Thank you all for your replies doseq rather than my loop is the ideal situation for me, looks a lot nicer than my loop. I have to get used to avoiding loops when i can, and not calling object methods functions! thanks again everyone
On 15 Dez., 22:18, Laurent PETIT <laurent.pe...@gmail.com> wrote: > Hello, > > so you have a mutating object. To mutate it you must call a method (please > note, I don't use the term function, which has a different meaning than a > class method, especially in clojure where functions are first class). > > You want a final call something like that: > (mystery-fn-or-macro object method-to-call list-of-items) > > If you can afford in your situation of passing a real higher order function > to mystery-fn-or-macro , like (fn [obj item] (.method-to-call obj item)), > then mystery-fn-or-macro is simply based on doseq : > > (defn mystery-fn [object fn-calling-method list-of-items] > (doseq [item list-of-items] (fn-calling-method obj item))) > > and you call it as such : > (mystery-fn object (fn [obj item] (.method-to-call obj item)) list-of-items) > > There's also the memfn macro in clojure.core for exactly this purpose: > (mystery-fn object (memfn method-to-call item) list-of-items) > > But note that those days, memfn is somewhat deprecated in favor of raw (fn > ...) or #(...) constructs. > > HTH, > > -- > Laurent > > 2009/12/15 tristan <tristan.k...@gmail.com> > > > > > Hi guys, > > > I have a list (which i don't know the size of) and i want to do > > something like this: > > (doto (MutatingJavaObject.) (.add (first list-items)) (.add (second > > list-items)) ..... (.add (last list-items))) > > > Now I may be doing this the complete wrong way, so if you have a > > better solution please tell me. but i've been trying to build a macro > > to expand this out, given the object, the function to call and the > > list of items. > > > i've been playing with various things, and manage to get a few things > > that work if i pass the list of items in without being a list (i.e. (1 > > 1 1) rather than '(1 1 1) or (list 1 1 1)) for example (defmacro d2 > > [obj func inputs] (concat (list 'doto obj) (map #(list func %) > > inputs))) but if i try and pass in my list-items variable it just > > complains that it "Don't know how to create ISeq from: > > clojure.lang.Symbol". > > > perhaps i'm not fully grasping the concept of macros? i'm very new to > > lisp and FP in general. > > > while writing this email i had a light switch on that i could simply > > do it like this: > > (let [obj (MutatingJavaObject.)] > > (loop [in list-items] > > (when (not (empty? in)) > > (.add obj (first in)) > > (recur (rest in)))) > > obj) > > but i would still like to know if there is a way i could get the macro > > i wanted going. > > > please help! my googling and trauling through Stuart Halloway's book > > have come up naught. > > > thanks in advance! > > -Tristan > > > -- > > 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<clojure%2bunsubscr...@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
