It would be great to optimize singletons out of comprehensions, since I (and probably others) have macros that expand into singleton constructors that are much better suited to just be a rebinding.
> (time (for ([n (in-range 1 1000000)]) (for ([k (in-set (set n))]) (random > k)))) cpu time: 340 real time: 338 gc time: 16 > (time (for ([n (in-range 1 1000000)]) (for ([k (in-value n)]) (random k)))) cpu time: 120 real time: 118 gc time: 0 Is this easily added to for.rkt? -Ian _________________________ Racket Developers list: http://lists.racket-lang.org/dev