Re: Proxying in clojure
Chooser, Please send me yours then. Emeka --~--~-~--~~~---~--~~ 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 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 -~--~~~~--~~--~--~---
Re: Help with Slime
> > Kogu > > Below is the relevant part of my init.el. Which file is init.el? Where can I find it? I use windows vista. Emeka --~--~-~--~~~---~--~~ 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 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 -~--~~~~--~~--~--~---
Re: Proxying in clojure
On Fri, Dec 26, 2008 at 4:40 AM, Emeka wrote: > Chooser, "Chouser" > Please send me yours then. Already did: http://groups.google.com/group/clojure/msg/4f00d2a3b5da8444 And Mr. Gilardi improved on it here: http://groups.google.com/group/clojure/msg/90316675320091cf --Chouser --~--~-~--~~~---~--~~ 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 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 -~--~~~~--~~--~--~---
How To Make Code More Functional?
Hi all, I'm just getting started with clojure from a functional background, and while I like playing with clojure and accomplishing script like tasks, I have no experience with anything larger than about 20 lines. I wanted to try to take something with "alot of state" and put it into clojure. I decided to code Tarjan's Algorithm for finding all the strongly connected components of a graph (http://en.wikipedia.org/wiki/ Tarjan's_strongly_connected_components_algorithm). I've written this code in Java and it's about a 100 lines. Sadly, my clojure version is about a 100 lines too. I am more-or-less translating my java code (which is more or less translated from Psuedo-Code), but I don't see a good way to make this problem more functional, but this is probably due to my imperative roots. I have the code posted as an attachment here or posted at http://www.cs.berkeley.edu/~aria42/tarjan.clj. Let me know if there's more canonical / functional ways to do something like this. Thanks, Aria --~--~-~--~~~---~--~~ 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 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 -~--~~~~--~~--~--~---
Re: How To Make Code More Functional?
Clojure for Tajan's Algorithm uploaded here http://clojure.googlegroups.com/web/tarjan.clj?gsc=yOHJ-CEAAAB3Fq8nFW3O6gqQkWXH_xrOYRvSPFZyhAT412614U6EGkzfKN-m9S9niuHrq-IEXAE - aria On Dec 26, 6:30 am, aria42 wrote: > Hi all, > I'm just getting started with clojure from a functional background, > and while I like playing with clojure and accomplishing script like > tasks, I have no experience with anything larger than about 20 lines. > I wanted to try to take something with "alot of state" and put it into > clojure. I decided to code Tarjan's Algorithm for finding all the > strongly connected components of a graph (http://en.wikipedia.org/wiki/ > Tarjan's_strongly_connected_components_algorithm). I've written this > code in Java and it's about a 100 lines. Sadly, my clojure version is > about a 100 lines too. I am more-or-less translating my java code > (which is more or less translated from Psuedo-Code), but I don't see a > good way to make this problem more functional, but this is probably > due to my imperative roots. > > I have the code posted as an attachment here or posted > athttp://www.cs.berkeley.edu/~aria42/tarjan.clj. > > Let me know if there's more canonical / functional ways to do > something like this. > > Thanks, Aria --~--~-~--~~~---~--~~ 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 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 -~--~~~~--~~--~--~---
Re: Exercise: words frequency ranking
Instead of #(- (val %)), one could also use the compose function :
(comp - val)
My 0,02 EURO,
--
Laurent
On Dec 25, 4:58 pm, Mibu wrote:
> My version:
>
> (defn top-words [input-filename result-filename]
> (spit result-filename
> (apply str
>(map #(format "%s : %d\n" (first %) (second %))
> (sort-by #(-(val %))
> (reduce #(conj %1 { %2 (inc (%1 %2 0)) }) {}
> (map #(.toLowerCase %)
> (re-seq #"\w+"
> (slurp
> input-filename)
>
> Mibu
>
> On Dec 25, 2:16 pm, Piotr 'Qertoip' Włodarek
> wrote:
>
> > Given the input text file, the program should write to disk a ranking
> > of words sorted by frequency, like:
>
> > the : 52483
> > and : 32558
> > of : 23477
> >a : 22486
> > to : 21993
>
> > My first implementation:
>
> > (defn topwords [in-filepath, out-filepath]
> > (def words (.split (.toLowerCase (slurp in-filepath)) "\\s+"))
>
> > (spit out-filepath
> > (apply str
> > (concat
> > (map (fn [pair] (format "%20s : %5d \r\n" (key pair)
> > (val pair)))
> >(sort-by #( -(val %) )
> > (reduce
> > (fn [counted-words word]
> > ( assoc counted-words
> > word
> > (inc (get counted-words
> > word 0)) ))
> > {}
> > words)))
> > ["\r\n"]
>
> > Somehow I feel it's far from optimal. Could you please advise and
> > improve? What is the best, idiomatic implementation of this simple
> > problem?
>
> > regards,
> > Piotrek
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Re: Exercise: words frequency ranking
What would you think of this form of coding ?
- The rationale is to separate functions that deal with system
"boundaries" from "core algorithmic functions".
So you should at least have two functions : one that does not deal
with input/output formats : will only deal with clojure/java
constructs.
- Don't expose "too early" functions that are just here to simplify
the algorithm : there's already the possibility to use defn- , but
there's also the possibility to embed functions in the principal
function by using let and inner functions
- And I also tried to write the "core algorithmic function" as
"functional" as I can.
Do you think the functional version is more ore less "obfuscated" ?
Here would be the "core function" (taking a string as an input, and
outputting the sorted sequence of ["word" 2] vectors) :
(defn topwords [str]
"Takes a string as an input, and returns a sequence of vectors of
pairs [word nb-of-word-occurences]"
(let [words (let [ls (System/getProperty "line.separator")]
#(.split % ls))
freqs (partial reduce #(merge-with + %1 {%2 1}) {})
sort (partial sort-by (comp - val))]
(-> str words freqs sort)))
HTH,
--
Laurent
On Dec 26, 4:37 pm, lpetit wrote:
> Instead of #(- (val %)), one could also use the compose function :
> (comp - val)
>
> My 0,02 EURO,
>
> --
> Laurent
>
> On Dec 25, 4:58 pm, Mibu wrote:
>
> > My version:
>
> > (defn top-words [input-filename result-filename]
> > (spit result-filename
> > (apply str
> > (map #(format "%s : %d\n" (first %) (second %))
> > (sort-by #(-(val %))
> > (reduce #(conj %1 { %2 (inc (%1 %2 0)) }) {}
> > (map #(.toLowerCase %)
> > (re-seq #"\w+"
> > (slurp
> > input-filename)
>
> > Mibu
>
> > On Dec 25, 2:16 pm, Piotr 'Qertoip' Włodarek
> > wrote:
>
> > > Given the input text file, the program should write to disk a ranking
> > > of words sorted by frequency, like:
>
> > > the : 52483
> > > and : 32558
> > > of : 23477
> > > a : 22486
> > > to : 21993
>
> > > My first implementation:
>
> > > (defn topwords [in-filepath, out-filepath]
> > > (def words (.split (.toLowerCase (slurp in-filepath)) "\\s+"))
>
> > > (spit out-filepath
> > > (apply str
> > > (concat
> > > (map (fn [pair] (format "%20s : %5d \r\n" (key pair)
> > > (val pair)))
> > > (sort-by #( -(val %) )
> > > (reduce
> > > (fn [counted-words word]
> > > ( assoc counted-words
> > > word
> > > (inc (get counted-words
> > > word 0)) ))
> > > {}
> > > words)))
> > > ["\r\n"]
>
> > > Somehow I feel it's far from optimal. Could you please advise and
> > > improve? What is the best, idiomatic implementation of this simple
> > > problem?
>
> > > regards,
> > > Piotrek
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Re: Exercise: words frequency ranking
On Dec 25, 4:58 pm, Mibu wrote:
> My version:
>
> (defn top-words [input-filename result-filename]
> (spit result-filename
> (apply str
> (map #(format "%s : %d\n" (first %) (second %))
> (sort-by #(-(val %))
> (reduce #(conj %1 { %2 (inc (%1 %2 0)) }) {}
> (map #(.toLowerCase %)
> (re-seq #"\w+"
> (slurp
> input-filename)
>
> Mibu
Once you move .toLowerCase right after slurp, it gets 3 times faster.
regards,
Piotrek
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Re: Proxying in clojure
This might be off-topic, but when I launched "snake" from SLIME (via load-file and then "run-snake"), the app didn't receive any UI Events. I thought at first it might be because the snake Frame didn't have focus, but even when I gave it focus, it still didn't receive any Events. When I ran it from the clojure REPL (outside of SLIME), it worked appropriately. Is this expected behavior from SLIME? -Matt On Dec 26, 4:34 am, Chouser wrote: > On Fri, Dec 26, 2008 at 4:40 AM, Emeka wrote: > > Chooser, > > "Chouser" > > > Please send me yours then. > > Already did:http://groups.google.com/group/clojure/msg/4f00d2a3b5da8444 > > And Mr. Gilardi improved on it > here:http://groups.google.com/group/clojure/msg/90316675320091cf > > --Chouser --~--~-~--~~~---~--~~ 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 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 -~--~~~~--~~--~--~---
sync vs. dosync
What is the difference between the sync and dosync functions? Their documentation strings are identical. -- R. Mark Volkmann Object Computing, Inc. --~--~-~--~~~---~--~~ 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 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 -~--~~~~--~~--~--~---
println output
Why does (for [x (range 3)] (println x)) output (0 nil 1 nil 2 nil) when run in the REPL instead of 0 1 2 and nothing at all when run from a script? -- R. Mark Volkmann Object Computing, Inc. --~--~-~--~~~---~--~~ 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 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 -~--~~~~--~~--~--~---
Re: sync vs. dosync
On Fri, Dec 26, 2008 at 9:44 PM, Mark Volkmann wrote: > > What is the difference between the sync and dosync functions? Their > documentation strings are identical. sync has an extra flags argument. At the moment they are the same, but presumably sync will do different things depending on the flags in future. Here is how they are currently defined: (defmacro sync "transaction-flags => TBD, pass nil for now Runs the exprs (in an implicit do) in a transaction that encompasses exprs and any nested calls. Starts a transaction if none is already running on this thread. Any uncaught exception will abort the transaction and flow out of sync. The exprs may be run more than once, but any effects on Refs will be atomic." [flags-ignored-for-now & body] `(. clojure.lang.LockingTransaction (runInTransaction (fn [] ~...@body (defmacro dosync "Runs the exprs (in an implicit do) in a transaction that encompasses exprs and any nested calls. Starts a transaction if none is already running on this thread. Any uncaught exception will abort the transaction and flow out of dosync. The exprs may be run more than once, but any effects on Refs will be atomic." [& exprs] `(sync nil ~...@exprs)) -- Michael Wood --~--~-~--~~~---~--~~ 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 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 -~--~~~~--~~--~--~---
Re: println output
On Fri, 26 Dec 2008 14:43:23 -0600 "Mark Volkmann" wrote: > >Why does > >(for [x (range 3)] (println x)) > >output > >(0 >nil 1 >nil 2 >nil) > >when run in the REPL instead of > >0 >1 >2 > >and nothing at all when run from a script? > The seq of nils is the return value of `(for ...)'. It is printed because the REPL shows return values and interpersed with println's output, because `for' is lazy and the printlns are executed while the seq is printed. When run from a script (as a top level form, I assume), the return value of the form is not used, therefore the tail-functions of the lazy sequence aren't evaluated and nothing at all is printed. This can be remedied by surrounding the `(for ...)' form with a `doall' or `dorun' form, which both evaluate the whole sequence (they differ in their return values). In this case `doseq' should be used instead of `for'. --~--~-~--~~~---~--~~ 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 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 -~--~~~~--~~--~--~---
Re: println output
On Fri, Dec 26, 2008 at 10:43 PM, Mark Volkmann wrote: > > Why does > > (for [x (range 3)] (println x)) > > output > > (0 > nil 1 > nil 2 > nil) > > when run in the REPL instead of > > 0 > 1 > 2 This is because println returns nil every time it's run. user=> (println "test") test nil user=> Also: user=> (for [x (range 3)] nil) (nil nil nil) user=> So the result of the for is a seq containing three nils. The output from println is interspersed with the printing of the seq. > and nothing at all when run from a script? It doesn't print anything when run from a script because range returns a lazy sequence. Here's a recent post with a similar question: http://groups.google.com/group/clojure/browse_thread/thread/53a32d222c3b40e3# Chouser said the following: > > This does not work - prints nothing - why?: > > (defn pretty-print-row [row] > > (map print row)) > > Because 'map' is lazy, and won't evaluate 'print' on any of the items > sequence unless necessary. For functions with side-effects (like > 'print') you'll generally need 'doseq', loop/recur, or 'dorun'. -- Michael Wood --~--~-~--~~~---~--~~ 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 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 -~--~~~~--~~--~--~---
Accessing "this" in gen-class constructor
Hi,
I've hit a stumbling block using Clojure's gen-class facility for
constructors.
Is there anyway to access "this" inside Clojure's constructor/init
function?
ie. The following type of code is quite common in Java. How would you
do the same in Clojure?
public class MyDerivedClass extends SuperClass{ //<-- Derived Class
public MyDerivedClass (){
super("derived class"); //<-- Call superclass constructor
setDescription("this is a derived class"); //<-- Call inherited
method
}
}
Thanks
-Patrick
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Re: Proxying in clojure
Works for me from SLIME. Check your *inferior-lisp* buffer for exceptions. On 12/27/08, MattyDub wrote: > > This might be off-topic, but when I launched "snake" from SLIME (via > load-file and then "run-snake"), the app didn't receive any UI > Events. I thought at first it might be because the snake Frame didn't > have focus, but even when I gave it focus, it still didn't receive any > Events. When I ran it from the clojure REPL (outside of SLIME), it > worked appropriately. Is this expected behavior from SLIME? > -Matt > > On Dec 26, 4:34 am, Chouser wrote: >> On Fri, Dec 26, 2008 at 4:40 AM, Emeka wrote: >> > Chooser, >> >> "Chouser" >> >> > Please send me yours then. >> >> Already did:http://groups.google.com/group/clojure/msg/4f00d2a3b5da8444 >> >> And Mr. Gilardi improved on it >> here:http://groups.google.com/group/clojure/msg/90316675320091cf >> >> --Chouser > > > -- Abhishek Reddy http://abhishek.geek.nz --~--~-~--~~~---~--~~ 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 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 -~--~~~~--~~--~--~---
Re: How To Make Code More Functional?
I'm just getting started myself, and I found Stuart Halloway's blog of great use. Perhaps it'll be of some help to you also. -Patrick --~--~-~--~~~---~--~~ 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 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 -~--~~~~--~~--~--~---
distinct broken?
Hi All, I've been trying to learn clojure lately by solving the project euler problems with it, and I think the distinct function is broken (or it doesn't quite work as I assume it would). here is the code i'm running (defn pow [nbr pwr] (if (< pwr 2) nbr (* nbr (pow nbr (dec pwr) (count (sort (distinct (apply concat (map (fn [i] (map (fn [j] (pow i j)) (range 2 101))) (range 2 101)) for which the result shows 9188, but should be 9183. I wrote my own distinct function which gives the correct result but runs a LOT slower (defn in? [lst n] (if (nil? lst) false (if (= (first lst) n) true (in? (rest lst) n (defn unique [lst] (loop [l lst n (list)] (if (nil? l) (sort n) (if (in? n (first l)) (recur (rest l) n) (recur (rest l) (cons (first l) n)) i'm using revision 1185. is this a bug or am i doing something wrong? thanks -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 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 -~--~~~~--~~--~--~---
macro help
I'm attempting what should be a simple transformation using a macro called dlg in the following code: (defn fld [parent lay id text field] '...) ;; dlg macro. For this input: ;; ;; (dlg "test" ;; (field fld-1 "Field number one" (JTextField.)) ;; (field fld-2 "Field number two" (JTextField.))) ;; ;; we want this output: ;; ;; (fn [parent layout] ;; (fld parent layout 'fld-1 "Field number one" (JTextField.)) ;; (fld parent layout 'fld-2 "Field number two" (JTextField.)) ;; parent) (defmacro dlg [dlgid# & fields#] `(fn [parent# layout#] ~@(map (fn [[f# id# text# type#]] `(fld parent# layout# '~id# ~text# ~type#)) fields#))) (def inp '(dlg "test" (field fld-1 "Field number one" (JTextField.)) (field fld-2 "Field number two" (JTextField. (macroexpand inp) ;; => ;; (fn* ([parent__6 layout__7] ;; (user/fld parent__4 layout__5 (quote fld-1) "Field number one" (JTextField.)) ;; (user/fld parent__4 layout__5 (quote fld-2) "Field number two" (JTextField. (eval inp) ;; => ;; java.lang.Exception: Unable to resolve symbol: parent__4 in this context (NO_SOURCE_FILE:24) I'm wondering why the macro produces 2 different "parent" symbols--I'd like both references to be the same parent. Any suggestions? --~--~-~--~~~---~--~~ 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 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 -~--~~~~--~~--~--~---
macro help
I'm attempting what should be a simple macro transformation (dlg below): (defn fld [parent lay id text field] '...) ;; dlg macro. For this input: ;; ;; (dlg "test" ;; (field fld-1 "Field number one" (JTextField.)) ;; (field fld-2 "Field number two" (JTextField.))) ;; ;; we want this output: ;; ;; (fn [parent layout] ;; (fld parent layout 'fld-1 "Field number one" (JTextField.)) ;; (fld parent layout 'fld-2 "Field number two" (JTextField.)) ;; parent) (defmacro dlg [dlgid# & fields#] `(fn [parent# layout#] ~@(map (fn [[f# id# text# type#]] `(fld parent# layout# '~id# ~text# ~type#)) fields#))) (def inp '(dlg "test" (field fld-1 "Field number one" (JTextField.)) (field fld-2 "Field number two" (JTextField. (macroexpand inp) ;; => ;; (fn* ([parent__6 layout__7] ;; (user/fld parent__4 layout__5 (quote fld-1) "Field number one" (JTextField.)) ;; (user/fld parent__4 layout__5 (quote fld-2) "Field number two" (JTextField. (eval inp) ;; => ;; java.lang.Exception: Unable to resolve symbol: parent__4 in this context (NO_SOURCE_FILE:24) The dlg macro seems to be generating 2 different symbols for 'parent, when I'd like both to refer to the same symbol. Any suggestions? --~--~-~--~~~---~--~~ 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 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 -~--~~~~--~~--~--~---
IntelliJ Plugin
Hi, Is this the appropriate mailing list to talk about the Clojure IntelliJ plugin? The Google Code site didn't list any other mailing list. http://code.google.com/p/clojure-intellij-plugin/ I went through the process of building and installing the plugin on Windows XP with IntelliJ IDEA 8.0.1 and thought it might be helpful if I document what I did on the wiki. I also have a small suggestion that the build.xml file use environment variables instead of hard coded paths to java.home and idea.home. Thanks, Justin --~--~-~--~~~---~--~~ 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 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 -~--~~~~--~~--~--~---
macro help
I'm getting stuck on what should be a simple macro (dlg below). It produces 2 different symbols (for 'parent#) when I was expecting both to refer to the same symbol. Here's the code: (defn fld [parent lay id text field] '...) ;; dlg macro. For this input: ;; ;; (dlg "test" ;; (field fld-1 "Field number one" (JTextField.)) ;; (field fld-2 "Field number two" (JTextField.))) ;; ;; we want this output: ;; ;; (fn [parent layout] ;; (fld parent layout 'fld-1 "Field number one" (JTextField.)) ;; (fld parent layout 'fld-2 "Field number two" (JTextField.)) ;; parent) (defmacro dlg [dlgid# & fields#] `(fn [parent# layout#] ~@(map (fn [[f# id# text# type#]] `(fld parent# layout# '~id# ~text# ~type#)) fields#))) (def inp '(dlg "test" (field fld-1 "Field number one" (JTextField.)) (field fld-2 "Field number two" (JTextField. (macroexpand inp) ;; => ;; (fn* ([parent__6 layout__7] ;; (user/fld parent__4 layout__5 (quote fld-1) "Field number one" (JTextField.)) ;; (user/fld parent__4 layout__5 (quote fld-2) "Field number two" (JTextField. (eval inp) ;; => ;; java.lang.Exception: Unable to resolve symbol: parent__4 in this context (NO_SOURCE_FILE:24) Any suggestions? --~--~-~--~~~---~--~~ 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 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 -~--~~~~--~~--~--~---
macro help
I'm attempting what should be a simple transformation using a macro called dlg in the following code: (defn fld [parent lay id text field] '...) ;; dlg macro. For this input: ;; ;; (dlg "test" ;; (field fld-1 "Field number one" (JTextField.)) ;; (field fld-2 "Field number two" (JTextField.))) ;; ;; we want this output: ;; ;; (fn [parent layout] ;; (fld parent layout 'fld-1 "Field number one" (JTextField.)) ;; (fld parent layout 'fld-2 "Field number two" (JTextField.)) ;; parent) (defmacro dlg [dlgid# & fields#] `(fn [parent# layout#] ~@(map (fn [[f# id# text# type#]] `(fld parent# layout# '~id# ~text# ~type#)) fields#))) (def inp '(dlg "test" (field fld-1 "Field number one" (JTextField.)) (field fld-2 "Field number two" (JTextField. (macroexpand inp) ;; => ;; (fn* ([parent__6 layout__7] ;; (user/fld parent__4 layout__5 (quote fld-1) "Field number one" (JTextField.)) ;; (user/fld parent__4 layout__5 (quote fld-2) "Field number two" (JTextField. (eval inp) ;; => ;; java.lang.Exception: Unable to resolve symbol: parent__4 in this context (NO_SOURCE_FILE:24) I'm wondering why the macro produces 2 different "parent" symbols--I'd like both references to be the same parent. Any suggestions? --~--~-~--~~~---~--~~ 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 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 -~--~~~~--~~--~--~---
Re: Random Number Generation Issues
On Dec 23, 3:10 pm, Jason wrote: > For the time-being, you could try something like: > > user> (def *random* (java.util.Random.)) > #'user/*random* > > user> (defn my-rand-int [max-val] > (let [bit-length (.bitLength (BigInteger. (str max-val)))] > (loop [] > (let [x (BigInteger. bit-length *random*)] > (if (< x max-val) > x > (recur)) > #'user/my-rand-int BigInteger has a constructor that takes a byte[] array, so you could just give it an array of randomly generated bytes. I'll work on some code to do that. mfh --~--~-~--~~~---~--~~ 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 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 -~--~~~~--~~--~--~---
Re: How to encapsulate local state in closures
On Dec 22, 2:34 pm, "Mark Engelberg" wrote:
> On Mon, Dec 22, 2008 at 4:23 AM, Parth Malwankar
>
> wrote:
> > If I get it right, atoms are quite useful to maintain state
> > in the context of a single thread with memoization and
> > counter (within a thread) being two examples.
>
> No, RH said that atoms were definitely intended for multiple threads,
> not just single threads. But their use is highly specific. With
> memoization, it doesn't matter if things get retried, as long as
> things don't get "lost". atombasically guarantees that the ref and
> the set occur atomically (via swap), so you don't have to worry about
> two threads losing something from the cache as follows:
> Current cache {:a 1 :b 2}
> One thread tries to add :c 3, and another tries to add :d 4.
> Without atomic swap, one thread could try to update the cache to {:a 1
> :b 2 :c 3} and the other to {:a 1 :b 2 :d 4} (because they are both
> basing their updates on what they see). Whichever one wins, one of
> the values will be "lost" from the cache.)
> So atoms make this one guarantee, allowing safe multithread
> memoization, but at great risk for other types of applications,
> because most "seemingly-obvious" uses for atoms would probably be
> hosed by the possible retry.
>
> I fear a lot of people are going to end up misusing atoms. I assume
> they were necessary to make memoization perform better than under the
> ref-with-commute approach.
It's important to distinguish between updating atoms within
transactions and outside transactions. In the former case, one has to
ensure the update function can be retried without ill-effects.
However, outside a transaction, atoms are just mutable values, that
can safely be shared between threads, provided that their updating
does not need to be coordinated with other updates (to other atoms,
refs or agents).
Here's an example; say we have a multi-threaded service where we wish
to share a single counter to use as say a serial id. The following
code initializes serid to 0 and provides a function incserid to
increment it.
(def serid (atom 0))
(defn incserid [] (swap! serid inc))
(defn docount [n cntr] (dotimes [ind n] (cntr)))
Now, the following uses a thread factory to instantiate (nthreads)
number of threads, each which will execute the above incrementor
(ncount) number of times...
(import '(java.util.concurrent Executors))
(def th-factory (Executors/newSingleThreadExecutor))
(defn do-thrds [nthreads ncount] (dotimes [t nthreads] (.submit th-
factory (partial docount ncount incserid
So, if we then initiate 100 threads to each increment the serid 1
times...
(do-thrds 100 1)
@serid
=>100
We see that the threads have happily shared the atom and updated it
correctly with no ill-effects. Note the lack of requirement for
dosync.
So in summary, atoms are great (and should be used in preference to
refs) where the shared state needs to be mutable, shared and
independent (not requiring coordinated update with other objects).
Regards, Adrian.
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Re: How to encapsulate local state in closures
On Fri, Dec 26, 2008 at 8:35 PM, Adrian Cuthbertson wrote: > It's important to distinguish between updating atoms within > transactions and outside transactions. In the former case, one has to > ensure the update function can be retried without ill-effects. > However, outside a transaction, atoms are just mutable values, that > can safely be shared between threads, provided that their updating > does not need to be coordinated with other updates (to other atoms, > refs or agents). Yes, but when you write your atom-based code, you have no way to know whether you or others who want to reuse it will want to use it as part of a transaction. atom-based code is not generally safe for transactions, which is why I suggested it should be avoided. In your example, if incserid is used in a transaction, it is possible that certain serids will be skipped. This may be acceptable, in which case, go ahead and use an atom, but often programs rely on subtle assumptions (like the serids will be issued consecutively), and your program can become brittle if there's a chance your code won't follow these assumptions. Probably better off not to take the chance. Stick with something like refs which will yield more predictable behavior, and thus be easier to test. Memoization is a very special exception, because it really doesn't matter if something gets cached more than once. The whole point of Clojure seems to make as much code as possible safe for its software transactional memory. Thus the persistent data structures, and other design details. Although interoperating with Java also produces risk within transaction, generally speaking, if you stay within the "Clojure core", you're safe for transactions. Except atoms. --~--~-~--~~~---~--~~ 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 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 -~--~~~~--~~--~--~---
Re: Exercise: words frequency ranking
I wrote what I think is the idiomatic version. Idiomatically, you
delay execution of functions over lazy sequences, so if you get a
sequence of a million words and you only take the first 100, you don't
lowercase (or whatever else) the entire sequence. Also a smart
compiler on a multi-core machine could do a much better job dispensing
the computation with a program written this way. I doubt today's JITs
are this smart, but I'm sure someday soon they will be. Of course,
this doesn't apply to this specific example with slurp, because how it
works as the inner most function. But again, I was being idiomatic. If
you need a blazing fast implementation for this specific task, I
suspect perl would be a better choice.
Mibu
On Dec 26, 7:11 pm, Piotr 'Qertoip' Włodarek
wrote:
> On Dec 25, 4:58 pm, Mibu wrote:
>
> > My version:
>
> > (defn top-words [input-filename result-filename]
> > (spit result-filename
> > (apply str
> > (map #(format "%s : %d\n" (first %) (second %))
> > (sort-by #(-(val %))
> > (reduce #(conj %1 { %2 (inc (%1 %2 0)) }) {}
> > (map #(.toLowerCase %)
> > (re-seq #"\w+"
> > (slurp
> > input-filename)
>
> > Mibu
>
> Once you move .toLowerCase right after slurp, it gets 3 times faster.
>
> regards,
> Piotrek
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Re: Accessing "this" in gen-class constructor
I found that I can use another factory method to workaround this limitation. I can first instantialize the object to get a reference, and then initialize all it's settings. This works only if I don't expect this class to be derived from. Any subclass would expect the class to be fully initialized in the constructor, and not have to call another initialize_settings() function. --~--~-~--~~~---~--~~ 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 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 -~--~~~~--~~--~--~---
sorted-map-by value
Is there a way to sort a sorted-map-by by value without a letrec? --~--~-~--~~~---~--~~ 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 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 -~--~~~~--~~--~--~---
