Re: heaps in clojure
Thanks Jason, I think some sort of priority queue may be the solution. Thanks, Sunil. On Wed, Sep 14, 2011 at 12:39 AM, Jason Wolfe ja...@w01fe.com wrote: There is java.util.PriorityQueue, which is heap-based: http://download.oracle.com/javase/1,5.0/docs/api/java/util/PriorityQueue.html -Jason On Sep 13, 4:44 am, Sunil S Nandihalli sunil.nandiha...@gmail.com wrote: Hi Everybody, I have a very large, but with finite size, collection. I would like to get like first 10 elements in the sorted list . I would use a heap if I were in c++ .. is there a inbuilt implementation of this in clojure? .. Is there some other way to achieve this? some sort of lazy sort would be perfect. I know I need the full collection to start with .. but that is fine. Thanks, Sunil. -- 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 -- 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
Re: confusion with map and dosync
Map is lazy so it only gets called when you need something from the sequence. To force it to be called you use doall so it would be (doall (map queue-copy-fetch fetches-seq)). You only need the do sequence in queue-copy-fetch but not in process-indexes. Matt Hoyt From: c.taylor colin.tay...@gmail.com To: Clojure clojure@googlegroups.com Sent: Thursday, September 15, 2011 12:39 AM Subject: confusion with map and dosync I'm sure this is very straightforward but can someone enlighten me why queue copy fetch is seemingly never called from within process-indexes (the 'pre add' line is printed but the 'adding' debug line is never printed). I've verified the correct contents of fetches-seq. For a bonus point can I ask if need the dosync inside q-c-f if its only ever called from p-i ? Any comments on style appreciated too. (defn- queue-copy-fetch [cfetch] (println adding cfetch) (dosync (alter copy-fetch-queue conj cfetch))) (defn process-indexes [] (while (seq @index-process-queue) (let [an-index (qpop index-process-queue) index-source (:source (:fetch an-index)) index-content (:doc-seq an-index) links-seq ((:copy-link-selector index-source) index-content) fetches-seq (map (partial fetch index-source) links-seq)] (println pre add) (dosync (map queue-copy-fetch fetches-seq) -- 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 -- 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
Re: confusion with map and dosync
Map returns a lazy sequence, the list of values is not realized yet, you need to consume the lazy seq to obtain the values. You should use (doseq [f fetches-seq] (queue-copy-fetch f))) if you have only side effects to generate and do not care about reusing the values returned by queue-copy-fetch. doseq returns nil. If you need to reuse the results from the calls later, look at doall. This one will retain the head as in: (doall (map queue-copy-fetch fetches-seq)) It takes some time to get used to lazy sequences. Look carefully at the API doc to spot fns that return lazy sequences. It's not because the REPL gives an output that you are not dealing with a lazy sequence. The REPL will consume the lazy seq if it's the last result available and walk through it to print you an output. Luc P. On Wed, 14 Sep 2011 22:39:42 -0700 (PDT) c.taylor colin.tay...@gmail.com wrote: I'm sure this is very straightforward but can someone enlighten me why queue copy fetch is seemingly never called from within process-indexes (the 'pre add' line is printed but the 'adding' debug line is never printed). I've verified the correct contents of fetches-seq. For a bonus point can I ask if need the dosync inside q-c-f if its only ever called from p-i ? Any comments on style appreciated too. (defn- queue-copy-fetch [cfetch] (println adding cfetch) (dosync (alter copy-fetch-queue conj cfetch))) (defn process-indexes [] (while (seq @index-process-queue) (let [an-index (qpop index-process-queue) index-source (:source (:fetch an-index)) index-content (:doc-seq an-index) links-seq ((:copy-link-selector index-source) index-content) fetches-seq (map (partial fetch index-source) links-seq)] (println pre add) (dosync (map queue-copy-fetch fetches-seq) -- Luc P. The rabid Muppet -- 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
Re: confusion with map and dosync
You only need the do sequence in queue-copy-fetch but not in process-indexes should be You only need the dosync in queue-copy-fetch but not in process-indexes. Matt Hoyt From: Matt Hoyt mrho...@yahoo.com To: clojure@googlegroups.com clojure@googlegroups.com Sent: Thursday, September 15, 2011 1:01 AM Subject: Re: confusion with map and dosync Map is lazy so it only gets called when you need something from the sequence. To force it to be called you use doall so it would be (doall (map queue-copy-fetch fetches-seq)). You only need the do sequence in queue-copy-fetch but not in process-indexes. Matt Hoyt From: c.taylor colin.tay...@gmail.com To: Clojure clojure@googlegroups.com Sent: Thursday, September 15, 2011 12:39 AM Subject: confusion with map and dosync I'm sure this is very straightforward but can someone enlighten me why queue copy fetch is seemingly never called from within process-indexes (the 'pre add' line is printed but the 'adding' debug line is never printed). I've verified the correct contents of fetches-seq. For a bonus point can I ask if need the dosync inside q-c-f if its only ever called from p-i ? Any comments on style appreciated too. (defn- queue-copy-fetch [cfetch] (println adding cfetch) (dosync (alter copy-fetch-queue conj cfetch))) (defn process-indexes [] (while (seq @index-process-queue) (let [an-index (qpop index-process-queue) index-source (:source (:fetch an-index)) index-content (:doc-seq an-index) links-seq ((:copy-link-selector index-source) index-content) fetches-seq (map (partial fetch index-source) links-seq)] (println pre add) (dosync (map queue-copy-fetch fetches-seq) -- 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 -- 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 -- 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
Re: Rounding the edges of an Emacs beginner
Nice. Thanks Peter. I use the n, p and v navigations now, but always want to do that vim / Ctrl-d thing, lol. I figure I just need to spend some time getting used to emacs' navigation idioms. It's going to take a lot of doing to pull me away from vim habits. Tim On Wed, Sep 14, 2011 at 8:50 PM, Peter Buckley buckmeist...@gmail.comwrote: ** In emacs you can give a number to preface many commands, e.g. C-37 C-n will perform next line 37 times, and C-37 C-p will perform previous line 37 times. You can setup keybindings for these as well, but I find the basic navigation commands like C-v/M-v (up/down a page) and C-l (center current line in the buffer) to be sufficient. -- *From: * Timothy Washington twash...@gmail.com *Sender: * clojure@googlegroups.com *Date: *Wed, 14 Sep 2011 20:08:28 -0400 *To: *clojure@googlegroups.com *ReplyTo: * clojure@googlegroups.com *Subject: *Re: Rounding the edges of an Emacs beginner Far out - this is great stuff. Thanks guys. Wrt to moving down (or up) a block, vim-style, what I mean is the following (all functionality in 'Command Mode'). In Vim , you press *Ctrl-d* and *Ctrl-u* to go down and up a block respectively. Depending on the size of your window, it moves the cursor about 1/3rd of the way down (or up) the screen. This is very handy to have when just browsing a buffer. You can be more precise by pressing 37k, to move the cursor up 37 lines, etc. For whatever reason, I haven't been able to find something similar in Emacs. Tim On Wed, Sep 14, 2011 at 3:53 AM, Stefan Kamphausen ska2...@googlemail.com wrote: Hi, just a few follow-ups... On Wednesday, September 14, 2011 4:13:47 AM UTC+2, frye wrote: - ? howto list modes engaged Aside from the already mentioned C-h m (aka M-x describe-mode) you will want to use * C-h k (M-x describe-key) followed by some keybinding to find out what that keybinding does * C-h w (M-x where-is) followed by the name of some command to find out what keybinding exists for that command * C-h a PATTERN (M-x apropos) to search for PATTERN in command names and variables (ah, I miss hyper-apropos from XEmacs) * C-h v VARIABLE (M-x describe-variable) to see the documentation for a variable in ELisp (use C-c C-d d on Clojure symbols to see their documentation from SLIME) * C-h f FUNCTION (M-x describe-function) to see docs for an Elisp-function * and finally C-h ? to find out what other help is available The built-in help system of Emacs is one of its greatest strengths. - ? Can you use Emacs / Slime / CDT (debugging) with Ruby / Rails ? howto do Code completion (clojure, and elisp ) Try TAB in the REPL and M-TAB in a Clojure-buffer when you are connected to a running image. As a VIM'er, I'm trying to do the following using emacs navigation, but seem to have missed the levers to pull. I'm using a vim navigation plugin http://gitorious.org/evil/pages/Home, which helps a lot. - ? set line numbers I use linum.el written by Markus Triska: (when (try-require 'linum) ;; try require is just a minor wrapper which checks, whether a lib is available (global-linum-mode)) - ? go to line 'n' Since my fingers are used to M-g I bind that key to goto-line : (global-set-key (kbd M-g) #'goto-line) - ? how to jump to matching parentheses Meta with left and right cursor keys. Actually those are forward-sexpand backward-sexp - ? move down a chunk like in vim What does that mean? - ? yank 'n' lines - emacs yank puts back some 'killed' text ; HOWTO copy Mark things by first enabling the mark with C-SPC. Move around using your usual command. Copy to the kill-ring with M-w or cut the text and copy it to the kill-ring using C-w. After that you can yank (Emacsspeak for 'paste') from the kill ring with C-y. Try M-y right after a C-y to get older elements on the kill-ring. For marking, try what C-M-SPC does, also hit it several times in a row. Warning: if your finger's memory learns this, using modern IDEs may feel awkward. Regards, Stefan -- 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 -- 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 -- You received this message because
using finger trees in two dimensions
Hi everybody, Thanks to Chouser's finger tree data structure, it makes it very simple to keep some elements in a tree/sequence and efficiently maintain values by some associative operation on all the elements of the collection .. I guess chouser himself has given series of talks on that. However, I am trying to see if I can do something like that for two-dimensional data. For example, let us say I have points spread on XY plane, and two axes each parallel to one of the coordinate axes. So, this would divide the data/points among the 4 quadrants. Now I would like to be able to efficiently divide the data using the two axes at random and x's and y's and obtain the value of the associative operation on the elements of each quadrant. for now it could simply be the sum of the points coordinate wise.. While I have thought of a few options to make it work for two dimensions but nothing seems right .. I would love to hear what others might have to say about this. Thanks Sunil. -- 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
Re: Rounding the edges of an Emacs beginner
Hi, we're getting totally OT here and should probably better head for gnu.emacs.help. Anyway, just one more bark from me and then I'll be quiet (but will respond to mail ;-) On Thursday, September 15, 2011 2:08:28 AM UTC+2, frye wrote: In Vim , you press *Ctrl-d* and *Ctrl-u* to go down and up a block respectively. Depending on the size of your window, it moves the cursor about 1/3rd of the way down (or up) the screen. This is very handy to have when just browsing a buffer. You can be more precise by pressing 37k, to move the cursor up 37 lines, etc. For whatever reason, I haven't been able to find something similar in Emacs. OK, I tried what it does in vim. Some things come to my mind. 1. PgUp/PgDn obviously 2. Try hitting C-l (that's an 'l' like in 'like') several times in a row. It won't move your cursor but the line it's on. 3. I've been using some personal binding on my home and end keys for ages which moves me to the beginning/end of a line, beginning/end of the currently displayed window and beginning/end of the whole buffer on successive hits. See chb-home and chb-end on http://www.skamphausen.de/cgi-bin/ska/dot-emacs.d-slash-init.el. Combine that with C-l. 4. You might want to try out swiss-move.el (shameless self-plug). Maybe it's confusing, maybe helpful. Cheers, Stefan -- 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
autoboxing in 1.3 RC-0
Hi, Is it a bug or I'm doing something wrong? I can't get rid of auto-boxing in the second example, neither by type hinting nor by type coercing of changed* locals. (set! *warn-on-reflection* true) This compiles fine: (loop [x 1 changed 0] (if (= x 10) changed (recur (inc x) changed))) And this gives the warning recur arg for primitive local: changed is not matching primitive, had: Object, needed: long Auto-boxing loop arg: change (loop [x 1 changed 0] (if (= x 10) changed (recur (inc x) (loop [y 1 changed-y changed] changed-y P.S. I omitted recur for the inner loop for clarity. -- 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
Re: heaps in clojure
You can do one linear pass over your data, accumulating a sorted set of the best 10 items you've found so far. You seed the sorted set with the first 10 items from your list, then continue traversing your list. With each new item you encounter, you ask if it is any better than the worst of the best-10-sorted-set. If it is, then you add it to the sorted-set and boot out the worst. Since the sorted set never exceeds 10 items, there is a small, constant bound for how long the operations on the sorted set will take. Thus this is a O(n) algorithm. On Wed, Sep 14, 2011 at 10:59 PM, Sunil S Nandihalli sunil.nandiha...@gmail.com wrote: Hi chouser, Thanks for your response. but correct me if I am wrong.. wouldn't sorted-set completely sort the complete collection without actually taking into account that only the first few elements are needed? Thanks, Sunil. On Tue, Sep 13, 2011 at 7:15 PM, Chouser chou...@gmail.com wrote: On Tue, Sep 13, 2011 at 7:44 AM, Sunil S Nandihalli sunil.nandiha...@gmail.com wrote: Hi Everybody, I have a very large, but with finite size, collection. I would like to get like first 10 elements in the sorted list . I would use a heap if I were in c++ .. is there a inbuilt implementation of this in clojure? .. Is there some other way to achieve this? some sort of lazy sort would be perfect. I know I need the full collection to start with .. but that is fine. A seq on a sorted set should be pretty efficient. (take 3 (sorted-set 8 2 1 4 6 9 7 3)) ;= (1 2 3) --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 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 -- 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 -- 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
Re: heaps in clojure
Does that work? There is no guarantee that the top 10 of the overall list matches the top 10 of earlier prefixes, so the candidates that get discarded might be part of the overall top 10, and the elements that pushed them out could just be local maxima. -- Dave On 15 Sep 2011 08:23, Mark Engelberg mark.engelb...@gmail.com wrote: You can do one linear pass over your data, accumulating a sorted set of the best 10 items you've found so far. You seed the sorted set with the first 10 items from your list, then continue traversing your list. With each new item you encounter, you ask if it is any better than the worst of the best-10-sorted-set. If it is, then you add it to the sorted-set and boot out the worst. Since the sorted set never exceeds 10 items, there is a small, constant bound for how long the operations on the sorted set will take. Thus this is a O(n) algorithm. On Wed, Sep 14, 2011 at 10:59 PM, Sunil S Nandihalli sunil.nandiha...@gmail.com wrote: Hi chouser, Thanks for your response. but correct me if I am wrong.. wouldn't sorted-set completely sort the complete collection without actually taking into account that only the first few elements are needed? Thanks, Sunil. On Tue, Sep 13, 2011 at 7:15 PM, Chouser chou...@gmail.com wrote: On Tue, Sep 13, 2011 at 7:44 AM, Sunil S Nandihalli sunil.nandiha...@gmail.com wrote: Hi Everybody, I have a very large, but with finite size, collection. I would like to get like first 10 elements in the sorted list . I would use a heap if I were in c++ .. is there a inbuilt implementation of this in clojure? .. Is there some other way to achieve this? some sort of lazy sort would be perfect. I know I need the full collection to start with .. but that is fine. A seq on a sorted set should be pretty efficient. (take 3 (sorted-set 8 2 1 4 6 9 7 3)) ;= (1 2 3) --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 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 -- 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 -- 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 -- 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
Re: heaps in clojure
If you maintain the invariant that at each point, your sorted set contains the top 10 you've seen so far, then from that invariant you can conclude that at the end of the traversal, your sorted set contains the top 10 for the overall list. On Thu, Sep 15, 2011 at 12:34 AM, David Powell d...@djpowell.net wrote: Does that work? There is no guarantee that the top 10 of the overall list matches the top 10 of earlier prefixes, so the candidates that get discarded might be part of the overall top 10, and the elements that pushed them out could just be local maxima. -- Dave On 15 Sep 2011 08:23, Mark Engelberg mark.engelb...@gmail.com wrote: You can do one linear pass over your data, accumulating a sorted set of the best 10 items you've found so far. You seed the sorted set with the first 10 items from your list, then continue traversing your list. With each new item you encounter, you ask if it is any better than the worst of the best-10-sorted-set. If it is, then you add it to the sorted-set and boot out the worst. Since the sorted set never exceeds 10 items, there is a small, constant bound for how long the operations on the sorted set will take. Thus this is a O(n) algorithm. On Wed, Sep 14, 2011 at 10:59 PM, Sunil S Nandihalli sunil.nandiha...@gmail.com wrote: Hi chouser, Thanks for your response. but correct me if I am wrong.. wouldn't sorted-set completely sort the complete collection without actually taking into account that only the first few elements are needed? Thanks, Sunil. On Tue, Sep 13, 2011 at 7:15 PM, Chouser chou...@gmail.com wrote: On Tue, Sep 13, 2011 at 7:44 AM, Sunil S Nandihalli sunil.nandiha...@gmail.com wrote: Hi Everybody, I have a very large, but with finite size, collection. I would like to get like first 10 elements in the sorted list . I would use a heap if I were in c++ .. is there a inbuilt implementation of this in clojure? .. Is there some other way to achieve this? some sort of lazy sort would be perfect. I know I need the full collection to start with .. but that is fine. A seq on a sorted set should be pretty efficient. (take 3 (sorted-set 8 2 1 4 6 9 7 3)) ;= (1 2 3) --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 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 -- 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 -- 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 -- 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 -- 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
Re: heaps in clojure
But when an element is dropped from the list, you're effectively resetting its seen-count to zero. It might be seen again, and it might (if you hadn't reset the seen-count), have ended up in the top 10. Or have I misunderstood? -- Dave On 15 Sep 2011 08:54, Mark Engelberg mark.engelb...@gmail.com wrote: If you maintain the invariant that at each point, your sorted set contains the top 10 you've seen so far, then from that invariant you can conclude that at the end of the traversal, your sorted set contains the top 10 for the overall list. On Thu, Sep 15, 2011 at 12:34 AM, David Powell d...@djpowell.net wrote: Does that work? There is no guarantee that the top 10 of the overall list matches the top 10 of earlier prefixes, so the candidates that get discarded might be part of the overall top 10, and the elements that pushed them out could just be local maxima. -- Dave On 15 Sep 2011 08:23, Mark Engelberg mark.engelb...@gmail.com wrote: You can do one linear pass over your data, accumulating a sorted set of the best 10 items you've found so far. You seed the sorted set with the first 10 items from your list, then continue traversing your list. With each new item you encounter, you ask if it is any better than the worst of the best-10-sorted-set. If it is, then you add it to the sorted-set and boot out the worst. Since the sorted set never exceeds 10 items, there is a small, constant bound for how long the operations on the sorted set will take. Thus this is a O(n) algorithm. On Wed, Sep 14, 2011 at 10:59 PM, Sunil S Nandihalli sunil.nandiha...@gmail.com wrote: Hi chouser, Thanks for your response. but correct me if I am wrong.. wouldn't sorted-set completely sort the complete collection without actually taking into account that only the first few elements are needed? Thanks, Sunil. On Tue, Sep 13, 2011 at 7:15 PM, Chouser chou...@gmail.com wrote: On Tue, Sep 13, 2011 at 7:44 AM, Sunil S Nandihalli sunil.nandiha...@gmail.com wrote: Hi Everybody, I have a very large, but with finite size, collection. I would like to get like first 10 elements in the sorted list . I would use a heap if I were in c++ .. is there a inbuilt implementation of this in clojure? .. Is there some other way to achieve this? some sort of lazy sort would be perfect. I know I need the full collection to start with .. but that is fine. A seq on a sorted set should be pretty efficient. (take 3 (sorted-set 8 2 1 4 6 9 7 3)) ;= (1 2 3) --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 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 -- 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 -- 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 -- 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 -- 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 -- 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
Re: heaps in clojure
The initial problem statement is to figure out what would be the first 10 items if you sorted the list. I don't see anything about frequency or how many times you've seen a given item in the statement of the problem. When I talk about a best item, I mean it is the first with regard to whatever comparison method you're using. On Thu, Sep 15, 2011 at 1:04 AM, David Powell d...@djpowell.net wrote: But when an element is dropped from the list, you're effectively resetting its seen-count to zero. It might be seen again, and it might (if you hadn't reset the seen-count), have ended up in the top 10. Or have I misunderstood? -- Dave On 15 Sep 2011 08:54, Mark Engelberg mark.engelb...@gmail.com wrote: If you maintain the invariant that at each point, your sorted set contains the top 10 you've seen so far, then from that invariant you can conclude that at the end of the traversal, your sorted set contains the top 10 for the overall list. On Thu, Sep 15, 2011 at 12:34 AM, David Powell d...@djpowell.net wrote: Does that work? There is no guarantee that the top 10 of the overall list matches the top 10 of earlier prefixes, so the candidates that get discarded might be part of the overall top 10, and the elements that pushed them out could just be local maxima. -- Dave On 15 Sep 2011 08:23, Mark Engelberg mark.engelb...@gmail.com wrote: You can do one linear pass over your data, accumulating a sorted set of the best 10 items you've found so far. You seed the sorted set with the first 10 items from your list, then continue traversing your list. With each new item you encounter, you ask if it is any better than the worst of the best-10-sorted-set. If it is, then you add it to the sorted-set and boot out the worst. Since the sorted set never exceeds 10 items, there is a small, constant bound for how long the operations on the sorted set will take. Thus this is a O(n) algorithm. On Wed, Sep 14, 2011 at 10:59 PM, Sunil S Nandihalli sunil.nandiha...@gmail.com wrote: Hi chouser, Thanks for your response. but correct me if I am wrong.. wouldn't sorted-set completely sort the complete collection without actually taking into account that only the first few elements are needed? Thanks, Sunil. On Tue, Sep 13, 2011 at 7:15 PM, Chouser chou...@gmail.com wrote: On Tue, Sep 13, 2011 at 7:44 AM, Sunil S Nandihalli sunil.nandiha...@gmail.com wrote: Hi Everybody, I have a very large, but with finite size, collection. I would like to get like first 10 elements in the sorted list . I would use a heap if I were in c++ .. is there a inbuilt implementation of this in clojure? .. Is there some other way to achieve this? some sort of lazy sort would be perfect. I know I need the full collection to start with .. but that is fine. A seq on a sorted set should be pretty efficient. (take 3 (sorted-set 8 2 1 4 6 9 7 3)) ;= (1 2 3) --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 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 -- 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 -- 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 -- 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 -- 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
Re: heaps in clojure
Ah yeah. Sorry, I'd superimposed something I was thinking about on to the original problem. -- Dave On 15 Sep 2011 09:07, Mark Engelberg mark.engelb...@gmail.com wrote: The initial problem statement is to figure out what would be the first 10 items if you sorted the list. I don't see anything about frequency or how many times you've seen a given item in the statement of the problem. When I talk about a best item, I mean it is the first with regard to whatever comparison method you're using. On Thu, Sep 15, 2011 at 1:04 AM, David Powell d...@djpowell.net wrote: But when an element is dropped from the list, you're effectively resetting its seen-count to zero. It might be seen again, and it might (if you hadn't reset the seen-count), have ended up in the top 10. Or have I misunderstood? -- Dave On 15 Sep 2011 08:54, Mark Engelberg mark.engelb...@gmail.com wrote: If you maintain the invariant that at each point, your sorted set contains the top 10 you've seen so far, then from that invariant you can conclude that at the end of the traversal, your sorted set contains the top 10 for the overall list. On Thu, Sep 15, 2011 at 12:34 AM, David Powell d...@djpowell.net wrote: Does that work? There is no guarantee that the top 10 of the overall list matches the top 10 of earlier prefixes, so the candidates that get discarded might be part of the overall top 10, and the elements that pushed them out could just be local maxima. -- Dave On 15 Sep 2011 08:23, Mark Engelberg mark.engelb...@gmail.com wrote: You can do one linear pass over your data, accumulating a sorted set of the best 10 items you've found so far. You seed the sorted set with the first 10 items from your list, then continue traversing your list. With each new item you encounter, you ask if it is any better than the worst of the best-10-sorted-set. If it is, then you add it to the sorted-set and boot out the worst. Since the sorted set never exceeds 10 items, there is a small, constant bound for how long the operations on the sorted set will take. Thus this is a O(n) algorithm. On Wed, Sep 14, 2011 at 10:59 PM, Sunil S Nandihalli sunil.nandiha...@gmail.com wrote: Hi chouser, Thanks for your response. but correct me if I am wrong.. wouldn't sorted-set completely sort the complete collection without actually taking into account that only the first few elements are needed? Thanks, Sunil. On Tue, Sep 13, 2011 at 7:15 PM, Chouser chou...@gmail.com wrote: On Tue, Sep 13, 2011 at 7:44 AM, Sunil S Nandihalli sunil.nandiha...@gmail.com wrote: Hi Everybody, I have a very large, but with finite size, collection. I would like to get like first 10 elements in the sorted list . I would use a heap if I were in c++ .. is there a inbuilt implementation of this in clojure? .. Is there some other way to achieve this? some sort of lazy sort would be perfect. I know I need the full collection to start with .. but that is fine. A seq on a sorted set should be pretty efficient. (take 3 (sorted-set 8 2 1 4 6 9 7 3)) ;= (1 2 3) --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 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 -- 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 -- 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 -- 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
Re: Mocking out namespaces
On Wednesday, September 14, 2011 11:19:13 AM UTC-4, Brian Hurt wrote: Say I have two name spaces, A and B, with A depending on B. I want to test namespace A, replacing module B with a mock B for testing purposes- preferably without having to load B at all (B sucks in a bunch of stuff, like dependencies on databases and external web sites and etc. that I don't want to deal with in testing). What is the easy, clojure-approved, mechanism for doing this? I tried: my-project |-- src | |-- A.clj | |-- B.clj | -- mocks | |-- B.clj |-- testdriver.clj # Run with the real B: java -cp clojure.jar:src clojure.main testdriver.clj # Run with the mock B: java -cp clojure.jar:mocks:src clojure.main testdriver.clj I don't know if my ascii-art directory tree makes any sense at all, but the point is that if you put mocks earlier in the classpath than src, then the mock B should get loaded instead of the real one. - Chris -- 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
Re: Overtone 0.3 released
Thanks, Sam! I'm really looking forward to play a bit more in depth with overtone and try to use it in a jam session. kind regards -- __ Herwig Hochleitner -- 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
Re: Binding *out*
Thanks Stuart and Dave. On Sep 14, 10:30 am, Stuart Sierra the.stuart.sie...@gmail.com wrote: Hi Nick, *out* and *err* are already dynamic, which is what allows `binding` to work. You can the root binding of any Var (even non-dynamic Vars) with `def` or `alter-var-root`. -Stuart Sierra -- 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
Re: How to convert general recursion to loop .. recur syntax
Hi, as you might know, the original version actually does run in fixed stack space, thanks to lazy sequences. (defn skl [tree] (map skl (filter seq? tree))) loop .. recur is the moral equivalent of a while(true) loop in imperative style. i.e. a slightly disguised (and somewhat more structured) goto Only use that as a lowlevel implementation detail. You can express mostly anything with the sequence library of clojure Consider (defn find-in-tree ([tree pred?] (concat (filter pred? tree) (mapcat find-in-tree (filter sequential? tree) (repeat pred?) which of course is much simpler written as (defn find-in-tree ([tree pred?] (filter pred? (flatten tree all of which are lazy, hence consume constant stack space kind regards -- __ Herwig Hochleitner -- 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
Re: Clojure vs Scala - anecdote
Impressive, wonder if they were running this on a single node or more widespread? In a wide spread environment I think Erlang would be the true winner, though it does not natively have macros :-( There is an implementation of Lisp for Erlang called LFE (lisp flavored Erlang) which I looked at, which does have macros and a real engine underneath. But clojure is an awesome combination On Sep 7, 7:32 am, Sean Corfield seancorfi...@gmail.com wrote: I just wanted to share this experience from World Singles... Back in November 2009, we started developing with Scala. We needed a long-running process that published large volumes of changes from our member database as XML packets published to a custom search engine. The mapping from half a dozen tables in the database to a flat XML schema was pretty complex and the company had tried a number of solutions with mixed success in the past. I introduced Scala based on the promises of performance, concurrency and type safety - and conciseness (especially with XML being a native data type in Scala). We've been running the Scala publishing daemons in production for most of two years. Generally they work pretty well but, under stress, they tend to hit Out of Memory exceptions and, after a lot of poking around, we became fairly convinced it was due (at least in part) to the default actor implementation in Scala. Scala is going to fold in Akka soon and we had been considering migrating to Akka anyone... But having introduced Clojure this year (after experimenting with it since about May last year), we figured we'd have a short spike to create a Clojure version of the Scala code to see how it worked out. It took about 15 hours to recreate the publishing daemon in Clojure and get it to pass all our tests. Today we ran a soak test publishing nearly 300,000 profiles in one run. The Scala code would fail with OoM exceptions if we hit it with 50,000 profiles in one run (sometimes less). The Clojure code sailed thru and is still happily running - so we'll be replacing the Scala code during our next production build. The other aspect that's interesting is that the Scala code totaled about 1,000 lines (about 31k characters of code). The Clojure replacement is just under 260 lines (around 11.5k characters of code). Neither code base has much in the way of comments (*ahem* - I'm not proud of that, just pointing out that there's no noise offsetting the code comparison). That doesn't include unit tests either, it's just the raw production code. The form of the Clojure code mostly follows the form of the Scala code, most of the same functions - it was very functional Scala - with some refactoring to helper functions to make it more modular and more maintainable. The net result is (obviously) that we'll be taking the Clojure publishing daemon to production and we'll be dropping Scala completely. Kudos to Rich Hickey and the Clojure/core team for creating a great general purpose language that can solve big problems - thank you! -- Sean A Corfield -- (904) 302-SEAN An Architect's View --http://corfield.org/ World Singles, LLC. --http://worldsingles.com/ Railo Technologies, Inc. --http://www.getrailo.com/ Perfection is the enemy of the good. -- Gustave Flaubert, French realist novelist (1821-1880) -- 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
Clojure videocast mentioning SuperCSV?
I've been watching a bunch of Clojure videocasts lately, and there was one which mentioned using the Java library SuperCSV. Unfortunately I can't recall which videocast it was, can someone remind me please? Many thanks. -- 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
Watching namespaces
Hello, Is it somehow possible to monitor all namespaces for new defs or re- defs (and defns etc). Generally, it it possible to implement some sort of notification whenever something is added or updated to a namespace? I don't mind even the solution is hacky or not very fast. The reason I'm asking is because such functionality would be very useful for creating development tools that would react to the developer eval-ing a function or re-compiling a file etc. Thanks, Stathis -- 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
Re: Watching namespaces
I was about to say that you best bet would be redefining the relevant functions/macros, when I realized that you cannot do that with def, because it's a special form. So short of patching clojure, I don't think one can monitor var interning. (addition to a namespace) What you can do, is monitoring redefinition: (def x old value) (add-watch #'x :redef println) (def x new value) :redef #'user/x old value new value kind regards 2011/9/15 Stathis Sideris side...@gmail.com: Hello, Is it somehow possible to monitor all namespaces for new defs or re- defs (and defns etc). Generally, it it possible to implement some sort of notification whenever something is added or updated to a namespace? I don't mind even the solution is hacky or not very fast. The reason I'm asking is because such functionality would be very useful for creating development tools that would react to the developer eval-ing a function or re-compiling a file etc. Thanks, Stathis -- 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 -- __ Herwig Hochleitner -- 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
ClojureScript auto-recompile option
Hello,
I've written a small hack for the ClojureScript compiler that is useful for
working with static HTML projects. When invoked with the :watch option, the
cljsc program watches a source directory and recompiles sources whenever a
change is detected.
https://github.com/harto/clojurescript/commit/f5bb720523f7121ab5fc8add014fd64846dc8e19
Usage: cljsc src '{:watch true}' foo.js
The change depends on the jpathwatch library, which should be downloaded (
http://sourceforge.net/projects/jpathwatch/files/jpathwatch-0-94.zip/download)
into the clojurescript/lib directory.
Regards,
Stuart
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Re: How to convert general recursion to loop .. recur syntax
On Thu, Sep 15, 2011 at 8:56 AM, Herwig Hochleitner hhochleit...@gmail.com wrote: Hi, as you might know, the original version actually does run in fixed stack space, thanks to lazy sequences. You are right! Without testing it I had thought that the way recursion was used would cause skl to overflow the stack if the input tree was very deep on its first elements. (defn skl [tree] (map skl (filter seq? tree))) But in testing this skl fn I couldn't get it to overflow. This is because the tree is not flattened, and so calling 'first' on the top level of the resulting tree only forces the top-level map, whose first item remains a lazy seq, neatly avoiding an overflow error. Good catch, Herwig! Consider (defn find-in-tree ([tree pred?] (concat (filter pred? tree) (mapcat find-in-tree (filter sequential? tree) (repeat pred?) which of course is much simpler written as (defn find-in-tree ([tree pred?] (filter pred? (flatten tree all of which are lazy, hence consume constant stack space Alas, this suffers from exactly the problem that I incorrectly believed skl suffered from. It works fine for some trees: (find-in-tree (reduce list (range 1000)) #(when-not (seq? %) (even? %))) ;= (0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60 62 64 66 68 70 72 74 76 78 80 82 84 86 88 90 92 94 96 98 100 102 104 106 108 110 112 114 116 118 120 122 124 126 128 130 132 134 136 138 140 142 144 146 148 150 152 154 156 158 160 162 164 166 168 170 172 174 176 178 180 182 184 186 188 190 192 194 196 198 200 202 204 ...) But the lazy seqs form a chain so that in order to return the first element of the result, they seqs must each force the next in the chain, consuming call stack frames as they go. Provide a tree deep enough and it overflows the stack: (find-in-tree (reduce list (range 1)) #(when-not (seq? %) (even? %))) ; StackOverflowError clojure.lang.RT.boundedLength (RT.java:1607) Nevertheless let us now marvel for a moment at the beauty of lazy seqs, that they can sometimes avoid both premature computation and stack overflows, even in cases where no amount of tail-call-optimization would help! And all this while delivering code so similar to the problem statement and therefore concise, compared to the long and tortured loop/recur version I posted yesterday. --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 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
Re: Watching namespaces
2011/9/15 Stathis Sideris side...@gmail.com Hello, Is it somehow possible to monitor all namespaces for new defs or re- defs (and defns etc). Generally, it it possible to implement some sort of notification whenever something is added or updated to a namespace? Not that I'm aware of. I don't mind even the solution is hacky or not very fast. The reason I'm asking is because such functionality would be very useful for creating development tools that would react to the developer eval-ing a function or re-compiling a file etc. Thanks, Stathis -- 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 -- 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
Re: How to convert general recursion to loop .. recur syntax
On Thu, Sep 15, 2011 at 8:56 AM, Herwig Hochleitner hhochleit...@gmail.com wrote: Consider (defn find-in-tree ([tree pred?] (concat (filter pred? tree) (mapcat find-in-tree (filter sequential? tree) (repeat pred?) which of course is much simpler written as (defn find-in-tree ([tree pred?] (filter pred? (flatten tree Not quite -- these differ in the case where pred? sometimes fires for a subtree and not just for leaves. The latter will miss all the subtrees for which pred? returns logical true. -- Protege: What is this seething mass of parentheses?! Master: Your father's Lisp REPL. This is the language of a true hacker. Not as clumsy or random as C++; a language for a more civilized age. -- 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
Re: autoboxing in 1.3 RC-0
On Thu, Sep 15, 2011 at 3:18 AM, Sergey Didenko sergey.dide...@gmail.comwrote: Hi, Is it a bug or I'm doing something wrong? I can't get rid of auto-boxing in the second example, neither by type hinting nor by type coercing of changed* locals. (set! *warn-on-reflection* true) This compiles fine: (loop [x 1 changed 0] (if (= x 10) changed (recur (inc x) changed))) And this gives the warning recur arg for primitive local: changed is not matching primitive, had: Object, needed: long Auto-boxing loop arg: change (loop [x 1 changed 0] (if (= x 10) changed (recur (inc x) (loop [y 1 changed-y changed] changed-y P.S. I omitted recur for the inner loop for clarity. Loop itself will return boxed values I think. David -- 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
Re: Clojure vs Scala - anecdote
On Wed, Sep 14, 2011 at 11:15 PM, cig clifford.goldb...@gmail.com wrote: Impressive, wonder if they were running this on a single node or more widespread? We run an instance of the process on multiple nodes, configured slightly differently. We needed some parallelization to improve throughput but didn't need a massive net of processes. And we needed JVM interop so Erlang is out (and Erjang isn't yet mature enough - at least, not last time I looked). But clojure is an awesome combination Indeed. -- Sean A Corfield -- (904) 302-SEAN An Architect's View -- http://corfield.org/ World Singles, LLC. -- http://worldsingles.com/ Railo Technologies, Inc. -- http://www.getrailo.com/ Perfection is the enemy of the good. -- Gustave Flaubert, French realist novelist (1821-1880) -- 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
Re: ClojureScript gets defrecord
Great news! Looking forward to trying it out this afternoon. Cheers, Devin On Sep 14, 2011, at 2:48 PM, Tom Hickey wrote: Hi all, With sign-off from Rich, I have pushed my defrecord work onto master. Please try it out and let me know if you experience any issues. Cheers, Tom Hickey -- 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 -- 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
Re: Rounding the edges of an Emacs beginner
M-{ and M-} in emacs go forward/backwards a paragraph. when in code,
this often translates well to moving around between
fragments/functions etc. you also have C-v and M-v for
forward/backward a page and then C-l for centering on the current
line. i use all of those a lot...
On Thu, Sep 15, 2011 at 2:15 AM, Stefan Kamphausen
ska2...@googlemail.com wrote:
Hi,
we're getting totally OT here and should probably better head for
gnu.emacs.help. Anyway, just one more bark from me and then I'll be quiet
(but will respond to mail ;-)
On Thursday, September 15, 2011 2:08:28 AM UTC+2, frye wrote:
In Vim , you press Ctrl-d and Ctrl-u to go down and up a block
respectively. Depending on the size of your window, it moves the cursor
about 1/3rd of the way down (or up) the screen. This is very handy to have
when just browsing a buffer. You can be more precise by pressing 37k, to
move the cursor up 37 lines, etc.
For whatever reason, I haven't been able to find something similar in
Emacs.
OK, I tried what it does in vim. Some things come to my mind.
1. PgUp/PgDn obviously
2. Try hitting C-l (that's an 'l' like in 'like') several times in a row.
It won't move your cursor but the line it's on.
3. I've been using some personal binding on my home and end keys for ages
which moves me to the beginning/end of a line, beginning/end of the
currently displayed window and beginning/end of the whole buffer on
successive hits. See chb-home and chb-end on
http://www.skamphausen.de/cgi-bin/ska/dot-emacs.d-slash-init.el. Combine
that with C-l.
4. You might want to try out swiss-move.el (shameless self-plug). Maybe
it's confusing, maybe helpful.
Cheers,
Stefan
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Re: autoboxing in 1.3 RC-0
On Thu, Sep 15, 2011 at 7:50 AM, David Nolen dnolen.li...@gmail.com wrote: Loop itself will return boxed values I think. Looks that way. The following code has no reflection warning: (loop [x 1 changed 0] (if (= x 10) changed (recur (inc x) (long (loop [y 1 changed-y changed] changed-y) -- Sean A Corfield -- (904) 302-SEAN An Architect's View -- http://corfield.org/ World Singles, LLC. -- http://worldsingles.com/ Railo Technologies, Inc. -- http://www.getrailo.com/ Perfection is the enemy of the good. -- Gustave Flaubert, French realist novelist (1821-1880) -- 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
Re: Clojure vs Scala - anecdote
Native Erlang does have a macro facility, but it is not as powerful as Lisp/Clojure's. On Sep 15, 2:15 am, cig clifford.goldb...@gmail.com wrote: [snip] In a wide spread environment I think Erlang would be the true winner, though it does not natively have macros :-( [snip] -- 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
Re: Clojure vs Scala - anecdote
On Thu, Sep 15, 2011 at 9:24 AM, Edward Garson egar...@gmail.com wrote: Native Erlang does have a macro facility, but it is not as powerful as Lisp/Clojure's. lfe, baby, though of course that is not native erlang. -- 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
java interop question: how to access Class object statically
Hi all -- Trying to basically do something like Integer.class -- but ... user= (Integer/class) user= java.lang.NoSuchFieldException: class (NO_SOURCE_FILE:2) user= (Integer/getClass) java.lang.NoSuchFieldException: getClass (NO_SOURCE_FILE:4) Some (not so pretty) workarounds are (.getClass (Integer. 0)) (class 0) but there must be a better more idiomatic way to do this? Thanks -- 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
Re: java interop question: how to access Class object statically
How about just Integer? :) Clojure Integer java.lang.Integer Clojure (class Integer) java.lang.Class Dave On Thu, Sep 15, 2011 at 1:31 PM, Andrew Xue and...@lumoslabs.com wrote: Hi all -- Trying to basically do something like Integer.class -- but ... user= (Integer/class) user= java.lang.NoSuchFieldException: class (NO_SOURCE_FILE:2) user= (Integer/getClass) java.lang.NoSuchFieldException: getClass (NO_SOURCE_FILE:4) Some (not so pretty) workarounds are (.getClass (Integer. 0)) (class 0) but there must be a better more idiomatic way to do this? Thanks -- 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 -- 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
Re: ClojureScript gets defrecord
Any particular reason that records print differently than in Clojure? I also see that records don't print w/ their namespace attached. A related bug I encountered was that when I try to put the record literal back into the REPL, Java complains about not being able to find the class. David On Wed, Sep 14, 2011 at 3:48 PM, Tom Hickey thic...@gmail.com wrote: Hi all, With sign-off from Rich, I have pushed my defrecord work onto master. Please try it out and let me know if you experience any issues. Cheers, Tom Hickey -- 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 -- 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
Re: ClojureScript gets defrecord
Printing is not meant to be different. Maybe I was using against an older version of Clojure when I was comparing output. Should be fixed on master. Thanks for the report. Tom On Sep 15, 4:00 pm, David Nolen dnolen.li...@gmail.com wrote: Any particular reason that records print differently than in Clojure? I also see that records don't print w/ their namespace attached. A related bug I encountered was that when I try to put the record literal back into the REPL, Java complains about not being able to find the class. David On Wed, Sep 14, 2011 at 3:48 PM, Tom Hickey thic...@gmail.com wrote: Hi all, With sign-off from Rich, I have pushed my defrecord work onto master. Please try it out and let me know if you experience any issues. Cheers, Tom Hickey -- 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 -- 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
Re: Watching namespaces
Yes, this has been suggested in the past, and would enable all sorts of useful tooling features. The off-the-top-of-my-head solution (a priori of a proper statement of the problem :-P would be for all namespaces (c.l.Namespace/namespaces) and each namespace's aliases and mappings to be held in atoms — which could then have watches set on them. Each aliases and mappings are already held in AtomicReferences, so things are halfway there in a sense. Along the same lines, there's been talk in the past of attempting to make loading code transactional. At a minimum, this would imply using refs instead of atoms for the structures mentioned above, with each ns/require/use/load usage implying a dosync over the affected references. There may well be bootstrapping issues with such changes. - Chas On Sep 15, 2011, at 9:03 AM, Stathis Sideris wrote: Hello, Is it somehow possible to monitor all namespaces for new defs or re- defs (and defns etc). Generally, it it possible to implement some sort of notification whenever something is added or updated to a namespace? I don't mind even the solution is hacky or not very fast. The reason I'm asking is because such functionality would be very useful for creating development tools that would react to the developer eval-ing a function or re-compiling a file etc. Thanks, Stathis -- 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 -- 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
Re: autoboxing in 1.3 RC-0
On Thu, Sep 15, 2011 at 10:50 AM, David Nolen dnolen.li...@gmail.com wrote: On Thu, Sep 15, 2011 at 3:18 AM, Sergey Didenko sergey.dide...@gmail.com wrote: Auto-boxing loop arg: change (loop [x 1 changed 0] (if (= x 10) changed (recur (inc x) (loop [y 1 changed-y changed] changed-y Loop itself will return boxed values I think. David It shouldn't, if all the return paths out of the loop return an unboxed primitive of the same type and an unboxed primitive of that type is an acceptable input to the enclosing expression, which is the case here. -- Protege: What is this seething mass of parentheses?! Master: Your father's Lisp REPL. This is the language of a true hacker. Not as clumsy or random as C++; a language for a more civilized age. -- 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
Re: How to convert general recursion to loop .. recur syntax
Thanks for clarifying the stack space issue. I got confused with the original implementation, and was unsure it would run with a large sequence. -- 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
Re: Clojure vs Scala - anecdote
On Tuesday, September 13, 2011 1:44:09 PM UTC-5, Sean Corfield wrote: It was intended to be purely anecdotal but that doesn't seem to satisfy anyone! :) Homer: You know, when I was a boy, I really wanted a catcher's mitt, but my dad wouldn't get it for me. So I held my breath until I passed out and banged my head on the coffee table. The doctor thought I might have brain damage. Bart: Dad, what's the point of this story? Homer: I like stories. -- 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
Re: autoboxing in 1.3 RC-0
I ran into this exact issue on an alioth benchmark. Adding the explicit (long ...) conversion gets rid of the reflection warning, but didn't have a significant effect on performance. The inner loop is still boxing the return value. On Thursday, September 15, 2011 8:36:53 AM UTC-7, Sean Corfield wrote: On Thu, Sep 15, 2011 at 7:50 AM, David Nolen dnolen...@gmail.com wrote: Loop itself will return boxed values I think. Looks that way. The following code has no reflection warning: (loop [x 1 changed 0] (if (= x 10) changed (recur (inc x) (long (loop [y 1 changed-y changed] changed-y) -- Sean A Corfield -- (904) 302-SEAN An Architect's View -- http://corfield.org/ World Singles, LLC. -- http://worldsingles.com/ Railo Technologies, Inc. -- http://www.getrailo.com/ Perfection is the enemy of the good. -- Gustave Flaubert, French realist novelist (1821-1880) -- 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
Re: autoboxing in 1.3 RC-0
see https://github.com/clojure/test.benchmark/blob/master/src/main/clojure/alioth/mandelbrot.clj#L49 There's two ways to get rid of the reflection warning: 1) another function, appropriately type hinted 2) explicit conversion to long According to my measurements for this particular case, option 2 is fractionally faster by ~3% over option 1. Expectation would be the explicit conversion to long shouldn't be needed. On Thursday, September 15, 2011 8:16:10 PM UTC-7, pmbauer wrote: I ran into this exact issue on an alioth benchmark. Adding the explicit (long ...) conversion gets rid of the reflection warning, but didn't have a significant effect on performance. The inner loop is still boxing the return value. On Thursday, September 15, 2011 8:36:53 AM UTC-7, Sean Corfield wrote: On Thu, Sep 15, 2011 at 7:50 AM, David Nolen dnol...@gmail.com wrote: Loop itself will return boxed values I think. Looks that way. The following code has no reflection warning: (loop [x 1 changed 0] (if (= x 10) changed (recur (inc x) (long (loop [y 1 changed-y changed] changed-y) -- Sean A Corfield -- (904) 302-SEAN An Architect's View -- http://corfield.org/ World Singles, LLC. -- http://worldsingles.com/ Railo Technologies, Inc. -- http://www.getrailo.com/ Perfection is the enemy of the good. -- Gustave Flaubert, French realist novelist (1821-1880) -- 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
Re: ClojureScript auto-recompile option
FWIW there's also cljs-watch:
http://github.com/ibdknox/cljs-watch
On Sep 15, 6:35 am, Stuart Campbell stu...@harto.org wrote:
Hello,
I've written a small hack for the ClojureScript compiler that is useful for
working with static HTML projects. When invoked with the :watch option, the
cljsc program watches a source directory and recompiles sources whenever a
change is detected.
https://github.com/harto/clojurescript/commit/f5bb720523f7121ab5fc8ad...
Usage: cljsc src '{:watch true}' foo.js
The change depends on the jpathwatch library, which should be downloaded
(http://sourceforge.net/projects/jpathwatch/files/jpathwatch-0-94.zip/...)
into the clojurescript/lib directory.
Regards,
Stuart
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