An attributed variable can have any number of attributes. The attributes are accessed by their name. Before an attribute can be created and used, it must be declared with the predicate meta_attribute/2. The declaration has the format
meta_attribute(Name, HandlerList)
Name is an atom denoting the attribute name and usually it is the name of the module where this attribute is being created and used. HandlerList is a (possibly empty) list of handler specifications for this attribute (see Section 17.7).