A metalevel is a special kind of object that has as feature values the
methods that can be possibly be used in to infer the feature values of the
corresponding referent. In this section, we will see that--since
metalevels are just plain feature terms-- a metalevel feature can also be
specified by means of a method that infers a feature value. Certainly, a
feature value inferred by a metalevel method should be a method or set of
methods
.
There are two basic ways in which a method can produce as result other methods: searching for already defined methods or constructing new methods (basically putting together other defined methods or built-in methods). We will presently explain metalevel methods that search for and selects from other methods--for creating new methods see Chapter 14.
In the following example, a metalevel method is defined for
family-name. Since family names in women change when they marry in
several countries (albeit not in all) and family names of men do not,
methods for family-names are separately specified in woman and
man. The metalevel method for
family-name is specified in a way that accesses and obtains different methods for
inferring the family names of man and women after consulting the
gender of a particular person. The referent construct is a
reflective operation that denotes the referent of a metalevel--in this
case the person of the metalevel involved.
