Addressing

An Address value is used as an interface between vectors and indices. The index maps keys of various types to address, which is then used to get a value from the vector.

Details

In the most common case, the address will be int (and can represent index in an array), but it is possible to imagine other addresses - int64 could be used with arrays of arrays (to handle very large data). A lazily loaded vector might use something completely different (perhaps a date?). In principle this should be generic, but that is hard to do - we want something like:

Series.Create : \forall 'TKey, 'TValue. \exists 'TAddress. 
  Index<'TKey, 'TAddress> * Vector<'TAddress, 'TValue> -> Series<'TKey, 'TValue>

The .NET encoding of this is a bit ugly. So instead, we just have Address which currently supports Int and Int64, but we keep all operations in the Address module, so that this can be easily extended.