clojure

问题 The following piece of Clojure code results in java.lang.StackOverflowError when I call it with (avg-bids 4000 10 5). I try to figure out why, since sum-bids is written as a tail-recursive function, so that should work. Using Clojure 1.2. Anyone knows why this happens? (ns fixedprice.core (:use (incanter core stats charts))) (def *bid-mean* 100) (defn bid [x std-dev] (sample-normal x :mean *bid-mean* :sd std-dev)) (defn sum-bids [n offers std-dev] (loop [n n sum (repeat offers 0)] (if (zero?

问题 I installed and run lein, but it seems to slow on My Mac (10.6.4). Running 'time lein help' gives me real 11m8.674s user 0m54.297s sys 1m32.621s I tried once more. real 15m25.560s user 1m36.087s sys 2m52.745s What's wrong with this? Is anyone experiencing similar problem? Is there anyway to check what's the problem? Added When I install, I used 'sudo lein deps', as I got some errors using 'lein deps'. I guess it caused some problem accessing files. When I run ' sudo lein SOMETHING', it works

问题 The following piece of Clojure code results in java.lang.StackOverflowError when I call it with (avg-bids 4000 10 5). I try to figure out why, since sum-bids is written as a tail-recursive function, so that should work. Using Clojure 1.2. Anyone knows why this happens? (ns fixedprice.core (:use (incanter core stats charts))) (def *bid-mean* 100) (defn bid [x std-dev] (sample-normal x :mean *bid-mean* :sd std-dev)) (defn sum-bids [n offers std-dev] (loop [n n sum (repeat offers 0)] (if (zero?

问题 I'm having one little hiccup in understanding Lisp. According to the Common Lisp standard, a form is an atom or list that is meant to be evaluated. That seems easy enough. In the real world, at the moment, we store programs in files. SBCL, Clojure, and the like all have the notion of a file that can also be evaluated. How is this understood? Is a file treated ultimately like a single form to be evaluated, is it a collection of forms? For some reason, this has been really confusing me. 回答1:

问题 I have a small Clojure consumer/publisher receiving messages, processing them and sending them off to other consumers, all via RabbitMQ. I've defined a message-handler that handles messages in a separate thread (separate from the main thread that is). As can be seen in the code below, the thread synchronously receives and sends messages, all happening in an event loop started by the lcm/subscribe function. So, the question is, what would be the "Clojure way" to create a N-sized thread pool of

问题 In my Clojure codebase, I have defined several protocols and several defrecords. I am using clojure.test to unit test the concrete functions defined within my defrecords. For example, let's say I have the following source files: In src/foo/protocols.clj: (ns foo.protocols) (defprotocol RequestAcceptability (desired-accepted-charset [this])) In src/foo/types.clj: (ns foo.types (:use [foo.protocols :only [RequestAcceptability desired-accepted-charset]]) (defrecord RequestProcessor [field-1

问题 $ time java -jar clojure-1.4.0.jar -e '(println "Hello world")' Hello world real 0m4.586s $ time python clojure.py -c '(py/print "Hello world")' real 0m14.690s $ time mono Clojure.Main.exe -e '(println "hello world")' hello world real 0m4.843s /* clojure-metal is not tested due to not being written at the moment */ Can Clojure startup time be little, as like when I run Perl or Python scripts? Is slow startup time an underlying framework's or Clojure's issue (which can be fixed sooner or later

问题 $ time java -jar clojure-1.4.0.jar -e '(println "Hello world")' Hello world real 0m4.586s $ time python clojure.py -c '(py/print "Hello world")' real 0m14.690s $ time mono Clojure.Main.exe -e '(println "hello world")' hello world real 0m4.843s /* clojure-metal is not tested due to not being written at the moment */ Can Clojure startup time be little, as like when I run Perl or Python scripts? Is slow startup time an underlying framework's or Clojure's issue (which can be fixed sooner or later

问题 I have been writing some Clojure recently, and I found myself using the following pattern frequently enough: (let [x (bam) y (boom)] {:x x :y y}) So I went ahead and wrote the following macro: (defmacro make-keyword-map [& syms] `(hash-map ~@(mapcat (fn [s] [(keyword (name s)) s]) syms))) With that, code now looks like: (let [x (bam) y (boom)] (make-keyword-map x y) Would this sort of macro be considered idiomatic? Or am I doing something wrong, and missing some already established pattern to

问题 Is it possible to compose for example: (defn- multiple-of-three? [n] (zero? (mod n 3)) (defn- multiple-of-five? [n] (zero? (mod n 5)) into: multiple-of-three-or-five? so I can use it for filtering: (defn sum-of-multiples [n] (->> (range 1 n) (filter multiple-of-three-or-five?) (reduce +))) Also I don't want to define it like this: (defn- multiple-of-three-or-five? [n] (or (multiple-of-three? n) (multiple-of-five? n))) For example with Javascript module Ramda it would be achieved as: http:/