Sounds interesting, I'd love to hear more about the use case. We ran into this issue as well when implementing the new positional compilation for Graph. We filed a ticket [1], and worked around it with a funny trick:
Suppose you want to eval a complicated thing, and the crux of the issue is that this fails: (let [y 1 f (fn [x] (+ x y))] (eval `(~f 1))) A solution is to rework what you eval, so that it has a 'hole' for the function and you slot the function into this hole afterwards (which Hotspot seems to be able to optimize just fine): (let [y 1 f (fn [x] (+ x y))] ((eval `(fn [g#] (g# 1))) f)) Happy to elaborate if you like. Cheers, Jason [1] http://dev.clojure.org/jira/browse/CLJ-1206 On Wednesday, August 28, 2013 10:59:19 AM UTC-7, Jamie Brandon wrote: > > That sort of works for my use case. > > What I want to do is define a grammar... > > (def num-graph > (graph > num ~(or ~succ ~zero) > succ (succ ^x ~num) > zero zero)) > > ... attach actions .... > > (def num-out > (output-in num-graph > 'zero (fnk [] 0) > 'succ (fnk [x] (inc x)))) > > ... and compile the result ... > > strucjure.regression.tests> (graph->view 'num num-out) > (clojure.core/letfn > [(num ...) > (succ ...) > (zero ...)] > (clojure.core/fn > [input__2288__auto__] > (num input__2288__auto__))) > > This works fine as long as the fnks dont close over anything, but > that's very limiting. > > If I eval that code and *then* wrap it in (binding ...) I can have > closures but that now means that I can't do call-site compilation. > I'll have to poke around a bit more... > > On 28 August 2013 18:32, Aaron Cohen <aa...@assonance.org <javascript:>> > wrote: > > I'm not sure if you'll consider this hacky or not. > > > > (def ^:dynamic *fn-helper*) > > > > (defn eval-at-one [f] (binding [*fn-helper* f] (eval '(*fn-helper* 1)))) > > > > > > On Wed, Aug 28, 2013 at 1:28 PM, Jamie Brandon > > <ja...@scattered-thoughts.net <javascript:>> wrote: > >> > >> 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 <wol...@gmail.com <javascript:>> > wrote: > >> > On Wed, Aug 28, 2013 at 9:27 AM, Jamie Brandon > >> > <ja...@scattered-thoughts.net <javascript:>> 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 > >> > clo...@googlegroups.com<javascript:> > >> > Note that posts from new members are moderated - please be patient > with > >> > your > >> > first post. > >> > To unsubscribe from this group, send email to > >> > clojure+u...@googlegroups.com <javascript:> > >> > 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+u...@googlegroups.com <javascript:>. > >> > 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 clo...@googlegroups.com<javascript:> > >> Note that posts from new members are moderated - please be patient with > >> your first post. > >> To unsubscribe from this group, send email to > >> clojure+u...@googlegroups.com <javascript:> > >> 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+u...@googlegroups.com <javascript:>. > >> 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 clo...@googlegroups.com<javascript:> > > Note that posts from new members are moderated - please be patient with > your > > first post. > > To unsubscribe from this group, send email to > > clojure+u...@googlegroups.com <javascript:> > > 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+u...@googlegroups.com <javascript:>. > > 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. 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