[<<][plt][>>][..]Tue May 5 10:22:50 CEST 2009
Immutable hash tables
From the PLT Scheme reference manual:
3.13 Hash Tables
"A hash table (or simply hash) maps each of its keys to a single
value. For a given hash table, keys are equivalent via equal?, eqv?,
or eq?, and keys are retained either strongly or weakly (see Weak
Boxes). A hash table is also either mutable or immutable; immutable
tables support constant-time functional update.
I didn't know about the immutable constant-time functional update.
That's pretty cool! I wonder how it is implemented.
Red-black trees  .