Re: run macro for executable namespaces
Thanks Steve! That's very neat. Pretty much a canonical macro example. Adrian. On Tue, Jun 2, 2009 at 5:50 AM, Stephen C. Gilardi squee...@mac.com wrote: Here's a macro I've found useful for loading and running Clojure programs from the REPL: (defmacro run Loads the specified namespace and invokes its \main\ function with optional args. ns-name is not evaluated. [ns-name args] `(do (require '~ns-name :reload-all) ((ns-resolve '~ns-name '~'main) ~...@args))) An example namespace that works with it (in hello.clj at a classpath root): (ns hello) (defn main [ args] (apply println hi args)) and a REPL session: user= (run hello) hi nil user= (run hello :clojure is \# (.gcd (bigint 1169687) (bigint 311791))) hi :clojure is # 1 nil user= I think the quoting on main in the ns-resolve call is quite interesting. macroexpand-ing variations on it is a heap of educational Clojure macro-fu fun! --Steve --~--~-~--~~~---~--~~ 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: run macro for executable namespaces
On 02.06.2009, at 05:50, Stephen C. Gilardi wrote: Here's a macro I've found useful for loading and running Clojure programs from the REPL: (defmacro run Loads the specified namespace and invokes its \main\ function with optional args. ns-name is not evaluated. [ns-name args] `(do (require '~ns-name :reload-all) ((ns-resolve '~ns-name '~'main) ~...@args))) That looks like a perfect candidate for clojure.contrib.repl-utils! Konrad --~--~-~--~~~---~--~~ 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 -~--~~~~--~~--~--~---
Good examples of defmulti polymorphism
I'm used to polymorphism in OO systems where everything in driven from inheritance hierarchy. Clojures defmulti style polymorphism seems powerful but has left me wondering how to most effectively use it. I'm looking for some good real world examples of how people have used polymorphism in clojure. Regards, Glen Stampoultzis --~--~-~--~~~---~--~~ 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: Concerns About Pushing Clojure 1.0.0 to Maven Central Repo?
The upload bundle, which is found at http://jira.codehaus.org/browse/MAVENUPLOAD-2464, promotes Clojure as org.clojure:clojure:1.0.0. It hasn't received any atention from the Upload team yet, but I do hope it gets uploaded within the next weeks. Maybe voting could speed it up... dysinger dysin...@gmail.com writes: I personally have used the -lang qualifier in my own POM work so as to have an (unspoken) consensus with Howard's POM work. However, I would rather clojure proper just be named org.clojure:clojure in maven/ivy-land myself and I have heard that from quite a few others. On May 10, 1:17 pm, d...@kronkltd.net (Daniel E. Renfer) wrote: Phil Hagelberg p...@hagelb.org writes: Howard Lewis Ship hls...@gmail.com writes: clojure-lang because there will be a clojure-contrib artifact for the same group. And this is ... a bad thing? I'm lost. -Phil Good, at least I'm not the only one. Why can't we have both clojure and clojure-contrib as Id's? Daniel E. Renfer --~--~-~--~~~---~--~~ 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: Concerns About Pushing Clojure 1.0.0 to Maven Central Repo?
I signed up and voted. Only took about 30 seconds. Thanks for the work everyone. I would love to see Clojure get into the Maven repo. Paul On Tue, Jun 2, 2009 at 6:04 AM, Stefan Hübner sthueb...@googlemail.comwrote: The upload bundle, which is found at http://jira.codehaus.org/browse/MAVENUPLOAD-2464, promotes Clojure as org.clojure:clojure:1.0.0. It hasn't received any atention from the Upload team yet, but I do hope it gets uploaded within the next weeks. Maybe voting could speed it up... dysinger dysin...@gmail.com writes: I personally have used the -lang qualifier in my own POM work so as to have an (unspoken) consensus with Howard's POM work. However, I would rather clojure proper just be named org.clojure:clojure in maven/ivy-land myself and I have heard that from quite a few others. On May 10, 1:17 pm, d...@kronkltd.net (Daniel E. Renfer) wrote: Phil Hagelberg p...@hagelb.org writes: Howard Lewis Ship hls...@gmail.com writes: clojure-lang because there will be a clojure-contrib artifact for the same group. And this is ... a bad thing? I'm lost. -Phil Good, at least I'm not the only one. Why can't we have both clojure and clojure-contrib as Id's? Daniel E. Renfer --~--~-~--~~~---~--~~ 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: Good examples of defmulti polymorphism
On 02.06.2009, at 12:01, Glen Stampoultzis wrote: I'm used to polymorphism in OO systems where everything in driven from inheritance hierarchy. Clojures defmulti style polymorphism seems powerful but has left me wondering how to most effectively use it. I'm looking for some good real world examples of how people have used polymorphism in clojure. There are a couple of generic interfaces implemented as multimethods in clojure-contrib: http://code.google.com/p/clojure-contrib/source/browse/#svn/trunk/ src/clojure/contrib/generic An implementation of complex numbers based on these interfaces is there as well: http://code.google.com/p/clojure-contrib/source/browse/trunk/src/ clojure/contrib/complex_numbers.clj Konrad. --~--~-~--~~~---~--~~ 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: run macro for executable namespaces
On Jun 2, 2009, at 3:35 AM, Adrian Cuthbertson wrote: Thanks Steve! That's very neat. Pretty much a canonical macro example. You're welcome! I'm glad you like it. On Jun 2, 2009, at 4:45 AM, Konrad Hinsen wrote: That looks like a perfect candidate for clojure.contrib.repl-utils! Thanks! After a little more discussion, I'd like to put it in there. After thinking about other macro advice I've seen (from Meikel Brandmeyer and elsewhere), I came up with this version that does most of the work in a function and provides the macro just to control the evaluation of arguments: (defn run* Loads the specified namespace and invokes its \main\ function with optional args. [ns-sym args] (require ns-sym :reload-all) (apply (ns-resolve ns-sym 'main) args)) (defmacro run Loads the specified namespace and invokes its \main\ function with optional args. ns-name is not evaluated. [ns-name args] `(run* '~ns-name ~...@args)) I see the tradeoffs as: possible negative: - an extra name in the namespace positives: - the code is easier to understand - the function version composes better: it's easier to call from other code if that were desired. Overall I like the function/macro pair version better. Any thoughts? --Steve smime.p7s Description: S/MIME cryptographic signature
Re: Concerns About Pushing Clojure 1.0.0 to Maven Central Repo?
Christian Vest Hansen karmazi...@gmail.com writes: On Mon, May 18, 2009 at 8:59 AM, Stefan Hübner sthueb...@googlemail.com wrote: I've submitted the Maven bundle for Clojure 1.0.0 to http://jira.codehaus.org/browse/MAVENUPLOAD-2464. Processing the request might take a couple of days. The upload guide says four weeks. Repository synchronization is the long term solution, I think. Thats probably true. If someone from the core team/contributors has the resources to set this up, that would be cool. It would speed up promotion to Maven Central alot (fully automatic) - for future releases. --~--~-~--~~~---~--~~ 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: Spider with clojure
just reading through the book (http://pragprog.com/titles/shcloj/ programming-clojure) and having a lot of of fun learning. I was wondering if there are any examples out there like Dave Thomas' A First Erlang Program http://pragdave.pragprog.com/pragdave/2007/04/a_first_erlang_.html in Clojure. What I want to do is just read in a csv with a couple of hundred URLs and spider those in parallel (!) and save the results back to another file. The way I like to learn best is to find something and mold it to my needs. I tried searching, but couldn't find anything useful with spider clojure. Since clojure is touted as the perfect language for multi-threaded apps this would be a very nice and useful lesson for me. (Sorry, but I have no use at all for a versioning control system.) I am doing this with Ruby right now, but no in parallel. This seems to be an ideal use-case for Clojure Agents http://clojure.org/agents Try it out and share the code :) Regards, BG -- Baishampayan Ghose b.gh...@ocricket.com oCricket.com signature.asc Description: OpenPGP digital signature
STM Resource transactions
I've been looking at using the clojure.set functions to create a simple in-memory database cache. Basically when the app boost up, load entire db into memory, work with it through the basic relational algebra functions provided. Any mutations (create/update/delete) would be wrapped in a simple function that 1) updates the cache and 2) persists to the database in order to add the D to STM's ACI. So for example, you could have: (defn insert-product [product] (dosync (alter products conj product)) (with-connection db (transaction (insert-values XXXstuff hereXXX))) The dosync will run the alter within an STM transaction. The transaction will run the insert within a local resource (database) transaction. In Java, if you have two transactional systems, you can bridge them with JTA. STM, however, is a different beast. Has anyone done anything towards bridging STM and resource transactions? --~--~-~--~~~---~--~~ 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: run macro for executable namespaces
On Tue, Jun 2, 2009 at 7:49 AM, Stephen C. Gilardi squee...@mac.com wrote: On Jun 2, 2009, at 4:45 AM, Konrad Hinsen wrote: That looks like a perfect candidate for clojure.contrib.repl-utils! Thanks! After a little more discussion, I'd like to put it in there. I'm never sure what the etiquette is for adding to other people's files in contrib, but please don't hesitate to add this to repl-utils on my account. I see the tradeoffs as: possible negative: - an extra name in the namespace Eh... nobody cares. :-) positives: - the code is easier to understand - the function version composes better: it's easier to call from other code if that were desired. These are important, esp. the second one, at least in the general case. Overall I like the function/macro pair version better. Any thoughts? Using gen-class you can have a namespace that is runnable from the Java command line by providing a main() method. This usually defers to a function named -main that expects string arguments. From my reading of your 'run', it looks like you're using a function named main that expects symbol, string, etc. args. I assume this difference is intentional? --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: ClojureCLR updated
On Jun 1, 1:57 pm, David Miller dmiller2...@gmail.com wrote: It's important in that it means that the generated MSIL is not completely junk, in that I'm not missing any important optimizations, that I'm taking full advantage of type hints, avoiding reflection, etc.. The JVM bytecodes are an important check for me. What's interesting is that the methods used to generate the IL in the each implementation are very different. The two implementations generate AST from the clojure source that are pretty much identical. From the ASTs, the JVM implementation generates bytecodes using the ASM bytecode library--essentially, it's close to hand-generated. Rich and company have that code pretty finely tuned. The CLR implementation transforms the ASTs into DLR-Expression-Tree-Version-2 expressions. The DLR code handles compiling those expressions into either dynamic methods or into static methods for saving in assemblies. The DLR expression compiler should be generating decent MSIL. I think the closeness of the results are encouraging. I wonder if that project could be of some help/inspiration. It implements a JVM in .NET http://www.ikvm.net/ The JVM implementation does pull some tricks, such as nulling method arguments before tail calls or storing some temp values on the stack, that I can't figure out how to duplicate with ExpressionTrees. Also, the expression tree compiler can only generate static methods. Clojure functions are instances of a class implementing the IFn interface. I have to hand-code the class definitions and code the 'invoke' instance methods to call out to static methods in a base class. That adds an extra method call in many places. Whether all these little things add up to some of the performance differences is beyond my knowledge or the granularity of the profiling tools at my disposal. Unless some MSIL expert surfaces to give advice, I'll be spending time hand-coding some alternatives to benchmark certain constructs to see what works better. Worst case, I will end up discarding the MSIL and doing the MSIL generation myself. : It'd be much easier to play with if you provide a precompiled : executable :) I thought about that. Adding assembilies of my code as a download is easy enough. However, to get the thing running, you also need vjslib from the J# Redistributatable library plus DLLs generated from the DLR source -- care to advise me about the legal ramifications of me doing that directly? :) : Keep up the good work! I hope to someday use ClojureCLR for real : projects, so I can have all the functional, concurrent goodness of : Clojure in .NET. I think that day is not too far off. Thanks for the feedback. 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: STM Resource transactions
On Tue, Jun 2, 2009 at 8:12 AM, Robert Campbell rrc...@gmail.com wrote: I've been looking at using the clojure.set functions to create a simple in-memory database cache. Basically when the app boost up, load entire db into memory, work with it through the basic relational algebra functions provided. Any mutations (create/update/delete) would be wrapped in a simple function that 1) updates the cache and 2) persists to the database in order to add the D to STM's ACI. So for example, you could have: (defn insert-product [product] (dosync (alter products conj product)) (with-connection db (transaction (insert-values XXXstuff hereXXX))) The dosync will run the alter within an STM transaction. The transaction will run the insert within a local resource (database) transaction. In Java, if you have two transactional systems, you can bridge them with JTA. STM, however, is a different beast. Has anyone done anything towards bridging STM and resource transactions? There was a thread about this awhile back: http://groups.google.com/group/clojure/browse_thread/thread/aa22a709501a64ac/b578f0915b55c4be?#b578f0915b55c4be There is apparently an attachment to the list which modifies the Clojure STM in the necessary ways, but it may not work with the latest anymore. Sounds like Rich may be willing to work with you to integrate it into the trunk.. /mike. --~--~-~--~~~---~--~~ 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: Spider with clojure
Hi BG,
This seems to be an ideal use-case for Clojure Agents
http://clojure.org/agents
This code is still a little too general for me. I guess if I stare at it long
enough, I will eventually get it ;)
Try it out and share the code :)
Will do, but I hope that someone has something more concrete. Here is what I
do in Ruby (shortened and with all error handling stripped out).
require 'rubygems'
require 'mechanize'
require 'faster_csv'
urls = '...urls in csv format...'
fcsv_options = {:headers = true, :header_converters = :symbol}
FasterCSV.open('results.csv', 'w') do |csv|
csv %w[url acrank refdomain anchortext title body]
FasterCSV.parse(urls, fcsv_options) do |line|
page = WWW::Mechanize.new { |ag|
ag.read_timeout = 10
}.get(line[:url])
# push result to csv
end
end
a typical spider. I would love to read some source code of something similiar
done in clojure. If it doesn't exist yet, I will eventually create it. Right
now I would even know which libs to use or even if there are any. I guess even
the parsing of the csv could be multithreaded. Feelin kinda frustrated right
now, because I know how to do it in a couple other languages, but just got
started with Clojure. I have done this in Ruby even multithreaded, which
quickly became *very* complicated because of it's mutable variables.
-sasa
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Re: run macro for executable namespaces
Hi, Am 02.06.2009 um 13:49 schrieb Stephen C. Gilardi: I see the tradeoffs as: possible negative: - an extra name in the namespace I don't see this as a big negative. I usually stick with the convention that the function is named after the macro with a star added. As in your example: run = run*. This doesn't use up additional names since they are either named with two stars (one on either side) or no star at all. So I can live with that trade-off.. positives: - the code is easier to understand - the function version composes better: it's easier to call from other code if that were desired. Overall I like the function/macro pair version better. Any thoughts? I think the advantages weight up the additional name. Did you further think about your previous suggestion to provide the functionality of calling a qualified function from the command line of clojure.main? I'd still like to suggest a '-E' flag, which basically specifies the entry point to call. So one could do clojure.main -E some.namespace/some-func This would require some.namespace to be on the classpath. clojure.main some/file.clj would just execute some/file.clj as a script. clojure.main -E some.namespace/some-func some/namespace.clj would first read some/namespace.clj and then execute some.namespace/some-func. This would not require some.namespace to be on the classpath, because it could be defined in the given file. This would allow to make the loading of script files side-effect free, which would ease their use during debugging. And it would allow different entry points in a single script. Finally the script would not need to reside somewhere on the classpath. Sincerely Meikel smime.p7s Description: S/MIME cryptographic signature
Re: run macro for executable namespaces
On Jun 2, 2009, at 8:59 AM, Chouser wrote: On Tue, Jun 2, 2009 at 7:49 AM, Stephen C. Gilardi squee...@mac.com wrote: On Jun 2, 2009, at 4:45 AM, Konrad Hinsen wrote: That looks like a perfect candidate for clojure.contrib.repl-utils! Thanks! After a little more discussion, I'd like to put it in there. I'm never sure what the etiquette is for adding to other people's files in contrib, but please don't hesitate to add this to repl-utils on my account. I agree on the etiquette thing. I planned to track you down and ask you. Thanks for the permission! In clojure.contrib.core, Laurent put in a clause at the top giving blanket permission. In that case I marked off a section for my contribs (dissoc-in and new-by-name) so anyone who wants to ask about them can find me. Any thoughts? Using gen-class you can have a namespace that is runnable from the Java command line by providing a main() method. This usually defers to a function named -main that expects string arguments. From my reading of your 'run', it looks like you're using a function named main that expects symbol, string, etc. args. I assume this difference is intentional? It is intentional. I see them as having slightly different roles given the more flexible types that main can see vs. the just strings that - main (prefixmain in the general case) would see. In cases where they can be unified it can be done easily with a small stub, a def, or a clojure.contrib.def/defalias. I think it would be a cool idea for ns to support a :main clause that would let you specify the function to run when this namespace is executed using run. I would default it to main, but it could be specified as -main if that's appropriate or another name with more meaning in general. --Steve smime.p7s Description: S/MIME cryptographic signature
Re: You know you've been writing too much Clojure when...
On Fri, May 29, 2009 at 2:51 PM, Paul Stadig p...@stadig.name wrote: You meant to type disclosure, but instead you typed disclojure. Paul How about when you try to write code in other languages, and reflexively place parentheses before function/method names? (len 'Foo') -- not valid Python. :( /mike. --~--~-~--~~~---~--~~ 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: run macro for executable namespaces
2009/6/2 Stephen C. Gilardi squee...@mac.com: On Jun 2, 2009, at 8:59 AM, Chouser wrote: On Tue, Jun 2, 2009 at 7:49 AM, Stephen C. Gilardi squee...@mac.com wrote: On Jun 2, 2009, at 4:45 AM, Konrad Hinsen wrote: That looks like a perfect candidate for clojure.contrib.repl-utils! Thanks! After a little more discussion, I'd like to put it in there. I'm never sure what the etiquette is for adding to other people's files in contrib, but please don't hesitate to add this to repl-utils on my account. I agree on the etiquette thing. I planned to track you down and ask you. Thanks for the permission! In clojure.contrib.core, Laurent put in a clause at the top giving blanket permission. In that case I marked off a section for my contribs (dissoc-in and new-by-name) so anyone who wants to ask about them can find me. There also still the possibility to have, per namespace, a file that just loads other files (belonging to the same namespace) with one contributor per file. But I see this as counter productive because there will be a lot of little files per namespace, and sometimes there will be problems with the orders of the functions definitions eventually leading to the creation of several files per namespace per contributo ... so not a so great idea after all :-) Any thoughts? Using gen-class you can have a namespace that is runnable from the Java command line by providing a main() method. This usually defers to a function named -main that expects string arguments. From my reading of your 'run', it looks like you're using a function named main that expects symbol, string, etc. args. I assume this difference is intentional? It is intentional. I see them as having slightly different roles given the more flexible types that main can see vs. the just strings that -main (prefixmain in the general case) would see. In cases where they can be unified it can be done easily with a small stub, a def, or a clojure.contrib.def/defalias. I think it would be a cool idea for ns to support a :main clause that would let you specify the function to run when this namespace is executed using run. I would default it to main, but it could be specified as -main if that's appropriate or another name with more meaning in general. --Steve --~--~-~--~~~---~--~~ 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: You know you've been writing too much Clojure when...
2009/6/2 Michael Reid kid.me...@gmail.com: On Fri, May 29, 2009 at 2:51 PM, Paul Stadig p...@stadig.name wrote: You meant to type disclosure, but instead you typed disclojure. Paul How about when you try to write code in other languages, and reflexively place parentheses before function/method names? (len 'Foo') -- not valid Python. :( And when you're stuck with java, and have to implement the Visitor design pattern yet again, instead of being able to use multimethods :-( (that was my case the last two weeks !) --~--~-~--~~~---~--~~ 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: You know you've been writing too much Clojure when...
On Tue, Jun 2, 2009 at 9:52 AM, Michael Reid kid.me...@gmail.com wrote: On Fri, May 29, 2009 at 2:51 PM, Paul Stadig p...@stadig.name wrote: You meant to type disclosure, but instead you typed disclojure. Paul How about when you try to write code in other languages, and reflexively place parentheses before function/method names? (len 'Foo') -- not valid Python. :( /mike. Don't forget, commas are NOT optional! irb(main) a = [1 2 3] SyntaxError: compile error! --~--~-~--~~~---~--~~ 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: You know you've been writing too much Clojure when...
On Tue, Jun 2, 2009 at 10:06 AM, Shawn Hoover shawn.hoo...@gmail.comwrote: On Tue, Jun 2, 2009 at 9:52 AM, Michael Reid kid.me...@gmail.com wrote: On Fri, May 29, 2009 at 2:51 PM, Paul Stadig p...@stadig.name wrote: You meant to type disclosure, but instead you typed disclojure. Paul How about when you try to write code in other languages, and reflexively place parentheses before function/method names? (len 'Foo') -- not valid Python. :( /mike. Don't forget, commas are NOT optional! irb(main) a = [1 2 3] SyntaxError: compile error! Hehe, yeah that one's gotten me before. :) Paul --~--~-~--~~~---~--~~ 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: You know you've been writing too much Clojure when...
Same here with the commas. Since I've been neck deep in Clojure, I've been pathologically forgetting to add them with other languages. On Jun 2, 10:06 am, Shawn Hoover shawn.hoo...@gmail.com wrote: On Tue, Jun 2, 2009 at 9:52 AM, Michael Reid kid.me...@gmail.com wrote: On Fri, May 29, 2009 at 2:51 PM, Paul Stadig p...@stadig.name wrote: You meant to type disclosure, but instead you typed disclojure. Paul How about when you try to write code in other languages, and reflexively place parentheses before function/method names? (len 'Foo') -- not valid Python. :( /mike. Don't forget, commas are NOT optional! irb(main) a = [1 2 3] SyntaxError: compile error! --~--~-~--~~~---~--~~ 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: run macro for executable namespaces
On Jun 2, 2009, at 8:59 AM, Chouser wrote: I'm never sure what the etiquette is for adding to other people's files in contrib, but please don't hesitate to add this to repl-utils on my account. Thanks again. I've checked in run*/run to clojure.contrib.repl-utils. Cheers, --Steve smime.p7s Description: S/MIME cryptographic signature
Re: Good examples of defmulti polymorphism
Hi Glen,
(1) Real-world example: I use polymorphism on the types of two
different arguments to define implicit conversions:
(defmulti coerce
(fn [dest-class src-inst] [dest-class (class src-inst)]))
(defmethod coerce [java.io.File String] [_ str]
(java.io.File. str))
(defmethod coerce [Boolean/TYPE String] [_ str]
(contains? #{on yes true} (.toLowerCase str)))
(2) Made-up, but realistic example: using polymorphism on two
different inheritance hierarchies on a single argument:
(defmulti service-charge (fn [acct] [(account-level acct) (:tag acct)]))
(defmethod service-charge [::acc/Basic ::acc/Checking] [_] 25)
(defmethod service-charge [::acc/Basic ::acc/Savings][_] 10)
(defmethod service-charge [::acc/Premium ::acc/Account] [_] 0)
(3) Example from inside Clojure itself: using external tags to layer a
hierarchy onto existing objects without their knowledge (inspector.clj).
All of these are documented in the book [1] and you can view the
sample code at [2].
Cheers,
Stu
[1] http://www.pragprog.com/titles/shcloj/programming-clojure
[2] http://github.com/stuarthalloway/programming-clojure/. See
examples/multimethods*
I'm used to polymorphism in OO systems where everything in driven
from inheritance hierarchy. Clojures defmulti style polymorphism
seems powerful but has left me wondering how to most effectively use
it. I'm looking for some good real world examples of how people
have used polymorphism in clojure.
Regards,
Glen Stampoultzis
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Re: You know you've been writing too much Clojure when...
People keep looking at me funny when I point out variables as code smells during code review... Stu Same here with the commas. Since I've been neck deep in Clojure, I've been pathologically forgetting to add them with other languages. On Jun 2, 10:06 am, Shawn Hoover shawn.hoo...@gmail.com wrote: On Tue, Jun 2, 2009 at 9:52 AM, Michael Reid kid.me...@gmail.com wrote: On Fri, May 29, 2009 at 2:51 PM, Paul Stadig p...@stadig.name wrote: You meant to type disclosure, but instead you typed disclojure. Paul How about when you try to write code in other languages, and reflexively place parentheses before function/method names? (len 'Foo') -- not valid Python. :( /mike. Don't forget, commas are NOT optional! irb(main) a = [1 2 3] SyntaxError: compile error! --~--~-~--~~~---~--~~ 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 -~--~~~~--~~--~--~---
feature request: docstring for defstruct
I would like to see defstruct take an optional docstring. Would such a patch be welcome? Stu --~--~-~--~~~---~--~~ 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 -~--~~~~--~~--~--~---
filter on sequence
Apologies in advance on a very newbie question.
I've constructed a sequence
(take 10 (iterate (fn [[a b]] [(* 2 a) (/ a (Math/log a))]) [2 (/ 2
(Math/log 2))])
doing a take 10 on it, produce the pairs I expect.
what I like to know is, how do I filter for with value b is X
for example, the first 10 produces.
([2 2.8853900817779268] [4 2.8853900817779268] [8 2.8853900817779268]
[16 3.8471867757039027] [32 5.7707801635558535] [64 9.233248261689365]
[128 15.38874710281561] [256 26.380709319112476] [512
46.16624130844683] [1024 82.07331788168325])
what if I want to filter so I only get pairs for which the 2nd value
is 10. I couldn't figure out how to get
filter to work for pair values.
a 2nd question is more of general clojure idiom, in trying to covert
the following java
code from michaelg's java 1 presentation
private int calcSize(){
int max = 2;
while ((max/Math.log(max)) size
max Integer.MAX_VALUE max 0){
max *=2;
}
return max;
}
My first reaction was to do it using a sequence. Is this the clojure
idiomatic way to convert a
while loop from other languages?
Thanks,
Mac
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Re: feature request: docstring for defstruct
This would encourage documenting structs, so I think this is a good idea. Sean On Jun 2, 11:31 am, Stuart Halloway stuart.hallo...@gmail.com wrote: I would like to see defstruct take an optional docstring. Would such a patch be welcome? Stu --~--~-~--~~~---~--~~ 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: filter on sequence
On Jun 2, 2009, at 11:35 AM, Wilson MacGyver wrote: what I like to know is, how do I filter for with value b is X You can use destructuring in your predicate's arg list: (filter (fn [[_ x]] ( x 10)) *1) In English, the function takes an argument which can be accessed sequentially. Destruture it such that its first two elements are named _ (a conventional name for I don't care) and x. Then the body of the predicate can operate on x. --Steve smime.p7s Description: S/MIME cryptographic signature
Re: filter on sequence
On 02.06.2009, at 17:35, Wilson MacGyver wrote:
for example, the first 10 produces.
([2 2.8853900817779268] [4 2.8853900817779268] [8 2.8853900817779268]
[16 3.8471867757039027] [32 5.7707801635558535] [64 9.233248261689365]
[128 15.38874710281561] [256 26.380709319112476] [512
46.16624130844683] [1024 82.07331788168325])
what if I want to filter so I only get pairs for which the 2nd value
is 10. I couldn't figure out how to get
filter to work for pair values.
Try this:
(take 3
(filter #( (second %) 10)
(iterate (fn [[a b]] [(* 2 a) (/ a (Math/log a))])
[2 (/ 2 (Math/log 2))])))
If you try to take 10 values, you will create an endless loop because
with the given parameters your sequence actually has less than ten
elements that satisfy the condition!
a 2nd question is more of general clojure idiom, in trying to covert
the following java code from michaelg's java 1 presentation
private int calcSize(){
int max = 2;
while ((max/Math.log(max)) size
max Integer.MAX_VALUE max 0){
max *=2;
}
return max;
}
My first reaction was to do it using a sequence. Is this the clojure
idiomatic way to convert a while loop from other languages?
Clojure has loops as well:
(let [size 10] ;made up
(loop [max 2]
(if (or (= (/ max (Math/log max)) size)
(= max Integer/MAX_VALUE)
(= max 0))
max
(recur (* 2 max)
Konrad.
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Re: filter on sequence
You can use destructuring in your predicate's arg list: Not to hijack the thread but...is there some reason clojure doesn't just just call this pattern-matching? Is it different somehow? --~--~-~--~~~---~--~~ 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: filter on sequence
On Tue, Jun 2, 2009 at 5:35 PM, Wilson MacGyver wmacgy...@gmail.com wrote:
Apologies in advance on a very newbie question.
I've constructed a sequence
(take 10 (iterate (fn [[a b]] [(* 2 a) (/ a (Math/log a))]) [2 (/ 2
(Math/log 2))])
doing a take 10 on it, produce the pairs I expect.
what I like to know is, how do I filter for with value b is X
for example, the first 10 produces.
([2 2.8853900817779268] [4 2.8853900817779268] [8 2.8853900817779268]
[16 3.8471867757039027] [32 5.7707801635558535] [64 9.233248261689365]
[128 15.38874710281561] [256 26.380709319112476] [512
46.16624130844683] [1024 82.07331788168325])
what if I want to filter so I only get pairs for which the 2nd value
is 10. I couldn't figure out how to get
filter to work for pair values.
How about:
(take-while (fn [[a b]] ( b 10))
(iterate (fn [[a b]] [(* 2 a) (/ a (Math/log a))])
[2 (/ 2 (Math/log 2))]))
a 2nd question is more of general clojure idiom, in trying to covert
the following java
code from michaelg's java 1 presentation
private int calcSize(){
int max = 2;
while ((max/Math.log(max)) size
max Integer.MAX_VALUE max 0){
max *=2;
}
return max;
}
My first reaction was to do it using a sequence. Is this the clojure
idiomatic way to convert a
while loop from other languages?
I suppose it would depend on the loop, but yes, I think so.
--
Michael Wood esiot...@gmail.com
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Re: filter on sequence
ah, got it. thanks! On Tue, Jun 2, 2009 at 11:48 AM, Stephen C. Gilardi squee...@mac.com wrote: On Jun 2, 2009, at 11:35 AM, Wilson MacGyver wrote: what I like to know is, how do I filter for with value b is X You can use destructuring in your predicate's arg list: (filter (fn [[_ x]] ( x 10)) *1) In English, the function takes an argument which can be accessed sequentially. Destruture it such that its first two elements are named _ (a conventional name for I don't care) and x. Then the body of the predicate can operate on x. --Steve -- Omnem crede diem tibi diluxisse supremum. --~--~-~--~~~---~--~~ 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: filter on sequence
actually I had the exact same reaction. So I'd echo Andrew's comment. Is this different than pattern-matching in say haskell/scala? On Tue, Jun 2, 2009 at 11:55 AM, Andrew Wagner wagner.and...@gmail.com wrote: You can use destructuring in your predicate's arg list: Not to hijack the thread but...is there some reason clojure doesn't just just call this pattern-matching? Is it different somehow? -- Omnem crede diem tibi diluxisse supremum. --~--~-~--~~~---~--~~ 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: filter on sequence
Ditto what everyone else said, plus let's get rid of the duplicated
call to Math/log by splitting the iterate into an iterate + a map:
(take-while
(fn [[_ second]] ( second 10))
(map (fn [x] [x (/ x (Math/log x))])
(iterate #(* % 2) 2)))
Stu
On 02.06.2009, at 17:35, Wilson MacGyver wrote:
for example, the first 10 produces.
([2 2.8853900817779268] [4 2.8853900817779268] [8 2.8853900817779268]
[16 3.8471867757039027] [32 5.7707801635558535] [64
9.233248261689365]
[128 15.38874710281561] [256 26.380709319112476] [512
46.16624130844683] [1024 82.07331788168325])
what if I want to filter so I only get pairs for which the 2nd value
is 10. I couldn't figure out how to get
filter to work for pair values.
Try this:
(take 3
(filter #( (second %) 10)
(iterate (fn [[a b]] [(* 2 a) (/ a (Math/log a))])
[2 (/ 2 (Math/log 2))])))
If you try to take 10 values, you will create an endless loop because
with the given parameters your sequence actually has less than ten
elements that satisfy the condition!
a 2nd question is more of general clojure idiom, in trying to covert
the following java code from michaelg's java 1 presentation
private int calcSize(){
int max = 2;
while ((max/Math.log(max)) size
max Integer.MAX_VALUE max 0){
max *=2;
}
return max;
}
My first reaction was to do it using a sequence. Is this the clojure
idiomatic way to convert a while loop from other languages?
Clojure has loops as well:
(let [size 10] ;made up
(loop [max 2]
(if (or (= (/ max (Math/log max)) size)
(= max Integer/MAX_VALUE)
(= max 0))
max
(recur (* 2 max)
Konrad.
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Re: filter on sequence
I saw that clojure has loop. But in other functional languages, using loops are always discouraged. So I didn't know if loop was the clojure idiomatic way of doing this. On Tue, Jun 2, 2009 at 11:52 AM, Konrad Hinsen konrad.hin...@laposte.net wrote: My first reaction was to do it using a sequence. Is this the clojure idiomatic way to convert a while loop from other languages? Clojure has loops as well: (let [size 10] ;made up (loop [max 2] (if (or (= (/ max (Math/log max)) size) (= max Integer/MAX_VALUE) (= max 0)) max (recur (* 2 max) Konrad. -- Omnem crede diem tibi diluxisse supremum. --~--~-~--~~~---~--~~ 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: filter on sequence
On Tue, Jun 2, 2009 at 5:55 PM, Andrew Wagner wagner.and...@gmail.com wrote: You can use destructuring in your predicate's arg list: Not to hijack the thread but...is there some reason clojure doesn't just just call this pattern-matching? Is it different somehow? Why doesn't Ruby just call it destructuring like Lisp has been doing for decades? ;) (Actually I know next to nothing about Ruby and its pattern matching and not much more about Lisp.) -- Michael Wood esiot...@gmail.com --~--~-~--~~~---~--~~ 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: filter on sequence
On Tue, Jun 2, 2009 at 6:02 PM, Michael Wood esiot...@gmail.com wrote: On Tue, Jun 2, 2009 at 5:55 PM, Andrew Wagner wagner.and...@gmail.com wrote: You can use destructuring in your predicate's arg list: Not to hijack the thread but...is there some reason clojure doesn't just just call this pattern-matching? Is it different somehow? Why doesn't Ruby just call it destructuring like Lisp has been doing for decades? ;) (Actually I know next to nothing about Ruby and its pattern matching and not much more about Lisp.) Or was that Haskell? Sorry, I'll shut up now. -- Michael Wood esiot...@gmail.com --~--~-~--~~~---~--~~ 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: filter on sequence
Why doesn't Ruby just call it destructuring like Lisp has been doing for decades? ;) So that non-academics have a prayer at not getting scared away by an unnecessarily-technical name? --~--~-~--~~~---~--~~ 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: filter on sequence
On Jun 2, 2009, at 11:55 AM, Andrew Wagner wrote: Not to hijack the thread but...is there some reason clojure doesn't just just call this pattern-matching? Is it different somehow? This thread has some info on that: http://groups.google.com/group/clojure/browse_frm/thread/0aa57ab265f7474a/074428b031af70ac#074428b031af70ac (Rich Hickey's messages especially) --Steve smime.p7s Description: S/MIME cryptographic signature
Re: filter on sequence
On 02.06.2009, at 18:00, Wilson MacGyver wrote: actually I had the exact same reaction. So I'd echo Andrew's comment. Is this different than pattern-matching in say haskell/scala? The difference is that a pattern match can fail, and in that case other patterns are tried. Clojure's destructuring assumes that the value has the right structure. If it doesn't, then you will get an exception thrown. On 02.06.2009, at 18:02, Wilson MacGyver wrote: I saw that clojure has loop. But in other functional languages, using loops are always discouraged. So I didn't know if loop was the clojure idiomatic way of doing this. Loops in Clojure are purely functional. They are in fact equivalent to an embedded recursive function. Unlike the typical use of loops in, say, Java, nothing is changed inside a loop, so there are no side effects. Here's your example with the loop rewritten as an explicit recursive function: (let [size 10 loop-fn (fn [max] (if (or (= (/ max (Math/log max)) size) (= max Integer/MAX_VALUE) (= max 0)) max (recur (* 2 max] (loop-fn 2)) As you can see, the differences are cosmetic. There is no need to have a bad functional conscience for using loops! Konrad. --~--~-~--~~~---~--~~ 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: filter on sequence
I see. very clever. I'm not used to loop constructs with no side effect. On Tue, Jun 2, 2009 at 12:21 PM, Konrad Hinsen konrad.hin...@laposte.net wrote: I saw that clojure has loop. But in other functional languages, using loops are always discouraged. So I didn't know if loop was the clojure idiomatic way of doing this. Loops in Clojure are purely functional. They are in fact equivalent to an embedded recursive function. Unlike the typical use of loops in, say, Java, nothing is changed inside a loop, so there are no side effects. Here's your example with the loop rewritten as an explicit recursive function: (let [size 10 loop-fn (fn [max] (if (or (= (/ max (Math/log max)) size) (= max Integer/MAX_VALUE) (= max 0)) max (recur (* 2 max] (loop-fn 2)) As you can see, the differences are cosmetic. There is no need to have a bad functional conscience for using loops! Konrad. -- Omnem crede diem tibi diluxisse supremum. --~--~-~--~~~---~--~~ 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: You know you've been writing too much Clojure when...
people in math discussions raise their eyebrow at my new comma-less
tuple and set notation:
(a_1 a_2 ... a_n a_(n+1) .. ) in R^|N|
{1 2 3 4 5} = {a in N+ | a 6}
Haskel hated it that time I wrote:
fold:: (b a b) b [a]
or
sum x y zs = fold (+) 0 x:y:zs, where:
sum 1 2 3 4 5 6 7 = haskell compiler smacks yo momma.
And finally, in C, I caught this line before I tried to do anything
silly:
defmacro();
Cheers!
~max
On Jun 2, 11:27 am, Stuart Halloway stuart.hallo...@gmail.com wrote:
People keep looking at me funny when I point out variables as code
smells during code review...
Stu
Same here with the commas. Since I've been neck deep in Clojure, I've
been pathologically forgetting to add them with other languages.
On Jun 2, 10:06 am, Shawn Hoover shawn.hoo...@gmail.com wrote:
On Tue, Jun 2, 2009 at 9:52 AM, Michael Reid kid.me...@gmail.com
wrote:
On Fri, May 29, 2009 at 2:51 PM, Paul Stadig p...@stadig.name
wrote:
You meant to type disclosure, but instead you typed disclojure.
Paul
How about when you try to write code in other languages, and
reflexively place parentheses before function/method names?
(len 'Foo') -- not valid Python. :(
/mike.
Don't forget, commas are NOT optional!
irb(main) a = [1 2 3]
SyntaxError: compile error!
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Re: feature request: docstring for defstruct
it would conform to the clojure way. On Jun 2, 8:45 am, Sean Devlin francoisdev...@gmail.com wrote: This would encourage documenting structs, so I think this is a good idea. Sean On Jun 2, 11:31 am, Stuart Halloway stuart.hallo...@gmail.com wrote: I would like to see defstruct take an optional docstring. Would such a patch be welcome? Stu --~--~-~--~~~---~--~~ 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: You know you've been writing too much Clojure when...
I now write all my Java code without any types... and then realize I have to go back and add them in later. --~--~-~--~~~---~--~~ 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: filter on sequence
Wilson MacGyver wmacgy...@gmail.com writes: Hi Wilson, I saw that clojure has loop. But in other functional languages, using loops are always discouraged. So I didn't know if loop was the clojure idiomatic way of doing this. Clojure's `loop' (with `recur') is no real loop in an imperative sense. It's a form of (non-mutual) recursion optimized to be space efficient on the JVM which lacks tail call optimization. Using it is perfectly idiomatic, although it's not the way to go for each and every problem. Bye, Tassilo --~--~-~--~~~---~--~~ 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 would I do this functionally? (internally mutable state)
As mentioned before, most file systems have the ability of providing callback to changes in files/directories, at SE 6 using this ability requires resorting to native code (JNA or JNI, see http://jnotify.sourceforge.net/) , in SE 7 this will be implemented in NIO 2 (http://java.sun.com/ developer/technicalArticles/javase/nio/). I would look into rsync, as far as i know it implements a very efficient algorithm for comparing folders, there is a Java implementation http://jarsync.sourceforge.net/ On May 29, 4:09 pm, Korny Sietsma ko...@sietsma.com wrote: I keep reading this thread when I should be going to bed :) Sadly, this stuff is in what I call my 0.2% time so I'm not working very hard on it right now. The ruby code, which basically works (but is rather ugly in parts) relies on reading the whole file tree into memory, and then traversing the tree, saving each node (file or dir) in a repostory, which internally detects duplicates as they are added. The repository stores all known nodes, indexed by size, and then grouped into clumps of identical nodes. When you add a new node, it compares it to all clumps of the same size as the node, looking for an identical clump; if it finds one, the new node is added to the clump, otherwise it forms a new clump. (sorry if this is a bit of a vague description, I haven't worked on this code for a while so all the details are a bit vague) Once the repository is built, it's pretty easy to throw away all non-duplicate nodes, and report on the duplicates. This works, but has some issues: - it's got some kind-of ugly handling for some special cases, like making sure a directory doesn't match it's own children if it only has one child - it's a bit slow, and uses a lot of memory - it *only* handles exact matches. I've been playing with shingling and sketching algorithms that are used by search engines to identify nearly-identical documents, and I think they could be applied to this problem; in fact I suspect they could speed it up considerably. (If you want to know more about this the best reference online seems to be the book Introduction to Information Retrieval which is athttp://www-csli.stanford.edu/~hinrich/information-retrieval-book.html - the chapter most relevant is athttp://nlp.stanford.edu/IR-book/html/htmledition/near-duplicates-and-... ) But, like I said, this is my 0.2% time project, so it might be some time before I really do more than think about this. :) - Korny On Fri, May 29, 2009 at 4:51 PM, Daniel Lyons fus...@storytotell.org wrote: For whatever reason I just can't seem to put this problem down. I have rewritten the code substantially. A major bottleneck was using Java's MD5 classes. The Fast MD5 library really is, and that helped a lot. I did get the - notation to work and I have a reasonable HOF now for doing the winnowing, which might even be applicable to another program someday, maybe. Anyway I uploaded it here: http://clojure.googlegroups.com/web/dupfinder.clj and again I'd love any feedback anyone cares to give. Just to add insult to injury, I went ahead and programmed it again in Ruby. The good news is that I can't seem to get Ruby to find all the files the Clojure one finds, but the bad news is that the Ruby version is like four times faster. I'd love to understand that. So I uploaded that too: http://clojure.googlegroups.com/web/dupfinder.rb. Of course it must be benefiting to some extent from the fact that the Ruby version has a lot less abstraction, but I don't see how the approach is fundamentally any different or why there would be such a large performance disparity. I must be missing something big. On May 28, 2009, at 6:50 AM, Korny Sietsma wrote: By the way, in response to whoever suggested pre-sorting files; I sort-of do this (in the old ruby version) but actually, mostly the program is looking for duplicate *directories* of files - the goal is to point it at my archive disk, and have it find the biggest identical subdirectories. Duplicate file checking is needed for this, but it's only a tiny part. And I'm playing with sketching algorithms at work right now, which look very handy for the next phase, which is to find the biggest *similar* subdirectories. That's the real goal - point a program at a terabyte archive disk, and have it spit out : /archive/old_disks/laptop_2007a is 312gb and 99% similar to /archive/misc/stuff_from_2007 ... or sorting by file count: /archive/source/old_projects/c_stuff/1996 is 20,324 files and 97% similar to /archive/old/disks/laptop2006/unsorted/old_drives/ old_archive/c_cpp_stuff/90s I can think of three ways to approach this, none of which are particularly easy. The first is to take the duplicate file finding function and look for common suffixes of paths. It could almost be like running a fuzzy duplicate finder against your duplicates. I suspect the performance
swing-utils: patch - returning the listeners
May I suggest a small change in the add-*-listener functions in contrib.swing-utils? It's handy to have them return the listeners (and be able to disable/remove them later etc). Patch attached. -Roland -- [ http://www.haltingproblem.net/ - my homepage ] --~--~-~--~~~---~--~~ 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 -~--~~~~--~~--~--~--- swing_utils_patch.diff Description: Binary data
Re: swing-utils: patch - returning the listeners
On Jun 2, 2009, at 7:31 PM, Roland Sadowski wrote: May I suggest a small change in the add-*-listener functions in contrib.swing-utils? It's handy to have them return the listeners (and be able to disable/remove them later etc). Patch attached. Nice change, Roland. I see that you're on the list at clojure.org/ contributing . Patch applied. Thanks! --Steve smime.p7s Description: S/MIME cryptographic signature
Re: Good examples of defmulti polymorphism
Some work in which I'm currently engaged uses ad hoc hierarchies for dispatching on a handler and either a message method or a method and response code. In the realm of HTTP clients -- imagine that the response arrives as a method invocation -- the equivalent would be writing something like (defmethod do-response [MyHandler :post :ok] ;; Handle a success response to my POST request ) (defmethod do-response [MyHandler :any-method :failure] ;; Handle any kind of failure response to any method (GET, POST, PUT...). ) The dispatch function can introspect the message itself to extract the method, code, etc. etc. -- this is basically polymorphism over any facet of the arguments, with full programmatic power to extract those facets. Most importantly, applications can themselves augment the hierarchy to include meaningful groupings -- in my example above, the various methods all derive from :any-method, and you could easily imagine a server having a :methods-i-cant-handle node in its hierarchy, making that piece of logic explicit in the tree. This example doesn't look that compelling, except that my real domain has a rich hierarchy of message and response types, which allows a great deal of abstraction in message handling. (I hope one day to be able to unveil what I'm doing. It's not that innovative, but it's not done yet!) --~--~-~--~~~---~--~~ 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: filter on sequence
Not to hijack the thread but...is there some reason clojure doesn't just just call this pattern-matching? Is it different somehow? I guess the simplest answer is because it's destructuring, not pattern-matching :) As Rich explained in the thread to which Stephen linked, pattern matching (at least as I know it in Erlang) is usually used primarily for dispatch -- a structure-analyzing switch, basically. Clojure's destructuring is a logical extension of Common Lisp's destructuring-bind, which takes an input list and binds variables to parts of the list. Clojure's destructuring does exactly what its name implies: it takes some structure and de-structures it into its constituents. The pattern matching that Clojure does is just to correctly map the matching structure (and its variables) against the input. It's not used to match as part of a switch. --~--~-~--~~~---~--~~ 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: You know you've been writing too much Clojure when...
I now write all my Java code without any types... and then realize I have to go back and add them in later. Heh, very often I allow the IDE to fill them in, because I'm too lazy to type that much! --~--~-~--~~~---~--~~ 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: filter on sequence
On Jun 2, 7:55 am, Andrew Wagner wagner.and...@gmail.com wrote: You can use destructuring in your predicate's arg list: Not to hijack the thread but...is there some reason clojure doesn't just just call this pattern-matching? Is it different somehow? Pattern matching matches not only structure but also values. For example foo 5 = 0 foo 7 = 1 foo x = x * 2 --~--~-~--~~~---~--~~ 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: Good examples of defmulti polymorphism
Some good examples from everyone. Thank you. 2009/6/3 Richard Newman holyg...@gmail.com Some work in which I'm currently engaged uses ad hoc hierarchies for dispatching on a handler and either a message method or a method and response code. In the realm of HTTP clients -- imagine that the response arrives as a method invocation -- the equivalent would be writing something like (defmethod do-response [MyHandler :post :ok] ;; Handle a success response to my POST request ) (defmethod do-response [MyHandler :any-method :failure] ;; Handle any kind of failure response to any method (GET, POST, PUT...). ) The dispatch function can introspect the message itself to extract the method, code, etc. etc. -- this is basically polymorphism over any facet of the arguments, with full programmatic power to extract those facets. Most importantly, applications can themselves augment the hierarchy to include meaningful groupings -- in my example above, the various methods all derive from :any-method, and you could easily imagine a server having a :methods-i-cant-handle node in its hierarchy, making that piece of logic explicit in the tree. This example doesn't look that compelling, except that my real domain has a rich hierarchy of message and response types, which allows a great deal of abstraction in message handling. (I hope one day to be able to unveil what I'm doing. It's not that innovative, but it's not done yet!) --~--~-~--~~~---~--~~ 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 -~--~~~~--~~--~--~---
unit testing private methods?
I have a namespace with some public functions, and some private functions. I would like to write unit tests for the functions, and put them in a separate file from the main name space. I would also like to have an (ns) declaration in my tests file, because the tests require several libraries. Of course, if I have private methods in namespace A, I can't call them from namespace B. Right now, it seems I have several options: 1) put the unit tests in the same file 2) put the unit tests in a separate file, in the same namespace 3) make the private functions public 4) ??? I don't really like the first three options. Ideally, the private functions would remain private to every namespace except the testing name space. Is there a good solution for this? Allen --~--~-~--~~~---~--~~ 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: unit testing private methods?
Hi Allen, You could write a function that uses the clojure.contrib.with-ns/with- ns macro to dip into the namespace being tested and return the private function, assigning it to a local name in the test namespace. I need this too, and have been meaning to ping the other Stuart about either (a) adding something like this to test-is, or (b) creating a new test-helpers library in contrib that would include this function. Stu I have a namespace with some public functions, and some private functions. I would like to write unit tests for the functions, and put them in a separate file from the main name space. I would also like to have an (ns) declaration in my tests file, because the tests require several libraries. Of course, if I have private methods in namespace A, I can't call them from namespace B. Right now, it seems I have several options: 1) put the unit tests in the same file 2) put the unit tests in a separate file, in the same namespace 3) make the private functions public 4) ??? I don't really like the first three options. Ideally, the private functions would remain private to every namespace except the testing name space. Is there a good solution for this? Allen --~--~-~--~~~---~--~~ 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 -~--~~~~--~~--~--~---
subtractng sequence?
More newbie questions. :) If I have two sequences as follow: (2 3 4 5 6 7 8 9 10) (4 6 8 10) what's the best way to subtract the 2nd sequence from the first one? The best I can come up with was to do (first) on 2nd sequence and turn around and do a (remove) on the first sequence, etc until I exhaust the 2nd sequence. is there a better way? Thanks, -- Omnem crede diem tibi diluxisse supremum. --~--~-~--~~~---~--~~ 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: Good examples of defmulti polymorphism
Actually considering I'm currently writing a game in clojure that contains a
lot of state this _is_ a good real world example for me. Thanks very much
Laurent.
2009/6/3 Laurent PETIT laurent.pe...@gmail.com
Hi,
Here is an example of the implementation of the Visitor design
pattern in clojure.
Multimethods are sufficiently powerfull and there is nothing explictly
named xxVisitor in the code example, since with clojure the Visitor
pattern is a non-issue and solved by the more general multimethod
concept.
Find the code in the files section of clojure google group :
http://clojure.googlegroups.com/web/state.clj
And find here an example of using the code :
1:6 designpatterns.state= (- (create-photo-booth 3) insert-coin
button-identity-photo insert-coin button-release-coin)
Insert coin
Select your photo
Take your identity photo
Select your photo
liberer piece
{:photos 2, :state :needs-coin}
1:7 designpatterns.state=
It's more a tutorial-like example than a real life example, but I
hope it will help,
Regards,
--
Laurent
2009/6/2 Glen Stampoultzis gst...@gmail.com:
I'm used to polymorphism in OO systems where everything in driven from
inheritance hierarchy. Clojures defmulti style polymorphism seems
powerful
but has left me wondering how to most effectively use it. I'm looking
for
some good real world examples of how people have used polymorphism in
clojure.
Regards,
Glen Stampoultzis
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Re: subtractng sequence?
Wilson MacGyver a écrit :
More newbie questions. :)
If I have two sequences as follow:
(2 3 4 5 6 7 8 9 10)
(4 6 8 10)
what's the best way to subtract the 2nd sequence from the first one?
Is the order of the second sequence important? If not:
(defn subtract [a b]
(remove (into #{} b) a)) ; turns b into a set for efficient
(logarithmic) lookup
; user= (subtract [2 3 4 5 6 7 8 9 10] [4 6 8 10])
; (2 3 5 7 9)
It works well as long as you don't have nil or false values in the
second seq (in such cases you'll have to use 'contains?).
Christophe
--
Professional: http://cgrand.net/ (fr)
On Clojure: http://clj-me.blogspot.com/ (en)
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