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Object versions

----- LAW OF DEMETER FOR CLOS (object version) -----------
All function calls inside a method M must have
one of the following objects passed by their method selection arguments:
  - a value of M's parameters or
  - an immediate part (the value of a slot) 
      of a method selection argument of M.
(Objects created by the method and objects in global 
variables are viewed as being passed by arguments.
A method selection argument is an argument which is used
for identifying the applicable methods.)
----------------------------------------------------------
User has to be aware of whether a function call is generic or not.
Idea of Law: The user has only to think about the classes
of the method selection arguments and the classes of the 
immediate subparts of those arguments when reading a method.
-------------------- 2 ------------
In all function calls inside a method M all values of method
selection arguments must be objects which are either
passed by an argument of M or which are a value of
an immediate part of a method selection argument of M.
MESSAGE PASSING: only the first argument is a method selection argument
---------------------3--------------------------------------
In all function calls inside a method M all method selection arguments
must belong to one of the following classes:
 - an argument class of M.
 - a class of an immediate part of a method selection argument of M.
------------------------4-----------------------------------
In all function calls inside a method M all objects passed by
method selection arguments must be instances of a class associated
with one of the following classes:
 - argument classes
 - classes associated with instance variable classes of a method
     selection argument of M.
-----------------------5------------------------------------
In all function calls inside a method M all objects passed by
method selection arguments must have a most specific type from the
following classes:
 - argument classes
 - instance variable classes of a method selection argument of M.
--------------------------------
problem with alternations.
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