You will also run into problems if your functions close over any data: user> (let [f (fn [] 1)] (eval `(~f))) 1 nil user> (let [x 1 f (fn [] x)] (eval `(~f))) IllegalArgumentException No matching ctor found for class user$eval38616$f__38617 clojure.lang.Reflector.invokeConstructor (Reflector.java:163)
I'm struggling with this as well, I'm definitely interested in finding a non-hacky way to pass closures through eval without leaking memory. Perhaps something like: (let [x 1 f (fn [] x) f-sym (gensym)] (intern *ns* gensym (weak-ref f)) (with-meta (eval `(fn [] (do-stuff-with @~f))) {::strong-ref f})) So that way f will be freed up when the resulting fn is gced. On 28 August 2013 17:59, Ben Wolfson <wolf...@gmail.com> wrote: > On Wed, Aug 28, 2013 at 9:27 AM, Jamie Brandon > <ja...@scattered-thoughts.net> wrote: >> >> >> If you aren't worried about leaking memory, a possible workaround is >> to intern the fn in some namespace and then put the symbol in the >> macro output. > > > Hrm, I hope it doesn't come to that---as long as I'm creating the functions > with their metadata, I can make things work, because I can add extra > information to the with-meta call or do extra things when making the call. > What I'd like, though, is for it to be possible to copy the metadata over to > a new function by client code, just using the regular (with-meta (fn [blah] > blah) (meta old-fn)) mechanism. But then the sneaky symbol, or whatever > extra thing, in the metadata, that's used in the form to be eval-ed is > pointing to the original function, not the one passed in. Maybe just > providing a utility for fixing up the metadata is the right move, though > it's kidn of dissatisfying. > > > -- > Ben Wolfson > "Human kind has used its intelligence to vary the flavour of drinks, which > may be sweet, aromatic, fermented or spirit-based. ... Family and social > life also offer numerous other occasions to consume drinks for pleasure." > [Larousse, "Drink" entry] > > -- > -- > 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/groups/opt_out. -- -- 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/groups/opt_out.