In the IDLWAVE Shell (see The IDLWAVE Shell), objects on which
methods are being invoked have a special property: they must exist as
variables, and so their class can be determined (for instance, using the
obj_class() function). In the Shell, when attempting completion,
routine info, or online help within a method routine, a query is sent to
determine the class of the object. If this query is successful, the
class found will be used to select appropriate completions, routine
info, or help. If unsuccessful, information from all known classes will
be used (as in the buffer).