factor

Author	SHA1	Message	Date
Slava Pestov	3723b2e640	vlists: immutable sequences with mostly-O(1) push and pop, O(n) behavior when sharing: optimized for the unshared case. also contains valists, which are assocs built on vlists with O(n) search starting from the end, and mostly-O(1) insertion that shadows prior entries. Behaves similar to Lisp/Scheme alists	2008-11-13 00:12:14 -06:00