Allow creation of user class types from Python

Author: Marcus Tomlinson

example/main.cpp

@@ -79,6 +79,22 @@ class Simple
   std::string lastMessage;
 };
 
+// Simple Class Factory
+// ====================
+class SimpleFactory
+{
+public:
+    void* NewSimple( std::string firstMessage )
+    {
+        return new Simple( firstMessage );
+    }
+
+    void DeleteSimple( void* simple )
+    {
+        delete ( ( Simple* )simple );
+    }
+};
+
 // Register Classes + Methods
 // ==========================
 ECS_REGISTER_CLASS( Simple )
@@ -88,6 +104,10 @@ ECS_REGISTER_METHOD_VOID( Simple, ShowLots, unsigned long, char* )
 ECS_REGISTER_METHOD_RETURN( Simple, GetLastMessage, std::string )
 ECS_REGISTER_METHOD_VOID( Simple, ShowPtr, void* )
 
+ECS_REGISTER_CLASS( SimpleFactory )
+ECS_REGISTER_METHOD_RETURN( SimpleFactory, NewSimple, void*, std::string )
+ECS_REGISTER_METHOD_VOID( SimpleFactory, DeleteSimple, void* )
+
 //=================================================================================================
 
 // Main
@@ -103,17 +123,19 @@ int main()
   Ecs_Init_Simple_GetLastMessage();
   Ecs_Init_Simple_ShowPtr();
 
+  Ecs_Init_SimpleFactory();
+  Ecs_Init_SimpleFactory_NewSimple();
+  Ecs_Init_SimpleFactory_DeleteSimple();
+
   // Initialize EcsPython
   // ====================
   Ecs_Initialize();
 
-  // Create New Class Instance
-  // =========================
-  Simple* newSimple = new Simple( "(first message)" );
 
-  // Expose Class Instance To Python
-  // ===============================
-  Ecs_Expose_Object( newSimple, "newSimple" );
+  // Create And Expose Class Instance To Python
+  // ==========================================
+  Simple newSimple( "(first message)" );
+  Ecs_Expose_Object( &newSimple, "newSimple" );
 
   // Use Exposed Class Instance From Python
   // ======================================
@@ -136,9 +158,21 @@ int main()
 
   // Use Class Instance From C++
   // ===========================
-  std::cout << newSimple->GetLastMessage().c_str();
+  std::cout << "Ok, " << newSimple.GetLastMessage().c_str() << std::endl;
+
+
+  // Create And Expose Factory To Python
+  // ===================================
+  SimpleFactory simpleFactory;
+  Ecs_Expose_Object( &simpleFactory, "simpleFactory" );
+
+  Ecs_Python_Cmd( "anotherSimple = Simple( simpleFactory.NewSimple( '\\'Allo ' ) )" );
+  Ecs_Python_Cmd( "print( anotherSimple.GetLastMessage() + '\\'Allo!')" );
+  Ecs_Python_Cmd( "simpleFactory.DeleteSimple( anotherSimple() )" );
+
   getchar();
 
+
   // Finalize EcsPython
   // ==================
   Ecs_Finalize();

include/ecspython/EcsMacros.h

@@ -186,6 +186,8 @@ static void Ecs_Init##_##Class()\
 {\
   EcsPythonClassesDict.push_back( new EcsClass( #Class, typeid( Class ) ) );\
   EcsPythonClassesDef.append("class " #Class ":\n\
+\tdef __init__( self, ecsPtr ):\n\
+\t\tself._self = ecsPtr\n\
 \tdef __call__( self ):\n\
 \t\treturn self._self\n");\
 }

src/EcsPython.cpp

@@ -209,11 +209,7 @@ void _Ecs_Expose_Object( char* pyObject, std::string pyClassName, std::string py
   module = PyImport_ImportModule( "__main__" );
   PyObject_SetAttrString( module, "ecsPtr", newPyObject );
 
-  pythonCall.append( pyObjectName ).append( " = " ).append( pyClassName ).append( "()" );
-  Ecs_Python_Cmd( pythonCall );
-
-  pythonCall.clear();
-  pythonCall.append( pyObjectName ).append( "._self = ecsPtr" );
+  pythonCall.append( pyObjectName ).append( " = " ).append( pyClassName ).append( "(ecsPtr)" );
   Ecs_Python_Cmd( pythonCall );
 
   Ecs_Python_Cmd( "del ecsPtr" );