4.1 Introduction

With LuaCOM it is possible to implement full-fledged COM objects and OLE controls using Lua. Here we understand a COM object as a composite of these parts:

• a server, which implements one or more COM objects;
• registry information, which associates a CLSID (Class ID) to a triple server - type library - default interface;
• a ProgID (Programmatic Identifier) which is a name associated to a CLSID;
• a type library containing a CoClass element.

The registry information maps a ProgID to a CLSID, which is, in turn, mapped to a server. The type information describes the component, that is, which interfaces it exposes and what is the default interface. LuaCOM simplifies these tasks providing some helper functions to deal with registration and instantiation of COM servers. LuaCOM suports both local (EXE) and in-process (DLL) servers. LuaCOM also provides helper functions to register and instantiate OLE controls (with their user interface embedded in the hosting application). This kind of object needs an in-process server, and a supported Lua GUI toolkit (IUP, for now).