factor

Author	SHA1	Message	Date
Slava Pestov	3f4eb5a09a	Add changed-nth combinator: like change-nth but for persistent sequences	2008-11-13 00:10:55 -06:00
Slava Pestov	efb6c73f28	Move persistent collections to basis	2008-08-06 04:59:58 -05:00