This package allows R users to explore type information coming from either type libraries or COM objects. The functions provide information about a class in terms of its properties; methods and their argument and return types; the names and values of enumerated types, and fields in structures and unions. One can find type information by loading a type library or by obtaining a reference to a COM object. Suppose we have the ADO (ActiveX Data Object) library on our system at it is located at C:/Program Files/Common Files/system/ado/msado15.dll. We load that library using LoadTypeLib
lib = LoadTypeLib("C:/Program Files/Common Files/system/ado/msado15.dll")
The resulting lib is a reference or handle to the C-level structure that identifies the object. We can use this to examine the different elements about which the library provides type information. When we are finished with it, we can release the library and free the resources it uses using UnloadTypeLib. (Not implemented yet.)

Essentially we can treat the type library as a named list. Each element is an object of type ITypeInfo in our world. This provides a reference to the elemenet in the type library and from that we can find out most things about that type.

Since the library reference is equivalent to a list in S, we can find out the names of the different elements it contains.
As one might expect, we can extract elements from the type library in the S style using either


Now that we know how to navigate the type library, we can examine its elements. We can also find out the types of these different elements using \SFunction{getTypeLibTypes}.
This describes the type of each element in the library by its type name such as dispatch, coclass, enum. These are indexed by the names of the type. If one wants to get the actual numeric type rather than the text descriptions (so that they can be used within the C code), use the byName argument and specify FALSE. We can ``zoom in'' and look at the type information for individual elements of the type library. We get a reference to the underlying C <c:struct>ITypeInfo</c:struct> object using the overloaded [[. One can index the type library reference either by the name or position of the desired element.
cmd = lib[["Command"]]
cmd = lib[[91]]
We can then get the details of the type of this element using this object. For example, we can find the collection of values in the enumeration BookMarkEnum.
Suppose we wanted to find all the enumerations within a library and obtain their definitions as a name-value vector for each enum type. We can do this in two steps
types = getTypeLibTypes(lib)
enums = which(types == "enum")

lapply(enums, function(x) getEnum(lib[[x]]))
If an element in the type library is a coclass type info object, then it can represent multiple interfaces. We get a list of the ITypeInfo objects for each of these interfaces by calling getElements. We can the operate on each of these ITypeInfo elements as we do above. The getElements function has a recursive argument
See for an article describing aspects of type libraries.


Records Check the number of names of the parameters is what we expect and not one less for PROPERTY_PUT methods.