Hi, On Thursday, September 13, 2012 7:37:09 AM UTC+2, bsmith.occs wrote: > > > Consider a simpler example with a vector, which doesn't produce an > error since it's allowed to have duplicates: > > (def k (atom 0)) > (defn generate-id [] (swap! k inc)) > > Now when the reader reads this: > > [(generate-id) (generate-id)] > > It returns a vector containing two lists, each of which contains the > symbol generate-id. > > It's only when this data structure is evaluated, that the functions > generate-id get called. In some order. I wouldn't rely on getting [1 > 2] and not [2 1]. > > you can examine, what the reader returns by using read-string, e.g.
user=> (read-string "[1 2]") [1 2] OK user=> (read-string "[(+ 1 2) 2]") [(+ 1 2) 2] Oops?! user=> (eval (read-string "[(+ 1 2) 2]")) [3 2] Aha. :-) And, of course, the same for maps with gensym: user=> (read-string "{(gensym) :value}") {(gensym) :value} user=> (eval (read-string "{(gensym) :value}")) {G__333 :value} Regards, Stefan -- 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