Hi I would like to submit a new project to common-lisp.net It is a full blown unifier for arbitrary CL objects. Think DESTRUCTURING-BIND on steroids. It may be useful as a building block for a Prolog-like implementation or for a type inferencer. You can have a look at the preliminary documentation at http://bioinformatics.nyu.edu/~marcoxa/common-lisp/code/unification/ docs/html/ Thanks Marco -- Marco Antoniotti http://bioinformatics.nyu.edu NYU Courant Bioinformatics Group tel. +1 - 212 - 998 3488 715 Broadway 10th FL fax. +1 - 212 - 998 3484 New York, NY, 10003, U.S.A.