Thanks everyone! Alyssa Kwan On Nov 17, 11:10 am, Stuart Halloway <stuart.hallo...@gmail.com> wrote: > I am wrong, there was a bug here, and Rich just fixed it. > > https://github.com/clojure/clojure/commit/8225407032ea643cbe3db7f35ef... > > Please retry against master, and sorry for inflicting more confusion. > > Stu > > > > > Meikel, > > > while a good description of how things work in 1.2, it's not accurate for > > 1.3, and my point was that Stu's description of how 1.3 works (by using > > words like "the function is recompiled") does not match with my own > > knowledge of what had been done in 1.3 the days just before the conj. > > > Since then, I've been away from #clojure (to my regret) and maybe I've > > missed new evolutions on the way it's handled in master. > > > Anyway, this concept of "the function is recompiled" feels "weird". > > > My own comprehension of how things work in 1.3: > > > Each function works through a cached set of var's values, and there's just > > a check to see if the cache is stale or not. If the cache is stale (some > > vars have been redef's, e.g. their root value has been changed), then the > > cache is recomputed. > > > 2010/11/17 Meikel Brandmeyer <m...@kotka.de> > > Hi, > > > On 17 Nov., 16:29, David Sletten <da...@bosatsu.net> wrote: > > > > > => (defn a > > > > ([x] x) > > > > ([x y] (+ (a x) (a y)))) > > > > #'user/a > > > > => (a 1 2) > > > > 3 > > > > => (def b a) > > > > #'user/b > > > > => (b 1 2) > > > > 3 > > > > => (defn a [x] > > > > (- x)) > > > > #'user/a > > > > => (b 1 2) > > > > -3 > > > > Let's call the original function assigned to 'a' a0 and the new one a1. > > > After 'a' has been redefined to a1, 'b' still refers to a0. So the 2nd > > > call to 'b' invokes a0 with two args (in fact, a1 only takes one arg > > > now). But within a0 itself the references to 'a' are being resolved at > > > runtime to a1 now, not as references to a0 as before. > > > > Are you saying that inside a0 Clojure detects that 'a' means something > > > else now and recompiles a0 to point to a1? > > > > In any case, this behavior seems weird. > > > Isn't that completely logical? Let's name things differently to keep > > functions and Vars apart. You define a function f and store it in Var > > a. f references Var a internally. Then you define Var b and store f in > > it by retrieving it from Var a. By executing (b 1 2) you basically > > retrieve f from b and call it with two arguments. Inside f, f itself > > is retrieved from the Var a and called with one argument. > > > Now you create a new function g, which you store in Var a (assumption: > > re-defing an existing Var just replaces its value and does not unmap > > and map again a fresh Var). Again you execute (b 1 2). Same thing > > happens: f is retrieved and called with two arguments. Inside f > > however, now g is retrieved from Var a and called with one argument. > > > This actually allows to define memoized recursive functions. > > > Sincerely > > Meikel > > > -- > > 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- Hide quoted text - > > - Show quoted text -
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