Here is the definition of our EmployeeMap once more:
Slice
dictionary<long, Employee> EmployeeMap;
As for sequences, the Ruby mapping does not create a separate named type for this definition. Instead, all dictionaries are simply instances of Ruby's hash collection type. For example:
Ruby
em = {}
e = Employee.new
e.number = 31
e.firstName = "James"
e.lastName = "Gosling"
em[e.number] = e
The Ice run time validates the elements of a dictionary to ensure that they are compatible with the declared type; a TypeError exception is raised if an incompatible type is encountered.