When I try to add metadata to an infinite lazy sequence in Clojure, I get a stack overflow, and if I take off the metadata, then it works just fine. Why does adding the with-meta macro break the lazy seq? First create an infinite seq of a very nice number: (defn good [] (lazy-seq (cons 42 (good)))) user> (take 5 (good)) ...
I have a function that reads one token from an input stream that is called (get-next-indicator stream indicator) and returns it. I am trying to use it to construct a map. But, when I run it, it locks up. If I remove one of the get-next-indicator function, it does work. Does both functions try to read the stream at the same time is this...
I have installed vimclojure to make it easier to start learning clojure. But, I haven't been able to setup REPL inside vim. This is essentially because I was not able to write a maplocalleader in vim(?) Based on the documentation in vimclojure/doc/clojure.txt I put the following in my .vimrc to start the REPL - :map <LocalLeader>sr *s...
What is the preferred way of deploying a compojure/sinatra applications? I have multiple sites running on the host so i can't run jetty/mongrel on port 80. How should i handle multiple sites/applications running at the same host? ...
How would I find what fields a struct has? For example, if i have the following: (defstruct bintree :data :left :right) (def a (struct bintree 0 nil nil)) how would i get a list,set, or vector of (:data :left :right) from a? I've tried (show a) but this gives no methods that look correct. ...
I'm trying to create a function to create a new basewith another struct as a base, and as a start I attempted to make a macro that would create a new struct with the same fields as the old one. The macro I have which i thought should do this is below, but it is giving the following error: java.lang.Exception: Can't use qualified name a...
I am trying to port this algorithm to clojure. My code is (defn calc-iterations [x y] (let [c (struct complex x y)] (loop [z (struct complex 0 0) iterations 0] (if (and (< 2.0 (abs z)) (> max-iterations iterations)) iterations (recur (add c (multiply z z)) (inc iterations)))))) ...
I understand what :state /does/. It creates a field, like in Java, in your class. What I don't understand is what is the point of this? It seems like I only see it done with Clojure-generated classes that extend other classes. http://www.fatvat.co.uk/2009/05/clojure-and-robocode.html being one example. I don't know Java, and I'm not very...
I've been reading through Programming Clojure, and I've been having some trouble understanding Stuarts primary Java Interop example. He extends DefaultHandler, and creates a startElement method, and then passes that handler to an XML parser. What I don't understand, is what exactly is happening. Does his implementation of startElement ov...
Has anyone encountered a problem with emacs on windows and java input ? (read-line) in the REPL does not recognise the delimiter (well thats my guess). Using a vanilla clojure in the box, same issue. Further clarification. Using (read-line) or the scanner class within the REPL in EMACS the reader will not respond to return (As in it...
Hello everyone I'm currently learning clojure, but I was wondering how to get and store user input in a clojure program. I was looking at the clojure api and I found a function called read-line, however I'm not sure how to use it if it's the right function to use... Anyhow, how do you get user input in clojure ? ...
Hello everyone, I have a few questions concerning Lists, classes and variables in clojure. This may seem quite stupid but how do I access elements in a List ? I'm coding a program that allows you to manipulate a phonebook; You can add an entry, delete one or print the information about one. This leads me to two questions : Is the...
I have a simple yet frustrating problem in Clojure, I have a function (let's call it read-function) which figures out what the user wants to do from his input then calls another function that does that (let's call it action-function). This action-function calls the read-function when it's done so the user can perform another task. Now ...
Title says it all, here's the code : (def entry {:name tempName :num tempNum}) (def tempList '(entry)) (println (get (nth tempList 0) (:name))) Exception in thread "main" java.lang.IllegalArgumentException: Wrong number of args passed to keyword: :name In this bit of code, I define a map called entry containing a :name and a :num...
Hi, I am a beginner in Clojure, and I have a simple (stupid) question. I am trying to to read 4 user input , and then storing those inputs into a List this is my code: (def in1 (read-line)) (def in2 (read-line)) (def in3 (read-line)) (def in4 (read-line)) (def mylist '(in1 in2 in3 in4)) However, when i print the list, it gives...
Hi, I am a beginner in Clojure, and I have a simple question Lets say i have a List, composed of Maps. Each Map has a :name and :age My code is: (def Person {:nom rob :age 31 } ) (def Persontwo {:nom sam :age 80 } ) (def Persontthree {:nom jim :age 21 } ) (def mylist (list Person Persontwo Personthree)) Now how do i traverse the lis...
Hi, I am having a bit of difficulty with Lists in Clojure I have a quick question concerning the filter function Let's say I have a List composed of Maps My code is: (def Person {:name Bob } ) (def Person2 {:name Eric } ) (def Person3 {:name Tim } ) (def mylist (list Person Person2 Person3)) How would i go about filtering my list so t...
what is a more efficient way to accomplish this in clojure: (defn ones ([n] (ones n 1 1)) ([n i res] (if (< i n) (recur n (inc i) (bit-set res i)) res))) preferably it should still "do the right thing" when it comes to numerical type. ...
Hi, I am a pretty decent programmer in Java, however I am new to programming in Clojure. My question is : In java, to force an exit in the program, the code is :System.exit(0) ..........Is there any equivalent to this code is Clojure? -Thank you ...
I have a program that draws shapes on an image. I have a separate namespace for each shape, and they are in separate files. com/name/box.clj --> has com.name.box namespace. com/name/triangle.clj --> has com.name.triangle namespace. They all share a common function called generate that draws them on screen, so if I use use, function nam...