Use the CLASS clause to give a name to a set of characters that you list in the clause.
For example, name the set of digits by coding the following clause:
CLASS DIGIT IS “0” THROUGH “9”
You can reference the class-name only in a class condition. (This user-defined class is not the same as an object-oriented class.)
You cannot use the CLASS clause when the code page indicated by the locale is a multibyte-character code page.