Return an array of all possible values from indexing the value x.
For strings an array of int with the ISO10646 codes of the characters in
the string is returned.
For a multiset an array filled with ones (1) is returned.
For arrays a single-level copy of x is returned.
For mappings the array may contain any value.
For objects which define _values() that return value will be used.
For other objects an array with the values of all non-static symbols
will be returned.