The hashtables.wrapped describes a protocol for defining hashtables that use custom hashing algorithms.

To create a custom wrapped hashtable, you must define a wrapper for your keys (usually a tuple class). For this wrapper, you have to define the following generics:

•	hashcode* for your wrapper, which will contain the hashing algorithm you want to use.
•	wrap-key which is effectively a constructor for wrapping keys.
•	equal? to check for equality of keys.

The key wrapper must implement underlying>> to retrieve the original key.

Other relevant generics are clone and new-assoc.

Examples of wrapped hastable objects can be seen in:

•	hashtables.identity
•	hashtables.sequences
•	hashtables.numbers