.
/2
terms
found in the arguments of a goal. This predicate evaluates the field
extraction described above, raising an exception if Function
is an atom (key) and Dict does not contain the
requested key. If Function is a compound term, it checks for
the predefined functions on dicts described in section
5.4.1.2 or executes a user defined function as described in
section 5.4.1.1.