Some code

If you're following along with the persistent storage thread, you may want to take a look at http://code.google.com/p/jrm-code-project/source/browse/#svn/trunk/PStore. You will find two Scheme files. object-map.scm implements an object-map based on a persistent binary tree that is in persistent-tree.scm. You will have to provide the serialize and deserialize procedures yourself.