A Slice enumerated type definition looks like the C++ version:
enum Fruit { Apple, Pear, Orange };
This definition introduces a type named Fruit that becomes a new type in its own right. Slice does not define how ordinal values are assigned to enumerators. For example, you cannot assume that the enumerator Orange will have the value 2 in different implementation languages. Slice guarantees only that the ordinal values of enumerators increase from left to right, so Apple compares less than Pear in all implementation languages.
Unlike C++, Slice does not permit you to control the ordinal values of enumerators (because many implementation languages do not support such a feature):
enum Fruit { Apple = 0, Pear = 7, Orange = 2 }; // Syntax error
In practice, you do not care about the values used for enumerators as long as you do not transmit the ordinal value of an enumerator between address spaces. For example, sending the value 0 to a server to mean Apple can cause problems because the server may not use 0 to represent Apple. Instead, simply send the value Apple itself. If Apple is represented by a different ordinal value in the receiving address space, that value will be appropriately translated by the Ice run time.
As with C++, Slice enumerators enter the enclosing namespace, so the following is illegal:
enum Fruit { Apple, Pear, Orange };
enum ComputerBrands { Apple, IBM, Sun, HP }; // Apple redefined
Slice does not permit empty enumerations.