::ForEachBlockEntityInChunk(int a_ChunkX, int a_ChunkZ, const cBlockEntityCallback & a_Callback)
 {
 	cCSLock Lock(m_CSChunks);
 	cChunkPtr Chunk = GetChunkNoGen(a_ChunkX, a_ChunkZ);
@@ -1900,7 +1857,7 @@ bool cChunkMap::ForEachBlockEntityInChunk(int a_ChunkX, int a_ChunkZ, cBlockEnti
 
 
 
-bool cChunkMap::ForEachBrewingstandInChunk(int a_ChunkX, int a_ChunkZ, cBrewingstandCallback & a_Callback)
+bool cChunkMap::ForEachBrewingstandInChunk(int a_ChunkX, int a_ChunkZ, const cBrewingstandCallback & a_Callback)
 {
 	cCSLock Lock(m_CSChunks);
 	cChunkPtr Chunk = GetChunkNoGen(a_ChunkX, a_ChunkZ);
@@ -1915,7 +1872,7 @@ bool cChunkMap::ForEachBrewingstandInChunk(int a_ChunkX, int a_ChunkZ, cBrewings
 
 
 
-bool cChunkMap::ForEachChestInChunk(int a_ChunkX, int a_ChunkZ, cChestCallback & a_Callback)
+bool cChunkMap::ForEachChestInChunk(int a_ChunkX, int a_ChunkZ, const cChestCallback & a_Callback)
 {
 	cCSLock Lock(m_CSChunks);
 	cChunkPtr Chunk = GetChunkNoGen(a_ChunkX, a_ChunkZ);
@@ -1930,7 +1887,7 @@ bool cChunkMap::ForEachChestInChunk(int a_ChunkX, int a_ChunkZ, cChestCallback &
 
 
 
-bool cChunkMap::ForEachDispenserInChunk(int a_ChunkX, int a_ChunkZ, cDispenserCallback & a_Callback)
+bool cChunkMap::ForEachDispenserInChunk(int a_ChunkX, int a_ChunkZ, const cDispenserCallback & a_Callback)
 {
 	cCSLock Lock(m_CSChunks);
 	cChunkPtr Chunk = GetChunkNoGen(a_ChunkX, a_ChunkZ);
@@ -1945,7 +1902,7 @@ bool cChunkMap::ForEachDispenserInChunk(int a_ChunkX, int a_ChunkZ, cDispenserCa
 
 
 
-bool cChunkMap::ForEachDropperInChunk(int a_ChunkX, int a_ChunkZ, cDropperCallback & a_Callback)
+bool cChunkMap::ForEachDropperInChunk(int a_ChunkX, int a_ChunkZ, const cDropperCallback & a_Callback)
 {
 	cCSLock Lock(m_CSChunks);
 	cChunkPtr Chunk = GetChunkNoGen(a_ChunkX, a_ChunkZ);
@@ -1960,7 +1917,7 @@ bool cChunkMap::ForEachDropperInChunk(int a_ChunkX, int a_ChunkZ, cDropperCallba
 
 
 
-bool cChunkMap::ForEachDropSpenserInChunk(int a_ChunkX, int a_ChunkZ, cDropSpenserCallback & a_Callback)
+bool cChunkMap::ForEachDropSpenserInChunk(int a_ChunkX, int a_ChunkZ, const cDropSpenserCallback & a_Callback)
 {
 	cCSLock Lock(m_CSChunks);
 	cChunkPtr Chunk = GetChunkNoGen(a_ChunkX, a_ChunkZ);
@@ -1975,7 +1932,7 @@ bool cChunkMap::ForEachDropSpenserInChunk(int a_ChunkX, int a_ChunkZ, cDropSpens
 
 
 
-bool cChunkMap::ForEachFurnaceInChunk(int a_ChunkX, int a_ChunkZ, cFurnaceCallback & a_Callback)
+bool cChunkMap::ForEachFurnaceInChunk(int a_ChunkX, int a_ChunkZ, const cFurnaceCallback & a_Callback)
 {
 	cCSLock Lock(m_CSChunks);
 	cChunkPtr Chunk = GetChunkNoGen(a_ChunkX, a_ChunkZ);
@@ -1990,7 +1947,7 @@ bool cChunkMap::ForEachFurnaceInChunk(int a_ChunkX, int a_ChunkZ, cFurnaceCallba
 
 
 
-bool cChunkMap::DoWithBlockEntityAt(int a_BlockX, int a_BlockY, int a_BlockZ, cBlockEntityCallback & a_Callback)
+bool cChunkMap::DoWithBlockEntityAt(int a_BlockX, int a_BlockY, int a_BlockZ, const cBlockEntityCallback & a_Callback)
 {
 	int ChunkX, ChunkZ;
 	int BlockX = a_BlockX, BlockY = a_BlockY, BlockZ = a_BlockZ;
@@ -2008,7 +1965,7 @@ bool cChunkMap::DoWithBlockEntityAt(int a_BlockX, int a_BlockY, int a_BlockZ, cB
 
 
 
-bool cChunkMap::DoWithBeaconAt(int a_BlockX, int a_BlockY, int a_BlockZ, cBeaconCallback & a_Callback)
+bool cChunkMap::DoWithBeaconAt(int a_BlockX, int a_BlockY, int a_BlockZ, const cBeaconCallback & a_Callback)
 {
 	int ChunkX, ChunkZ;
 	int BlockX = a_BlockX, BlockY = a_BlockY, BlockZ = a_BlockZ;
@@ -2026,7 +1983,7 @@ bool cChunkMap::DoWithBeaconAt(int a_BlockX, int a_BlockY, int a_BlockZ, cBeacon
 
 
 
-bool cChunkMap::DoWithBedAt(int a_BlockX, int a_BlockY, int a_BlockZ, cBedCallback & a_Callback)
+bool cChunkMap::DoWithBedAt(int a_BlockX, int a_BlockY, int a_BlockZ, const cBedCallback & a_Callback)
 {
 	int ChunkX, ChunkZ;
 	int BlockX = a_BlockX, BlockY = a_BlockY, BlockZ = a_BlockZ;
@@ -2044,7 +2001,7 @@ bool cChunkMap::DoWithBedAt(int a_BlockX, int a_BlockY, int a_BlockZ, cBedCallba
 
 
 
-bool cChunkMap::DoWithBrewingstandAt(int a_BlockX, int a_BlockY, int a_BlockZ, cBrewingstandCallback & a_Callback)
+bool cChunkMap::DoWithBrewingstandAt(int a_BlockX, int a_BlockY, int a_BlockZ, const cBrewingstandCallback & a_Callback)
 {
 	int ChunkX, ChunkZ;
 	int BlockX = a_BlockX, BlockY = a_BlockY, BlockZ = a_BlockZ;
@@ -2062,7 +2019,7 @@ bool cChunkMap::DoWithBrewingstandAt(int a_BlockX, int a_BlockY, int a_BlockZ, c
 
 
 
-bool cChunkMap::DoWithChestAt(int a_BlockX, int a_BlockY, int a_BlockZ, cChestCallback & a_Callback)
+bool cChunkMap::DoWithChestAt(int a_BlockX, int a_BlockY, int a_BlockZ, const cChestCallback & a_Callback)
 {
 	int ChunkX, ChunkZ;
 	int BlockX = a_BlockX, BlockY = a_BlockY, BlockZ = a_BlockZ;
@@ -2080,7 +2037,7 @@ bool cChunkMap::DoWithChestAt(int a_BlockX, int a_BlockY, int a_BlockZ, cChestCa
 
 
 
-bool cChunkMap::DoWithDispenserAt(int a_BlockX, int a_BlockY, int a_BlockZ, cDispenserCallback & a_Callback)
+bool cChunkMap::DoWithDispenserAt(int a_BlockX, int a_BlockY, int a_BlockZ, const cDispenserCallback & a_Callback)
 {
 	int ChunkX, ChunkZ;
 	int BlockX = a_BlockX, BlockY = a_BlockY, BlockZ = a_BlockZ;
@@ -2098,7 +2055,7 @@ bool cChunkMap::DoWithDispenserAt(int a_BlockX, int a_BlockY, int a_BlockZ, cDis
 
 
 
-bool cChunkMap::DoWithDropperAt(int a_BlockX, int a_BlockY, int a_BlockZ, cDropperCallback & a_Callback)
+bool cChunkMap::DoWithDropperAt(int a_BlockX, int a_BlockY, int a_BlockZ, const cDropperCallback & a_Callback)
 {
 	int ChunkX, ChunkZ;
 	int BlockX = a_BlockX, BlockY = a_BlockY, BlockZ = a_BlockZ;
@@ -2116,7 +2073,7 @@ bool cChunkMap::DoWithDropperAt(int a_BlockX, int a_BlockY, int a_BlockZ, cDropp
 
 
 
-bool cChunkMap::DoWithDropSpenserAt(int a_BlockX, int a_BlockY, int a_BlockZ, cDropSpenserCallback & a_Callback)
+bool cChunkMap::DoWithDropSpenserAt(int a_BlockX, int a_BlockY, int a_BlockZ, const cDropSpenserCallback & a_Callback)
 {
 	int ChunkX, ChunkZ;
 	int BlockX = a_BlockX, BlockY = a_BlockY, BlockZ = a_BlockZ;
@@ -2134,7 +2091,7 @@ bool cChunkMap::DoWithDropSpenserAt(int a_BlockX, int a_BlockY, int a_BlockZ, cD
 
 
 
-bool cChunkMap::DoWithFurnaceAt(int a_BlockX, int a_BlockY, int a_BlockZ, cFurnaceCallback & a_Callback)
+bool cChunkMap::DoWithFurnaceAt(int a_BlockX, int a_BlockY, int a_BlockZ, const cFurnaceCallback & a_Callback)
 {
 	int ChunkX, ChunkZ;
 	int BlockX = a_BlockX, BlockY = a_BlockY, BlockZ = a_BlockZ;
@@ -2151,7 +2108,7 @@ bool cChunkMap::DoWithFurnaceAt(int a_BlockX, int a_BlockY, int a_BlockZ, cFurna
 
 
 
-bool cChunkMap::DoWithNoteBlockAt(int a_BlockX, int a_BlockY, int a_BlockZ, cNoteBlockCallback & a_Callback)
+bool cChunkMap::DoWithNoteBlockAt(int a_BlockX, int a_BlockY, int a_BlockZ, const cNoteBlockCallback & a_Callback)
 {
 	int ChunkX, ChunkZ;
 	int BlockX = a_BlockX, BlockY = a_BlockY, BlockZ = a_BlockZ;
@@ -2168,7 +2125,7 @@ bool cChunkMap::DoWithNoteBlockAt(int a_BlockX, int a_BlockY, int a_BlockZ, cNot
 
 
 
-bool cChunkMap::DoWithCommandBlockAt(int a_BlockX, int a_BlockY, int a_BlockZ, cCommandBlockCallback & a_Callback)
+bool cChunkMap::DoWithCommandBlockAt(int a_BlockX, int a_BlockY, int a_BlockZ, const cCommandBlockCallback & a_Callback)
 {
 	int ChunkX, ChunkZ;
 	int BlockX = a_BlockX, BlockY = a_BlockY, BlockZ = a_BlockZ;
@@ -2186,7 +2143,7 @@ bool cChunkMap::DoWithCommandBlockAt(int a_BlockX, int a_BlockY, int a_BlockZ, c
 
 
 
-bool cChunkMap::DoWithMobHeadAt(int a_BlockX, int a_BlockY, int a_BlockZ, cMobHeadCallback & a_Callback)
+bool cChunkMap::DoWithMobHeadAt(int a_BlockX, int a_BlockY, int a_BlockZ, const cMobHeadCallback & a_Callback)
 {
 	int ChunkX, ChunkZ;
 	int BlockX = a_BlockX, BlockY = a_BlockY, BlockZ = a_BlockZ;
@@ -2204,7 +2161,7 @@ bool cChunkMap::DoWithMobHeadAt(int a_BlockX, int a_BlockY, int a_BlockZ, cMobHe
 
 
 
-bool cChunkMap::DoWithFlowerPotAt(int a_BlockX, int a_BlockY, int a_BlockZ, cFlowerPotCallback & a_Callback)
+bool cChunkMap::DoWithFlowerPotAt(int a_BlockX, int a_BlockY, int a_BlockZ, const cFlowerPotCallback & a_Callback)
 {
 	int ChunkX, ChunkZ;
 	int BlockX = a_BlockX, BlockY = a_BlockY, BlockZ = a_BlockZ;
@@ -2442,7 +2399,7 @@ bool cChunkMap::ForEachChunkInRect(int a_MinChunkX, int a_MaxChunkX, int a_MinCh
 
 
 
-bool cChunkMap::ForEachLoadedChunk(std::function<bool(int, int)> a_Callback)
+bool cChunkMap::ForEachLoadedChunk(const std::function<bool(int, int)> & a_Callback)
 {
 	cCSLock Lock(m_CSChunks);
 	for (const auto & Chunk : m_Chunks)
diff --git a/src/ChunkMap.h b/src/ChunkMap.h
index 66d1d4840..4f0ff47af 100644
--- a/src/ChunkMap.h
+++ b/src/ChunkMap.h
@@ -1,4 +1,4 @@
-
+
 // cChunkMap.h
 
 // Interfaces to the cChunkMap class representing the chunk storage for a single world
@@ -38,25 +38,23 @@ class cSetChunkData;
 class cBoundingBox;
 class cDeadlockDetect;
 
-typedef std::list<cClientHandle *>         cClientHandleList;
-typedef cChunk *                           cChunkPtr;
-typedef cItemCallback<cEntity>             cEntityCallback;
-typedef cItemCallback<cBlockEntity>        cBlockEntityCallback;
-typedef cItemCallback<cBeaconEntity>       cBeaconCallback;
-typedef cItemCallback<cBedEntity>          cBedCallback;
-typedef cItemCallback<cBrewingstandEntity> cBrewingstandCallback;
-typedef cItemCallback<cChestEntity>        cChestCallback;
-typedef cItemCallback<cDispenserEntity>    cDispenserCallback;
-typedef cItemCallback<cDropperEntity>      cDropperCallback;
-typedef cItemCallback<cDropSpenserEntity>  cDropSpenserCallback;
-typedef cItemCallback<cFlowerPotEntity>    cFlowerPotCallback;
-typedef cItemCallback<cFurnaceEntity>      cFurnaceCallback;
-typedef cItemCallback<cNoteEntity>         cNoteBlockCallback;
-typedef cItemCallback<cCommandBlockEntity> cCommandBlockCallback;
-typedef cItemCallback<cMobHeadEntity>      cMobHeadCallback;
-typedef cItemCallback<cChunk>              cChunkCallback;
-
-typedef std::function<bool (cEntity *)>    cLambdaEntityCallback;
+typedef std::list<cClientHandle *> cClientHandleList;
+typedef cChunk *                   cChunkPtr;
+using cEntityCallback       = std::function<bool(cEntity             &)>;
+using cBeaconCallback       = std::function<bool(cBeaconEntity       &)>;
+using cBedCallback          = std::function<bool(cBedEntity          &)>;
+using cBlockEntityCallback  = std::function<bool(cBlockEntity        &)>;
+using cBrewingstandCallback = std::function<bool(cBrewingstandEntity &)>;
+using cChestCallback        = std::function<bool(cChestEntity        &)>;
+using cChunkCallback        = std::function<bool(cChunk              &)>;
+using cDispenserCallback    = std::function<bool(cDispenserEntity    &)>;
+using cDropperCallback      = std::function<bool(cDropperEntity      &)>;
+using cDropSpenserCallback  = std::function<bool(cDropSpenserEntity  &)>;
+using cFurnaceCallback      = std::function<bool(cFurnaceEntity      &)>;
+using cNoteBlockCallback    = std::function<bool(cNoteEntity         &)>;
+using cCommandBlockCallback = std::function<bool(cCommandBlockEntity &)>;
+using cMobHeadCallback      = std::function<bool(cMobHeadEntity      &)>;
+using cFlowerPotCallback    = std::function<bool(cFlowerPotEntity    &)>;
 
 
 
@@ -106,10 +104,10 @@ public:
 	bool UseBlockEntity(cPlayer * a_Player, int a_X, int a_Y, int a_Z);
 
 	/** Calls the callback for the chunk specified, with ChunkMapCS locked; returns false if the chunk doesn't exist, otherwise returns the same value as the callback */
-	bool DoWithChunk(int a_ChunkX, int a_ChunkZ, cChunkCallback & a_Callback);
+	bool DoWithChunk(int a_ChunkX, int a_ChunkZ, const cChunkCallback & a_Callback);
 
 	/** Calls the callback for the chunk at the block position specified, with ChunkMapCS locked; returns false if the chunk doesn't exist, otherwise returns the same value as the callback */
-	bool DoWithChunkAt(Vector3i a_BlockPos, std::function<bool(cChunk &)> a_Callback);
+	bool DoWithChunkAt(Vector3i a_BlockPos, const cChunkCallback & a_Callback);
 
 	/** Wakes up simulators for the specified block */
 	void WakeUpSimulators(Vector3i a_Block);
@@ -230,102 +228,101 @@ public:
 	OwnedEntity RemoveEntity(cEntity & a_Entity);
 
 	/** Calls the callback for each entity in the entire world; returns true if all entities processed, false if the callback aborted by returning true */
-	bool ForEachEntity(cEntityCallback & a_Callback);  // Lua-accessible
+	bool ForEachEntity(const cEntityCallback & a_Callback);  // Lua-accessible
 
 	/** Calls the callback for each entity in the specified chunk; returns true if all entities processed, false if the callback aborted by returning true */
-	bool ForEachEntityInChunk(int a_ChunkX, int a_ChunkZ, cEntityCallback & a_Callback);  // Lua-accessible
+	bool ForEachEntityInChunk(int a_ChunkX, int a_ChunkZ, const cEntityCallback & a_Callback);  // Lua-accessible
 
 	/** Calls the callback for each entity that has a nonempty intersection with the specified boundingbox.
 	Returns true if all entities processed, false if the callback aborted by returning true.
 	If any chunk in the box is missing, ignores the entities in that chunk silently. */
-	bool ForEachEntityInBox(const cBoundingBox & a_Box, cEntityCallback & a_Callback);  // Lua-accessible
+	bool ForEachEntityInBox(const cBoundingBox & a_Box, const cEntityCallback & a_Callback);  // Lua-accessible
 
 	/** Destroys and returns a list of blocks destroyed in the explosion at the specified coordinates */
 	void DoExplosionAt(double a_ExplosionSize, double a_BlockX, double a_BlockY, double a_BlockZ, cVector3iArray & a_BlockAffected);
 
 	/** Calls the callback if the entity with the specified ID is found, with the entity object as the callback param.
 	Returns true if entity found and callback returned false. */
-	bool DoWithEntityByID(UInt32 a_EntityID, cEntityCallback & a_Callback);  // Lua-accessible
-	bool DoWithEntityByID(UInt32 a_EntityID, cLambdaEntityCallback a_Callback);  // Lambda version
+	bool DoWithEntityByID(UInt32 a_EntityID, const cEntityCallback & a_Callback);  // Lua-accessible
 
 	/** Calls the callback for each block entity in the specified chunk.
 	Returns true if all block entities processed, false if the callback aborted by returning true. */
-	bool ForEachBlockEntityInChunk(int a_ChunkX, int a_ChunkZ, cBlockEntityCallback & a_Callback);  // Lua-accessible
+	bool ForEachBlockEntityInChunk(int a_ChunkX, int a_ChunkZ, const cBlockEntityCallback & a_Callback);  // Lua-accessible
 
 	/** Calls the callback for brewingstand in the specified chunk.
 	Returns true if all brewingstands processed, false if the callback aborted by returning true. */
-	bool ForEachBrewingstandInChunk(int a_ChunkX, int a_ChunkZ, cBrewingstandCallback & a_Callback);  // Lua-accessible
+	bool ForEachBrewingstandInChunk(int a_ChunkX, int a_ChunkZ, const cBrewingstandCallback & a_Callback);  // Lua-accessible
 
 	/** Calls the callback for each chest in the specified chunk.
 	Returns true if all chests processed, false if the callback aborted by returning true. */
-	bool ForEachChestInChunk(int a_ChunkX, int a_ChunkZ, cChestCallback & a_Callback);  // Lua-accessible
+	bool ForEachChestInChunk(int a_ChunkX, int a_ChunkZ, const cChestCallback & a_Callback);  // Lua-accessible
 
 	/** Calls the callback for each dispenser in the specified chunk.
 	Returns true if all dispensers processed, false if the callback aborted by returning true. */
-	bool ForEachDispenserInChunk(int a_ChunkX, int a_ChunkZ, cDispenserCallback & a_Callback);
+	bool ForEachDispenserInChunk(int a_ChunkX, int a_ChunkZ, const cDispenserCallback & a_Callback);
 
 	/** Calls the callback for each dropper in the specified chunk.
 	Returns true if all droppers processed, false if the callback aborted by returning true. */
-	bool ForEachDropperInChunk(int a_ChunkX, int a_ChunkZ, cDropperCallback & a_Callback);
+	bool ForEachDropperInChunk(int a_ChunkX, int a_ChunkZ, const cDropperCallback & a_Callback);
 
 	/** Calls the callback for each dropspenser in the specified chunk.
 	Returns true if all dropspensers processed, false if the callback aborted by returning true. */
-	bool ForEachDropSpenserInChunk(int a_ChunkX, int a_ChunkZ, cDropSpenserCallback & a_Callback);
+	bool ForEachDropSpenserInChunk(int a_ChunkX, int a_ChunkZ, const cDropSpenserCallback & a_Callback);
 
 	/** Calls the callback for each furnace in the specified chunk.
 	Returns true if all furnaces processed, false if the callback aborted by returning true. */
-	bool ForEachFurnaceInChunk(int a_ChunkX, int a_ChunkZ, cFurnaceCallback & a_Callback);  // Lua-accessible
+	bool ForEachFurnaceInChunk(int a_ChunkX, int a_ChunkZ, const cFurnaceCallback & a_Callback);  // Lua-accessible
 
 	/** Calls the callback for the block entity at the specified coords.
 	Returns false if there's no block entity at those coords, true if found. */
-	bool DoWithBlockEntityAt(int a_BlockX, int a_BlockY, int a_BlockZ, cBlockEntityCallback & a_Callback);  // Lua-acessible
+	bool DoWithBlockEntityAt(int a_BlockX, int a_BlockY, int a_BlockZ, const cBlockEntityCallback & a_Callback);  // Lua-acessible
 
 	/** Calls the callback for the beacon at the specified coords.
 	Returns false if there's no beacon at those coords, true if found. */
-	bool DoWithBeaconAt(int a_BlockX, int a_BlockY, int a_BlockZ, cBeaconCallback & a_Callback);  // Lua-acessible
+	bool DoWithBeaconAt(int a_BlockX, int a_BlockY, int a_BlockZ, const cBeaconCallback & a_Callback);  // Lua-acessible
 
 	/** Calls the callback for the bed at the specified coords.
 	Returns false if there's no bed at those coords, true if found. */
-	bool DoWithBedAt(int a_BlockX, int a_BlockY, int a_BlockZ, cBedCallback & a_Callback);  // Lua-acessible
+	bool DoWithBedAt(int a_BlockX, int a_BlockY, int a_BlockZ, const cBedCallback & a_Callback);  // Lua-acessible
 
 	/** Calls the callback for the brewingstand at the specified coords; returns false if there's no brewingstand at those coords, true if found */
-	bool DoWithBrewingstandAt(int a_BlockX, int a_BlockY, int a_BlockZ, cBrewingstandCallback & a_Callback);  // Lua-acessible
+	bool DoWithBrewingstandAt(int a_BlockX, int a_BlockY, int a_BlockZ, const cBrewingstandCallback & a_Callback);  // Lua-acessible
 
 	/** Calls the callback for the chest at the specified coords.
 	Returns false if there's no chest at those coords, true if found. */
-	bool DoWithChestAt(int a_BlockX, int a_BlockY, int a_BlockZ, cChestCallback & a_Callback);  // Lua-acessible
+	bool DoWithChestAt(int a_BlockX, int a_BlockY, int a_BlockZ, const cChestCallback & a_Callback);  // Lua-acessible
 
 	/** Calls the callback for the dispenser at the specified coords.
 	Returns false if there's no dispenser at those coords or callback returns true, returns true if found. */
-	bool DoWithDispenserAt(int a_BlockX, int a_BlockY, int a_BlockZ, cDispenserCallback & a_Callback);  // Lua-accessible
+	bool DoWithDispenserAt(int a_BlockX, int a_BlockY, int a_BlockZ, const cDispenserCallback & a_Callback);  // Lua-accessible
 
 	/** Calls the callback for the dropper at the specified coords.
 	Returns false if there's no dropper at those coords or callback returns true, returns true if found. */
-	bool DoWithDropperAt(int a_BlockX, int a_BlockY, int a_BlockZ, cDropperCallback & a_Callback);  // Lua-accessible
+	bool DoWithDropperAt(int a_BlockX, int a_BlockY, int a_BlockZ, const cDropperCallback & a_Callback);  // Lua-accessible
 
 	/** Calls the callback for the dropspenser at the specified coords.
 	Returns false if there's no dropspenser at those coords or callback returns true, returns true if found. */
-	bool DoWithDropSpenserAt(int a_BlockX, int a_BlockY, int a_BlockZ, cDropSpenserCallback & a_Callback);  // Lua-accessible
+	bool DoWithDropSpenserAt(int a_BlockX, int a_BlockY, int a_BlockZ, const cDropSpenserCallback & a_Callback);  // Lua-accessible
 
 	/** Calls the callback for the furnace at the specified coords.
 	Returns false if there's no furnace at those coords or callback returns true, returns true if found. */
-	bool DoWithFurnaceAt(int a_BlockX, int a_BlockY, int a_BlockZ, cFurnaceCallback & a_Callback);  // Lua-accessible
+	bool DoWithFurnaceAt(int a_BlockX, int a_BlockY, int a_BlockZ, const cFurnaceCallback & a_Callback);  // Lua-accessible
 
 	/** Calls the callback for the noteblock at the specified coords.
 	Returns false if there's no noteblock at those coords or callback returns true, returns true if found. */
-	bool DoWithNoteBlockAt(int a_BlockX, int a_BlockY, int a_BlockZ, cNoteBlockCallback & a_Callback);  // Lua-accessible
+	bool DoWithNoteBlockAt(int a_BlockX, int a_BlockY, int a_BlockZ, const cNoteBlockCallback & a_Callback);  // Lua-accessible
 
 	/** Calls the callback for the command block at the specified coords.
 	Returns false if there's no command block at those coords or callback returns true, returns true if found. */
-	bool DoWithCommandBlockAt(int a_BlockX, int a_BlockY, int a_BlockZ, cCommandBlockCallback & a_Callback);  // Lua-accessible
+	bool DoWithCommandBlockAt(int a_BlockX, int a_BlockY, int a_BlockZ, const cCommandBlockCallback & a_Callback);  // Lua-accessible
 
 	/** Calls the callback for the mob head block at the specified coords.
 	Returns false if there's no mob head block at those coords or callback returns true, returns true if found. */
-	bool DoWithMobHeadAt(int a_BlockX, int a_BlockY, int a_BlockZ, cMobHeadCallback & a_Callback);  // Lua-accessible
+	bool DoWithMobHeadAt(int a_BlockX, int a_BlockY, int a_BlockZ, const cMobHeadCallback & a_Callback);  // Lua-accessible
 
 	/** Calls the callback for the flower pot at the specified coords.
 	Returns false if there's no flower pot at those coords or callback returns true, returns true if found. */
-	bool DoWithFlowerPotAt(int a_BlockX, int a_BlockY, int a_BlockZ, cFlowerPotCallback & a_Callback);  // Lua-accessible
+	bool DoWithFlowerPotAt(int a_BlockX, int a_BlockY, int a_BlockZ, const cFlowerPotCallback & a_Callback);  // Lua-accessible
 
 	/** Retrieves the test on the sign at the specified coords.
 	Returns false if there's no sign at those coords, true if found. */
@@ -363,7 +360,7 @@ public:
 	bool ForEachChunkInRect(int a_MinChunkX, int a_MaxChunkX, int a_MinChunkZ, int a_MaxChunkZ, cChunkDataCallback & a_Callback);
 
 	/** Calls the callback for each loaded chunk. Returns true if all chunks have been processed successfully */
-	bool ForEachLoadedChunk(std::function<bool(int, int)> a_Callback);
+	bool ForEachLoadedChunk(const std::function<bool(int, int)> & a_Callback);
 
 	/** Writes the block area into the specified coords. Returns true if all chunks have been processed. Prefer cBlockArea::Write() instead. */
 	bool WriteBlockArea(cBlockArea & a_Area, int a_MinBlockX, int a_MinBlockY, int a_MinBlockZ, int a_DataTypes);
diff --git a/src/ClientHandle.cpp b/src/ClientHandle.cpp
index 93ade0ac4..a0a77f522 100644
--- a/src/ClientHandle.cpp
+++ b/src/ClientHandle.cpp
@@ -722,9 +722,10 @@ bool cClientHandle::HandleLogin(const AString & a_Username)
 		// Let the plugins know about this event, they may refuse the player:
 		if (cRoot::Get()->GetPluginManager()->CallHookLogin(*this, m_ProtocolVersion, a_Username))
 		{
-			Destroy();
+			SendDisconnect("Login Rejected!");
 			return false;
 		}
+
 		m_State = csAuthenticating;
 	}  // lock(m_CSState)
 
@@ -1659,9 +1660,9 @@ void cClientHandle::HandleSlotSelected(Int16 a_SlotNum)
 
 void cClientHandle::HandleSpectate(const cUUID & a_PlayerUUID)
 {
-	m_Player->GetWorld()->DoWithPlayerByUUID(a_PlayerUUID, [=](cPlayer * a_ToSpectate)
+	m_Player->GetWorld()->DoWithPlayerByUUID(a_PlayerUUID, [=](cPlayer & a_ToSpectate)
 	{
-		m_Player->TeleportToEntity(*a_ToSpectate);
+		m_Player->TeleportToEntity(a_ToSpectate);
 		return true;
 	});
 }
@@ -1733,9 +1734,9 @@ void cClientHandle::HandleUseEntity(UInt32 a_TargetEntityID, bool a_IsLeftClick)
 	// If the player is a spectator, let him spectate
 	if (m_Player->IsGameModeSpectator() && a_IsLeftClick)
 	{
-		m_Player->GetWorld()->DoWithEntityByID(a_TargetEntityID, [=](cEntity * a_Entity)
+		m_Player->GetWorld()->DoWithEntityByID(a_TargetEntityID, [=](cEntity & a_Entity)
 		{
-			m_Player->AttachTo(a_Entity);
+			m_Player->AttachTo(&a_Entity);
 			return true;
 		});
 		return;
@@ -1744,20 +1745,18 @@ void cClientHandle::HandleUseEntity(UInt32 a_TargetEntityID, bool a_IsLeftClick)
 	// If it is a right click, call the entity's OnRightClicked() handler:
 	if (!a_IsLeftClick)
 	{
-		class cRclkEntity : public cEntityCallback
-		{
-			cPlayer & m_Player;
-			virtual bool Item(cEntity * a_Entity) override
+		cWorld * World = m_Player->GetWorld();
+		World->DoWithEntityByID(a_TargetEntityID, [=](cEntity & a_Entity)
 			{
 				if (
-					cPluginManager::Get()->CallHookPlayerRightClickingEntity(m_Player, *a_Entity) ||
+					cPluginManager::Get()->CallHookPlayerRightClickingEntity(*m_Player, a_Entity) ||
 					(
-						m_Player.IsGameModeSpectator() &&  // Spectators cannot interact with every entity
+						m_Player->IsGameModeSpectator() &&  // Spectators cannot interact with every entity
 						(
-							!a_Entity->IsMinecart() ||  // They can only interact with minecarts
+							!a_Entity.IsMinecart() ||  // They can only interact with minecarts
 							(
-								(reinterpret_cast<cMinecart *>(a_Entity)->GetPayload() != cMinecart::mpChest) &&  // And only if the type matches a minecart with a chest or
-								(reinterpret_cast<cMinecart *>(a_Entity)->GetPayload() != cMinecart::mpHopper)    // a minecart with a hopper
+								(static_cast<cMinecart &>(a_Entity).GetPayload() != cMinecart::mpChest) &&  // And only if the type matches a minecart with a chest or
+								(static_cast<cMinecart &>(a_Entity).GetPayload() != cMinecart::mpHopper)    // a minecart with a hopper
 							)
 						)
 					)
@@ -1765,52 +1764,34 @@ void cClientHandle::HandleUseEntity(UInt32 a_TargetEntityID, bool a_IsLeftClick)
 				{
 					return false;
 				}
-				a_Entity->OnRightClicked(m_Player);
+				a_Entity.OnRightClicked(*m_Player);
 				return false;
 			}
-		public:
-			cRclkEntity(cPlayer & a_Player) : m_Player(a_Player) {}
-		} Callback (*m_Player);
-
-		cWorld * World = m_Player->GetWorld();
-		World->DoWithEntityByID(a_TargetEntityID, Callback);
+		);
 		return;
 	}
 
 	// If it is a left click, attack the entity:
-	class cDamageEntity : public cEntityCallback
-	{
-	public:
-		cPlayer * m_Me;
-
-		cDamageEntity(cPlayer * a_Player) :
-			m_Me(a_Player)
+	m_Player->GetWorld()->DoWithEntityByID(a_TargetEntityID, [=](cEntity & a_Entity)
 		{
-		}
-
-		virtual bool Item(cEntity * a_Entity) override
-		{
-			if (!a_Entity->GetWorld()->IsPVPEnabled())
+			if (!a_Entity.GetWorld()->IsPVPEnabled())
 			{
 				// PVP is disabled, disallow players hurting other players:
-				if (a_Entity->IsPlayer())
+				if (a_Entity.IsPlayer())
 				{
 					// Player is hurting another player which is not allowed when PVP is disabled so ignore it
 					return true;
 				}
 			}
-			a_Entity->TakeDamage(*m_Me);
-			m_Me->AddFoodExhaustion(0.3);
-			if (a_Entity->IsPawn())
+			a_Entity.TakeDamage(*m_Player);
+			m_Player->AddFoodExhaustion(0.3);
+			if (a_Entity.IsPawn())
 			{
-				m_Me->NotifyNearbyWolves(static_cast<cPawn*>(a_Entity), true);
+				m_Player->NotifyNearbyWolves(static_cast<cPawn*>(&a_Entity), true);
 			}
 			return true;
 		}
-	} Callback(m_Player);
-
-	cWorld * World = m_Player->GetWorld();
-	World->DoWithEntityByID(a_TargetEntityID, Callback);
+	);
 }
 
 
@@ -1859,17 +1840,8 @@ bool cClientHandle::CheckMultiLogin(const AString & a_Username)
 		return false;
 	}
 
-	class cCallback :
-		public cPlayerListCallback
-	{
-		virtual bool Item(cPlayer * a_Player) override
-		{
-			return true;
-		}
-	} Callback;
-
 	// Check if the player is in any World.
-	if (cRoot::Get()->DoWithPlayer(a_Username, Callback))
+	if (cRoot::Get()->DoWithPlayer(a_Username, [](cPlayer &) { return true; }))
 	{
 		Kick("A player of the username is already logged in");
 		return false;
diff --git a/src/DeadlockDetect.cpp b/src/DeadlockDetect.cpp
index df14e610b..411d452f6 100644
--- a/src/DeadlockDetect.cpp
+++ b/src/DeadlockDetect.cpp
@@ -56,25 +56,12 @@ bool cDeadlockDetect::Start(int a_IntervalSec)
 	m_IntervalSec = a_IntervalSec;
 
 	// Read the initial world data:
-	class cFillIn :
-		public cWorldListCallback
-	{
-	public:
-		cFillIn(cDeadlockDetect * a_Detect) :
-			m_Detect(a_Detect)
-		{
-		}
-
-		virtual bool Item(cWorld * a_World) override
+	cRoot::Get()->ForEachWorld([=](cWorld & a_World)
 		{
-			m_Detect->SetWorldAge(a_World->GetName(), a_World->GetWorldAge());
+			SetWorldAge(a_World.GetName(), a_World.GetWorldAge());
 			return false;
 		}
-
-	protected:
-		cDeadlockDetect * m_Detect;
-	} FillIn(this);
-	cRoot::Get()->ForEachWorld(FillIn);
+	);
 	return super::Start();
 }
 
@@ -115,25 +102,12 @@ void cDeadlockDetect::Execute(void)
 	while (!m_ShouldTerminate)
 	{
 		// Check the world ages:
-		class cChecker :
-			public cWorldListCallback
-		{
-		public:
-			cChecker(cDeadlockDetect * a_Detect) :
-				m_Detect(a_Detect)
-			{
-			}
-
-		protected:
-			cDeadlockDetect * m_Detect;
-
-			virtual bool Item(cWorld * a_World) override
+		cRoot::Get()->ForEachWorld([=](cWorld & a_World)
 			{
-				m_Detect->CheckWorldAge(a_World->GetName(), a_World->GetWorldAge());
+				CheckWorldAge(a_World.GetName(), a_World.GetWorldAge());
 				return false;
 			}
-		} Checker(this);
-		cRoot::Get()->ForEachWorld(Checker);
+		);
 
 		std::this_thread::sleep_for(std::chrono::milliseconds(CYCLE_MILLISECONDS));
 	}  // while (should run)
diff --git a/src/Entities/Entity.cpp b/src/Entities/Entity.cpp
index 38443793e..956534856 100644
--- a/src/Entities/Entity.cpp
+++ b/src/Entities/Entity.cpp
@@ -306,38 +306,22 @@ void cEntity::TakeDamage(eDamageType a_DamageType, cEntity * a_Attacker, int a_R
 
 void cEntity::TakeDamage(eDamageType a_DamageType, UInt32 a_AttackerID, int a_RawDamage, double a_KnockbackAmount)
 {
-	class cFindEntity : public cEntityCallback
-	{
-	public:
-
-		cEntity * m_Entity;
-		eDamageType m_DamageType;
-		int m_RawDamage;
-		double m_KnockbackAmount;
-
-		virtual bool Item(cEntity * a_Attacker) override
+	m_World->DoWithEntityByID(a_AttackerID, [=](cEntity & a_Attacker)
 		{
 			cPawn * Attacker;
-			if (a_Attacker->IsPawn())
+			if (a_Attacker.IsPawn())
 			{
-				Attacker = static_cast<cPawn*>(a_Attacker);
+				Attacker = static_cast<cPawn*>(&a_Attacker);
 			}
 			else
 			{
 				Attacker = nullptr;
 			}
 
-
-			m_Entity->TakeDamage(m_DamageType, Attacker, m_RawDamage, m_KnockbackAmount);
+			TakeDamage(a_DamageType, Attacker, a_RawDamage, a_KnockbackAmount);
 			return true;
 		}
-	} Callback;
-
-	Callback.m_Entity = this;
-	Callback.m_DamageType = a_DamageType;
-	Callback.m_RawDamage = a_RawDamage;
-	Callback.m_KnockbackAmount = a_KnockbackAmount;
-	m_World->DoWithEntityByID(a_AttackerID, Callback);
+	);
 }
 
 
@@ -668,7 +652,7 @@ bool cEntity::ArmorCoversAgainst(eDamageType a_DamageType)
 
 int cEntity::GetEnchantmentCoverAgainst(const cEntity * a_Attacker, eDamageType a_DamageType, int a_Damage)
 {
-	int TotalEPF = 0.0;
+	int TotalEPF = 0;
 
 	const cItem ArmorItems[] = { GetEquippedHelmet(), GetEquippedChestplate(), GetEquippedLeggings(), GetEquippedBoots() };
 	for (size_t i = 0; i < ARRAYCOUNT(ArmorItems); i++)
@@ -1684,7 +1668,8 @@ void cEntity::SetSwimState(cChunk & a_Chunk)
 	m_IsSwimming = IsBlockWater(BlockIn);
 
 	// Check if the player is submerged:
-	VERIFY(a_Chunk.UnboundedRelGetBlockType(RelX, RelY + 1, RelZ, BlockIn));
+	int HeadHeight = CeilC(GetPosY() + GetHeight()) - 1;
+	VERIFY(a_Chunk.UnboundedRelGetBlockType(RelX, HeadHeight, RelZ, BlockIn));
 	m_IsSubmerged = IsBlockWater(BlockIn);
 }
 
@@ -1716,7 +1701,7 @@ void cEntity::DoSetSpeed(double a_SpeedX, double a_SpeedY, double a_SpeedZ)
 void cEntity::HandleAir(void)
 {
 	// Ref.: https://minecraft.gamepedia.com/Chunk_format
-	// See if the entity is /submerged/ water (block above is water)
+	// See if the entity is /submerged/ water (head is in water)
 	// Get the type of block the entity is standing in:
 
 	int RespirationLevel = static_cast<int>(GetEquippedHelmet().m_Enchantments.GetLevel(cEnchantments::enchRespiration));
diff --git a/src/Entities/Floater.cpp b/src/Entities/Floater.cpp
index eeaa6cf3d..de5824068 100644
--- a/src/Entities/Floater.cpp
+++ b/src/Entities/Floater.cpp
@@ -13,8 +13,7 @@
 
 ////////////////////////////////////////////////////////////////////////////////
 // cFloaterEntityCollisionCallback
-class cFloaterEntityCollisionCallback :
-	public cEntityCallback
+class cFloaterEntityCollisionCallback
 {
 public:
 	cFloaterEntityCollisionCallback(cFloater * a_Floater, const Vector3d & a_Pos, const Vector3d & a_NextPos) :
@@ -25,14 +24,14 @@ public:
 		m_HitEntity(nullptr)
 	{
 	}
-	virtual bool Item(cEntity * a_Entity) override
+	bool operator () (cEntity & a_Entity)
 	{
-		if (!a_Entity->IsMob())  // Floaters can only pull mobs not other entities.
+		if (!a_Entity.IsMob())  // Floaters can only pull mobs not other entities.
 		{
 			return false;
 		}
 
-		cBoundingBox EntBox(a_Entity->GetPosition(), a_Entity->GetWidth() / 2, a_Entity->GetHeight());
+		cBoundingBox EntBox(a_Entity.GetPosition(), a_Entity.GetWidth() / 2, a_Entity.GetHeight());
 
 		double LineCoeff;
 		eBlockFace Face;
@@ -47,7 +46,7 @@ public:
 		{
 			// The entity is closer than anything we've stored so far, replace it as the potential victim
 			m_MinCoeff = LineCoeff;
-			m_HitEntity = a_Entity;
+			m_HitEntity = &a_Entity;
 		}
 
 		// Don't break the enumeration, we want all the entities
@@ -75,32 +74,6 @@ protected:
 
 
 
-////////////////////////////////////////////////////////////////////////////////
-// cFloaterCheckEntityExist
-class cFloaterCheckEntityExist :
-	public cEntityCallback
-{
-public:
-	cFloaterCheckEntityExist(void) :
-		m_EntityExists(false)
-	{
-	}
-
-	bool Item(cEntity * a_Entity) override
-	{
-		m_EntityExists = true;
-		return false;
-	}
-
-	bool DoesExist(void) const { return m_EntityExists; }
-protected:
-	bool m_EntityExists;
-} ;
-
-
-
-
-
 cFloater::cFloater(double a_X, double a_Y, double a_Z, Vector3d a_Speed, UInt32 a_PlayerID, int a_CountDownTime) :
 	cEntity(etFloater, a_X, a_Y, a_Z, 0.2, 0.2),
 	m_BitePos(Vector3d(a_X, a_Y, a_Z)),
@@ -200,18 +173,16 @@ void cFloater::Tick(std::chrono::milliseconds a_Dt, cChunk & a_Chunk)
 		}
 	}
 
-	cFloaterCheckEntityExist EntityCallback;
-	m_World->DoWithEntityByID(m_PlayerID, EntityCallback);
-	if (!EntityCallback.DoesExist())  // The owner doesn't exist anymore. Destroy the floater entity.
+	if (!m_World->DoWithEntityByID(m_PlayerID, [](cEntity &) { return true; }))  // The owner doesn't exist anymore. Destroy the floater entity.
 	{
 		Destroy(true);
 	}
 
 	if (m_AttachedMobID != cEntity::INVALID_ID)
 	{
-		m_World->DoWithEntityByID(m_AttachedMobID, EntityCallback);  // The mob the floater was attached to doesn't exist anymore.
-		if (!EntityCallback.DoesExist())
+		if (!m_World->DoWithEntityByID(m_AttachedMobID, [](cEntity &) { return true; }))
 		{
+			// The mob the floater was attached to doesn't exist anymore.
 			m_AttachedMobID = cEntity::INVALID_ID;
 		}
 	}
diff --git a/src/Entities/LeashKnot.cpp b/src/Entities/LeashKnot.cpp
index a86dc9d53..51002531d 100644
--- a/src/Entities/LeashKnot.cpp
+++ b/src/Entities/LeashKnot.cpp
@@ -1,4 +1,4 @@
-
+
 #include "Globals.h"  // NOTE: MSVC stupidness requires this to be the same across all modules
 
 #include "LeashKnot.h"
@@ -38,58 +38,42 @@ void cLeashKnot::OnRightClicked(cPlayer & a_Player)
 
 
 
-void cLeashKnot::TiePlayersLeashedMobs(cPlayer & a_Player, bool a_ShouldBroadCast)
+void cLeashKnot::TiePlayersLeashedMobs(cPlayer & a_Player, bool a_ShouldBroadcast)
 {
 	// Check leashed nearby mobs to tie them to this knot
-	class LookForLeasheds : public cEntityCallback
-	{
-	public:
-		cLeashKnot * m_Knot;
-		cPlayer * m_Player;
-		bool m_ShouldBroadcast;
-
-		LookForLeasheds(cLeashKnot * a_Knot, cPlayer * a_PlayerLeashedTo, bool a_ShouldBroadcast) :
-			m_Knot(a_Knot),
-			m_Player(a_PlayerLeashedTo),
-			m_ShouldBroadcast(a_ShouldBroadcast)
-		{
-		}
-
-		virtual bool Item(cEntity * a_Entity) override
+	// taking world from player (instead from this) because this can be called before entity was initialized
+	a_Player.GetWorld()->ForEachEntityInBox(cBoundingBox(GetPosition(), 8, 8, -4), [&](cEntity & a_Entity)
 		{
 			// If the entity is not a monster skip it
-			if (a_Entity->GetEntityType() != cEntity::eEntityType::etMonster)
+			if (a_Entity.GetEntityType() != cEntity::eEntityType::etMonster)
 			{
 				return false;
 			}
 
-			cMonster * PotentialLeashed = static_cast<cMonster*>(a_Entity);
+			auto & PotentialLeashed = static_cast<cMonster&>(a_Entity);
 
 			// If can't be leashed skip it
-			if (!PotentialLeashed->CanBeLeashed())
+			if (!PotentialLeashed.CanBeLeashed())
 			{
 				return false;
 			}
 
 			// If it's not leashed to the player skip it
 			if (
-				!PotentialLeashed->IsLeashed() ||
-				!PotentialLeashed->GetLeashedTo()->IsPlayer() ||
-				(PotentialLeashed->GetLeashedTo()->GetUniqueID() != m_Player->GetUniqueID())
+				!PotentialLeashed.IsLeashed() ||
+				!PotentialLeashed.GetLeashedTo()->IsPlayer() ||
+				(PotentialLeashed.GetLeashedTo()->GetUniqueID() != a_Player.GetUniqueID())
 			)
 			{
 				return false;
 			}
 
 			// All conditions met, unleash from player and leash to fence
-			PotentialLeashed->Unleash(false, false);
-			PotentialLeashed->LeashTo(*m_Knot, m_ShouldBroadcast);
+			PotentialLeashed.Unleash(false, false);
+			PotentialLeashed.LeashTo(*this, a_ShouldBroadcast);
 			return false;
 		}
-	} LookForLeashedsCallback(this, &a_Player, a_ShouldBroadCast);
-
-	// taking world from player (instead from this) because this can be called before entity was initialized
-	a_Player.GetWorld()->ForEachEntityInBox(cBoundingBox(GetPosition(), 8, 8, -4), LookForLeashedsCallback);
+	);
 }
 
 
@@ -158,26 +142,19 @@ void cLeashKnot::Tick(std::chrono::milliseconds a_Dt, cChunk & a_Chunk)
 
 cLeashKnot * cLeashKnot::FindKnotAtPos(cWorldInterface & a_WorldInterface, Vector3i a_BlockPos)
 {
-	class LookForKnot : public cEntityCallback
-	{
-	public:
-		cLeashKnot * m_LeashKnot = nullptr;
-
-		virtual bool Item(cEntity * a_Entity) override
+	cLeashKnot * LeashKnot = nullptr;
+	a_WorldInterface.ForEachEntityInBox(cBoundingBox(a_BlockPos, 0.5, 1), [&](cEntity & a_Entity)
 		{
-			if (a_Entity->IsLeashKnot())
+			if (a_Entity.IsLeashKnot())
 			{
-				m_LeashKnot = reinterpret_cast<cLeashKnot *>(a_Entity);
+				LeashKnot = static_cast<cLeashKnot *>(&a_Entity);
 				return true;
 			}
 			return false;
 		}
+	);
 
-	} CallbackFindKnot;
-
-	a_WorldInterface.ForEachEntityInBox(cBoundingBox(a_BlockPos, 0.5, 1), CallbackFindKnot);
-
-	return CallbackFindKnot.m_LeashKnot;
+	return LeashKnot;
 }
 
 
diff --git a/src/Entities/Minecart.cpp b/src/Entities/Minecart.cpp
index 7f32dc910..8921f8894 100644
--- a/src/Entities/Minecart.cpp
+++ b/src/Entities/Minecart.cpp
@@ -20,8 +20,7 @@
 
 
 
-class cMinecartCollisionCallback :
-	public cEntityCallback
+class cMinecartCollisionCallback
 {
 public:
 	cMinecartCollisionCallback(Vector3d a_Pos, double a_Height, double a_Width, UInt32 a_UniqueID, UInt32 a_AttacheeUniqueID) :
@@ -35,33 +34,31 @@ public:
 	{
 	}
 
-	virtual bool Item(cEntity * a_Entity) override
+	bool operator () (cEntity & a_Entity)
 	{
-		ASSERT(a_Entity != nullptr);
-
 		if (
 			(
-				!a_Entity->IsPlayer() ||
-				reinterpret_cast<cPlayer *>(a_Entity)->IsGameModeSpectator()  // Spectators doesn't collide with anything
+				!a_Entity.IsPlayer() ||
+				static_cast<cPlayer &>(a_Entity).IsGameModeSpectator()  // Spectators doesn't collide with anything
 			) &&
-			!a_Entity->IsMob() &&
-			!a_Entity->IsMinecart() &&
-			!a_Entity->IsBoat()
+			!a_Entity.IsMob() &&
+			!a_Entity.IsMinecart() &&
+			!a_Entity.IsBoat()
 		)
 		{
 			return false;
 		}
-		else if ((a_Entity->GetUniqueID() == m_UniqueID) || (a_Entity->GetUniqueID() == m_AttacheeUniqueID))
+		else if ((a_Entity.GetUniqueID() == m_UniqueID) || (a_Entity.GetUniqueID() == m_AttacheeUniqueID))
 		{
 			return false;
 		}
 
-		cBoundingBox bbEntity(a_Entity->GetPosition(), a_Entity->GetWidth() / 2, a_Entity->GetHeight());
+		cBoundingBox bbEntity(a_Entity.GetPosition(), a_Entity.GetWidth() / 2, a_Entity.GetHeight());
 		cBoundingBox bbMinecart(Vector3d(m_Pos.x, floor(m_Pos.y), m_Pos.z), m_Width / 2, m_Height);
 
 		if (bbEntity.DoesIntersect(bbMinecart))
 		{
-			m_CollidedEntityPos = a_Entity->GetPosition();
+			m_CollidedEntityPos = a_Entity.GetPosition();
 			m_DoesIntersect = true;
 			return true;
 		}
diff --git a/src/Entities/Pawn.cpp b/src/Entities/Pawn.cpp
index 0fa11997b..ac8e4b1ab 100644
--- a/src/Entities/Pawn.cpp
+++ b/src/Entities/Pawn.cpp
@@ -1,4 +1,4 @@
-
+
 #include "Globals.h"  // NOTE: MSVC stupidness requires this to be the same across all modules
 
 #include "Pawn.h"
@@ -79,49 +79,37 @@ void cPawn::Tick(std::chrono::milliseconds a_Dt, cChunk & a_Chunk)
 		Effect->OnTick(*this);
 	}
 
-	class Pusher : public cEntityCallback
+	// Spectators cannot push entities around
+	if ((!IsPlayer()) || (!static_cast<cPlayer *>(this)->IsGameModeSpectator()))
 	{
-	public:
-		cEntity * m_Pusher;
-
-		Pusher(cEntity * a_Pusher) :
-			m_Pusher(a_Pusher)
-		{
-		}
-
-		virtual bool Item(cEntity * a_Entity) override
-		{
-			if (a_Entity->GetUniqueID() == m_Pusher->GetUniqueID())
-			{
-				return false;
-			}
-
-			// we only push other mobs, boats and minecarts
-			if ((a_Entity->GetEntityType() != etMonster) && (a_Entity->GetEntityType() != etMinecart) && (a_Entity->GetEntityType() != etBoat))
+		m_World->ForEachEntityInBox(cBoundingBox(GetPosition(), GetWidth(), GetHeight()), [=](cEntity & a_Entity)
 			{
+				if (a_Entity.GetUniqueID() == GetUniqueID())
+				{
+					return false;
+				}
+
+				// we only push other mobs, boats and minecarts
+				if ((a_Entity.GetEntityType() != etMonster) && (a_Entity.GetEntityType() != etMinecart) && (a_Entity.GetEntityType() != etBoat))
+				{
+					return false;
+				}
+
+				// do not push a boat / minecart you're sitting in
+				if (IsAttachedTo(&a_Entity))
+				{
+					return false;
+				}
+
+				Vector3d v3Delta = a_Entity.GetPosition() - GetPosition();
+				v3Delta.y = 0.0;  // we only push sideways
+				v3Delta *= 1.0 / (v3Delta.Length() + 0.01);  // we push harder if we're close
+				// QUESTION: is there an additional multiplier for this? current shoving seems a bit weak
+
+				a_Entity.AddSpeed(v3Delta);
 				return false;
 			}
-
-			// do not push a boat / minecart you're sitting in
-			if (m_Pusher->IsAttachedTo(a_Entity))
-			{
-				return false;
-			}
-
-			Vector3d v3Delta = a_Entity->GetPosition() - m_Pusher->GetPosition();
-			v3Delta.y = 0.0;  // we only push sideways
-			v3Delta *= 1.0 / (v3Delta.Length() + 0.01);  // we push harder if we're close
-			// QUESTION: is there an additional multiplier for this? current shoving seems a bit weak
-
-			a_Entity->AddSpeed(v3Delta);
-			return false;
-		}
-	} Callback(this);
-
-	// Spectators cannot push entities around
-	if ((!IsPlayer()) || (!reinterpret_cast<cPlayer *>(this)->IsGameModeSpectator()))
-	{
-		m_World->ForEachEntityInBox(cBoundingBox(GetPosition(), GetWidth(), GetHeight()), Callback);
+		);
 	}
 
 	super::Tick(a_Dt, a_Chunk);
diff --git a/src/Entities/Pickup.cpp b/src/Entities/Pickup.cpp
index 0c6c8feab..fcae586f6 100644
--- a/src/Entities/Pickup.cpp
+++ b/src/Entities/Pickup.cpp
@@ -17,8 +17,7 @@
 
 
 
-class cPickupCombiningCallback :
-	public cEntityCallback
+class cPickupCombiningCallback
 {
 public:
 	cPickupCombiningCallback(Vector3d a_Position, cPickup * a_Pickup) :
@@ -28,21 +27,21 @@ public:
 	{
 	}
 
-	virtual bool Item(cEntity * a_Entity) override
+	bool operator () (cEntity & a_Entity)
 	{
-		ASSERT(a_Entity->IsTicking());
-		if (!a_Entity->IsPickup() || (a_Entity->GetUniqueID() <= m_Pickup->GetUniqueID()) || !a_Entity->IsOnGround())
+		ASSERT(a_Entity.IsTicking());
+		if (!a_Entity.IsPickup() || (a_Entity.GetUniqueID() <= m_Pickup->GetUniqueID()) || !a_Entity.IsOnGround())
 		{
 			return false;
 		}
 
 
-		Vector3d EntityPos = a_Entity->GetPosition();
+		Vector3d EntityPos = a_Entity.GetPosition();
 		double Distance = (EntityPos - m_Position).Length();
 
-		cPickup * OtherPickup = static_cast<cPickup *>(a_Entity);
-		cItem & Item = OtherPickup->GetItem();
-		if ((Distance < 1.2) && Item.IsEqual(m_Pickup->GetItem()) && OtherPickup->CanCombine())
+		auto & OtherPickup = static_cast<cPickup &>(a_Entity);
+		cItem & Item = OtherPickup.GetItem();
+		if ((Distance < 1.2) && Item.IsEqual(m_Pickup->GetItem()) && OtherPickup.CanCombine())
 		{
 			short CombineCount = Item.m_ItemCount;
 			if ((CombineCount + m_Pickup->GetItem().m_ItemCount) > Item.GetMaxStackSize())
@@ -64,16 +63,16 @@ public:
 				int DiffX = FloorC(m_Pickup->GetPosX() * 32.0) - FloorC(EntityPos.x * 32.0);
 				int DiffY = FloorC(m_Pickup->GetPosY() * 32.0) - FloorC(EntityPos.y * 32.0);
 				int DiffZ = FloorC(m_Pickup->GetPosZ() * 32.0) - FloorC(EntityPos.z * 32.0);
-				a_Entity->GetWorld()->BroadcastEntityRelMove(*a_Entity, static_cast<char>(DiffX), static_cast<char>(DiffY), static_cast<char>(DiffZ));
+				a_Entity.GetWorld()->BroadcastEntityRelMove(a_Entity, static_cast<char>(DiffX), static_cast<char>(DiffY), static_cast<char>(DiffZ));
 				/* End of experimental animation */
-				a_Entity->Destroy();
+				a_Entity.Destroy();
 
 				// Reset the timer
 				m_Pickup->SetAge(0);
 			}
 			else
 			{
-				a_Entity->GetWorld()->BroadcastEntityMetadata(*a_Entity);
+				a_Entity.GetWorld()->BroadcastEntityMetadata(a_Entity);
 			}
 			m_FoundMatchingPickup = true;
 		}
diff --git a/src/Entities/Player.cpp b/src/Entities/Player.cpp
index 4189841b8..f17d53b42 100644
--- a/src/Entities/Player.cpp
+++ b/src/Entities/Player.cpp
@@ -1005,36 +1005,21 @@ bool cPlayer::DoTakeDamage(TakeDamageInfo & a_TDI)
 void cPlayer::NotifyNearbyWolves(cPawn * a_Opponent, bool a_IsPlayerInvolved)
 {
 	ASSERT(a_Opponent != nullptr);
-	class LookForWolves : public cEntityCallback
-	{
-	public:
-		cPlayer * m_Player;
-		cPawn * m_Attacker;
-		bool m_IsPlayerInvolved;
-
-		LookForWolves(cPlayer * a_Me, cPawn * a_MyAttacker, bool a_PlayerInvolved) :
-			m_Player(a_Me),
-			m_Attacker(a_MyAttacker),
-			m_IsPlayerInvolved(a_PlayerInvolved)
-		{
-		}
 
-		virtual bool Item(cEntity * a_Entity) override
+	m_World->ForEachEntityInBox(cBoundingBox(GetPosition(), 16), [&] (cEntity & a_Entity)
 		{
-			if (a_Entity->IsMob())
+			if (a_Entity.IsMob())
 			{
-				cMonster * Mob = static_cast<cMonster*>(a_Entity);
-				if (Mob->GetMobType() == mtWolf)
+				auto & Mob = static_cast<cMonster&>(a_Entity);
+				if (Mob.GetMobType() == mtWolf)
 				{
-					cWolf * Wolf = static_cast<cWolf*>(Mob);
-					Wolf->ReceiveNearbyFightInfo(m_Player->GetUUID(), m_Attacker, m_IsPlayerInvolved);
+					auto & Wolf = static_cast<cWolf&>(Mob);
+					Wolf.ReceiveNearbyFightInfo(GetUUID(), a_Opponent, a_IsPlayerInvolved);
 				}
 			}
 			return false;
 		}
-	} Callback(this, a_Opponent, a_IsPlayerInvolved);
-
-	m_World->ForEachEntityInBox(cBoundingBox(GetPosition(), 16), Callback);
+	);
 }
 
 
@@ -2432,17 +2417,12 @@ void cPlayer::HandleFloater()
 	{
 		return;
 	}
-	class cFloaterCallback :
-		public cEntityCallback
-	{
-	public:
-		virtual bool Item(cEntity * a_Entity) override
+	m_World->DoWithEntityByID(m_FloaterID, [](cEntity & a_Entity)
 		{
-			a_Entity->Destroy(true);
+			a_Entity.Destroy(true);
 			return true;
 		}
-	} Callback;
-	m_World->DoWithEntityByID(m_FloaterID, Callback);
+	);
 	SetIsFishing(false);
 }
 
@@ -2686,29 +2666,18 @@ bool cPlayer::DoesPlacingBlocksIntersectEntity(const sSetBlockVector & a_Blocks)
 	cWorld * World = GetWorld();
 
 	// Check to see if any entity intersects any block being placed
-	class DoesIntersectBlock : public cEntityCallback
-	{
-	public:
-		const std::vector<cBoundingBox> & m_BoundingBoxes;
-
-		// The distance inside the block the entity can still be.
-		const double EPSILON = 0.0005;
-
-		DoesIntersectBlock(const std::vector<cBoundingBox> & a_BoundingBoxes) :
-			m_BoundingBoxes(a_BoundingBoxes)
+	return !World->ForEachEntityInBox(PlacingBounds, [&](cEntity & a_Entity)
 		{
-		}
+			// The distance inside the block the entity can still be.
+			const double EPSILON = 0.0005;
 
-		virtual bool Item(cEntity * a_Entity) override
-		{
-			if (!a_Entity->DoesPreventBlockPlacement())
+			if (!a_Entity.DoesPreventBlockPlacement())
 			{
 				return false;
 			}
-			cBoundingBox EntBox(a_Entity->GetPosition(), a_Entity->GetWidth() / 2, a_Entity->GetHeight());
-			for (auto BlockBox: m_BoundingBoxes)
+			cBoundingBox EntBox(a_Entity.GetPosition(), a_Entity.GetWidth() / 2, a_Entity.GetHeight());
+			for (auto BlockBox : PlacementBoxes)
 			{
-
 				// Put in a little bit of wiggle room
 				BlockBox.Expand(-EPSILON, -EPSILON, -EPSILON);
 				if (EntBox.DoesIntersect(BlockBox))
@@ -2718,15 +2687,7 @@ bool cPlayer::DoesPlacingBlocksIntersectEntity(const sSetBlockVector & a_Blocks)
 			}
 			return false;
 		}
-	} Callback(PlacementBoxes);
-
-	// See if any entities in that bounding box collide with anyone
-	if (!World->ForEachEntityInBox(PlacingBounds, Callback))
-	{
-		return true;
-	}
-
-	return false;
+	);
 }
 
 
diff --git a/src/Entities/ProjectileEntity.cpp b/src/Entities/ProjectileEntity.cpp
index c2a1f782d..13ebe31bc 100644
--- a/src/Entities/ProjectileEntity.cpp
+++ b/src/Entities/ProjectileEntity.cpp
@@ -126,8 +126,7 @@ protected:
 ////////////////////////////////////////////////////////////////////////////////
 // cProjectileEntityCollisionCallback:
 
-class cProjectileEntityCollisionCallback :
-	public cEntityCallback
+class cProjectileEntityCollisionCallback
 {
 public:
 	cProjectileEntityCollisionCallback(cProjectileEntity * a_Projectile, const Vector3d & a_Pos, const Vector3d & a_NextPos) :
@@ -140,11 +139,11 @@ public:
 	}
 
 
-	virtual bool Item(cEntity * a_Entity) override
+	bool operator () (cEntity & a_Entity)
 	{
 		if (
-			(a_Entity == m_Projectile) ||          // Do not check collisions with self
-			(a_Entity->GetUniqueID() == m_Projectile->GetCreatorUniqueID())  // Do not check whoever shot the projectile
+			(&a_Entity == m_Projectile) ||          // Do not check collisions with self
+			(a_Entity.GetUniqueID() == m_Projectile->GetCreatorUniqueID())  // Do not check whoever shot the projectile
 		)
 		{
 			// Don't check creator only for the first 5 ticks so that projectiles can collide with the creator
@@ -154,7 +153,7 @@ public:
 			}
 		}
 
-		cBoundingBox EntBox(a_Entity->GetPosition(), a_Entity->GetWidth() / 2, a_Entity->GetHeight());
+		cBoundingBox EntBox(a_Entity.GetPosition(), a_Entity.GetWidth() / 2, a_Entity.GetHeight());
 
 		// Instead of colliding the bounding box with another bounding box in motion, we collide an enlarged bounding box with a hairline.
 		// The results should be good enough for our purposes
@@ -168,20 +167,20 @@ public:
 		}
 
 		if (
-			!a_Entity->IsMob() &&
-			!a_Entity->IsMinecart() &&
+			!a_Entity.IsMob() &&
+			!a_Entity.IsMinecart() &&
 			(
-				!a_Entity->IsPlayer() ||
-				static_cast<cPlayer *>(a_Entity)->IsGameModeSpectator()
+				!a_Entity.IsPlayer() ||
+				static_cast<cPlayer &>(a_Entity).IsGameModeSpectator()
 			) &&
-			!a_Entity->IsBoat()
+			!a_Entity.IsBoat()
 		)
 		{
 			// Not an entity that interacts with a projectile
 			return false;
 		}
 
-		if (cPluginManager::Get()->CallHookProjectileHitEntity(*m_Projectile, *a_Entity))
+		if (cPluginManager::Get()->CallHookProjectileHitEntity(*m_Projectile, a_Entity))
 		{
 			// A plugin disagreed.
 			return false;
@@ -191,7 +190,7 @@ public:
 		{
 			// The entity is closer than anything we've stored so far, replace it as the potential victim
 			m_MinCoeff = LineCoeff;
-			m_HitEntity = a_Entity;
+			m_HitEntity = &a_Entity;
 		}
 
 		// Don't break the enumeration, we want all the entities
@@ -327,20 +326,13 @@ void cProjectileEntity::OnHitEntity(cEntity & a_EntityHit, const Vector3d & a_Hi
 	// If we were created by a player and we hit a pawn, notify attacking player's wolves
 	if (a_EntityHit.IsPawn() && (GetCreatorName() != ""))
 	{
-		class cNotifyWolves : public cEntityCallback
-		{
-		public:
-			cPawn * m_EntityHit;
-
-			virtual bool Item(cEntity * a_Hitter) override
+		auto EntityHit = static_cast<cPawn *>(&a_EntityHit);
+		m_World->DoWithEntityByID(GetCreatorUniqueID(), [=](cEntity & a_Hitter)
 			{
-				static_cast<cPlayer*>(a_Hitter)->NotifyNearbyWolves(m_EntityHit, true);
+				static_cast<cPlayer&>(a_Hitter).NotifyNearbyWolves(EntityHit, true);
 				return true;
 			}
-		} Callback;
-
-		Callback.m_EntityHit = static_cast<cPawn*>(&a_EntityHit);
-		m_World->DoWithEntityByID(GetCreatorUniqueID(), Callback);
+		);
 	}
 }
 
diff --git a/src/Entities/SplashPotionEntity.cpp b/src/Entities/SplashPotionEntity.cpp
index af4008e83..35afe0fea 100644
--- a/src/Entities/SplashPotionEntity.cpp
+++ b/src/Entities/SplashPotionEntity.cpp
@@ -17,60 +17,6 @@
 
 
 ////////////////////////////////////////////////////////////////////////////////
-// cSplashPotionEntityCallback:
-
-/** Used to distribute the splashed potion effect among nearby entities */
-class cSplashPotionCallback :
-	public cEntityCallback
-{
-public:
-	/** Creates the callback.
-	@param a_HitPos            The position where the splash potion has splashed
-	@param a_EntityEffectType  The effect type of the potion
-	@param a_EntityEffect      The effect description */
-	cSplashPotionCallback(const Vector3d & a_HitPos, cEntityEffect::eType a_EntityEffectType, const cEntityEffect & a_EntityEffect) :
-		m_HitPos(a_HitPos),
-		m_EntityEffectType(a_EntityEffectType),
-		m_EntityEffect(a_EntityEffect)
-	{
-	}
-
-	/** Called by cWorld::ForEachEntity(), adds the stored entity effect to the entity, if it is close enough. */
-	virtual bool Item(cEntity * a_Entity) override
-	{
-		if (!a_Entity->IsPawn())
-		{
-			// Not an entity that can take effects
-			return false;
-		}
-
-		double SplashDistance = (a_Entity->GetPosition() - m_HitPos).Length();
-		if (SplashDistance >= 20)
-		{
-			// Too far away
-			return false;
-		}
-
-		// y = -0.25x + 1, where x is the distance from the player. Approximation for potion splash.
-		// TODO: better equation
-		double Reduction = -0.25 * SplashDistance + 1.0;
-		Reduction = std::max(Reduction, 0.0);
-
-		static_cast<cPawn *>(a_Entity)->AddEntityEffect(m_EntityEffectType, m_EntityEffect.GetDuration(), m_EntityEffect.GetIntensity(), Reduction);
-		return false;
-	}
-
-private:
-	const Vector3d & m_HitPos;
-	cEntityEffect::eType m_EntityEffectType;
-	const cEntityEffect & m_EntityEffect;
-};
-
-
-
-
-
-////////////////////////////////////////////////////////////////////////////////
 // cSplashPotionEntity:
 
 cSplashPotionEntity::cSplashPotionEntity(
@@ -119,8 +65,30 @@ void cSplashPotionEntity::OnHitEntity(cEntity & a_EntityHit, const Vector3d & a_
 
 void cSplashPotionEntity::Splash(const Vector3d & a_HitPos)
 {
-	cSplashPotionCallback Callback(a_HitPos, m_EntityEffectType, m_EntityEffect);
-	m_World->ForEachEntity(Callback);
+	m_World->ForEachEntity([=](cEntity & a_Entity)
+		{
+			if (!a_Entity.IsPawn())
+			{
+				// Not an entity that can take effects
+				return false;
+			}
+
+			double SplashDistance = (a_Entity.GetPosition() - a_HitPos).Length();
+			if (SplashDistance >= 20)
+			{
+				// Too far away
+				return false;
+			}
+
+			// y = -0.25x + 1, where x is the distance from the player. Approximation for potion splash.
+			// TODO: better equation
+			double Reduction = -0.25 * SplashDistance + 1.0;
+			Reduction = std::max(Reduction, 0.0);
+
+			static_cast<cPawn &>(a_Entity).AddEntityEffect(m_EntityEffectType, m_EntityEffect.GetDuration(), m_EntityEffect.GetIntensity(), Reduction);
+			return false;
+		}
+	);
 
 	m_World->BroadcastSoundParticleEffect(
 		EffectID::PARTICLE_SPLASH_POTION,
diff --git a/src/Entities/ThrownEnderPearlEntity.cpp b/src/Entities/ThrownEnderPearlEntity.cpp
index 4b2e2f9ff..cb0b3ada0 100644
--- a/src/Entities/ThrownEnderPearlEntity.cpp
+++ b/src/Entities/ThrownEnderPearlEntity.cpp
@@ -74,29 +74,12 @@ void cThrownEnderPearlEntity::TeleportCreator(const Vector3d & a_HitPos)
 		return;
 	}
 
-	class cProjectileCreatorCallbackForPlayers : public cPlayerListCallback
-	{
-	public:
-		cProjectileCreatorCallbackForPlayers(cEntity * a_Attacker, Vector3i a_CallbackHitPos) :
-			m_Attacker(a_Attacker),
-			m_HitPos(a_CallbackHitPos)
-		{
-		}
-
-		virtual bool Item(cPlayer * a_Entity) override
+	GetWorld()->FindAndDoWithPlayer(m_CreatorData.m_Name, [=](cPlayer & a_Entity)
 		{
 			// Teleport the creator here, make them take 5 damage:
-			a_Entity->TeleportToCoords(m_HitPos.x, m_HitPos.y + 0.2, m_HitPos.z);
-			a_Entity->TakeDamage(dtEnderPearl, m_Attacker, 5, 0);
+			a_Entity.TeleportToCoords(a_HitPos.x, a_HitPos.y + 0.2, a_HitPos.z);
+			a_Entity.TakeDamage(dtEnderPearl, this, 5, 0);
 			return true;
 		}
-
-	private:
-
-		cEntity * m_Attacker;
-		Vector3i m_HitPos;
-	};
-
-	cProjectileCreatorCallbackForPlayers PCCFP(this, a_HitPos);
-	GetWorld()->FindAndDoWithPlayer(m_CreatorData.m_Name, PCCFP);
+	);
 }
diff --git a/src/Globals.h b/src/Globals.h
index 0c48d2ad9..78c0539fb 100644
--- a/src/Globals.h
+++ b/src/Globals.h
@@ -416,20 +416,6 @@ template class SizeChecker<UInt8,  1>;
 
 
 
-
-/** A generic interface used mainly in ForEach() functions */
-template <typename Type> class cItemCallback
-{
-public:
-	virtual ~cItemCallback() {}
-
-	/** Called for each item in the internal list; return true to stop the loop, or false to continue enumerating */
-	virtual bool Item(Type * a_Type) = 0;
-} ;
-
-
-
-
 /** Clamp X to the specified range. */
 template <typename T>
 T Clamp(T a_Value, T a_Min, T a_Max)
diff --git a/src/Items/ItemFishingRod.h b/src/Items/ItemFishingRod.h
index 012f13a6c..0720cb3e1 100644
--- a/src/Items/ItemFishingRod.h
+++ b/src/Items/ItemFishingRod.h
@@ -20,8 +20,7 @@
 
 ////////////////////////////////////////////////////////////////////////////////
 // cFloaterCallback
-class cFloaterCallback :
-	public cEntityCallback
+class cFloaterCallback
 {
 public:
 	cFloaterCallback(void) :
@@ -30,13 +29,14 @@ public:
 	{
 	}
 
-	virtual bool Item(cEntity * a_Entity) override
+	bool operator () (cEntity & a_Entity)
 	{
-		m_CanPickup = reinterpret_cast<cFloater *>(a_Entity)->CanPickup();
-		m_Pos = Vector3d(a_Entity->GetPosX(), a_Entity->GetPosY(), a_Entity->GetPosZ());
-		m_BitePos = reinterpret_cast<cFloater *>(a_Entity)->GetBitePos();
-		m_AttachedMobID = reinterpret_cast<cFloater *>(a_Entity)->GetAttachedMobID();
-		a_Entity->Destroy(true);
+		auto & Floater = static_cast<cFloater &>(a_Entity);
+		m_CanPickup = Floater.CanPickup();
+		m_Pos = Floater.GetPosition();
+		m_BitePos = Floater.GetBitePos();
+		m_AttachedMobID = Floater.GetAttachedMobID();
+		Floater.Destroy(true);
 		return true;
 	}
 
@@ -57,33 +57,6 @@ protected:
 
 
 
-////////////////////////////////////////////////////////////////////////////////
-// cSweepEntityCallback:
-
-class cSweepEntityCallback :
-	public cEntityCallback
-{
-public:
-	cSweepEntityCallback(Vector3d a_PlayerPos) :
-		m_PlayerPos(a_PlayerPos)
-	{
-	}
-
-	virtual bool Item(cEntity * a_Entity) override
-	{
-		Vector3d Speed = m_PlayerPos - a_Entity->GetPosition();
-		a_Entity->AddSpeed(Speed);
-		return true;
-	}
-
-protected:
-	Vector3d m_PlayerPos;
-} ;
-
-
-
-
-
 class cItemFishingRodHandler :
 	public cItemHandler
 {
@@ -117,8 +90,13 @@ public:
 
 			if (FloaterInfo.IsAttached())
 			{
-				cSweepEntityCallback SweepEntity(a_Player->GetPosition());
-				a_World->DoWithEntityByID(FloaterInfo.GetAttachedMobID(), SweepEntity);
+				a_World->DoWithEntityByID(FloaterInfo.GetAttachedMobID(), [=](cEntity & a_Entity)
+					{
+						Vector3d Speed = a_Player->GetPosition() - a_Entity.GetPosition();
+						a_Entity.AddSpeed(Speed);
+						return true;
+					}
+				);
 			}
 			else if (FloaterInfo.CanPickup())
 			{
diff --git a/src/Items/ItemMobHead.h b/src/Items/ItemMobHead.h
index fdecabbbf..5cbcf52f7 100644
--- a/src/Items/ItemMobHead.h
+++ b/src/Items/ItemMobHead.h
@@ -62,42 +62,30 @@ public:
 		int a_BlockX, int a_BlockY, int a_BlockZ, eBlockFace a_BlockFace
 	)
 	{
-		// Use a callback to set the properties of the mob head block entity:
-		class cCallback : public cBlockEntityCallback
-		{
-			cPlayer & m_Player;
-			eMobHeadType m_HeadType;
-			NIBBLETYPE m_BlockMeta;
+		auto HeadType = static_cast<eMobHeadType>(a_EquippedItem.m_ItemDamage);
+		auto BlockMeta = static_cast<NIBBLETYPE>(a_BlockFace);
 
-			virtual bool Item(cBlockEntity * a_BlockEntity)
+		// Use a callback to set the properties of the mob head block entity:
+		a_World.DoWithBlockEntityAt(a_BlockX, a_BlockY, a_BlockZ, [&](cBlockEntity & a_BlockEntity)
 			{
-				if (a_BlockEntity->GetBlockType() != E_BLOCK_HEAD)
+				if (a_BlockEntity.GetBlockType() != E_BLOCK_HEAD)
 				{
 					return false;
 				}
-				auto MobHeadEntity = static_cast<cMobHeadEntity *>(a_BlockEntity);
+				auto & MobHeadEntity = static_cast<cMobHeadEntity &>(a_BlockEntity);
 
 				int Rotation = 0;
-				if (m_BlockMeta == 1)
+				if (BlockMeta == 1)
 				{
-					Rotation = FloorC(m_Player.GetYaw() * 16.0f / 360.0f + 0.5f) & 0x0f;
+					Rotation = FloorC(a_Player.GetYaw() * 16.0f / 360.0f + 0.5f) & 0x0f;
 				}
 
-				MobHeadEntity->SetType(m_HeadType);
-				MobHeadEntity->SetRotation(static_cast<eMobHeadRotation>(Rotation));
-				MobHeadEntity->GetWorld()->BroadcastBlockEntity(MobHeadEntity->GetPosX(), MobHeadEntity->GetPosY(), MobHeadEntity->GetPosZ());
+				MobHeadEntity.SetType(HeadType);
+				MobHeadEntity.SetRotation(static_cast<eMobHeadRotation>(Rotation));
+				MobHeadEntity.GetWorld()->BroadcastBlockEntity(MobHeadEntity.GetPosX(), MobHeadEntity.GetPosY(), MobHeadEntity.GetPosZ());
 				return false;
 			}
-
-		public:
-			cCallback (cPlayer & a_CBPlayer, eMobHeadType a_HeadType, NIBBLETYPE a_BlockMeta) :
-				m_Player(a_CBPlayer),
-				m_HeadType(a_HeadType),
-				m_BlockMeta(a_BlockMeta)
-			{}
-		};
-		cCallback Callback(a_Player, static_cast<eMobHeadType>(a_EquippedItem.m_ItemDamage), static_cast<NIBBLETYPE>(a_BlockFace));
-		a_World.DoWithBlockEntityAt(a_BlockX, a_BlockY, a_BlockZ, Callback);
+		);
 	}
 
 
@@ -243,24 +231,16 @@ public:
 			// If it is a mob head, check the correct head type using the block entity:
 			if (BlockType == E_BLOCK_HEAD)
 			{
-				class cHeadCallback: public cBlockEntityCallback
-				{
-					virtual bool Item(cBlockEntity * a_Entity) override
+				bool IsWitherHead = false;
+				a_World.DoWithBlockEntityAt(BlockX, BlockY, BlockZ, [&](cBlockEntity & a_Entity)
 					{
-						ASSERT(a_Entity->GetBlockType() == E_BLOCK_HEAD);
-						cMobHeadEntity * MobHead = static_cast<cMobHeadEntity *>(a_Entity);
-						m_IsWitherHead = (MobHead->GetType() == SKULL_TYPE_WITHER);
+						ASSERT(a_Entity.GetBlockType() == E_BLOCK_HEAD);
+						auto & MobHead = static_cast<cMobHeadEntity &>(a_Entity);
+						IsWitherHead = (MobHead.GetType() == SKULL_TYPE_WITHER);
 						return true;
 					}
-				public:
-					cHeadCallback(void):
-						m_IsWitherHead(false)
-					{
-					}
-					bool m_IsWitherHead;
-				} callback;
-				a_World.DoWithBlockEntityAt(BlockX, BlockY, BlockZ, callback);
-				if (!callback.m_IsWitherHead)
+				);
+				if (!IsWitherHead)
 				{
 					return false;
 				}
@@ -287,25 +267,18 @@ public:
 	/** Awards the achievement to all players close to the specified point. */
 	void AwardSpawnWitherAchievement(cWorld & a_World, int a_BlockX, int a_BlockY, int a_BlockZ)
 	{
-		class cPlayerCallback : public cPlayerListCallback
-		{
-			Vector3f m_Pos;
-
-			virtual bool Item(cPlayer * a_Player)
+		Vector3f Pos{ static_cast<float>(a_BlockX), static_cast<float>(a_BlockY), static_cast<float>(a_BlockZ) };
+		a_World.ForEachPlayer([=](cPlayer & a_Player)
 			{
 				// If player is close, award achievement:
-				double Dist = (a_Player->GetPosition() - m_Pos).Length();
+				double Dist = (a_Player.GetPosition() - Pos).Length();
 				if (Dist < 50.0)
 				{
-					a_Player->AwardAchievement(achSpawnWither);
+					a_Player.AwardAchievement(achSpawnWither);
 				}
 				return false;
 			}
-
-		public:
-			cPlayerCallback(const Vector3f & a_Pos) : m_Pos(a_Pos) {}
-		} PlayerCallback(Vector3f(static_cast<float>(a_BlockX), static_cast<float>(a_BlockY), static_cast<float>(a_BlockZ)));
-		a_World.ForEachPlayer(PlayerCallback);
+		);
 	}
 
 
diff --git a/src/LineBlockTracer.cpp b/src/LineBlockTracer.cpp
index 471d9e13b..e194ae653 100644
--- a/src/LineBlockTracer.cpp
+++ b/src/LineBlockTracer.cpp
@@ -199,12 +199,12 @@ bool cLineBlockTracer::Trace(double a_StartX, double a_StartY, double a_StartZ,
 	m_DiffY = m_EndY - m_StartY;
 	m_DiffZ = m_EndZ - m_StartZ;
 
-	// The actual trace is handled with ChunkMapCS locked by calling our Item() for the specified chunk
+	// The actual trace is handled with ChunkMapCS locked by calling our ChunkCallback for the specified chunk
 	int BlockX = FloorC(m_StartX);
 	int BlockZ = FloorC(m_StartZ);
 	int ChunkX, ChunkZ;
 	cChunkDef::BlockToChunk(BlockX, BlockZ, ChunkX, ChunkZ);
-	return m_World->DoWithChunk(ChunkX, ChunkZ, *this);
+	return m_World->DoWithChunk(ChunkX, ChunkZ, [this](cChunk & a_Chunk) { return ChunkCallback(&a_Chunk); });
 }
 
 
@@ -308,7 +308,7 @@ bool cLineBlockTracer::MoveToNextBlock(void)
 
 
 
-bool cLineBlockTracer::Item(cChunk * a_Chunk)
+bool cLineBlockTracer::ChunkCallback(cChunk * a_Chunk)
 {
 	ASSERT((m_CurrentY >= 0) && (m_CurrentY < cChunkDef::Height));  // This should be provided by FixStartAboveWorld() / FixStartBelowWorld()
 
diff --git a/src/LineBlockTracer.h b/src/LineBlockTracer.h
index 2851cfbd7..2204e3671 100644
--- a/src/LineBlockTracer.h
+++ b/src/LineBlockTracer.h
@@ -18,17 +18,12 @@
 // fwd: Chunk.h
 class cChunk;
 
-// fwd: cChunkMap.h
-typedef cItemCallback<cChunk> cChunkCallback;
-
-
 
 
 
 
 class cLineBlockTracer :
-	public cBlockTracer,
-	public cChunkCallback
+	public cBlockTracer
 {
 	typedef cBlockTracer super;
 
@@ -109,8 +104,7 @@ protected:
 	/** Moves m_Current to the next block on the line; returns false if no move is possible (reached the end) */
 	bool MoveToNextBlock(void);
 
-	// cChunkCallback overrides:
-	virtual bool Item(cChunk * a_Chunk) override;
+	bool ChunkCallback(cChunk * a_Chunk);
 } ;
 
 
diff --git a/src/Map.cpp b/src/Map.cpp
index 2fe901d8e..87cc9bfdf 100644
--- a/src/Map.cpp
+++ b/src/Map.cpp
@@ -120,27 +120,17 @@ bool cMap::UpdatePixel(unsigned int a_X, unsigned int a_Z)
 	int RelX = BlockX - (ChunkX * cChunkDef::Width);
 	int RelZ = BlockZ - (ChunkZ * cChunkDef::Width);
 
-	class cCalculatePixelCb :
-		public cChunkCallback
-	{
-		cMap * m_Map;
-
-		int m_RelX, m_RelZ;
-
-		ColorID m_PixelData;
-
-	public:
-		cCalculatePixelCb(cMap * a_Map, int a_RelX, int a_RelZ)
-			: m_Map(a_Map), m_RelX(a_RelX), m_RelZ(a_RelZ), m_PixelData(E_BASE_COLOR_TRANSPARENT) {}
+	ASSERT(m_World != nullptr);
 
-		virtual bool Item(cChunk * a_Chunk) override
+	ColorID PixelData;
+	m_World->DoWithChunk(ChunkX, ChunkZ, [&](cChunk & a_Chunk)
 		{
-			if (!a_Chunk->IsValid())
+			if (!a_Chunk.IsValid())
 			{
 				return false;
 			}
 
-			if (m_Map->GetDimension() == dimNether)
+			if (GetDimension() == dimNether)
 			{
 				// TODO 2014-02-22 xdot: Nether maps
 
@@ -151,22 +141,22 @@ bool cMap::UpdatePixel(unsigned int a_X, unsigned int a_Z)
 			BLOCKTYPE TargetBlock;
 			NIBBLETYPE TargetMeta;
 
-			auto Height = a_Chunk->GetHeight(m_RelX, m_RelZ);
+			auto Height = a_Chunk.GetHeight(RelX, RelZ);
 			auto ChunkHeight = cChunkDef::Height;
-			a_Chunk->GetBlockTypeMeta(m_RelX, Height, m_RelZ, TargetBlock, TargetMeta);
+			a_Chunk.GetBlockTypeMeta(RelX, Height, RelZ, TargetBlock, TargetMeta);
 			auto ColourID = BlockHandler(TargetBlock)->GetMapBaseColourID(TargetMeta);
 
 			if (IsBlockWater(TargetBlock))
 			{
 				ChunkHeight /= 4;
-				while (((--Height) != -1) && IsBlockWater(a_Chunk->GetBlock(m_RelX, Height, m_RelZ)))
+				while (((--Height) != -1) && IsBlockWater(a_Chunk.GetBlock(RelX, Height, RelZ)))
 				{
 					continue;
 				}
 			}
 			else if (ColourID == 0)
 			{
-				while (((--Height) != -1) && ((ColourID = BlockHandler(a_Chunk->GetBlock(m_RelX, Height, m_RelZ))->GetMapBaseColourID(a_Chunk->GetMeta(m_RelX, Height, m_RelZ))) == 0))
+				while (((--Height) != -1) && ((ColourID = BlockHandler(a_Chunk.GetBlock(RelX, Height, RelZ))->GetMapBaseColourID(a_Chunk.GetMeta(RelX, Height, RelZ))) == 0))
 				{
 					continue;
 				}
@@ -174,20 +164,12 @@ bool cMap::UpdatePixel(unsigned int a_X, unsigned int a_Z)
 
 			// Multiply base color ID by 4 and add brightness ID
 			const int BrightnessIDSize = static_cast<int>(BrightnessID.size());
-			m_PixelData = ColourID * 4 + BrightnessID[static_cast<size_t>(Clamp<int>((BrightnessIDSize * Height) / ChunkHeight, 0, BrightnessIDSize - 1))];
+			PixelData = ColourID * 4 + BrightnessID[static_cast<size_t>(Clamp<int>((BrightnessIDSize * Height) / ChunkHeight, 0, BrightnessIDSize - 1))];
 			return false;
 		}
+	);
 
-		ColorID GetPixelData(void) const
-		{
-			return m_PixelData;
-		}
-	} CalculatePixelCb(this, RelX, RelZ);
-
-	ASSERT(m_World != nullptr);
-	m_World->DoWithChunk(ChunkX, ChunkZ, CalculatePixelCb);
-
-	SetPixel(a_X, a_Z, CalculatePixelCb.GetPixelData());
+	SetPixel(a_X, a_Z, PixelData);
 
 	return true;
 }
diff --git a/src/MapManager.cpp b/src/MapManager.cpp
index 2729e67dd..abc3f16f2 100644
--- a/src/MapManager.cpp
+++ b/src/MapManager.cpp
@@ -1,4 +1,4 @@
-
+
 // MapManager.cpp
 
 #include "Globals.h"
@@ -22,7 +22,7 @@ cMapManager::cMapManager(cWorld * a_World)
 
 
 
-bool cMapManager::DoWithMap(UInt32 a_ID, cMapCallback & a_Callback)
+bool cMapManager::DoWithMap(UInt32 a_ID, const cMapCallback & a_Callback)
 {
 	cCSLock Lock(m_CS);
 	cMap * Map = GetMapData(a_ID);
@@ -33,7 +33,7 @@ bool cMapManager::DoWithMap(UInt32 a_ID, cMapCallback & a_Callback)
 	}
 	else
 	{
-		a_Callback.Item(Map);
+		a_Callback(*Map);
 		return true;
 	}
 }
diff --git a/src/MapManager.h b/src/MapManager.h
index 6730e515e..ef1e7588b 100644
--- a/src/MapManager.h
+++ b/src/MapManager.h
@@ -1,4 +1,4 @@
-
+
 // MapManager.h
 
 
@@ -11,12 +11,13 @@
 
 
 
+#include <functional>
 #include "Map.h"
 
 
 
 
-typedef cItemCallback<cMap> cMapCallback;
+using cMapCallback = std::function<bool(cMap &)>;
 
 
 
@@ -41,7 +42,7 @@ public:
 	/** Calls the callback for the map with the specified ID.
 	Returns true if the map was found and the callback called, false if map not found.
 	Callback return value is ignored. */
-	bool DoWithMap(UInt32 a_ID, cMapCallback & a_Callback);  // Exported in ManualBindings.cpp
+	bool DoWithMap(UInt32 a_ID, const cMapCallback & a_Callback);  // Exported in ManualBindings.cpp
 
 	/** Ticks each registered map */
 	void TickMaps(void);
diff --git a/src/MobSpawner.cpp b/src/MobSpawner.cpp
index 1e0db5175..eb5684202 100644
--- a/src/MobSpawner.cpp
+++ b/src/MobSpawner.cpp
@@ -369,7 +369,7 @@ cMonster * cMobSpawner::TryToSpawnHere(cChunk * a_Chunk, int a_RelX, int a_RelY,
 		auto NewMobPtr = newMob.get();
 		if (newMob)
 		{
-			m_Spawned.insert(std::move(newMob));
+			m_Spawned.push_back(std::move(newMob));
 		}
 		return NewMobPtr;
 	}
@@ -390,15 +390,6 @@ void cMobSpawner::NewPack()
 
 
 
-cMobSpawner::tSpawnedContainer & cMobSpawner::getSpawned(void)
-{
-	return m_Spawned;
-}
-
-
-
-
-
 bool cMobSpawner::CanSpawnAnything(void)
 {
 	return !m_AllowedTypes.empty();
diff --git a/src/MobSpawner.h b/src/MobSpawner.h
index 14c721ae3..c396637d5 100644
--- a/src/MobSpawner.h
+++ b/src/MobSpawner.h
@@ -37,8 +37,10 @@ public :
 	// return true if there is at least one allowed type
 	bool CanSpawnAnything(void);
 
-	typedef const std::set<std::unique_ptr<cMonster>> tSpawnedContainer;
-	tSpawnedContainer & getSpawned(void);
+	std::vector<std::unique_ptr<cMonster>> & getSpawned(void)
+	{
+		return m_Spawned;
+	}
 
 	/** Returns true if specified type of mob can spawn on specified block */
 	static bool CanSpawnHere(cChunk * a_Chunk, int a_RelX, int a_RelY, int a_RelZ, eMonsterType a_MobType, EMCSBiome a_Biome);
@@ -55,7 +57,7 @@ protected :
 	std::set<eMonsterType> m_AllowedTypes;
 	bool m_NewPack;
 	eMonsterType m_MobType;
-	std::set<std::unique_ptr<cMonster>> m_Spawned;
+	std::vector<std::unique_ptr<cMonster>> m_Spawned;
 } ;
 
 
diff --git a/src/Mobs/Creeper.cpp b/src/Mobs/Creeper.cpp
index 8de236863..c05076a1a 100644
--- a/src/Mobs/Creeper.cpp
+++ b/src/Mobs/Creeper.cpp
@@ -85,21 +85,16 @@ void cCreeper::GetDrops(cItems & a_Drops, cEntity * a_Killer)
 		a_Killer->IsProjectile() &&
 		((reinterpret_cast<cProjectileEntity *>(a_Killer))->GetCreatorUniqueID() != cEntity::INVALID_ID))
 	{
-		class cProjectileCreatorCallback : public cEntityCallback
-		{
-		public:
-			cProjectileCreatorCallback(void) {}
-
-			virtual bool Item(cEntity * a_Entity) override
+		auto ProjectileCreatorCallback = [](cEntity & a_Entity)
 			{
-				if (a_Entity->IsMob() && ((reinterpret_cast<cMonster *>(a_Entity))->GetMobType() == mtSkeleton))
+				if (a_Entity.IsMob() && ((static_cast<cMonster &>(a_Entity)).GetMobType() == mtSkeleton))
 				{
 					return true;
 				}
 				return false;
-			}
-		} PCC;
-		if (GetWorld()->DoWithEntityByID((reinterpret_cast<cProjectileEntity *>(a_Killer))->GetCreatorUniqueID(), PCC))
+			};
+
+		if (GetWorld()->DoWithEntityByID(static_cast<cProjectileEntity *>(a_Killer)->GetCreatorUniqueID(), ProjectileCreatorCallback))
 		{
 			AddRandomDropItem(a_Drops, 1, 1, static_cast<short>(m_World->GetTickRandomNumber(11) + E_ITEM_FIRST_DISC));
 		}
diff --git a/src/Mobs/Enderman.cpp b/src/Mobs/Enderman.cpp
index 72301b21a..65b771406 100644
--- a/src/Mobs/Enderman.cpp
+++ b/src/Mobs/Enderman.cpp
@@ -10,8 +10,7 @@
 
 ////////////////////////////////////////////////////////////////////////////////
 // cPlayerLookCheck
-class cPlayerLookCheck :
-	public cPlayerListCallback
+class cPlayerLookCheck
 {
 public:
 	cPlayerLookCheck(Vector3d a_EndermanPos, int a_SightDistance) :
@@ -21,29 +20,29 @@ public:
 	{
 	}
 
-	virtual bool Item(cPlayer * a_Player) override
+	bool operator () (cPlayer & a_Player)
 	{
 		// Don't check players who cannot be targeted
-		if (!a_Player->CanMobsTarget())
+		if (!a_Player.CanMobsTarget())
 		{
 			return false;
 		}
 
 		// Don't check players who are more than SightDistance (64) blocks away
-		auto Direction = m_EndermanPos - a_Player->GetPosition();
+		auto Direction = m_EndermanPos - a_Player.GetPosition();
 		if (Direction.Length() > m_SightDistance)
 		{
 			return false;
 		}
 
 		// Don't check if the player has a pumpkin on his head
-		if (a_Player->GetEquippedHelmet().m_ItemType == E_BLOCK_PUMPKIN)
+		if (a_Player.GetEquippedHelmet().m_ItemType == E_BLOCK_PUMPKIN)
 		{
 			return false;
 		}
 
 		// If the player's crosshair is within 5 degrees of the enderman, it counts as looking
-		auto LookVector = a_Player->GetLookVector();
+		auto LookVector = a_Player.GetLookVector();
 		auto dot = Direction.Dot(LookVector);
 		if (dot <= cos(0.09))  // 0.09 rad ~ 5 degrees
 		{
@@ -51,13 +50,13 @@ public:
 		}
 
 		// TODO: Check if endermen are angered through water in Vanilla
-		if (!cLineBlockTracer::LineOfSightTrace(*a_Player->GetWorld(), m_EndermanPos, a_Player->GetPosition(), cLineBlockTracer::losAirWater))
+		if (!cLineBlockTracer::LineOfSightTrace(*a_Player.GetWorld(), m_EndermanPos, a_Player.GetPosition(), cLineBlockTracer::losAirWater))
 		{
 			// No direct line of sight
 			return false;
 		}
 
-		m_Player = a_Player;
+		m_Player = &a_Player;
 		return true;
 	}
 
diff --git a/src/Mobs/Monster.cpp b/src/Mobs/Monster.cpp
index 51bc0637b..f16120b55 100644
--- a/src/Mobs/Monster.cpp
+++ b/src/Mobs/Monster.cpp
@@ -1331,9 +1331,24 @@ void cMonster::AttachTickBehavior(cBehavior * a_Behavior)
 
 void cMonster::AttachDestroyBehavior(cBehavior * a_Behavior)
 {
+<<<<<<< HEAD
 	ASSERT(a_Behavior != nullptr);
 	m_AttachedDestroyBehaviors.push_back(a_Behavior);
 }
+=======
+	// If the Y coord is out of range, return the most logical result without considering anything else:
+	int RelY = FloorC(a_Location.y);
+	if (RelY >= cChunkDef::Height)
+	{
+		// Always burn above the world
+		return true;
+	}
+	if (RelY <= 0)
+	{
+		// The mob is about to die, no point in burning
+		return false;
+	}
+>>>>>>> master
 
 
 
diff --git a/src/Mobs/Ocelot.cpp b/src/Mobs/Ocelot.cpp
index e89b18186..183cb74c4 100644
--- a/src/Mobs/Ocelot.cpp
+++ b/src/Mobs/Ocelot.cpp
@@ -91,30 +91,25 @@ void cOcelot::Tick(std::chrono::milliseconds a_Dt, cChunk & a_Chunk)
 
 void cOcelot::TickFollowPlayer()
 {
-	class cCallback :
-		public cPlayerListCallback
+	Vector3d OwnerPos;
+	bool OwnerFlying = false;
+	auto Callback = [&](cPlayer & a_Player)
 	{
-		virtual bool Item(cPlayer * a_Player) override
-		{
-			OwnerPos = a_Player->GetPosition();
-			OwnerFlying = a_Player->IsFlying();
-			return true;
-		}
-	public:
-		Vector3d OwnerPos;
-		bool OwnerFlying;
-	} Callback;
+		OwnerPos = a_Player.GetPosition();
+		OwnerFlying = a_Player.IsFlying();
+		return true;
+	};
 
 	if (m_World->DoWithPlayerByUUID(m_OwnerUUID, Callback))
 	{
 		// The player is present in the world, follow him:
-		double Distance = (Callback.OwnerPos - GetPosition()).Length();
+		double Distance = (OwnerPos - GetPosition()).Length();
 		if (Distance > 12)
 		{
-			if (!Callback.OwnerFlying)
+			if (!OwnerFlying)
 			{
-				Callback.OwnerPos.y = FindFirstNonAirBlockPosition(Callback.OwnerPos.x, Callback.OwnerPos.z);
-				TeleportToCoords(Callback.OwnerPos.x, Callback.OwnerPos.y, Callback.OwnerPos.z);
+				OwnerPos.y = FindFirstNonAirBlockPosition(OwnerPos.x, OwnerPos.z);
+				TeleportToCoords(OwnerPos.x, OwnerPos.y, OwnerPos.z);
 			}
 		}
 		if (Distance < 2)
@@ -123,9 +118,9 @@ void cOcelot::TickFollowPlayer()
 		}
 		else
 		{
-			if (!Callback.OwnerFlying)
+			if (!OwnerFlying)
 			{
-				MoveToPosition(Callback.OwnerPos);
+				MoveToPosition(OwnerPos);
 			}
 		}
 	}
@@ -206,27 +201,19 @@ void cOcelot::SpawnOn(cClientHandle & a_ClientHandle)
 
 
 
-class cFindSittingCat :
-	public cEntityCallback
-{
-	virtual bool Item(cEntity * a_Entity) override
-	{
-		return (
-			(a_Entity->GetEntityType() == cEntity::etMonster) &&
-			(static_cast<cMonster *>(a_Entity)->GetMobType() == eMonsterType::mtOcelot) &&
-			(static_cast<cOcelot *>(a_Entity)->IsSitting())
-		);
-	}
-};
-
-
-
-
-
 bool cOcelot::IsCatSittingOnBlock(cWorld * a_World, Vector3d a_BlockPosition)
 {
-	cFindSittingCat FindSittingCat;
-	return a_World->ForEachEntityInBox(cBoundingBox(Vector3d(a_BlockPosition.x, a_BlockPosition.y + 1, a_BlockPosition.z), 1), FindSittingCat);
+	return a_World->ForEachEntityInBox(
+		cBoundingBox(Vector3d(a_BlockPosition.x, a_BlockPosition.y + 1, a_BlockPosition.z), 1),
+		[=](cEntity & a_Entity)
+		{
+			return (
+				(a_Entity.GetEntityType() == cEntity::etMonster) &&
+				(static_cast<cMonster &>(a_Entity).GetMobType() == eMonsterType::mtOcelot) &&
+				(static_cast<cOcelot &>(a_Entity).IsSitting())
+			);
+		}
+	);
 }
 
 
diff --git a/src/Mobs/PassiveMonster.cpp b/src/Mobs/PassiveMonster.cpp
new file mode 100644
index 000000000..c9345662d
--- /dev/null
+++ b/src/Mobs/PassiveMonster.cpp
@@ -0,0 +1,246 @@
+
+#include "Globals.h"  // NOTE: MSVC stupidness requires this to be the same across all modules
+
+#include "PassiveMonster.h"
+#include "../World.h"
+#include "../Entities/Player.h"
+#include "BoundingBox.h"
+#include "../Items/ItemSpawnEgg.h"
+
+
+
+
+cPassiveMonster::cPassiveMonster(const AString & a_ConfigName, eMonsterType a_MobType, const AString & a_SoundHurt, const AString & a_SoundDeath, double a_Width, double a_Height) :
+	super(a_ConfigName, a_MobType, a_SoundHurt, a_SoundDeath, a_Width, a_Height),
+	m_LovePartner(nullptr),
+	m_LoveTimer(0),
+	m_LoveCooldown(0),
+	m_MatingTimer(0)
+{
+	m_EMPersonality = PASSIVE;
+}
+
+
+
+
+
+bool cPassiveMonster::DoTakeDamage(TakeDamageInfo & a_TDI)
+{
+	if (!super::DoTakeDamage(a_TDI))
+	{
+		return false;
+	}
+	if ((a_TDI.Attacker != this) && (a_TDI.Attacker != nullptr))
+	{
+		m_EMState = ESCAPING;
+	}
+	return true;
+}
+
+
+
+
+
+void cPassiveMonster::EngageLoveMode(cPassiveMonster * a_Partner)
+{
+	m_LovePartner = a_Partner;
+	m_MatingTimer = 50;  // about 3 seconds of mating
+}
+
+
+
+
+
+void cPassiveMonster::ResetLoveMode()
+{
+	m_LovePartner = nullptr;
+	m_LoveTimer = 0;
+	m_MatingTimer = 0;
+	m_LoveCooldown = 20 * 60 * 5;  // 5 minutes
+
+	// when an animal is in love mode, the client only stops sending the hearts if we let them know it's in cooldown, which is done with the "age" metadata
+	m_World->BroadcastEntityMetadata(*this);
+}
+
+
+
+
+
+void cPassiveMonster::Destroyed()
+{
+	if (m_LovePartner != nullptr)
+	{
+		m_LovePartner->ResetLoveMode();
+	}
+	super::Destroyed();
+}
+
+
+
+
+
+void cPassiveMonster::Tick(std::chrono::milliseconds a_Dt, cChunk & a_Chunk)
+{
+	super::Tick(a_Dt, a_Chunk);
+	if (!IsTicking())
+	{
+		// The base class tick destroyed us
+		return;
+	}
+
+	if (m_EMState == ESCAPING)
+	{
+		CheckEventLostPlayer();
+	}
+
+	// if we have a partner, mate
+	if (m_LovePartner != nullptr)
+	{
+
+		if (m_MatingTimer > 0)
+		{
+			// If we should still mate, keep bumping into them until baby is made
+			Vector3d Pos = m_LovePartner->GetPosition();
+			MoveToPosition(Pos);
+		}
+		else
+		{
+			// Mating finished. Spawn baby
+			Vector3f Pos = (GetPosition() + m_LovePartner->GetPosition()) * 0.5;
+			UInt32 BabyID = m_World->SpawnMob(Pos.x, Pos.y, Pos.z, GetMobType(), true);
+
+			cPassiveMonster * Baby = nullptr;
+
+			m_World->DoWithEntityByID(BabyID, [&](cEntity & a_Entity)
+				{
+					Baby = static_cast<cPassiveMonster *>(&a_Entity);
+					return true;
+				}
+			);
+
+			if (Baby != nullptr)
+			{
+				Baby->InheritFromParents(this, m_LovePartner);
+			}
+
+			m_World->SpawnExperienceOrb(Pos.x, Pos.y, Pos.z, GetRandomProvider().RandInt(1, 6));
+
+			m_LovePartner->ResetLoveMode();
+			ResetLoveMode();
+		}
+	}
+	else
+	{
+		// We have no partner, so we just chase the player if they have our breeding item
+		cItems FollowedItems;
+		GetFollowedItems(FollowedItems);
+		if (FollowedItems.Size() > 0)
+		{
+			cPlayer * a_Closest_Player = m_World->FindClosestPlayer(GetPosition(), static_cast<float>(m_SightDistance));
+			if (a_Closest_Player != nullptr)
+			{
+				cItem EquippedItem = a_Closest_Player->GetEquippedItem();
+				if (FollowedItems.ContainsType(EquippedItem))
+				{
+					Vector3d PlayerPos = a_Closest_Player->GetPosition();
+					MoveToPosition(PlayerPos);
+				}
+			}
+		}
+	}
+
+	// If we are in love mode but we have no partner, search for a partner neabry
+	if (m_LoveTimer > 0)
+	{
+		if (m_LovePartner == nullptr)
+		{
+			m_World->ForEachEntityInBox(cBoundingBox(GetPosition(), 8, 8), [=](cEntity & a_Entity)
+				{
+					// If the entity is not a monster, don't breed with it
+					// Also, do not self-breed
+					if ((a_Entity.GetEntityType() != etMonster) || (&a_Entity == this))
+					{
+						return false;
+					}
+
+					auto & Me = static_cast<cPassiveMonster&>(*this);
+					auto & PotentialPartner = static_cast<cPassiveMonster&>(a_Entity);
+
+					// If the potential partner is not of the same species, don't breed with it
+					if (PotentialPartner.GetMobType() != Me.GetMobType())
+					{
+						return false;
+					}
+
+					// If the potential partner is not in love
+					// Or they already have a mate, do not breed with them
+					if ((!PotentialPartner.IsInLove()) || (PotentialPartner.GetPartner() != nullptr))
+					{
+						return false;
+					}
+
+					// All conditions met, let's breed!
+					PotentialPartner.EngageLoveMode(&Me);
+					Me.EngageLoveMode(&PotentialPartner);
+					return true;
+				}
+			);
+		}
+
+		m_LoveTimer--;
+	}
+	if (m_MatingTimer > 0)
+	{
+		m_MatingTimer--;
+	}
+	if (m_LoveCooldown > 0)
+	{
+		m_LoveCooldown--;
+	}
+}
+
+
+
+
+
+void cPassiveMonster::OnRightClicked(cPlayer & a_Player)
+{
+	super::OnRightClicked(a_Player);
+
+	const cItem & EquippedItem = a_Player.GetEquippedItem();
+
+	// If a player holding breeding items right-clicked me, go into love mode
+	if ((m_LoveCooldown == 0) && !IsInLove() && !IsBaby())
+	{
+		cItems Items;
+		GetBreedingItems(Items);
+		if (Items.ContainsType(EquippedItem.m_ItemType))
+		{
+			if (!a_Player.IsGameModeCreative())
+			{
+				a_Player.GetInventory().RemoveOneEquippedItem();
+			}
+			m_LoveTimer = 20 * 30;  // half a minute
+			m_World->BroadcastEntityStatus(*this, esMobInLove);
+		}
+	}
+	// If a player holding my spawn egg right-clicked me, spawn a new baby
+	if (EquippedItem.m_ItemType == E_ITEM_SPAWN_EGG)
+	{
+		eMonsterType MonsterType = cItemSpawnEggHandler::ItemDamageToMonsterType(EquippedItem.m_ItemDamage);
+		if (
+			(MonsterType == m_MobType) &&
+			(m_World->SpawnMob(GetPosX(), GetPosY(), GetPosZ(), m_MobType, true) != cEntity::INVALID_ID)  // Spawning succeeded
+		)
+		{
+			if (!a_Player.IsGameModeCreative())
+			{
+				// The mob was spawned, "use" the item:
+				a_Player.GetInventory().RemoveOneEquippedItem();
+			}
+		}
+	}
+}
+
+
+
diff --git a/src/Mobs/Squid.h b/src/Mobs/Squid.h
index 20d87dbca..8039089e3 100644
--- a/src/Mobs/Squid.h
+++ b/src/Mobs/Squid.h
@@ -24,7 +24,6 @@ public:
 
 	// Squids do not drown (or float)
 	virtual void HandleAir(void) override {}
-	virtual void SetSwimState(cChunk & a_Chunk) override {}
 
 private:
 	cBehaviorDoNothing m_BehaviorDoNothing;
diff --git a/src/Mobs/Wither.cpp b/src/Mobs/Wither.cpp
index 99b9a3ce8..195c90fd2 100644
--- a/src/Mobs/Wither.cpp
+++ b/src/Mobs/Wither.cpp
@@ -102,28 +102,19 @@ void cWither::KilledBy(TakeDamageInfo & a_TDI)
 {
 	super::KilledBy(a_TDI);
 
-	class cPlayerCallback : public cPlayerListCallback
-	{
-		Vector3f m_Pos;
-
-		virtual bool Item(cPlayer * a_Player)
+	Vector3d Pos = GetPosition();
+	m_World->ForEachPlayer([=](cPlayer & a_Player)
 		{
 			// TODO 2014-05-21 xdot: Vanilla minecraft uses an AABB check instead of a radius one
-			double Dist = (a_Player->GetPosition() - m_Pos).Length();
+			double Dist = (a_Player.GetPosition() - Pos).Length();
 			if (Dist < 50.0)
 			{
 				// If player is close, award achievement
-				a_Player->AwardAchievement(achKillWither);
+				a_Player.AwardAchievement(achKillWither);
 			}
 			return false;
 		}
-
-	public:
-		cPlayerCallback(const Vector3f & a_Pos) : m_Pos(a_Pos) {}
-
-	} PlayerCallback(GetPosition());
-
-	m_World->ForEachPlayer(PlayerCallback);
+	);
 }
 
 
diff --git a/src/Mobs/Wolf.cpp b/src/Mobs/Wolf.cpp
index c08e572fb..f1c082ce7 100644
--- a/src/Mobs/Wolf.cpp
+++ b/src/Mobs/Wolf.cpp
@@ -83,19 +83,22 @@ void cWolf::NotifyAlliesOfFight(cPawn * a_Opponent)
 		return;
 	}
 	m_NotificationCooldown = 15;
-	class cCallback : public cPlayerListCallback
-	{
-		virtual bool Item(cPlayer * a_Player) override
+
+	m_World->DoWithPlayerByUUID(m_OwnerUUID, [=](cPlayer & a_Player)
 		{
-			a_Player->NotifyNearbyWolves(m_Opponent, false);
+			a_Player.NotifyNearbyWolves(a_Opponent, false);
 			return false;
 		}
+<<<<<<< HEAD
 	public:
 		cPawn * m_Opponent;
 	} Callback;
 
 	Callback.m_Opponent = a_Opponent;
 	m_World->DoWithPlayerByUUID(m_OwnerUUID, Callback);*/
+=======
+	);
+>>>>>>> master
 }
 
 /*bool cWolf::Attack(std::chrono::milliseconds a_Dt)
@@ -356,31 +359,31 @@ void cWolf::Tick(std::chrono::milliseconds a_Dt, cChunk & a_Chunk)
 
 void cWolf::TickFollowPlayer()
 {
+<<<<<<< HEAD
 	/*
 	class cCallback :
 		public cPlayerListCallback
+=======
+	Vector3d OwnerPos;
+	bool OwnerFlying;
+	auto Callback = [&](cPlayer & a_Player)
+>>>>>>> master
 	{
-		virtual bool Item(cPlayer * a_Player) override
-		{
-			OwnerPos = a_Player->GetPosition();
-			OwnerFlying = a_Player->IsFlying();
-			return true;
-		}
-	public:
-		Vector3d OwnerPos;
-		bool OwnerFlying;
-	} Callback;
+		OwnerPos = a_Player.GetPosition();
+		OwnerFlying = a_Player.IsFlying();
+		return true;
+	};
 
 	if (m_World->DoWithPlayerByUUID(m_OwnerUUID, Callback))
 	{
 		// The player is present in the world, follow him:
-		double Distance = (Callback.OwnerPos - GetPosition()).Length();
+		double Distance = (OwnerPos - GetPosition()).Length();
 		if (Distance > 20)
 		{
-			if (!Callback.OwnerFlying)
+			if (!OwnerFlying)
 			{
-				Callback.OwnerPos.y = FindFirstNonAirBlockPosition(Callback.OwnerPos.x, Callback.OwnerPos.z);
-				TeleportToCoords(Callback.OwnerPos.x, Callback.OwnerPos.y, Callback.OwnerPos.z);
+				OwnerPos.y = FindFirstNonAirBlockPosition(OwnerPos.x, OwnerPos.z);
+				TeleportToCoords(OwnerPos.x, OwnerPos.y, OwnerPos.z);
 				SetTarget(nullptr);
 			}
 		}
@@ -395,9 +398,9 @@ void cWolf::TickFollowPlayer()
 		{
 			if (GetTarget() == nullptr)
 			{
-				if (!Callback.OwnerFlying)
+				if (!OwnerFlying)
 				{
-					MoveToPosition(Callback.OwnerPos);
+					MoveToPosition(OwnerPos);
 				}
 			}
 		}
diff --git a/src/Root.cpp b/src/Root.cpp
index 3e30d8a07..f773ab06e 100644
--- a/src/Root.cpp
+++ b/src/Root.cpp
@@ -1,4 +1,4 @@
-
+
 #include "Globals.h"  // NOTE: MSVC stupidness requires this to be the same across all modules
 
 #include "Root.h"
@@ -352,22 +352,16 @@ void cRoot::Start(std::unique_ptr<cSettingsRepositoryInterface> a_OverridesRepo)
 void cRoot::StopServer()
 {
 	// Kick all players from the server with custom disconnect message
-	class cPlayerCallback : public cPlayerListCallback
-	{
-		AString m_ShutdownMessage;
-		virtual bool Item(cPlayer * a_Player)
+
+	bool SentDisconnect = false;
+	cRoot::Get()->ForEachPlayer([&](cPlayer & a_Player)
 		{
-			a_Player->GetClientHandlePtr()->Kick(m_ShutdownMessage);
-			m_HasSentDisconnect = true;
+			a_Player.GetClientHandlePtr()->Kick(m_Server->GetShutdownMessage());
+			SentDisconnect = true;
 			return false;
 		}
-	public:
-		bool m_HasSentDisconnect;
-		cPlayerCallback(AString a_ShutdownMessage) : m_ShutdownMessage(a_ShutdownMessage) { m_HasSentDisconnect = false; }
-	} PlayerCallback(m_Server->GetShutdownMessage());
-
-	cRoot::Get()->ForEachPlayer(PlayerCallback);
-	if (PlayerCallback.m_HasSentDisconnect)
+	);
+	if (SentDisconnect)
 	{
 		std::this_thread::sleep_for(std::chrono::seconds(1));
 	}
@@ -584,14 +578,13 @@ cWorld * cRoot::GetWorld(const AString & a_WorldName)
 
 
 
-bool cRoot::ForEachWorld(cWorldListCallback & a_Callback)
+bool cRoot::ForEachWorld(const cWorldListCallback & a_Callback)
 {
-	for (WorldMap::iterator itr = m_WorldsByName.begin(), itr2 = itr; itr != m_WorldsByName.end(); itr = itr2)
+	for (auto & World : m_WorldsByName)
 	{
-		++itr2;
-		if (itr->second != nullptr)
+		if (World.second != nullptr)
 		{
-			if (a_Callback.Item(itr->second))
+			if (a_Callback(*World.second))
 			{
 				return false;
 			}
@@ -750,7 +743,7 @@ void cRoot::BroadcastChat(const cCompositeChat & a_Message)
 
 
 
-bool cRoot::ForEachPlayer(cPlayerListCallback & a_Callback)
+bool cRoot::ForEachPlayer(const cPlayerListCallback & a_Callback)
 {
 	for (WorldMap::iterator itr = m_WorldsByName.begin(), itr2 = itr; itr != m_WorldsByName.end(); itr = itr2)
 	{
@@ -767,20 +760,22 @@ bool cRoot::ForEachPlayer(cPlayerListCallback & a_Callback)
 
 
 
-bool cRoot::FindAndDoWithPlayer(const AString & a_PlayerName, cPlayerListCallback & a_Callback)
+bool cRoot::FindAndDoWithPlayer(const AString & a_PlayerName, const cPlayerListCallback & a_Callback)
 {
-	class cCallback : public cPlayerListCallback
+	class cCallback
 	{
 		size_t        m_BestRating;
 		size_t        m_NameLength;
 		const AString m_PlayerName;
 
-		virtual bool Item (cPlayer * a_pPlayer)
+	public:
+
+		bool operator () (cPlayer & a_Player)
 		{
-			size_t Rating = RateCompareString (m_PlayerName, a_pPlayer->GetName());
+			size_t Rating = RateCompareString (m_PlayerName, a_Player.GetName());
 			if ((Rating > 0) && (Rating >= m_BestRating))
 			{
-				m_BestMatch = a_pPlayer->GetName();
+				m_BestMatch = a_Player.GetName();
 				if (Rating > m_BestRating)
 				{
 					m_NumMatches = 0;
@@ -795,7 +790,6 @@ bool cRoot::FindAndDoWithPlayer(const AString & a_PlayerName, cPlayerListCallbac
 			return false;
 		}
 
-	public:
 		cCallback (const AString & a_CBPlayerName) :
 			m_BestRating(0),
 			m_NameLength(a_CBPlayerName.length()),
@@ -820,7 +814,7 @@ bool cRoot::FindAndDoWithPlayer(const AString & a_PlayerName, cPlayerListCallbac
 
 
 
-bool cRoot::DoWithPlayerByUUID(const cUUID & a_PlayerUUID, cPlayerListCallback & a_Callback)
+bool cRoot::DoWithPlayerByUUID(const cUUID & a_PlayerUUID, const cPlayerListCallback & a_Callback)
 {
 	for (WorldMap::iterator itr = m_WorldsByName.begin(); itr !=  m_WorldsByName.end(); ++itr)
 	{
@@ -836,7 +830,7 @@ bool cRoot::DoWithPlayerByUUID(const cUUID & a_PlayerUUID, cPlayerListCallback &
 
 
 
-bool cRoot::DoWithPlayer(const AString & a_PlayerName, cPlayerListCallback & a_Callback)
+bool cRoot::DoWithPlayer(const AString & a_PlayerName, const cPlayerListCallback & a_Callback)
 {
 	for (auto World : m_WorldsByName)
 	{
@@ -1028,25 +1022,11 @@ int cRoot::GetFurnaceFuelBurnTime(const cItem & a_Fuel)
 AStringVector cRoot::GetPlayerTabCompletionMultiWorld(const AString & a_Text)
 {
 	AStringVector Results;
-	class cWorldCallback : public cWorldListCallback
-	{
-	public:
-		cWorldCallback(AStringVector & a_Results, const AString & a_Search) :
-			m_Results(a_Results),
-			m_Search(a_Search)
+	ForEachWorld([&](cWorld & a_World)
 		{
-		}
-
-		virtual bool Item(cWorld * a_World) override
-		{
-			a_World->TabCompleteUserName(m_Search, m_Results);
+			a_World.TabCompleteUserName(a_Text, Results);
 			return false;
 		}
-	private:
-		AStringVector & m_Results;
-		const AString & m_Search;
-	} WC(Results, a_Text);
-
-	Get()->ForEachWorld(WC);
+	);
 	return Results;
 }
diff --git a/src/Root.h b/src/Root.h
index 44567018d..09e2c7880 100644
--- a/src/Root.h
+++ b/src/Root.h
@@ -1,10 +1,11 @@
-
+
 #pragma once
 
 #include "Protocol/Authenticator.h"
 #include "Protocol/MojangAPI.h"
 #include "HTTP/HTTPServer.h"
 #include "Defines.h"
+#include <functional>
 #include "RankManager.h"
 
 
@@ -27,8 +28,8 @@ class cSettingsRepositoryInterface;
 class cDeadlockDetect;
 class cUUID;
 
-typedef cItemCallback<cPlayer> cPlayerListCallback;
-typedef cItemCallback<cWorld>  cWorldListCallback;
+using cPlayerListCallback =  std::function<bool(cPlayer &)>;
+using cWorldListCallback  =  std::function<bool(cWorld  &)>;
 
 namespace Json
 {
@@ -76,7 +77,7 @@ public:
 	// tolua_end
 
 	/** Calls the callback for each world; returns true if the callback didn't abort (return true) */
-	bool ForEachWorld(cWorldListCallback & a_Callback);  // >> Exported in ManualBindings <<
+	bool ForEachWorld(const cWorldListCallback & a_Callback);  // >> Exported in ManualBindings <<
 
 	/** Writes chunkstats, for each world and totals, to the output callback */
 	void LogChunkStats(cCommandOutputCallback & a_Output);
@@ -136,16 +137,16 @@ public:
 	void SaveAllChunks(void);  // tolua_export
 
 	/** Calls the callback for each player in all worlds */
-	bool ForEachPlayer(cPlayerListCallback & a_Callback);  // >> EXPORTED IN MANUALBINDINGS <<
+	bool ForEachPlayer(const cPlayerListCallback & a_Callback);  // >> EXPORTED IN MANUALBINDINGS <<
 
 	/** Finds a player from a partial or complete player name and calls the callback - case-insensitive */
-	bool FindAndDoWithPlayer(const AString & a_PlayerName, cPlayerListCallback & a_Callback);  // >> EXPORTED IN MANUALBINDINGS <<
+	bool FindAndDoWithPlayer(const AString & a_PlayerName, const cPlayerListCallback & a_Callback);  // >> EXPORTED IN MANUALBINDINGS <<
 
 	/** Finds the player over his uuid and calls the callback */
-	bool DoWithPlayerByUUID(const cUUID & a_PlayerUUID, cPlayerListCallback & a_Callback);  // >> EXPORTED IN MANUALBINDINGS <<
+	bool DoWithPlayerByUUID(const cUUID & a_PlayerUUID, const cPlayerListCallback & a_Callback);  // >> EXPORTED IN MANUALBINDINGS <<
 
 	/** Finds the player using it's complete username and calls the callback */
-	bool DoWithPlayer(const AString & a_PlayerName, cPlayerListCallback & a_Callback);
+	bool DoWithPlayer(const AString & a_PlayerName, const cPlayerListCallback & a_Callback);
 
 	/** Send playerlist of all worlds to player */
 	void SendPlayerLists(cPlayer * a_DestPlayer);
diff --git a/src/Scoreboard.cpp b/src/Scoreboard.cpp
index 4dde5b2dd..5faf88f39 100644
--- a/src/Scoreboard.cpp
+++ b/src/Scoreboard.cpp
@@ -1,4 +1,4 @@
-
+
 // Scoreboard.cpp
 
 // Implementation of a scoreboard that keeps track of specified objectives
@@ -487,7 +487,7 @@ cObjective * cScoreboard::GetObjectiveIn(eDisplaySlot a_Slot)
 
 
 
-bool cScoreboard::ForEachObjectiveWith(cObjective::eType a_Type, cObjectiveCallback & a_Callback)
+bool cScoreboard::ForEachObjectiveWith(cObjective::eType a_Type, const cObjectiveCallback & a_Callback)
 {
 	cCSLock Lock(m_CSObjectives);
 
@@ -496,7 +496,7 @@ bool cScoreboard::ForEachObjectiveWith(cObjective::eType a_Type, cObjectiveCallb
 		if (it->second.GetType() == a_Type)
 		{
 			// Call callback
-			if (a_Callback.Item(&it->second))
+			if (a_Callback(it->second))
 			{
 				return false;
 			}
@@ -509,14 +509,14 @@ bool cScoreboard::ForEachObjectiveWith(cObjective::eType a_Type, cObjectiveCallb
 
 
 
-bool cScoreboard::ForEachObjective(cObjectiveCallback & a_Callback)
+bool cScoreboard::ForEachObjective(const cObjectiveCallback & a_Callback)
 {
 	cCSLock Lock(m_CSObjectives);
 
 	for (cObjectiveMap::iterator it = m_Objectives.begin(); it != m_Objectives.end(); ++it)
 	{
 		// Call callback
-		if (a_Callback.Item(&it->second))
+		if (a_Callback(it->second))
 		{
 			return false;
 		}
@@ -528,14 +528,14 @@ bool cScoreboard::ForEachObjective(cObjectiveCallback & a_Callback)
 
 
 
-bool cScoreboard::ForEachTeam(cTeamCallback & a_Callback)
+bool cScoreboard::ForEachTeam(const cTeamCallback & a_Callback)
 {
 	cCSLock Lock(m_CSTeams);
 
 	for (cTeamMap::iterator it = m_Teams.begin(); it != m_Teams.end(); ++it)
 	{
 		// Call callback
-		if (a_Callback.Item(&it->second))
+		if (a_Callback(it->second))
 		{
 			return false;
 		}
diff --git a/src/Scoreboard.h b/src/Scoreboard.h
index 597c502c7..047a0cf7b 100644
--- a/src/Scoreboard.h
+++ b/src/Scoreboard.h
@@ -1,4 +1,4 @@
-
+
 // Scoreboard.h
 
 // Implementation of a scoreboard that keeps track of specified objectives
@@ -11,14 +11,15 @@
 
 
 
+#include <functional>
 
 
 class cObjective;
 class cTeam;
 class cWorld;
 
-typedef cItemCallback<cObjective> cObjectiveCallback;
-typedef cItemCallback<cTeam>      cTeamCallback;
+using cObjectiveCallback = std::function<bool(cObjective &)>;
+using cTeamCallback      = std::function<bool(cTeam &)>;
 
 
 
@@ -266,15 +267,15 @@ public:
 
 	/** Execute callback for each objective with the specified type
 	Returns true if all objectives processed, false if the callback aborted by returning true. */
-	bool ForEachObjectiveWith(cObjective::eType a_Type, cObjectiveCallback & a_Callback);
+	bool ForEachObjectiveWith(cObjective::eType a_Type, const cObjectiveCallback & a_Callback);
 
 	/** Execute callback for each objective.
 	Returns true if all objectives have been processed, false if the callback aborted by returning true. */
-	bool ForEachObjective(cObjectiveCallback & a_Callback);  // Exported in ManualBindings.cpp
+	bool ForEachObjective(const cObjectiveCallback & a_Callback);  // Exported in ManualBindings.cpp
 
 	/** Execute callback for each team.
 	Returns true if all teams have been processed, false if the callback aborted by returning true. */
-	bool ForEachTeam(cTeamCallback & a_Callback);  // Exported in ManualBindings.cpp
+	bool ForEachTeam(const cTeamCallback & a_Callback);  // Exported in ManualBindings.cpp
 
 	void SetDisplay(cObjective * a_Objective, eDisplaySlot a_Slot);
 
diff --git a/src/Server.cpp b/src/Server.cpp
index 6ddb14ae5..89dccb1f1 100644
--- a/src/Server.cpp
+++ b/src/Server.cpp
@@ -498,26 +498,20 @@ void cServer::ExecuteConsoleCommand(const AString & a_Cmd, cCommandOutputCallbac
 	}
 	if (split[0] == "destroyentities")
 	{
-		class WorldCallback : public cWorldListCallback
-		{
-			virtual bool Item(cWorld * a_World) override
+		cRoot::Get()->ForEachWorld([](cWorld & a_World)
 			{
-				class EntityCallback : public cEntityCallback
-				{
-					virtual bool Item(cEntity * a_Entity) override
+				a_World.ForEachEntity([](cEntity & a_Entity)
 					{
-						if (!a_Entity->IsPlayer())
+						if (!a_Entity.IsPlayer())
 						{
-							a_Entity->Destroy();
+							a_Entity.Destroy();
 						}
 						return false;
 					}
-				} EC;
-				a_World->ForEachEntity(EC);
+				);
 				return false;
 			}
-		} WC;
-		cRoot::Get()->ForEachWorld(WC);
+		);
 		a_Output.Out("Destroyed all entities");
 		a_Output.Finished();
 		return;
diff --git a/src/Simulator/IncrementalRedstoneSimulator/CommandBlockHandler.h b/src/Simulator/IncrementalRedstoneSimulator/CommandBlockHandler.h
index 91fbe05ff..de0f23620 100644
--- a/src/Simulator/IncrementalRedstoneSimulator/CommandBlockHandler.h
+++ b/src/Simulator/IncrementalRedstoneSimulator/CommandBlockHandler.h
@@ -44,17 +44,12 @@ public:
 			return {};
 		}
 
-		class cSetPowerToCommandBlock : public cCommandBlockCallback
-		{
-		public:
-			virtual bool Item(cCommandBlockEntity * a_CommandBlock) override
+		a_World.DoWithCommandBlockAt(a_Position.x, a_Position.y, a_Position.z, [](cCommandBlockEntity & a_CommandBlock)
 			{
-				a_CommandBlock->Activate();
+				a_CommandBlock.Activate();
 				return false;
 			}
-		} CmdBlockSP;
-
-		a_World.DoWithCommandBlockAt(a_Position.x, a_Position.y, a_Position.z, CmdBlockSP);
+		);
 		return {};
 	}
 
diff --git a/src/Simulator/IncrementalRedstoneSimulator/DropSpenserHandler.h b/src/Simulator/IncrementalRedstoneSimulator/DropSpenserHandler.h
index 62b37eb1d..4974324a0 100644
--- a/src/Simulator/IncrementalRedstoneSimulator/DropSpenserHandler.h
+++ b/src/Simulator/IncrementalRedstoneSimulator/DropSpenserHandler.h
@@ -56,18 +56,12 @@ public:
 		bool WasPoweredPreviously = IsActivated(a_Meta);
 		if (IsPoweredNow && !WasPoweredPreviously)
 		{
-			class cSetPowerToDropSpenser :
-				public cDropSpenserCallback
-			{
-			public:
-				virtual bool Item(cDropSpenserEntity * a_DropSpenser) override
+			a_World.DoWithDropSpenserAt(a_Position.x, a_Position.y, a_Position.z, [](cDropSpenserEntity & a_DropSpenser)
 				{
-					a_DropSpenser->Activate();
+					a_DropSpenser.Activate();
 					return false;
 				}
-			} DrSpSP;
-
-			a_World.DoWithDropSpenserAt(a_Position.x, a_Position.y, a_Position.z, DrSpSP);
+			);
 		}
 
 		// Update the internal dropspenser state if necessary
diff --git a/src/Simulator/IncrementalRedstoneSimulator/NoteBlockHandler.h b/src/Simulator/IncrementalRedstoneSimulator/NoteBlockHandler.h
index add608654..ba6c695d6 100644
--- a/src/Simulator/IncrementalRedstoneSimulator/NoteBlockHandler.h
+++ b/src/Simulator/IncrementalRedstoneSimulator/NoteBlockHandler.h
@@ -45,17 +45,12 @@ public:
 			return {};
 		}
 
-		class cSetPowerToNoteBlock : public cNoteBlockCallback
-		{
-		public:
-			virtual bool Item(cNoteEntity * a_NoteBlock) override
+		a_World.DoWithNoteBlockAt(a_Position.x, a_Position.y, a_Position.z, [](cNoteEntity & a_NoteBlock)
 			{
-				a_NoteBlock->MakeSound();
+				a_NoteBlock.MakeSound();
 				return false;
 			}
-		} NoteBlockSP;
-
-		a_World.DoWithNoteBlockAt(a_Position.x, a_Position.y, a_Position.z, NoteBlockSP);
+		);
 
 		return {};
 	}
diff --git a/src/Simulator/IncrementalRedstoneSimulator/PressurePlateHandler.h b/src/Simulator/IncrementalRedstoneSimulator/PressurePlateHandler.h
index 14d7baf85..93759408d 100644
--- a/src/Simulator/IncrementalRedstoneSimulator/PressurePlateHandler.h
+++ b/src/Simulator/IncrementalRedstoneSimulator/PressurePlateHandler.h
@@ -27,49 +27,37 @@ public:
 	{
 		UNUSED(a_Meta);
 
-		class cPressurePlateCallback :
-			public cEntityCallback
-		{
-		public:
-			cPressurePlateCallback(void) :
-				m_NumberOfEntities(0),
-				m_FoundPlayer(false)
+		unsigned int NumberOfEntities;
+		bool FoundPlayer;
+		a_World.ForEachEntityInBox(cBoundingBox(Vector3d(0.5, 0, 0.5) + a_Position, 0.5, 0.5), [&](cEntity & a_Entity)
 			{
-			}
-
-			virtual bool Item(cEntity * a_Entity) override
-			{
-				if (a_Entity->IsPlayer())
+				if (a_Entity.IsPlayer())
 				{
-					m_FoundPlayer = true;
+					FoundPlayer = true;
 				}
 
-				m_NumberOfEntities++;
+				NumberOfEntities++;
 				return false;
 			}
-
-			unsigned int m_NumberOfEntities;
-			bool m_FoundPlayer;
-		} PressurePlateCallback;
-		a_World.ForEachEntityInBox(cBoundingBox(Vector3d(0.5, 0, 0.5) + a_Position, 0.5, 0.5), PressurePlateCallback);
+		);
 
 		switch (a_BlockType)
 		{
 			case E_BLOCK_STONE_PRESSURE_PLATE:
 			{
-				return (PressurePlateCallback.m_FoundPlayer ? 15 : 0);
+				return (FoundPlayer ? 15 : 0);
 			}
 			case E_BLOCK_WOODEN_PRESSURE_PLATE:
 			{
-				return (PressurePlateCallback.m_NumberOfEntities != 0 ? 15 : 0);
+				return (NumberOfEntities != 0 ? 15 : 0);
 			}
 			case E_BLOCK_HEAVY_WEIGHTED_PRESSURE_PLATE:
 			{
-				return std::min(static_cast<unsigned char>(CeilC(PressurePlateCallback.m_NumberOfEntities / 10.f)), static_cast<unsigned char>(15));
+				return std::min(static_cast<unsigned char>(CeilC(NumberOfEntities / 10.f)), static_cast<unsigned char>(15));
 			}
 			case E_BLOCK_LIGHT_WEIGHTED_PRESSURE_PLATE:
 			{
-				return std::min(static_cast<unsigned char>(PressurePlateCallback.m_NumberOfEntities), static_cast<unsigned char>(15));
+				return std::min(static_cast<unsigned char>(NumberOfEntities), static_cast<unsigned char>(15));
 			}
 			default:
 			{
diff --git a/src/Simulator/IncrementalRedstoneSimulator/RedstoneComparatorHandler.h b/src/Simulator/IncrementalRedstoneSimulator/RedstoneComparatorHandler.h
index 55efee6b5..6e3d080aa 100644
--- a/src/Simulator/IncrementalRedstoneSimulator/RedstoneComparatorHandler.h
+++ b/src/Simulator/IncrementalRedstoneSimulator/RedstoneComparatorHandler.h
@@ -44,17 +44,12 @@ public:
 		UNUSED(a_Position);
 		UNUSED(a_BlockType);
 
-		class cContainerCallback : public cBlockEntityCallback
-		{
-		public:
-			cContainerCallback() : m_SignalStrength(0)
-			{
-			}
-
-			virtual bool Item(cBlockEntity * a_BlockEntity) override
+		UInt8 SignalStrength = 0;
+		auto RearCoordinate = cBlockComparatorHandler::GetRearCoordinate(a_Position, a_Meta & 0x3);
+		a_World.DoWithBlockEntityAt(RearCoordinate.x, RearCoordinate.y, RearCoordinate.z, [&](cBlockEntity & a_BlockEntity)
 			{
 				// Skip BlockEntities that don't have slots
-				auto BlockEntityWithItems = dynamic_cast<cBlockEntityWithItems *>(a_BlockEntity);
+				auto BlockEntityWithItems = dynamic_cast<cBlockEntityWithItems *>(&a_BlockEntity);
 				if (BlockEntityWithItems == nullptr)
 				{
 					return false;
@@ -68,23 +63,18 @@ public:
 					Fullness += static_cast<float>(Contents.GetSlot(Slot).m_ItemCount) / Contents.GetSlot(Slot).GetMaxStackSize();
 				}
 
-				m_SignalStrength = (Fullness < 0.001 /* container empty? */) ? 0 : static_cast<unsigned char>(1 + (Fullness / Contents.GetNumSlots()) * 14);
+				SignalStrength = (Fullness < 0.001 /* container empty? */) ? 0 : static_cast<UInt8>(1 + (Fullness / Contents.GetNumSlots()) * 14);
 				return false;
 			}
-
-			unsigned char m_SignalStrength;
-		} CCB;
-
-		auto RearCoordinate = cBlockComparatorHandler::GetRearCoordinate(a_Position, a_Meta & 0x3);
-		a_World.DoWithBlockEntityAt(RearCoordinate.x, RearCoordinate.y, RearCoordinate.z, CCB);
-		auto RearPower = CCB.m_SignalStrength;
+		);
+		auto RearPower = SignalStrength;
 		auto RearType = a_World.GetBlock(RearCoordinate);
 
 		auto PotentialSourceHandler = cIncrementalRedstoneSimulator::GetComponentHandler(RearType);
 		if (PotentialSourceHandler != nullptr)
 		{
 			NIBBLETYPE RearMeta = a_World.GetBlockMeta(RearCoordinate);
-			RearPower = std::max(CCB.m_SignalStrength, PotentialSourceHandler->GetPowerDeliveredToPosition(a_World, RearCoordinate, RearType, RearMeta, a_Position, a_BlockType));
+			RearPower = std::max(SignalStrength, PotentialSourceHandler->GetPowerDeliveredToPosition(a_World, RearCoordinate, RearType, RearMeta, a_Position, a_BlockType));
 		}
 
 		return RearPower;
diff --git a/src/Simulator/IncrementalRedstoneSimulator/TrappedChestHandler.h b/src/Simulator/IncrementalRedstoneSimulator/TrappedChestHandler.h
index 8b7b82d49..d280f73e3 100644
--- a/src/Simulator/IncrementalRedstoneSimulator/TrappedChestHandler.h
+++ b/src/Simulator/IncrementalRedstoneSimulator/TrappedChestHandler.h
@@ -1,4 +1,4 @@
-
+
 #pragma once
 
 #include "RedstoneHandler.h"
@@ -28,38 +28,15 @@ public:
 		UNUSED(a_BlockType);
 		UNUSED(a_Meta);
 
-		class cGetTrappedChestPlayers :
-			public cItemCallback<cChestEntity>
-		{
-		public:
-			cGetTrappedChestPlayers(void) :
-				m_NumberOfPlayers(0)
-			{
-			}
-
-			virtual ~cGetTrappedChestPlayers() override
-			{
-			}
-
-			virtual bool Item(cChestEntity * a_Chest) override
+		int NumberOfPlayers = 0;
+		VERIFY(!a_World.DoWithChestAt(a_Position.x, a_Position.y, a_Position.z, [&](cChestEntity & a_Chest)
 			{
-				ASSERT(a_Chest->GetBlockType() == E_BLOCK_TRAPPED_CHEST);
-				m_NumberOfPlayers = a_Chest->GetNumberOfPlayers();
+				ASSERT(a_Chest.GetBlockType() == E_BLOCK_TRAPPED_CHEST);
+				NumberOfPlayers = a_Chest.GetNumberOfPlayers();
 				return true;
 			}
-
-			unsigned char GetPowerLevel(void) const
-			{
-				return static_cast<unsigned char>(std::min(m_NumberOfPlayers, 15));
-			}
-
-		private:
-			int m_NumberOfPlayers;
-
-		} GTCP;
-
-		VERIFY(!a_World.DoWithChestAt(a_Position.x, a_Position.y, a_Position.z, GTCP));
-		return GTCP.GetPowerLevel();
+		));
+		return static_cast<unsigned char>(std::min(NumberOfPlayers, 15));
 	}
 
 	virtual cVector3iArray Update(cWorld & a_World, const Vector3i & a_Position, BLOCKTYPE a_BlockType, NIBBLETYPE a_Meta, PoweringData a_PoweringData) const override
diff --git a/src/Simulator/IncrementalRedstoneSimulator/TripwireHookHandler.h b/src/Simulator/IncrementalRedstoneSimulator/TripwireHookHandler.h
index 85c05430c..2fb85f58c 100644
--- a/src/Simulator/IncrementalRedstoneSimulator/TripwireHookHandler.h
+++ b/src/Simulator/IncrementalRedstoneSimulator/TripwireHookHandler.h
@@ -39,26 +39,7 @@ public:
 
 			if (Type == E_BLOCK_TRIPWIRE)
 			{
-				class cTripwireCallback :
-					public cEntityCallback
-				{
-				public:
-					cTripwireCallback(void) :
-						m_NumberOfEntities(0),
-						m_FoundPlayer(false)
-					{
-					}
-
-					virtual bool Item(cEntity * a_Entity) override
-					{
-						return true;
-					}
-
-					unsigned int m_NumberOfEntities;
-					bool m_FoundPlayer;
-				} TripwireCallback;
-
-				if (!a_World.ForEachEntityInBox(cBoundingBox(Vector3d(0.5, 0, 0.5) + Position, 0.5, 0.5), TripwireCallback))
+				if (!a_World.ForEachEntityInBox(cBoundingBox(Vector3d(0.5, 0, 0.5) + Position, 0.5, 0.5), [](cEntity &) { return true; }))
 				{
 					FoundActivated = true;
 				}
diff --git a/src/UI/Window.cpp b/src/UI/Window.cpp
index 8bbc4f482..9fbc4d988 100644
--- a/src/UI/Window.cpp
+++ b/src/UI/Window.cpp
@@ -1,4 +1,4 @@
-#include "Globals.h"  // NOTE: MSVC stupidness requires this to be the same across all modules
+#include "Globals.h"  // NOTE: MSVC stupidness requires this to be the same across all modules
 
 #include "Window.h"
 #include "WindowOwner.h"
@@ -362,12 +362,12 @@ void cWindow::OwnerDestroyed()
 
 
 
-bool cWindow::ForEachPlayer(cItemCallback<cPlayer> & a_Callback)
+bool cWindow::ForEachPlayer(const cPlayerListCallback & a_Callback)
 {
 	cCSLock Lock(m_CS);
-	for (cPlayerList::iterator itr = m_OpenedBy.begin(), end = m_OpenedBy.end(); itr != end; ++itr)
+	for (auto & Player : m_OpenedBy)
 	{
-		if (a_Callback.Item(*itr))
+		if (a_Callback(*Player))
 		{
 			return false;
 		}
@@ -379,12 +379,12 @@ bool cWindow::ForEachPlayer(cItemCallback<cPlayer> & a_Callback)
 
 
 
-bool cWindow::ForEachClient(cItemCallback<cClientHandle> & a_Callback)
+bool cWindow::ForEachClient(cClientHandleCallback & a_Callback)
 {
 	cCSLock Lock(m_CS);
-	for (cPlayerList::iterator itr = m_OpenedBy.begin(), end = m_OpenedBy.end(); itr != end; ++itr)
+	for (auto & Player : m_OpenedBy)
 	{
-		if (a_Callback.Item((*itr)->GetClientHandle()))
+		if (a_Callback(*Player->GetClientHandle()))
 		{
 			return false;
 		}
diff --git a/src/UI/Window.h b/src/UI/Window.h
index d7a29dc47..f2023c731 100644
--- a/src/UI/Window.h
+++ b/src/UI/Window.h
@@ -1,4 +1,4 @@
-
+
 // Window.h
 
 // Interfaces to the cWindow class representing a UI window for a specific block
@@ -9,6 +9,7 @@
 
 #pragma once
 
+#include <functional>
 #include "../ItemGrid.h"
 
 
@@ -31,7 +32,8 @@ class cWorld;
 
 typedef std::list<cPlayer *> cPlayerList;
 typedef std::vector<cSlotArea *> cSlotAreas;
-
+using cPlayerListCallback   = std::function<bool(cPlayer       &)>;
+using cClientHandleCallback = std::function<bool(cClientHandle &)>;
 
 
 
@@ -151,10 +153,10 @@ public:
 	void OwnerDestroyed(void);
 
 	/** Calls the callback safely for each player that has this window open; returns true if all players have been enumerated */
-	bool ForEachPlayer(cItemCallback<cPlayer> & a_Callback);
+	bool ForEachPlayer(const cPlayerListCallback & a_Callback);
 
 	/** Calls the callback safely for each client that has this window open; returns true if all clients have been enumerated */
-	bool ForEachClient(cItemCallback<cClientHandle> & a_Callback);
+	bool ForEachClient(cClientHandleCallback & a_Callback);
 
 	/** Called on shift-clicking to distribute the stack into other areas; Modifies a_ItemStack as it is distributed!
 	if a_ShouldApply is true, the changes are written into the slots;
diff --git a/src/WebAdmin.cpp b/src/WebAdmin.cpp
index eefe57b73..335b6b94e 100644
--- a/src/WebAdmin.cpp
+++ b/src/WebAdmin.cpp
@@ -22,30 +22,6 @@ static const char DEFAULT_WEBADMIN_PORTS[] = "8080";
 
 
 ////////////////////////////////////////////////////////////////////////////////
-// cPlayerAccum:
-
-/** Helper class - appends all player names together in an HTML list */
-class cPlayerAccum :
-	public cPlayerListCallback
-{
-	virtual bool Item(cPlayer * a_Player) override
-	{
-		m_Contents.append("<li>");
-		m_Contents.append(a_Player->GetName());
-		m_Contents.append("</li>");
-		return false;
-	}
-
-public:
-
-	AString m_Contents;
-} ;
-
-
-
-
-
-////////////////////////////////////////////////////////////////////////////////
 // cWebadminRequestData
 
 /** The form parser callbacks for requests in the "/webadmin" and "/~webadmin" paths */
diff --git a/src/World.cpp b/src/World.cpp
index acec3049e..9baf9500a 100644
--- a/src/World.cpp
+++ b/src/World.cpp
@@ -1,4 +1,4 @@
-
+
 #include "Globals.h"  // NOTE: MSVC stupidness requires this to be the same across all modules
 
 #include "World.h"
@@ -1117,59 +1117,52 @@ void cWorld::TickMobs(std::chrono::milliseconds a_Dt)
 			{
 				m_ChunkMap->SpawnMobs(Spawner);
 				// do the spawn
-				for (cMobSpawner::tSpawnedContainer::const_iterator itr2 = Spawner.getSpawned().begin(); itr2 != Spawner.getSpawned().end(); ++itr2)
+				for (auto & Mob : Spawner.getSpawned())
 				{
-					SpawnMobFinalize(std::move(const_cast<std::unique_ptr<cMonster> &>(*itr2)));
+					SpawnMobFinalize(std::move(Mob));
 				}
 			}
 		}  // for i - AllFamilies[]
 	}  // if (Spawning enabled)
 
-	class cCallback : public cEntityCallback
-	{
-		virtual bool Item(cEntity * a_Entity) override
+	ForEachEntity([=](cEntity & a_Entity)
 		{
-			if (!a_Entity->IsMob())
+			if (!a_Entity.IsMob())
 			{
 				return false;
 			}
-			if (!a_Entity->IsTicking())
+			if (!a_Entity.IsTicking())
 			{
 				return false;
 			}
 
-			auto Monster = static_cast<cMonster *>(a_Entity);
-			ASSERT(Monster->GetParentChunk() != nullptr);  // A ticking entity must have a valid parent chunk
+			auto & Monster = static_cast<cMonster &>(a_Entity);
+			ASSERT(Monster.GetParentChunk() != nullptr);  // A ticking entity must have a valid parent chunk
 
 			// Tick close mobs
-			if (Monster->GetParentChunk()->HasAnyClients())
+			if (Monster.GetParentChunk()->HasAnyClients())
 			{
-				Monster->Tick(m_Dt, *(a_Entity->GetParentChunk()));
+				Monster.Tick(a_Dt, *(a_Entity.GetParentChunk()));
 			}
 			// Destroy far hostile mobs except if last target was a player
-			else if ((Monster->GetMobFamily() == cMonster::eFamily::mfHostile) && !Monster->WasLastTargetAPlayer())
+			else if ((Monster.GetMobFamily() == cMonster::eFamily::mfHostile) && !Monster.WasLastTargetAPlayer())
 			{
-				if (Monster->GetMobType() != eMonsterType::mtWolf)
+				if (Monster.GetMobType() != eMonsterType::mtWolf)
 				{
-					Monster->Destroy(true);
+					Monster.Destroy(true);
 				}
 				else
 				{
-					auto Wolf = static_cast<cWolf *>(Monster);
-					if (Wolf->IsAngry())
+					auto & Wolf = static_cast<cWolf &>(Monster);
+					if (Wolf.IsAngry())
 					{
-						Monster->Destroy(true);
+						Monster.Destroy(true);
 					}
 				}
 			}
 			return false;
 		}
-	public:
-		std::chrono::milliseconds m_Dt;
-	} Callback;
-
-	Callback.m_Dt = a_Dt;
-	ForEachEntity(Callback);
+	);
 }
 
 
@@ -1321,7 +1314,7 @@ void cWorld::WakeUpSimulatorsInArea(const cCuboid & a_Area)
 
 
 
-bool cWorld::ForEachBlockEntityInChunk(int a_ChunkX, int a_ChunkZ, cBlockEntityCallback & a_Callback)
+bool cWorld::ForEachBlockEntityInChunk(int a_ChunkX, int a_ChunkZ, const cBlockEntityCallback & a_Callback)
 {
 	return m_ChunkMap->ForEachBlockEntityInChunk(a_ChunkX, a_ChunkZ, a_Callback);
 }
@@ -1330,7 +1323,7 @@ bool cWorld::ForEachBlockEntityInChunk(int a_ChunkX, int a_ChunkZ, cBlockEntityC
 
 
 
-bool cWorld::ForEachBrewingstandInChunk(int a_ChunkX, int a_ChunkZ, cBrewingstandCallback & a_Callback)
+bool cWorld::ForEachBrewingstandInChunk(int a_ChunkX, int a_ChunkZ, const cBrewingstandCallback & a_Callback)
 {
 	return m_ChunkMap->ForEachBrewingstandInChunk(a_ChunkX, a_ChunkZ, a_Callback);
 }
@@ -1339,7 +1332,7 @@ bool cWorld::ForEachBrewingstandInChunk(int a_ChunkX, int a_ChunkZ, cBrewingstan
 
 
 
-bool cWorld::ForEachChestInChunk(int a_ChunkX, int a_ChunkZ, cChestCallback & a_Callback)
+bool cWorld::ForEachChestInChunk(int a_ChunkX, int a_ChunkZ, const cChestCallback & a_Callback)
 {
 	return m_ChunkMap->ForEachChestInChunk(a_ChunkX, a_ChunkZ, a_Callback);
 }
@@ -1348,7 +1341,7 @@ bool cWorld::ForEachChestInChunk(int a_ChunkX, int a_ChunkZ, cChestCallback & a_
 
 
 
-bool cWorld::ForEachDispenserInChunk(int a_ChunkX, int a_ChunkZ, cDispenserCallback & a_Callback)
+bool cWorld::ForEachDispenserInChunk(int a_ChunkX, int a_ChunkZ, const cDispenserCallback & a_Callback)
 {
 	return m_ChunkMap->ForEachDispenserInChunk(a_ChunkX, a_ChunkZ, a_Callback);
 }
@@ -1357,7 +1350,7 @@ bool cWorld::ForEachDispenserInChunk(int a_ChunkX, int a_ChunkZ, cDispenserCallb
 
 
 
-bool cWorld::ForEachDropperInChunk(int a_ChunkX, int a_ChunkZ, cDropperCallback & a_Callback)
+bool cWorld::ForEachDropperInChunk(int a_ChunkX, int a_ChunkZ, const cDropperCallback & a_Callback)
 {
 	return m_ChunkMap->ForEachDropperInChunk(a_ChunkX, a_ChunkZ, a_Callback);
 }
@@ -1366,7 +1359,7 @@ bool cWorld::ForEachDropperInChunk(int a_ChunkX, int a_ChunkZ, cDropperCallback
 
 
 
-bool cWorld::ForEachDropSpenserInChunk(int a_ChunkX, int a_ChunkZ, cDropSpenserCallback & a_Callback)
+bool cWorld::ForEachDropSpenserInChunk(int a_ChunkX, int a_ChunkZ, const cDropSpenserCallback & a_Callback)
 {
 	return m_ChunkMap->ForEachDropSpenserInChunk(a_ChunkX, a_ChunkZ, a_Callback);
 }
@@ -1375,7 +1368,7 @@ bool cWorld::ForEachDropSpenserInChunk(int a_ChunkX, int a_ChunkZ, cDropSpenserC
 
 
 
-bool cWorld::ForEachFurnaceInChunk(int a_ChunkX, int a_ChunkZ, cFurnaceCallback & a_Callback)
+bool cWorld::ForEachFurnaceInChunk(int a_ChunkX, int a_ChunkZ, const cFurnaceCallback & a_Callback)
 {
 	return m_ChunkMap->ForEachFurnaceInChunk(a_ChunkX, a_ChunkZ, a_Callback);
 }
@@ -1430,7 +1423,7 @@ void cWorld::DoExplosionAt(double a_ExplosionSize, double a_BlockX, double a_Blo
 
 
 
-bool cWorld::DoWithBlockEntityAt(int a_BlockX, int a_BlockY, int a_BlockZ, cBlockEntityCallback & a_Callback)
+bool cWorld::DoWithBlockEntityAt(int a_BlockX, int a_BlockY, int a_BlockZ, const cBlockEntityCallback & a_Callback)
 {
 	return m_ChunkMap->DoWithBlockEntityAt(a_BlockX, a_BlockY, a_BlockZ, a_Callback);
 }
@@ -1439,7 +1432,7 @@ bool cWorld::DoWithBlockEntityAt(int a_BlockX, int a_BlockY, int a_BlockZ, cBloc
 
 
 
-bool cWorld::DoWithBeaconAt(int a_BlockX, int a_BlockY, int a_BlockZ, cBeaconCallback & a_Callback)
+bool cWorld::DoWithBeaconAt(int a_BlockX, int a_BlockY, int a_BlockZ, const cBeaconCallback & a_Callback)
 {
 	return m_ChunkMap->DoWithBeaconAt(a_BlockX, a_BlockY, a_BlockZ, a_Callback);
 }
@@ -1448,7 +1441,7 @@ bool cWorld::DoWithBeaconAt(int a_BlockX, int a_BlockY, int a_BlockZ, cBeaconCal
 
 
 
-bool cWorld::DoWithBedAt(int a_BlockX, int a_BlockY, int a_BlockZ, cBedCallback & a_Callback)
+bool cWorld::DoWithBedAt(int a_BlockX, int a_BlockY, int a_BlockZ, const cBedCallback & a_Callback)
 {
 	return m_ChunkMap->DoWithBedAt(a_BlockX, a_BlockY, a_BlockZ, a_Callback);
 }
@@ -1457,7 +1450,7 @@ bool cWorld::DoWithBedAt(int a_BlockX, int a_BlockY, int a_BlockZ, cBedCallback
 
 
 
-bool cWorld::DoWithBrewingstandAt(int a_BlockX, int a_BlockY, int a_BlockZ, cBrewingstandCallback & a_Callback)
+bool cWorld::DoWithBrewingstandAt(int a_BlockX, int a_BlockY, int a_BlockZ, const cBrewingstandCallback & a_Callback)
 {
 	return m_ChunkMap->DoWithBrewingstandAt(a_BlockX, a_BlockY, a_BlockZ, a_Callback);
 }
@@ -1466,7 +1459,7 @@ bool cWorld::DoWithBrewingstandAt(int a_BlockX, int a_BlockY, int a_BlockZ, cBre
 
 
 
-bool cWorld::DoWithChestAt(int a_BlockX, int a_BlockY, int a_BlockZ, cChestCallback & a_Callback)
+bool cWorld::DoWithChestAt(int a_BlockX, int a_BlockY, int a_BlockZ, const cChestCallback & a_Callback)
 {
 	return m_ChunkMap->DoWithChestAt(a_BlockX, a_BlockY, a_BlockZ, a_Callback);
 }
@@ -1475,7 +1468,7 @@ bool cWorld::DoWithChestAt(int a_BlockX, int a_BlockY, int a_BlockZ, cChestCallb
 
 
 
-bool cWorld::DoWithDispenserAt(int a_BlockX, int a_BlockY, int a_BlockZ, cDispenserCallback & a_Callback)
+bool cWorld::DoWithDispenserAt(int a_BlockX, int a_BlockY, int a_BlockZ, const cDispenserCallback & a_Callback)
 {
 	return m_ChunkMap->DoWithDispenserAt(a_BlockX, a_BlockY, a_BlockZ, a_Callback);
 }
@@ -1484,7 +1477,7 @@ bool cWorld::DoWithDispenserAt(int a_BlockX, int a_BlockY, int a_BlockZ, cDispen
 
 
 
-bool cWorld::DoWithDropperAt(int a_BlockX, int a_BlockY, int a_BlockZ, cDropperCallback & a_Callback)
+bool cWorld::DoWithDropperAt(int a_BlockX, int a_BlockY, int a_BlockZ, const cDropperCallback & a_Callback)
 {
 	return m_ChunkMap->DoWithDropperAt(a_BlockX, a_BlockY, a_BlockZ, a_Callback);
 }
@@ -1493,7 +1486,7 @@ bool cWorld::DoWithDropperAt(int a_BlockX, int a_BlockY, int a_BlockZ, cDropperC
 
 
 
-bool cWorld::DoWithDropSpenserAt(int a_BlockX, int a_BlockY, int a_BlockZ, cDropSpenserCallback & a_Callback)
+bool cWorld::DoWithDropSpenserAt(int a_BlockX, int a_BlockY, int a_BlockZ, const cDropSpenserCallback & a_Callback)
 {
 	return m_ChunkMap->DoWithDropSpenserAt(a_BlockX, a_BlockY, a_BlockZ, a_Callback);
 }
@@ -1502,7 +1495,7 @@ bool cWorld::DoWithDropSpenserAt(int a_BlockX, int a_BlockY, int a_BlockZ, cDrop
 
 
 
-bool cWorld::DoWithFurnaceAt(int a_BlockX, int a_BlockY, int a_BlockZ, cFurnaceCallback & a_Callback)
+bool cWorld::DoWithFurnaceAt(int a_BlockX, int a_BlockY, int a_BlockZ, const cFurnaceCallback & a_Callback)
 {
 	return m_ChunkMap->DoWithFurnaceAt(a_BlockX, a_BlockY, a_BlockZ, a_Callback);
 }
@@ -1511,7 +1504,7 @@ bool cWorld::DoWithFurnaceAt(int a_BlockX, int a_BlockY, int a_BlockZ, cFurnaceC
 
 
 
-bool cWorld::DoWithNoteBlockAt(int a_BlockX, int a_BlockY, int a_BlockZ, cNoteBlockCallback & a_Callback)
+bool cWorld::DoWithNoteBlockAt(int a_BlockX, int a_BlockY, int a_BlockZ, const cNoteBlockCallback & a_Callback)
 {
 	return m_ChunkMap->DoWithNoteBlockAt(a_BlockX, a_BlockY, a_BlockZ, a_Callback);
 }
@@ -1520,7 +1513,7 @@ bool cWorld::DoWithNoteBlockAt(int a_BlockX, int a_BlockY, int a_BlockZ, cNoteBl
 
 
 
-bool cWorld::DoWithCommandBlockAt(int a_BlockX, int a_BlockY, int a_BlockZ, cCommandBlockCallback & a_Callback)
+bool cWorld::DoWithCommandBlockAt(int a_BlockX, int a_BlockY, int a_BlockZ, const cCommandBlockCallback & a_Callback)
 {
 	return m_ChunkMap->DoWithCommandBlockAt(a_BlockX, a_BlockY, a_BlockZ, a_Callback);
 }
@@ -1529,7 +1522,7 @@ bool cWorld::DoWithCommandBlockAt(int a_BlockX, int a_BlockY, int a_BlockZ, cCom
 
 
 
-bool cWorld::DoWithMobHeadAt(int a_BlockX, int a_BlockY, int a_BlockZ, cMobHeadCallback & a_Callback)
+bool cWorld::DoWithMobHeadAt(int a_BlockX, int a_BlockY, int a_BlockZ, const cMobHeadCallback & a_Callback)
 {
 	return m_ChunkMap->DoWithMobHeadAt(a_BlockX, a_BlockY, a_BlockZ, a_Callback);
 }
@@ -1538,7 +1531,7 @@ bool cWorld::DoWithMobHeadAt(int a_BlockX, int a_BlockY, int a_BlockZ, cMobHeadC
 
 
 
-bool cWorld::DoWithFlowerPotAt(int a_BlockX, int a_BlockY, int a_BlockZ, cFlowerPotCallback & a_Callback)
+bool cWorld::DoWithFlowerPotAt(int a_BlockX, int a_BlockY, int a_BlockZ, const cFlowerPotCallback & a_Callback)
 {
 	return m_ChunkMap->DoWithFlowerPotAt(a_BlockX, a_BlockY, a_BlockZ, a_Callback);
 }
@@ -1556,7 +1549,7 @@ bool cWorld::GetSignLines(int a_BlockX, int a_BlockY, int a_BlockZ, AString & a_
 
 
 
-bool cWorld::DoWithChunk(int a_ChunkX, int a_ChunkZ, cChunkCallback & a_Callback)
+bool cWorld::DoWithChunk(int a_ChunkX, int a_ChunkZ, const cChunkCallback & a_Callback)
 {
 	return m_ChunkMap->DoWithChunk(a_ChunkX, a_ChunkZ, a_Callback);
 }
@@ -1565,31 +1558,7 @@ bool cWorld::DoWithChunk(int a_ChunkX, int a_ChunkZ, cChunkCallback & a_Callback
 
 
 
-bool cWorld::DoWithChunk(int a_ChunkX, int a_ChunkZ, std::function<bool(cChunk &)> a_Callback)
-{
-	struct cCallBackWrapper : cChunkCallback
-	{
-		cCallBackWrapper(std::function<bool(cChunk &)> a_InnerCallback) :
-			m_Callback(a_InnerCallback)
-		{
-		}
-
-		virtual bool Item(cChunk * a_Chunk)
-		{
-			return m_Callback(*a_Chunk);
-		}
-
-	private:
-		std::function<bool(cChunk &)> m_Callback;
-	} callback(a_Callback);
-	return m_ChunkMap->DoWithChunk(a_ChunkX, a_ChunkZ, callback);
-}
-
-
-
-
-
-bool cWorld::DoWithChunkAt(Vector3i a_BlockPos, std::function<bool(cChunk &)>  a_Callback)
+bool cWorld::DoWithChunkAt(Vector3i a_BlockPos, const cChunkCallback & a_Callback)
 {
 	return m_ChunkMap->DoWithChunkAt(a_BlockPos, a_Callback);
 }
@@ -3163,18 +3132,13 @@ bool cWorld::IsPlayerReferencedInWorldOrChunk(cPlayer & a_Player)
 
 
 
-bool cWorld::ForEachPlayer(cPlayerListCallback & a_Callback)
+bool cWorld::ForEachPlayer(const cPlayerListCallback & a_Callback)
 {
 	// Calls the callback for each player in the list
 	cCSLock Lock(m_CSPlayers);
-	for (cPlayerList::iterator itr = m_Players.begin(), itr2 = itr; itr != m_Players.end(); itr = itr2)
+	for (auto & Player : m_Players)
 	{
-		++itr2;
-		if (!(*itr)->IsTicking())
-		{
-			continue;
-		}
-		if (a_Callback.Item(*itr))
+		if (Player->IsTicking() && a_Callback(*Player))
 		{
 			return false;
 		}
@@ -3186,19 +3150,15 @@ bool cWorld::ForEachPlayer(cPlayerListCallback & a_Callback)
 
 
 
-bool cWorld::DoWithPlayer(const AString & a_PlayerName, cPlayerListCallback & a_Callback)
+bool cWorld::DoWithPlayer(const AString & a_PlayerName, const cPlayerListCallback & a_Callback)
 {
 	// Calls the callback for the specified player in the list
 	cCSLock Lock(m_CSPlayers);
-	for (cPlayerList::iterator itr = m_Players.begin(); itr != m_Players.end(); ++itr)
+	for (auto & Player : m_Players)
 	{
-		if (!(*itr)->IsTicking())
-		{
-			continue;
-		}
-		if (NoCaseCompare((*itr)->GetName(), a_PlayerName) == 0)
+		if (Player->IsTicking() && (NoCaseCompare(Player->GetName(), a_PlayerName) == 0))
 		{
-			a_Callback.Item(*itr);
+			a_Callback(*Player);
 			return true;
 		}
 	}  // for itr - m_Players[]
@@ -3209,7 +3169,7 @@ bool cWorld::DoWithPlayer(const AString & a_PlayerName, cPlayerListCallback & a_
 
 
 
-bool cWorld::FindAndDoWithPlayer(const AString & a_PlayerNameHint, cPlayerListCallback & a_Callback)
+bool cWorld::FindAndDoWithPlayer(const AString & a_PlayerNameHint, const cPlayerListCallback & a_Callback)
 {
 	cPlayer * BestMatch = nullptr;
 	size_t BestRating = 0;
@@ -3236,7 +3196,7 @@ bool cWorld::FindAndDoWithPlayer(const AString & a_PlayerNameHint, cPlayerListCa
 
 	if (BestMatch != nullptr)
 	{
-		return a_Callback.Item (BestMatch);
+		return a_Callback(*BestMatch);
 	}
 	return false;
 }
@@ -3245,27 +3205,14 @@ bool cWorld::FindAndDoWithPlayer(const AString & a_PlayerNameHint, cPlayerListCa
 
 
 
-bool cWorld::DoWithPlayerByUUID(const cUUID & a_PlayerUUID, cPlayerListCallback & a_Callback)
-{
-	return DoWithPlayerByUUID(a_PlayerUUID, std::bind(&cPlayerListCallback::Item, &a_Callback, std::placeholders::_1));
-}
-
-
-
-
-
-bool cWorld::DoWithPlayerByUUID(const cUUID & a_PlayerUUID, cLambdaPlayerCallback a_Callback)
+bool cWorld::DoWithPlayerByUUID(const cUUID & a_PlayerUUID, const cPlayerListCallback & a_Callback)
 {
 	cCSLock Lock(m_CSPlayers);
-	for (cPlayerList::iterator itr = m_Players.begin(); itr != m_Players.end(); ++itr)
+	for (auto & Player : m_Players)
 	{
-		if (!(*itr)->IsTicking())
+		if (Player->IsTicking() && (Player->GetUUID() == a_PlayerUUID))
 		{
-			continue;
-		}
-		if ((*itr)->GetUUID() == a_PlayerUUID)
-		{
-			return a_Callback(*itr);
+			return a_Callback(*Player);
 		}
 	}
 	return false;
@@ -3333,7 +3280,7 @@ void cWorld::SendPlayerList(cPlayer * a_DestPlayer)
 
 
 
-bool cWorld::ForEachEntity(cEntityCallback & a_Callback)
+bool cWorld::ForEachEntity(const cEntityCallback & a_Callback)
 {
 	return m_ChunkMap->ForEachEntity(a_Callback);
 }
@@ -3342,7 +3289,7 @@ bool cWorld::ForEachEntity(cEntityCallback & a_Callback)
 
 
 
-bool cWorld::ForEachEntityInChunk(int a_ChunkX, int a_ChunkZ, cEntityCallback & a_Callback)
+bool cWorld::ForEachEntityInChunk(int a_ChunkX, int a_ChunkZ, const cEntityCallback & a_Callback)
 {
 	return m_ChunkMap->ForEachEntityInChunk(a_ChunkX, a_ChunkZ, a_Callback);
 }
@@ -3351,7 +3298,7 @@ bool cWorld::ForEachEntityInChunk(int a_ChunkX, int a_ChunkZ, cEntityCallback &
 
 
 
-bool cWorld::ForEachEntityInBox(const cBoundingBox & a_Box, cEntityCallback & a_Callback)
+bool cWorld::ForEachEntityInBox(const cBoundingBox & a_Box, const cEntityCallback & a_Callback)
 {
 	return m_ChunkMap->ForEachEntityInBox(a_Box, a_Callback);
 }
@@ -3360,16 +3307,7 @@ bool cWorld::ForEachEntityInBox(const cBoundingBox & a_Box, cEntityCallback & a_
 
 
 
-bool cWorld::DoWithEntityByID(UInt32 a_UniqueID, cEntityCallback & a_Callback)
-{
-	return DoWithEntityByID(a_UniqueID, std::bind(&cEntityCallback::Item, &a_Callback, std::placeholders::_1));
-}
-
-
-
-
-
-bool cWorld::DoWithEntityByID(UInt32 a_UniqueID, cLambdaEntityCallback a_Callback)
+bool cWorld::DoWithEntityByID(UInt32 a_UniqueID, const cEntityCallback & a_Callback)
 {
 	// First check the entities-to-add:
 	{
@@ -3378,7 +3316,7 @@ bool cWorld::DoWithEntityByID(UInt32 a_UniqueID, cLambdaEntityCallback a_Callbac
 		{
 			if (ent->GetUniqueID() == a_UniqueID)
 			{
-				a_Callback(ent.get());
+				a_Callback(*ent);
 				return true;
 			}
 		}  // for ent - m_EntitiesToAdd[]
@@ -3510,20 +3448,12 @@ bool cWorld::SetSignLines(int a_BlockX, int a_BlockY, int a_BlockZ, const AStrin
 
 bool cWorld::SetCommandBlockCommand(int a_BlockX, int a_BlockY, int a_BlockZ, const AString & a_Command)
 {
-	class cUpdateCommandBlock : public cCommandBlockCallback
-	{
-		AString m_Command;
-	public:
-		cUpdateCommandBlock(const AString & a_CallbackCommand) : m_Command(a_CallbackCommand) {}
-
-		virtual bool Item(cCommandBlockEntity * a_CommandBlock) override
+	return DoWithCommandBlockAt(a_BlockX, a_BlockY, a_BlockZ, [&](cCommandBlockEntity & a_CommandBlock)
 		{
-			a_CommandBlock->SetCommand(m_Command);
+			a_CommandBlock.SetCommand(a_Command);
 			return false;
 		}
-	} CmdBlockCB (a_Command);
-
-	return DoWithCommandBlockAt(a_BlockX, a_BlockY, a_BlockZ, CmdBlockCB);
+	);
 }
 
 
@@ -3618,7 +3548,7 @@ bool cWorld::ForEachChunkInRect(int a_MinChunkX, int a_MaxChunkX, int a_MinChunk
 
 
 
-bool cWorld::ForEachLoadedChunk(std::function<bool(int, int)> a_Callback)
+bool cWorld::ForEachLoadedChunk(const std::function<bool(int, int)> & a_Callback)
 {
 	return m_ChunkMap->ForEachLoadedChunk(a_Callback);
 }
@@ -3649,7 +3579,7 @@ void cWorld::QueueSaveAllChunks(void)
 void cWorld::QueueTask(std::function<void(cWorld &)> a_Task)
 {
 	cCSLock Lock(m_CSTasks);
-	m_Tasks.emplace_back(0, a_Task);
+	m_Tasks.emplace_back(0, std::move(a_Task));
 }
 
 
@@ -3663,7 +3593,7 @@ void cWorld::ScheduleTask(int a_DelayTicks, std::function<void (cWorld &)> a_Tas
 	// Insert the task into the list of scheduled tasks
 	{
 		cCSLock Lock(m_CSTasks);
-		m_Tasks.emplace_back(TargetTick, a_Task);
+		m_Tasks.emplace_back(TargetTick, std::move(a_Task));
 	}
 }
 
diff --git a/src/World.h b/src/World.h
index cbaf9cb95..b627c4e95 100644
--- a/src/World.h
+++ b/src/World.h
@@ -1,4 +1,4 @@
-
+
 #pragma once
 
 #define MAX_PLAYERS 65535
@@ -58,21 +58,6 @@ typedef std::list< std::pair< std::unique_ptr<cPlayer>, cWorld * > > cAwaitingPl
 typedef std::unique_ptr<cSetChunkData> cSetChunkDataPtr;
 typedef std::vector<cSetChunkDataPtr> cSetChunkDataPtrs;
 
-typedef cItemCallback<cPlayer>             cPlayerListCallback;
-typedef cItemCallback<cEntity>             cEntityCallback;
-typedef cItemCallback<cBeaconEntity>       cBeaconCallback;
-typedef cItemCallback<cBrewingstandEntity> cBrewingstandCallback;
-typedef cItemCallback<cChestEntity>        cChestCallback;
-typedef cItemCallback<cDispenserEntity>    cDispenserCallback;
-typedef cItemCallback<cFurnaceEntity>      cFurnaceCallback;
-typedef cItemCallback<cNoteEntity>         cNoteBlockCallback;
-typedef cItemCallback<cCommandBlockEntity> cCommandBlockCallback;
-typedef cItemCallback<cMobHeadEntity>      cMobHeadCallback;
-typedef cItemCallback<cFlowerPotEntity>    cFlowerPotCallback;
-
-typedef std::function<bool (cPlayer *)>    cLambdaPlayerCallback;
-typedef std::function<bool (cEntity *)>    cLambdaEntityCallback;
-
 
 
 
@@ -275,21 +260,20 @@ public:
 #endif
 
 	/** Calls the callback for each player in the list; returns true if all players processed, false if the callback aborted by returning true */
-	virtual bool ForEachPlayer(cPlayerListCallback & a_Callback) override;  // >> EXPORTED IN MANUALBINDINGS <<
+	virtual bool ForEachPlayer(const cPlayerListCallback & a_Callback) override;  // >> EXPORTED IN MANUALBINDINGS <<
 
 	/** Calls the callback for the player of the given name; returns true if the player was found and the callback called, false if player not found.
 	Callback return value is ignored. If there are multiple players of the same name, only (random) one is processed by the callback. */
-	bool DoWithPlayer(const AString & a_PlayerName, cPlayerListCallback & a_Callback);  // >> EXPORTED IN MANUALBINDINGS <<
+	bool DoWithPlayer(const AString & a_PlayerName, const cPlayerListCallback & a_Callback);  // >> EXPORTED IN MANUALBINDINGS <<
 
 	/** Finds a player from a partial or complete player name and calls the callback - case-insensitive */
-	bool FindAndDoWithPlayer(const AString & a_PlayerNameHint, cPlayerListCallback & a_Callback);  // >> EXPORTED IN MANUALBINDINGS <<
+	bool FindAndDoWithPlayer(const AString & a_PlayerNameHint, const cPlayerListCallback & a_Callback);  // >> EXPORTED IN MANUALBINDINGS <<
 
 	// TODO: This interface is dangerous - rewrite to DoWithClosestPlayer(pos, sight, action)
 	cPlayer * FindClosestPlayer(Vector3d a_Pos, float a_SightLimit, bool a_CheckLineOfSight = true);
 
 	/** Finds the player over his uuid and calls the callback */
-	bool DoWithPlayerByUUID(const cUUID & a_PlayerUUID, cPlayerListCallback & a_Callback);  // >> EXPORTED IN MANUALBINDINGS <<
-	bool DoWithPlayerByUUID(const cUUID & a_PlayerUUID, cLambdaPlayerCallback a_Callback);  // Lambda version
+	bool DoWithPlayerByUUID(const cUUID & a_PlayerUUID, const cPlayerListCallback & a_Callback);  // >> EXPORTED IN MANUALBINDINGS <<
 
 	void SendPlayerList(cPlayer * a_DestPlayer);  // Sends playerlist to the player
 
@@ -302,20 +286,19 @@ public:
 	bool HasEntity(UInt32 a_UniqueID);
 
 	/** Calls the callback for each entity in the entire world; returns true if all entities processed, false if the callback aborted by returning true */
-	bool ForEachEntity(cEntityCallback & a_Callback);  // Exported in ManualBindings.cpp
+	bool ForEachEntity(const cEntityCallback & a_Callback);  // Exported in ManualBindings.cpp
 
 	/** Calls the callback for each entity in the specified chunk; returns true if all entities processed, false if the callback aborted by returning true */
-	bool ForEachEntityInChunk(int a_ChunkX, int a_ChunkZ, cEntityCallback & a_Callback);  // Exported in ManualBindings.cpp
+	bool ForEachEntityInChunk(int a_ChunkX, int a_ChunkZ, const cEntityCallback & a_Callback);  // Exported in ManualBindings.cpp
 
 	/** Calls the callback for each entity that has a nonempty intersection with the specified boundingbox.
 	Returns true if all entities processed, false if the callback aborted by returning true.
 	If any chunk in the box is missing, ignores the entities in that chunk silently. */
-	virtual bool ForEachEntityInBox(const cBoundingBox & a_Box, cEntityCallback & a_Callback) override;  // Exported in ManualBindings.cpp
+	virtual bool ForEachEntityInBox(const cBoundingBox & a_Box, const cEntityCallback & a_Callback) override;  // Exported in ManualBindings.cpp
 
 	/** Calls the callback if the entity with the specified ID is found, with the entity object as the callback param.
 	Returns true if entity found and callback returned false. */
-	bool DoWithEntityByID(UInt32 a_UniqueID, cEntityCallback & a_Callback);  // Exported in ManualBindings.cpp
-	bool DoWithEntityByID(UInt32 a_UniqueID, cLambdaEntityCallback a_Callback);  // Lambda version
+	bool DoWithEntityByID(UInt32 a_UniqueID, const cEntityCallback & a_Callback);  // Exported in ManualBindings.cpp
 
 	/** Compares clients of two chunks, calls the callback accordingly */
 	void CompareChunkClients(int a_ChunkX1, int a_ChunkZ1, int a_ChunkX2, int a_ChunkZ2, cClientDiffCallback & a_Callback);
@@ -379,7 +362,7 @@ public:
 	virtual bool ForEachChunkInRect(int a_MinChunkX, int a_MaxChunkX, int a_MinChunkZ, int a_MaxChunkZ, cChunkDataCallback & a_Callback) override;
 
 	/** Calls the callback for each loaded chunk. Returns true if all chunks have been processed successfully */
-	bool ForEachLoadedChunk(std::function<bool(int, int)> a_Callback);
+	bool ForEachLoadedChunk(const std::function<bool(int, int)> & a_Callback);
 
 	// tolua_begin
 
@@ -516,25 +499,25 @@ public:
 	inline cRedstoneSimulator * GetRedstoneSimulator(void) { return m_RedstoneSimulator; }
 
 	/** Calls the callback for each block entity in the specified chunk; returns true if all block entities processed, false if the callback aborted by returning true */
-	bool ForEachBlockEntityInChunk(int a_ChunkX, int a_ChunkZ, cBlockEntityCallback & a_Callback);  // Exported in ManualBindings.cpp
+	bool ForEachBlockEntityInChunk(int a_ChunkX, int a_ChunkZ, const cBlockEntityCallback & a_Callback);  // Exported in ManualBindings.cpp
 
 	/** Calls the callback for each brewingstand in the specified chunk; returns true if all brewingstands processed, false if the callback aborted by returning true */
-	bool ForEachBrewingstandInChunk(int a_ChunkX, int a_ChunkZ, cBrewingstandCallback & a_Callback);  // Exported in ManualBindings.cpp
+	bool ForEachBrewingstandInChunk(int a_ChunkX, int a_ChunkZ, const cBrewingstandCallback & a_Callback);  // Exported in ManualBindings.cpp
 
 	/** Calls the callback for each chest in the specified chunk; returns true if all chests processed, false if the callback aborted by returning true */
-	bool ForEachChestInChunk(int a_ChunkX, int a_ChunkZ, cChestCallback & a_Callback);  // Exported in ManualBindings.cpp
+	bool ForEachChestInChunk(int a_ChunkX, int a_ChunkZ, const cChestCallback & a_Callback);  // Exported in ManualBindings.cpp
 
 	/** Calls the callback for each dispenser in the specified chunk; returns true if all dispensers processed, false if the callback aborted by returning true */
-	bool ForEachDispenserInChunk(int a_ChunkX, int a_ChunkZ, cDispenserCallback & a_Callback);
+	bool ForEachDispenserInChunk(int a_ChunkX, int a_ChunkZ, const cDispenserCallback & a_Callback);
 
 	/** Calls the callback for each dropper in the specified chunk; returns true if all droppers processed, false if the callback aborted by returning true */
-	bool ForEachDropperInChunk(int a_ChunkX, int a_ChunkZ, cDropperCallback & a_Callback);
+	bool ForEachDropperInChunk(int a_ChunkX, int a_ChunkZ, const cDropperCallback & a_Callback);
 
 	/** Calls the callback for each dropspenser in the specified chunk; returns true if all dropspensers processed, false if the callback aborted by returning true */
-	bool ForEachDropSpenserInChunk(int a_ChunkX, int a_ChunkZ, cDropSpenserCallback & a_Callback);
+	bool ForEachDropSpenserInChunk(int a_ChunkX, int a_ChunkZ, const cDropSpenserCallback & a_Callback);
 
 	/** Calls the callback for each furnace in the specified chunk; returns true if all furnaces processed, false if the callback aborted by returning true */
-	bool ForEachFurnaceInChunk(int a_ChunkX, int a_ChunkZ, cFurnaceCallback & a_Callback);  // Exported in ManualBindings.cpp
+	bool ForEachFurnaceInChunk(int a_ChunkX, int a_ChunkZ, const cFurnaceCallback & a_Callback);  // Exported in ManualBindings.cpp
 
 	/** Does an explosion with the specified strength at the specified coordinates.
 	Executes the HOOK_EXPLODING and HOOK_EXPLODED hooks as part of the processing.
@@ -543,43 +526,43 @@ public:
 	virtual void DoExplosionAt(double a_ExplosionSize, double a_BlockX, double a_BlockY, double a_BlockZ, bool a_CanCauseFire, eExplosionSource a_Source, void * a_SourceData) override;
 
 	/** Calls the callback for the block entity at the specified coords; returns false if there's no block entity at those coords, true if found */
-	virtual bool DoWithBlockEntityAt(int a_BlockX, int a_BlockY, int a_BlockZ, cBlockEntityCallback & a_Callback) override;  // Exported in ManualBindings.cpp
+	virtual bool DoWithBlockEntityAt(int a_BlockX, int a_BlockY, int a_BlockZ, const cBlockEntityCallback & a_Callback) override;  // Exported in ManualBindings.cpp
 
 	/** Calls the callback for the beacon at the specified coords; returns false if there's no beacon at those coords, true if found */
-	bool DoWithBeaconAt(int a_BlockX, int a_BlockY, int a_BlockZ, cBeaconCallback & a_Callback);  // Exported in ManualBindings.cpp
+	bool DoWithBeaconAt(int a_BlockX, int a_BlockY, int a_BlockZ, const cBeaconCallback & a_Callback);  // Exported in ManualBindings.cpp
 
 	/** Calls the callback for the bed at the specified coords; returns false if there's no bed at those coords, true if found */
-	virtual bool DoWithBedAt(int a_BlockX, int a_BlockY, int a_BlockZ, cBedCallback & a_Callback) override;  // Exported in ManualBindings.cpp
+	virtual bool DoWithBedAt(int a_BlockX, int a_BlockY, int a_BlockZ, const cBedCallback & a_Callback) override;  // Exported in ManualBindings.cpp
 
 	/** Calls the callback for the brewingstand at the specified coords; returns false if there's no brewingstand at those coords, true if found */
-	bool DoWithBrewingstandAt(int a_BlockX, int a_BlockY, int a_BlockZ, cBrewingstandCallback & a_Callback);  // Lua-acessible
+	bool DoWithBrewingstandAt(int a_BlockX, int a_BlockY, int a_BlockZ, const cBrewingstandCallback & a_Callback);  // Lua-acessible
 
 	/** Calls the callback for the chest at the specified coords; returns false if there's no chest at those coords, true if found */
-	bool DoWithChestAt(int a_BlockX, int a_BlockY, int a_BlockZ, cChestCallback & a_Callback);  // Exported in ManualBindings.cpp
+	bool DoWithChestAt(int a_BlockX, int a_BlockY, int a_BlockZ, const cChestCallback & a_Callback);  // Exported in ManualBindings.cpp
 
 	/** Calls the callback for the dispenser at the specified coords; returns false if there's no dispenser at those coords or callback returns true, returns true if found */
-	bool DoWithDispenserAt(int a_BlockX, int a_BlockY, int a_BlockZ, cDispenserCallback & a_Callback);  // Exported in ManualBindings.cpp
+	bool DoWithDispenserAt(int a_BlockX, int a_BlockY, int a_BlockZ, const cDispenserCallback & a_Callback);  // Exported in ManualBindings.cpp
 
 	/** Calls the callback for the dropper at the specified coords; returns false if there's no dropper at those coords or callback returns true, returns true if found */
-	bool DoWithDropperAt(int a_BlockX, int a_BlockY, int a_BlockZ, cDropperCallback & a_Callback);  // Exported in ManualBindings.cpp
+	bool DoWithDropperAt(int a_BlockX, int a_BlockY, int a_BlockZ, const cDropperCallback & a_Callback);  // Exported in ManualBindings.cpp
 
 	/** Calls the callback for the dropspenser at the specified coords; returns false if there's no dropspenser at those coords or callback returns true, returns true if found */
-	bool DoWithDropSpenserAt(int a_BlockX, int a_BlockY, int a_BlockZ, cDropSpenserCallback & a_Callback);  // Exported in ManualBindings.cpp
+	bool DoWithDropSpenserAt(int a_BlockX, int a_BlockY, int a_BlockZ, const cDropSpenserCallback & a_Callback);  // Exported in ManualBindings.cpp
 
 	/** Calls the callback for the furnace at the specified coords; returns false if there's no furnace at those coords or callback returns true, returns true if found */
-	bool DoWithFurnaceAt(int a_BlockX, int a_BlockY, int a_BlockZ, cFurnaceCallback & a_Callback);  // Exported in ManualBindings.cpp
+	bool DoWithFurnaceAt(int a_BlockX, int a_BlockY, int a_BlockZ, const cFurnaceCallback & a_Callback);  // Exported in ManualBindings.cpp
 
 	/** Calls the callback for the noteblock at the specified coords; returns false if there's no noteblock at those coords or callback returns true, returns true if found */
-	bool DoWithNoteBlockAt(int a_BlockX, int a_BlockY, int a_BlockZ, cNoteBlockCallback & a_Callback);  // Exported in ManualBindings.cpp
+	bool DoWithNoteBlockAt(int a_BlockX, int a_BlockY, int a_BlockZ, const cNoteBlockCallback & a_Callback);  // Exported in ManualBindings.cpp
 
 	/** Calls the callback for the command block at the specified coords; returns false if there's no command block at those coords or callback returns true, returns true if found */
-	bool DoWithCommandBlockAt(int a_BlockX, int a_BlockY, int a_BlockZ, cCommandBlockCallback & a_Callback);  // Exported in ManualBindings.cpp
+	bool DoWithCommandBlockAt(int a_BlockX, int a_BlockY, int a_BlockZ, const cCommandBlockCallback & a_Callback);  // Exported in ManualBindings.cpp
 
 	/** Calls the callback for the mob head block at the specified coords; returns false if there's no mob head block at those coords or callback returns true, returns true if found */
-	bool DoWithMobHeadAt(int a_BlockX, int a_BlockY, int a_BlockZ, cMobHeadCallback & a_Callback);  // Exported in ManualBindings.cpp
+	bool DoWithMobHeadAt(int a_BlockX, int a_BlockY, int a_BlockZ, const cMobHeadCallback & a_Callback);  // Exported in ManualBindings.cpp
 
 	/** Calls the callback for the flower pot at the specified coords; returns false if there's no flower pot at those coords or callback returns true, returns true if found */
-	bool DoWithFlowerPotAt(int a_BlockX, int a_BlockY, int a_BlockZ, cFlowerPotCallback & a_Callback);  // Exported in ManualBindings.cpp
+	bool DoWithFlowerPotAt(int a_BlockX, int a_BlockY, int a_BlockZ, const cFlowerPotCallback & a_Callback);  // Exported in ManualBindings.cpp
 
 	/** Retrieves the test on the sign at the specified coords; returns false if there's no sign at those coords, true if found */
 	bool GetSignLines (int a_BlockX, int a_BlockY, int a_BlockZ, AString & a_Line1, AString & a_Line2, AString & a_Line3, AString & a_Line4);  // Exported in ManualBindings.cpp
@@ -587,13 +570,13 @@ public:
 	/** a_Player is using block entity at [x, y, z], handle that: */
 	void UseBlockEntity(cPlayer * a_Player, int a_BlockX, int a_BlockY, int a_BlockZ) {m_ChunkMap->UseBlockEntity(a_Player, a_BlockX, a_BlockY, a_BlockZ); }  // tolua_export
 
-	/** Calls the callback for the chunk specified, with ChunkMapCS locked; returns false if the chunk doesn't exist, otherwise returns the same value as the callback */
-	bool DoWithChunk(int a_ChunkX, int a_ChunkZ, cChunkCallback & a_Callback);
-	bool DoWithChunk(int a_ChunkX, int a_ChunkZ, std::function<bool(cChunk &)> a_Callback);
+	/** Calls the callback for the chunk specified, with ChunkMapCS locked.
+	Returns false if the chunk doesn't exist, otherwise returns the same value as the callback */
+	bool DoWithChunk(int a_ChunkX, int a_ChunkZ, const cChunkCallback & a_Callback);
 
 	/** Calls the callback for the chunk at the block position specified, with ChunkMapCS locked.
 	Returns false if the chunk isn't loaded, otherwise returns the same value as the callback */
-	bool DoWithChunkAt(Vector3i a_BlockPos, std::function<bool(cChunk &)> a_Callback);
+	bool DoWithChunkAt(Vector3i a_BlockPos, const cChunkCallback & a_Callback);
 
 	void GrowTreeImage(const sSetBlockVector & a_Blocks);