[plt-scheme] How to make unit functors?

At Thu, 29 May 2003 16:49:39 +0200 (CEST), Zbyszek Jurkiewicz wrote:
> OK, there is a server, where people can leave private information.
> The person who leaves the information uses some symbol as a key
> for putting it into data structure.  Then, only people knowing
> a key can get it.
> 
> The key is not stored in the datastructure, so someone reading the
> datastructure information (by legal or illegal browsing of it) would not 
> know to what key it belongs.
> 
> A little bit artificial, but useful. 

Well, as Matthew has pointed out, that won't work, since two different
values may have the same hash code. The same value is required to have
the same hash code, but different ones aren't required to be different.

Robby