Hello Guilers, Over on Racket Users, Marco Maggi points out that ASSERT should return the value of the expression if it is true[0][1]. I have attached a simple patch to fix this behaviour in guile. Regards, Ian 0. http://lists.racket-lang.org/users/archive/2011-April/045046.html 1. http://www.r6rs.org/final/html/r6rs/r6rs-Z-H-14.html#node_sec_11.14