On Mon, Dec 21, 2009 at 6:07 PM, Gabi <bugspy...@gmail.com> wrote: > The problem with is that I need to execute the same function with > different bindings each time. So caching won't help me > For example I need to do something like: > > (dotimes [_ 1000] > (intern 'user 'x (rand)) > (eval '(prn (+(* x x) 5))))
So, 'x' is an open term within your expression. Simply define a function (fn [x] (prn (+ (* x x) 5))) instead, and call it with your binding for 'x'. No need for eval here -- maybe once to define the function, but certainly not to evaluate the expression. Best, Graham > > On Dec 21, 11:53 pm, AlexK <alexander.konstanti...@informatik.haw- > hamburg.de> wrote: >> What eval does, is wrapping (fn* [] <expression>) around its >> arguments, compiling that, and calling the resulting function object >> (except if your list starts with a 'do or a 'def). >> >> While Clojure's compiler is pretty fast, you should try not to use >> eval. If you want to pass code around you should try something like >> storing functions in a map or something similar. >> >> If you think that you have to eval lists, try wrapping them in (fn >> [] ...) and eval that form instead. You'll get a function object which >> was compiled once, but can be called as many times as you want. >> >> eg. >> >> (defn form->fn [list-to-eval] >> (eval (list 'fn [] list-to-eval))) ;this returns a fn >> >> (def form->fn (memoize form->fn)) ;caches the resulting fns, beware of >> memory leaks though >> >> ((form->fn '(println "Hello World"))) >> ((form->fn '(println "Hello World"))) >> ((form->fn '(println "Hello World"))) ; should compile only once >> >> Alex > > -- > 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 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
