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  • handleOpenURL not called using a custom url schema in iPhone OS

    - by favo
    Hi, I have successfuly added my own url schemes to my App. The App correctly launches using the schemes. Now I want to handle the incoming data but the delegate is not called. It is an universal app and I have added the following function to both AppDelegates: - (BOOL)application:(UIApplication *)application handleOpenURL:(NSURL *)url { if (!url) { return NO; } NSString *URLString = [url absoluteString]; UIAlertView *alert = [[UIAlertView alloc] initWithTitle:NSLocalizedString(@"test message", nil) message:URLString delegate:self cancelButtonTitle:nil otherButtonTitles:@"OK", nil]; [alert show]; [alert release]; return YES; } I am testing with a schema like: myapp://appalarm.com …and would expect to be appalarm.com in the URLString What is wrong with it? Thanks for your responses!

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  • Looking for examples of "real" uses of continuations

    - by Sébastien RoccaSerra
    I'm trying to grasp the concept of continuations and I found several small teaching examples like this one from the Wikipedia article: (define the-continuation #f) (define (test) (let ((i 0)) ; call/cc calls its first function argument, passing ; a continuation variable representing this point in ; the program as the argument to that function. ; ; In this case, the function argument assigns that ; continuation to the variable the-continuation. ; (call/cc (lambda (k) (set! the-continuation k))) ; ; The next time the-continuation is called, we start here. (set! i (+ i 1)) i)) I understand what this little function does, but I can't see any obvious application of it. While I don't expect to use continuations all over my code anytime soon, I wish I knew a few cases where they can be appropriate. So I'm looking for more explicitely usefull code samples of what continuations can offer me as a programmer. Cheers!

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  • Racket list in struct

    - by Tim
    I just started programming with Racket and now I have the following problem. I have a struct with a list and I have to add up all prices in the list. (define-struct item (name category price)) (define some-items (list (make-item "Book1" 'Book 40.97) (make-item "Book2" 'Book 5.99) (make-item "Book3" 'Book 20.60) (make-item "Item" 'KitchenAccessory 2669.90))) I know that I can return the price with: (item-price (first some-items)) or (item-price (car some-items)). The problem is, that I dont know how I can add up all Items prices with this. Answer to Óscar López: May i filled the blanks not correctly, but Racket mark the code black when I press start and don't return anything. (define (add-prices items) (if (null? items) (+ 0 items) ; Here I don't really know what to write for a 0. ; I tried differnt thnigs like null and this version. (+ (item-price (first some-items)) (add-prices (item-price (rest some-items))))))

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  • Inserting mutable pairs into a mutable list

    - by Romelus
    How can I push a mutable pair onto a stack such that i'm only creating one stack. I have some code that works but creates lists within lists within lists.... Here is what I believe should work but throws an error. (define func (arg1 arg2 arg3) // Where arg3 is an empty list (mappend (mcons arg1 arg2) arg3)) The above code complains and says: "mcar: expects argument of type ; given ... Can anyone show me how I can get a result that looks like so,: (list (arg1 arg2) (arg# arg#) ...)

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  • mutation...........

    - by superguay
    Hey everybody, I'm kinda confused..... (define m (list 1 2 3 '(5 8))) (let ((l (cdr m))) (set! l '(28 88))) ==>(1 2 3 (5 8)) (define o (list 1 2 3 '(5 8))) (let ((l (cdr o))) (set-car! l '(28 88))) ==> (1 (28 88) 3 (5 8)) Why does (set! l '(28 88))) not update m?

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  • SICP making change

    - by RyanD
    So; I'm a hobbiest who's trying to work through SICP (it's free!) and there is an example procedure in the first chapter that is meant to count the possible ways to make change with american coins; (change-maker 100) = 292. It's implemented something like: (define (change-maker amount) (define (coin-value n) (cond ((= n 1) 1) ((= n 2) 5) ((= n 3) 10) ((= n 4) 25) ((= n 5) 50))) (define (iter amount coin-type) (cond ((= amount 0) 1) ((or (= coin-type 0) (< amount 0)) 0) (else (+ (iter amount (- coin-type 1)) (iter (- amount (coin-value coin-type)) coin-type))))) (iter amount 5)) Anyway; this is a tree-recursive procedure, and the author "leaves as a challenge" finding an iterative procedure to solve the same problem (ie fixed space). I have not had luck figuring this out or finding an answer after getting frustrated. I'm wondering if it's a brain fart on my part, or if the author's screwing with me.

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  • Vector addition of lists

    - by ntimes
    If I had a N lists each of length M, how could I write a nice clean function to return a single list of length M, where each element is the sum of the corresponding elements in the N lists? (starting to learn lisp - go easy!)

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  • What is the best color combination for readability, easy of use, and reduced eye strain?

    - by Nick Berardi
    I am trying to pick out the optimal set of colors for a new website project. I want to do a traditional black on white look and feel for the main content. However my partner on the project wants to do a color combination that more looks like the traditional Windows Forms look and feel. Is there any research available on the best color combination's to use for readability, ease of use, and reduced eye strain?

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  • Choosing colour schemes

    - by DanDan
    How do you choose your colour schemes for your applications and/or web designs? Is it a gut instinct thing or can logic be applied here too? I have looked at some colour theory but my combinations seemed wrong. I am looking at a monochrome webpage. Rather than pluck colours out of the air as usual I would like to see if there is a science behind this. Links and opinions welcome.

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  • How to parse out base file name using Script-Fu

    - by ongle
    Using Gimp 2.6.6 for MAC OS X (under X11) as downloaded from gimp.org. I'm trying to automate a boring manual process with Script-Fu. I needed to parse the image file name to save off various layers as new files using a suffix on the original file name. My original attempts went like this but failed because (string-search ...) doesn't seem to be available under 2.6 (a change to the scripting engine?). (set! basefilename (substring filename 0 (string-search "." filename))) Then I tried to use this information to parse out the base file name using regex but (re-match-nth ...) is not recognized either. (if (re-match "^(.*)[.]([^.]+)$" filename buffer) (set! basefilename (re-match-nth orig-name buffer 1)) ) And while pulling the value out of the vector ran without error, the resulting value is not considered a string when it is passed into (string-append ...). (if (re-match "^(.*)[.]([^.]+)$" filename buffer) (set! basefilename (vector-ref buffer 1)) ) So I guess my question is, how would I parse out the base file name?

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  • How Can I Improve This Algorithm (LCS)

    - by superguay
    (define (lcs lst1 lst2) (define (except-last-pair list) (if (pair? (cdr list)) (cons (car list) (except-last-pair (cdr list))) '())) (define (car-last-pair list) (if (pair? (cdr list)) (car-last-pair (cdr list)) (car list))) (if (or (null? lst1) (null? lst2)) null (if (= (car-last-pair lst1) (car-last-pair lst2)) (append (lcs (except-last-pair lst1) (except-last-pair lst2)) (cons (car-last-pair lst1) '())) **(if (> (length (lcs lst1 (except-last-pair lst2))) (length (lcs lst2 (except-last-pair lst1)))) (lcs lst1 (except-last-pair lst2)) (lcs lst2 (except-last-pair lst1)))))) I dont want it to run over and over.. Regards, Superguay

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  • Day dreaming about automatic RGB color function in PHP

    - by Sam
    Hello fellow earthlings. A quesion about RGB color and its usefulness in a simple tiny php code: Imagine I have variable $colorA containning a valid six char color. say B1B100, a greenish natural color. Now If I would like to make a new color from that, which is, say, ten steps lighter thatn that original color, roughly. $colorA = B1B100 // original color php code with little color engine lightening stuff up goes here $colorB = ?????? // original color lightened up Is there a php ready function that KNOWS rgb colors something like php function RGB ( input color, what to do, output color) Where what to do could be +/- 255 values of brightness etc etc. Is something like this already possible or am I day dreaming? rgb($colorA, +10, $colorB) If this does not exist, what would be the shortest code for doing this? Link suffices. Suggestions and ideas are answers to me. Thanks.

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  • Equivalence Classes

    - by orcik
    I need to write a program for equivalence classes and get this outputs... (equiv '((a b) (a c) (d e) (e f) (c g) (g h))) => ((a b c g h) (d e f)) (equiv '((a b) (c d) (e f) (f g) (a e))) => ((a b e f g) (c d)) Basically, A set is a list in which the order doesn't matter, but elements don't appear more than once. The function should accept a list of pairs (elements which are related according to some equivalence relation), and return a set of equivalence classes without using iteration or assignment statements (e.g. do, set!, etc.). However, set utilities such as set-intersection, set-union and a function which eliminates duplicates in a list and built-in functions union, intersection, and remove-duplicates are allowed. Thanks a lot! By the way, It's not a homework question. A friend of mine need this piece of code to solve smilar questions.

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  • How to decide which colors to use that look most similar across most screens/monitors?

    - by Lyon
    Hi, I'm baffled. I'm trying to find suitable colors for a logo that would look similar across most monitors/screens. I know it's near impossible, but how does one end up with the color palette that new Google logo and Facebook "blue" uses for example? I've a monitor that has been calibrated, and a few laptop screens that have default settings. Yet both the Google logo and facebook's look similar (although they aren't using colors restricted to the web safe 216 palette. Any ideas? thoughts? Thanks

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  • Java style FOR loop in a clojure interpeter ?

    - by Kevin
    I have a basic interpreter in clojure. Now i need to implement for (initialisation; finish-test; loop-update) { statements } inside my interpreter. I will attach my interpreter code I got so far. Any help is appreciated. Interpreter (declare interpret make-env) ;; (def do-trace false) ;; ;; simple utilities (def third ; return third item in a list (fn [a-list] (second (rest a-list)))) (def fourth ; return fourth item in a list (fn [a-list] (third (rest a-list)))) (def run ; make it easy to test the interpreter (fn [e] (println "Processing: " e) (println "=> " (interpret e (make-env))))) ;; for the environment (def make-env (fn [] '())) (def add-var (fn [env var val] (cons (list var val) env))) (def lookup-var (fn [env var] (cond (empty? env) 'error (= (first (first env)) var) (second (first env)) :else (lookup-var (rest env) var)))) ;; -- define numbers (def is-number? (fn [expn] (number? expn))) (def interpret-number (fn [expn env] expn)) ;; -- define symbols (def is-symbol? (fn [expn] (symbol? expn))) (def interpret-symbol (fn [expn env] (lookup-var env expn))) ;; -- define boolean (def is-boolean? (fn [expn] (or (= expn 'true) (= expn 'false)))) (def interpret-boolean (fn [expn env] expn)) ;; -- define functions (def is-function? (fn [expn] (and (list? expn) (= 3 (count expn)) (= 'lambda (first expn))))) (def interpret-function (fn [expn env] expn)) ;; -- define addition (def is-plus? (fn [expn] (and (list? expn) (= 3 (count expn)) (= '+ (first expn))))) (def interpret-plus (fn [expn env] (+ (interpret (second expn) env) (interpret (third expn) env)))) ;; -- define subtraction (def is-minus? (fn [expn] (and (list? expn) (= 3 (count expn)) (= '- (first expn))))) (def interpret-minus (fn [expn env] (- (interpret (second expn) env) (interpret (third expn) env)))) ;; -- define multiplication (def is-times? (fn [expn] (and (list? expn) (= 3 (count expn)) (= '* (first expn))))) (def interpret-times (fn [expn env] (* (interpret (second expn) env) (interpret (third expn) env)))) ;; -- define division (def is-divides? (fn [expn] (and (list? expn) (= 3 (count expn)) (= '/ (first expn))))) (def interpret-divides (fn [expn env] (/ (interpret (second expn) env) (interpret (third expn) env)))) ;; -- define equals test (def is-equals? (fn [expn] (and (list? expn) (= 3 (count expn)) (= '= (first expn))))) (def interpret-equals (fn [expn env] (= (interpret (second expn) env) (interpret (third expn) env)))) ;; -- define greater-than test (def is-greater-than? (fn [expn] (and (list? expn) (= 3 (count expn)) (= '> (first expn))))) (def interpret-greater-than (fn [expn env] (> (interpret (second expn) env) (interpret (third expn) env)))) ;; -- define not (def is-not? (fn [expn] (and (list? expn) (= 2 (count expn)) (= 'not (first expn))))) (def interpret-not (fn [expn env] (not (interpret (second expn) env)))) ;; -- define or (def is-or? (fn [expn] (and (list? expn) (= 3 (count expn)) (= 'or (first expn))))) (def interpret-or (fn [expn env] (or (interpret (second expn) env) (interpret (third expn) env)))) ;; -- define and (def is-and? (fn [expn] (and (list? expn) (= 3 (count expn)) (= 'and (first expn))))) (def interpret-and (fn [expn env] (and (interpret (second expn) env) (interpret (third expn) env)))) ;; -- define with (def is-with? (fn [expn] (and (list? expn) (= 3 (count expn)) (= 'with (first expn))))) (def interpret-with (fn [expn env] (interpret (third expn) (add-var env (first (second expn)) (interpret (second (second expn)) env))))) ;; -- define if (def is-if? (fn [expn] (and (list? expn) (= 4 (count expn)) (= 'if (first expn))))) (def interpret-if (fn [expn env] (cond (interpret (second expn) env) (interpret (third expn) env) :else (interpret (fourth expn) env)))) ;; -- define function-application (def is-function-application? (fn [expn env] (and (list? expn) (= 2 (count expn)) (is-function? (interpret (first expn) env))))) (def interpret-function-application (fn [expn env] (let [function (interpret (first expn) env)] (interpret (third function) (add-var env (first (second function)) (interpret (second expn) env)))))) ;; the interpreter itself (def interpret (fn [expn env] (cond do-trace (println "Interpret is processing: " expn)) (cond ; basic values (is-number? expn) (interpret-number expn env) (is-symbol? expn) (interpret-symbol expn env) (is-boolean? expn) (interpret-boolean expn env) (is-function? expn) (interpret-function expn env) ; built-in functions (is-plus? expn) (interpret-plus expn env) (is-minus? expn) (interpret-minus expn env) (is-times? expn) (interpret-times expn env) (is-divides? expn) (interpret-divides expn env) (is-equals? expn) (interpret-equals expn env) (is-greater-than? expn) (interpret-greater-than expn env) (is-not? expn) (interpret-not expn env) (is-or? expn) (interpret-or expn env) (is-and? expn) (interpret-and expn env) ; special syntax (is-with? expn) (interpret-with expn env) (is-if? expn) (interpret-if expn env) ; functions (is-function-application? expn env) (interpret-function-application expn env) :else 'error)))

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  • Fermat factorization method limit

    - by Fakrudeen
    I am trying to implement Fermat's factorization [Algorithm C in Art of computer programming Vol. 2]. Unfortunately in my edition [ISBN 81-7758-335-2], this algorithm is printed incorrectly. what should be the condition on factor-inner loop below? I am running the loop till y <= n [passed in as limit]. (if (< limit y) 0 (factor-inner x (+ y 2) (- r y) limit)) Is there anyway to avoid this condition altogether, as it will double the speed of loop? (define (factor n) (let ( ( square-root (inexact->exact (floor (sqrt n))) ) ) (factor-inner (+ (* 2 square-root) 1) 1 (- (* square-root square-root) n) n) ) ) (define (factor-inner x y r limit) (if (= r 0) (/ (- x y) 2) (begin (display x)(display " ")(display y)(display " ")(display r)(newline) ;(sleep-current-thread 1) (if (< r 0) (factor-inner (+ x 2) y (+ r x) limit) (if (< limit y) 0 (factor-inner x (+ y 2) (- r y) limit)) ) ) ) )

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  • Help me write my LISP :) LISP environments, Ruby Hashes...

    - by MikeC8
    I'm implementing a rudimentary version of LISP in Ruby just in order to familiarize myself with some concepts. I'm basing my implementation off of Peter Norvig's Lispy (http://norvig.com/lispy.html). There's something I'm missing here though, and I'd appreciate some help... He subclasses Python's dict as follows: class Env(dict): "An environment: a dict of {'var':val} pairs, with an outer Env." def __init__(self, parms=(), args=(), outer=None): self.update(zip(parms,args)) self.outer = outer def find(self, var): "Find the innermost Env where var appears." return self if var in self else self.outer.find(var) He then goes on to explain why he does this rather than just using a dict. However, for some reason, his explanation keeps passing in through my eyes and out through the back of my head. Why not use a dict, and then inside the eval function, when a new "sub-environment" needs to be created, just take the existing dict and update the key/value pairs that need to be updated, and pass that new dict into the next eval? Won't the Python interpreter keep track of the previous "outer" envs? And won't the nature of the recursion ensure that the values are pulled out from "inner" to "outer"? I'm using Ruby, and I tried to implement things this way. Something's not working though, and it might be because of this, or perhaps not. Here's my eval function, env being a regular Hash: def eval(x, env = $global_env) ........ elsif x[0] == "lambda" then ->(*args) { eval(x[2], env.merge(Hash[*x[1].zip(args).flatten(1)])) } ........ end The line that matters of course is the "lambda" one. If there is a difference, what's importantly different between what I'm doing here and what Norvig did with his Env class? If there's no difference, then perhaps someone can enlighten me as to why Norvig uses the Env class. Thanks :)

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  • No idea how to solve SICP exercise 1.11

    - by Javier Badia
    This is not homework. Exercise 1.11: A function f is defined by the rule that f(n) = n if n<3 and f(n) = f(n - 1) + 2f(n - 2) + 3f(n - 3) if n 3. Write a procedure that computes f by means of a recursive process. Write a procedure that computes f by means of an iterative process. Implementing it recursively is simple enough. But I couldn't figure out how to do it iteratively. I tried comparing with the Fibonacci example given, but I didn't know how to use it as an analogy. So I gave up (shame on me) and Googled for an explanation, and I found this: (define (f n) (if (< n 3) n (f-iter 2 1 0 n))) (define (f-iter a b c count) (if (< count 3) a (f-iter (+ a (* 2 b) (* 3 c)) a b (- count 1)))) After reading it, I understand the code and how it works. But what I don't understand is the process needed to get from the recursive defintion of the function to this. I don't get how the code formed in someone's head. Could you explain the thought process needed to arrive at the solution?

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  • Which option controls the color of this text?

    - by Tomas Lycken
    I have applied a color theme called Vibrant Ink (or some modification of it), and since I installed Visual Studio 2010 Pro Power Tools all my statement completion boxes are undreadable. What setting changes the colors of these boxes? Preferrably, I'd like to change the background color to something darker, but if that's not possible at least I want to change the text color.

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  • Is there a Moria like theme for Visual Studio 2010?

    - by Junior Mayhé
    Is there some cool Moria like theme for Visual Studio 2010? Mine is highlighting gray font with gray background! I just can't configure it on Tools-Options-Environment-Fonts and Colors menu. Visual Studio doesn't seem to show an item for this "highlighting keyword/tag system". You select a variable on variable called myVar, and it highlights all with the same name but with a grayer color and gray background. I just can't read it and can't set it.

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  • Color Themes for Eclipse?

    - by John Stauffer
    I am a recovering Emacs user, who is trying to ease into Eclipse usage. (Since I'm encouraging the rest of the team to use it, I guess I should at least try to get along). My current excuse is that it hurts my eyes. I'm currently using the excellent zenburn theme in emacs, and would love to find it for eclipse. However, I find that changing my color theme every few months makes for a great way to procrastinate, so ideally I'd like to find a repository for eclipse color themes. There don't appear to be any eclipse themes indexed by Google, so all the great themes must be sitting on your hard disk somewhere. Please share them. Thanks

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  • What the heck is the "Structure and Interpretation of Computer Programs" cover drawing about?

    - by Paul Reiners
    What the heck is the Structure and Interpretation of Computer Programs cover drawing about? I mean I know what "eval", "apply", and '?' all mean, but I'm having a hard time deciphering the rest of the picture. Who the heck is the maiden? Does she work for the wizard? Why the heck is she pointing at the table? Is she pointing at that little bowl-type thing? Or the books? Or the table in general? Is she trying to tell the wizard that he should apply some sort of Lisp wizardry to the table or the items on it? Or is she just telling him something prosaic, such as his food is getting cold? What the heck is the one leg on that table that looks like...a leg...with a foot at the end (as legs tend to have)? How does the table balance on one leg? (Or is that another leg in the shadows?) [Note: I'm waiting for a lengthy build to finish in case you were wondering.]

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