    class
    	CHARACTER_SET

    General
    	cluster: transfer
    	description: "Comparator for character sets"

    Ancestors
    	TO_SPECIAL [T]

    Queries
    	area: SPECIAL [BOOLEAN]
    	contains_character (c: CHARACTER_8): BOOLEAN
    	contains_string (s: STRING_8): BOOLEAN
    	infix "@" (i: INTEGER_32): BOOLEAN
    	is_empty: BOOLEAN
    	item alias "[]" (i: INTEGER_32): BOOLEAN
    	valid_index (i: INTEGER_32): BOOLEAN

    Commands
    	add (s: STRING_8)
    	define (s: STRING_8)
    	put (v: BOOLEAN; i: INTEGER_32)
    	remove (s: STRING_8)