add LuaReference::GetLuaType, LuaExpression

stepmania/src/LuaReference.cpp

@@ -66,6 +66,14 @@ bool LuaReference::IsSet() const
 	return m_iReference != LUA_NOREF;
 }
 
+int LuaReference::GetLuaType() const
+{
+	this->PushSelf();
+	int iRet = lua_type( LUA->L, -1 );
+	lua_pop( LUA->L, 1 );
+	return iRet;
+}
+
 void LuaReference::Register()
 {
 }
@@ -98,6 +106,20 @@ void LuaReference::ReRegister()
 }
 
 
+void LuaExpression::SetFromExpression( const CString &sExpression )
+{
+	m_sExpression = sExpression;
+	Register();
+}
+
+void LuaExpression::Register()
+{
+	LUA->RunScript( "return " + m_sExpression, 1 );
+
+	/* Store the result. */
+	this->SetFromStack();
+}
+
 /*
  * (c) 2005 Glenn Maynard, Chris Danford
  * All rights reserved.

stepmania/src/LuaReference.h

@@ -26,6 +26,9 @@ public:
 	/* Return true if set.  (SetFromNil() counts as being set.) */
 	bool IsSet() const;
 
+	/* Return the referenced type, or LUA_TNONE if not set. */
+	int GetLuaType() const;
+
 	static void ReRegisterAll();	// call this after resetting Lua
 
 protected:
@@ -40,6 +43,20 @@ private:
 	int m_iReference;
 };
 
+/* Evaluate an expression that returns an object; store the object in a reference.
+ * For example, evaluating "{ 1, 2, 3 }" will result in a reference to a table. */
+class LuaExpression: public LuaReference
+{
+public:
+	void SetFromExpression( const CString &sExpression );
+
+protected:
+	virtual void Register();
+
+private:
+	CString m_sExpression;
+};
+
 #endif
 
 /*