- ((mem (- (cdr (assoc 'cells r)) start-memory))
- (proc (cdr (assoc 'proc r)))
- (stack (cdr (assoc 'stack r)))
- (time (- (cdr (assoc 'time r)) start-time)))
+ ((mem (- (assoc-get 'cells r) start-memory))
+ (proc (assoc-get 'proc r))
+ (stack (assoc-get 'stack r))
+ (time (- (assoc-get 'time r) start-time)))