Space- and time-efficient enumerations

One or more non-transitory computer-accessible storage media storing program instructions that when executed on or across one or more processors cause the one or more processors to perform:

• obtaining an ordinal value of the object of a plurality of objects of an instantiated class, wherein individual objects, including the object, of the instantiated class respectively comprise a plurality of immutable items, and wherein the instantiated class comprises a plurality of different ordinal values including the ordinal value
• loading a memory address of the object from a location in a lookup table, the location identified using the obtained ordinal value as an index, wherein the memory address is different from the location in the lookup table, and wherein the lookup table comprises a plurality of memory addresses, including the memory address, respectively identified by individual ones of the plurality of different ordinal values;
• and
• accessing one or more of the plurality of immutable data items of the object using the loaded memory address.

A system, comprising:

• one or more processors and a memory comprising program instructions executable by the one or more processors to implement an application configured to:
• obtain an ordinal value of the object of a plurality of objects of an instantiated class, wherein individual objects, including the object, of the instantiated class respectively comprise a plurality of immutable items, and wherein the instantiated class comprises a plurality of different ordinal values including the ordinal value;
• load a memory address of the object from a location in a lookup table, the location identified using the obtained ordinal value as an index, wherein the memory address is different from the location in the lookup table, and wherein the lookup table comprises a plurality of memory addresses, including the memory address, respectively identified by individual ones of the plurality of different ordinal values;
• and
• access one or more of the plurality of immutable data items of the object using the loaded memory address.