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5.4.4 Extensible Interfaces
Some objects that have type information describing their interface (methods, properties, types of parameters etc), may add new methods and properties at runtime. This means that these methods and properties can only be accessed using the same mechanism LuaCOM uses for Generic COM object. This have some implications:
- when accessing properties, it's mandatory to access them as
methods and to use the set prefix to alter their values. If an
object foo has a property color not present in the
type information, it can only be accessed through foo:color()
(read access) or foo:setcolor() (write access);
- when calling methods, all parameters are treated as in-out. This
means that, beyond the return value, a call to a method of this type
will return all the parameters back, whether or not modified by the
callee. Anyway, one can ignore these values simply not assigning them
to a variable, e.g. x = foo:method(a,b) will ignore the values
of a and b, also returned by the call.
COM objects related to WMI have this behavior. For more information, see section 3.3.2.
Next: 5.4.5 Visual Basic© issue Up: 5.4 Important issues about Previous: 5.4.3 Receiving events Contents Fabio Mascarenhas de Queiroz 2005-01-07