2 files changed, 111 insertions, 4 deletions

diff --git a/src/Bindings/LuaState.cpp b/src/Bindings/LuaState.cpp
index fd29e8e34..b5832802d 100644
--- a/src/Bindings/LuaState.cpp
+++ b/src/Bindings/LuaState.cpp
@@ -341,6 +341,33 @@ void cLuaState::cStackTable::ForEachArrayElement(std::function<bool(cLuaState &
 
 
 
+void cLuaState::cStackTable::ForEachElement(std::function<bool(cLuaState & a_LuaState)> a_ElementCallback) const
+{
+	#ifdef _DEBUG
+		auto stackTop = lua_gettop(m_LuaState);
+	#endif
+	lua_pushvalue(m_LuaState, m_StackPos);  // Stk: <table>
+	lua_pushnil(m_LuaState);                // Stk: <table> nil
+	while (lua_next(m_LuaState, -2))        // Stk: <table> <key> <val>
+	{
+		auto shouldAbort = a_ElementCallback(m_LuaState);
+		ASSERT(lua_gettop(m_LuaState) == stackTop + 3);  // The element callback must not change the Lua stack below the value
+		lua_pop(m_LuaState, 1);  // Stk: <table> <key>
+		if (shouldAbort)
+		{
+			// The callback wants to abort
+			lua_pop(m_LuaState, 2);  // Stk: empty
+			return;
+		}
+	}
+	// Stk: <table>
+	lua_pop(m_LuaState, 1);  // Stk: empty
+}
+
+
+
+
+
 ////////////////////////////////////////////////////////////////////////////////
 // cLuaState:
 
@@ -748,6 +775,24 @@ void cLuaState::Push(const AString & a_String)
 
 
 
+void cLuaState::Push(const AStringMap & a_Dictionary)
+{
+	ASSERT(IsValid());
+
+	lua_createtable(m_LuaState, 0, static_cast<int>(a_Dictionary.size()));
+	int newTable = lua_gettop(m_LuaState);
+	for (const auto & item: a_Dictionary)
+	{
+		Push(item.first);   // key
+		Push(item.second);  // value
+		lua_rawset(m_LuaState, newTable);
+	}
+}
+
+
+
+
+
 void cLuaState::Push(const AStringVector & a_Vector)
 {
 	ASSERT(IsValid());
@@ -1113,6 +1158,37 @@ bool cLuaState::GetStackValue(int a_StackPos, AString & a_Value)
 
 
 
+bool cLuaState::GetStackValue(int a_StackPos, AStringMap & a_Value)
+{
+	// Retrieve all values in a string => string dictionary table:
+	if (!lua_istable(m_LuaState, a_StackPos))
+	{
+		return false;
+	}
+	cStackTable tbl(*this, a_StackPos);
+	bool isValid = true;
+	tbl.ForEachElement([&isValid, &a_Value](cLuaState & a_LuaState)
+		{
+			AString key, val;
+			if (a_LuaState.GetStackValues(-2, key, val))
+			{
+				a_Value[key] = val;
+			}
+			else
+			{
+				isValid = false;
+				return true;
+			}
+			return false;
+		}
+	);
+	return isValid;
+}
+
+
+
+
+
 bool cLuaState::GetStackValue(int a_StackPos, bool & a_ReturnedVal)
 {
 	a_ReturnedVal = (tolua_toboolean(m_LuaState, a_StackPos, a_ReturnedVal ? 1 : 0) > 0);
diff --git a/src/Bindings/LuaState.h b/src/Bindings/LuaState.h
index 60ae840b0..303a59327 100644
--- a/src/Bindings/LuaState.h
+++ b/src/Bindings/LuaState.h
@@ -309,6 +309,24 @@ public:
 	typedef UniquePtr<cTableRef> cTableRefPtr;
 
 
+	/** Represents a parameter that is optional - calling a GetStackValue() with this object will not fail if the value on the Lua stack is nil.
+	Note that the GetStackValue() will still fail if the param is present but of a different type.
+	The class itself is just a marker so that the template magic will select the correct GetStackValue() overload. */
+	template <typename T>
+	class cOptionalParam
+	{
+	public:
+		explicit cOptionalParam(T & a_Dest):
+			m_Dest(a_Dest)
+		{
+		}
+
+		T & GetDest(void) { return m_Dest; }
+
+	protected:
+		T & m_Dest;
+	};
+
 	/** A dummy class that's used only to delimit function args from return values for cLuaState::Call() */
 	class cRet
 	{
@@ -475,6 +493,7 @@ public:
 
 	// Push a const value onto the stack (keep alpha-sorted):
 	void Push(const AString & a_String);
+	void Push(const AStringMap & a_Dictionary);
 	void Push(const AStringVector & a_Vector);
 	void Push(const cCraftingGrid * a_Grid);
 	void Push(const cCraftingRecipe * a_Recipe);
@@ -508,6 +527,7 @@ public:
 	// Returns whether value was changed
 	// Enum values are checked for their allowed values and fail if the value is not assigned.
 	bool GetStackValue(int a_StackPos, AString & a_Value);
+	bool GetStackValue(int a_StackPos, AStringMap & a_Value);
 	bool GetStackValue(int a_StackPos, bool & a_Value);
 	bool GetStackValue(int a_StackPos, cCallback & a_Callback);
 	bool GetStackValue(int a_StackPos, cCallbackPtr & a_Callback);
@@ -549,6 +569,17 @@ public:
 		return true;
 	}
 
+	/** Retrieves an optional value on the stack - doesn't fail if the stack contains nil instead of the value. */
+	template <typename T>
+	bool GetStackValue(int a_StackPos, cOptionalParam<T> && a_ReturnedVal)
+	{
+		if (lua_isnoneornil(m_LuaState, a_StackPos))
+		{
+			return true;
+		}
+		return GetStackValue(a_StackPos, a_ReturnedVal.GetDest());
+	}
+
 	/** Pushes the named value in the table at the top of the stack.
 	a_Name may be a path containing multiple table levels, such as "cChatColor.Blue".
 	If the value is found, it is pushed on top of the stack and the returned cStackValue is valid.
@@ -606,14 +637,14 @@ public:
 	}
 
 	/** Retrieves a list of values from the Lua stack, starting at the specified index. */
-	template <typename T, typename... Args>
-	inline bool GetStackValues(int a_StartStackPos, T & a_Ret, Args &&... args)
+	template <typename Arg1, typename... Args>
+	inline bool GetStackValues(int a_StartStackPos, Arg1 && a_Arg1, Args &&... args)
 	{
-		if (!GetStackValue(a_StartStackPos, a_Ret))
+		if (!GetStackValue(a_StartStackPos, std::forward<Arg1>(a_Arg1)))
 		{
 			return false;
 		}
-		return GetStackValues(a_StartStackPos + 1, args...);
+		return GetStackValues(a_StartStackPos + 1, std::forward<Args>(args)...);
 	}
 
 	/** Returns true if the specified parameters on the stack are of the specified usertable type; also logs warning if not. Used for static functions */