Throwing an exception is probably the right thing to do if it's supposed to closely model the behavior of `nth`, but it wonder if it's the most usefull behavior in practice. I would guess that it introduces `not-empty` checks everywhere, instead of only for the cases where you want to be shure that the nil returned is actually an element of the collection.
cheers Jan > On 30 Sep 2015, at 20:18, Mark Engelberg <mark.engelb...@gmail.com> wrote: > >> On Wed, Sep 30, 2015 at 12:14 PM, Mark Engelberg <mark.engelb...@gmail.com> >> wrote: >> I also think it makes perfect sense for rand-nth to throw an error on an >> empty collection. That's because the first step is it needs to generate a >> random number between 0 and the length of the collection (0), which is >> impossible. So it should throw an error. Note that it is the *random >> generation of the index*, not the nth that conceptually is throwing the >> error. > > To be clear, when I say that nth "conceptually is throwing the error", I just > mean that's how I rationalize Clojure's behavior. That's not really what's > going on. (rand-int 0) returns 0 (which it probably shouldn't, given that > the input is meant to be an exclusive upper bound). So in fact, the error is > thrown by clojure.lang.RT.nthFrom, which is surprising. > > > -- > You received this message because you are subscribed to the Google > Groups "Clojure" group. > To post to this group, send email to clojure@googlegroups.com > Note that posts from new members are moderated - please be patient with your > first post. > To unsubscribe from this group, send email to > clojure+unsubscr...@googlegroups.com > For more options, visit this group at > http://groups.google.com/group/clojure?hl=en > --- > You received this message because you are subscribed to the Google Groups > "Clojure" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to clojure+unsubscr...@googlegroups.com. > For more options, visit https://groups.google.com/d/optout. -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups "Clojure" group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
