Re: (finally) got all class signature changes w/gen-class reloading at runtime
Hi George,
That's correct. I briefly mention the JVM's standard hot swapping
capabilities when running in debug mode. Unfortunately this hot
swapping is mostly limited to changing method bodies and not class
signatures (add/remove method, etc).
Normally this is not even a problem because - as you mentioned -
Clojure compiles _new_ classes on the fly, and these can be loaded
fine. The problem is limited to gen-class development when stub
classes are generated. During interactive development you'll probably
be adding/removing methods or otherwise changing the class signature.
This is a problem because the stub was already generated the first
time you called (compile) and loaded. Subsequent compiles - which
include the class sig changes - don't get reloaded due to JVM
limitations. This specific issue is solved via JRebel.
Rob
On Thu, Feb 10, 2011 at 12:21 AM, George Jahad
cloj...@blackbirdsystems.net wrote:
I studied it a bit more and noticed that the jdi redefineClasses
method can't add new methods, (as you imply in your blog.) That's
what's special about what JRebel offers.
The redefineClasses method is described here:
http://download.oracle.com/javase/6/docs/jdk/api/jpda/jdi/com/sun/jdi/VirtualMachine.html#redefineClasses(java.util.Map)
On Feb 9, 12:38 pm, George Jahad cloj...@blackbirdsystems.net wrote:
so i think most java debuggers, even jdb, are capable of reloading
classes aren't they?
i haven't tried your example, but in the cdt, you use
the .redefineClasses method to reload a java class
For example, I can hack on one of the classes in clojure compiler and
reload it, without restarting, like so:
(.redefineClasses
(vm)
{(first (find-classes #clojure.lang.Compiler\$DefExpr\$Parser))
(to-byte-array
(java.io.File.
/Users/georgejahad/incoming/clojure/classes/clojure/lang/Compiler
$DefExpr$Parser.class))})
is that what you are talking about, or am i missing something?
On Feb 9, 12:49 am, Robert Campbell rrc...@gmail.com wrote:
Back in January I found myself writing some gen-class to connect my
Clojure library to my Java project. Until now I'd been spoiled by
Clojure's dynamic, interactive nature, so running up against the whole
stub class signature can't change w/out jvm reboot thing hurt a bit.
I found a partial solution via JRebel, but it only worked with
invocations lacking type information and compiled to use reflection.
It failed on any invocation with enough type information present in
the sexpr to use invokevirtual. I actually met Jevgeni (CTO of ZT)
last week and he mentioned he might have some of their guys take a
look at the problem. Lo and behold, their latest nightly build fixes
the issue and it now seems that everything is working.
Here's how to set it up:http://blog.robert-campbell.com/post/2760935713
The company behind JRebel, ZeroTurnaround, gives out free licenses to
OSS and Scala developers. When I spoke with Jevgeni he seemed open to
the idea of adding Clojure development to that list provided there was
enough demand. While gen-class is a relatively rare/minor part of most
Clojure development, I think this tool allows us to smooth out one
rough patch in the dev experience.
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(finally) got all class signature changes w/gen-class reloading at runtime
Back in January I found myself writing some gen-class to connect my Clojure library to my Java project. Until now I'd been spoiled by Clojure's dynamic, interactive nature, so running up against the whole stub class signature can't change w/out jvm reboot thing hurt a bit. I found a partial solution via JRebel, but it only worked with invocations lacking type information and compiled to use reflection. It failed on any invocation with enough type information present in the sexpr to use invokevirtual. I actually met Jevgeni (CTO of ZT) last week and he mentioned he might have some of their guys take a look at the problem. Lo and behold, their latest nightly build fixes the issue and it now seems that everything is working. Here's how to set it up: http://blog.robert-campbell.com/post/2760935713 The company behind JRebel, ZeroTurnaround, gives out free licenses to OSS and Scala developers. When I spoke with Jevgeni he seemed open to the idea of adding Clojure development to that list provided there was enough demand. While gen-class is a relatively rare/minor part of most Clojure development, I think this tool allows us to smooth out one rough patch in the dev experience. -- 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/JVM languages internal presentation
Hi Shantanu, Good questions. Can you share some details about the language selection process? Was it based on developers consensus or it was a purely management decision? Was the presence or absence of enough number of Clojure/Scala experts in the team influential on the eventual decision? This was completely developer driven; management was mildly resistant to the idea from the beginning. I made my case for Clojure to the other tech/team leads and we all agreed to allow it on a case by case basis. Once the development organization was in agreement, it was run by management who pushed back due to staffing concerns. I negotiated a compromise (Scala) which (mostly) alleviated the staffing concern, but maintained many of the same benefits. This negotiation is partly reflected in the language selection slides, where number of books/training, developer acceptance/momentum, syntax were all used as selection criteria. To help me understand, would you like to share how was this conclusion derived (Clojure - being a Lisp dialect - has a steeper learning curve due to its syntax and more purely functional nature.)? When I show a typical Java developer some Clojure code, they immediately have to swim across two rivers: S expressions and functional concepts. We can agree that taking the plunge is incredibly rewarding, but we shouldn't deny that they present real obstacles to many developers. In contrast, when I show them some imperative-style Scala, they can immediately recognize syntax and patterns already familiar to them. This allows them to get up and running quickly, dipping their toe into functional concepts at their own rate. I do, however, agree that Clojure is simpler to use once you've crossed those rivers, helped deeply by its smaller, more consistent syntax. Clojure and Scala are both great languages that provide concrete improvements over vanilla Java. With this presentation I try to highlight two of those improvements that I found most compelling. Rob On Tue, Jan 18, 2011 at 7:21 PM, Shantanu Kumar kumar.shant...@gmail.com wrote: Rob, thanks for sharing this and congratulations on having IDC (your employer IIUC) adopting an alternate JVM language. Can you share some details about the language selection process? Was it based on developers consensus or it was a purely management decision? Was the presence or absence of enough number of Clojure/Scala experts in the team influential on the eventual decision? Finally, from your notes on slide #25: Clojure - being a Lisp dialect - has a steeper learning curve due to its syntax and more purely functional nature. Since Scala is instead a hybrid language, both object oriented and functional, it’s completely possible to write imperative, Java-style Scala. This allows developers to slowly ease into the language, adding more powerful functional techniques as they become more comfortable. So when management asks, “Where am I gonna find Scala programmers?”, we can answer, “The same places you find Java programmers: throughout IDC and the greater market,” almost honestly... To help me understand, would you like to share how was this conclusion derived (Clojure - being a Lisp dialect - has a steeper learning curve due to its syntax and more purely functional nature.)? Scala has more syntax/semantics than Clojure AFAICT. Was it familiarity with the Java syntax? Regards, Shantanu On Jan 18, 4:33 am, Robert Campbell rrc...@gmail.com wrote: Hey guys, This past summer I gave a presentation on JVM langauges at our company's worldwide developer summit. I tried to get approval for Clojure but had to settle for Scala because its syntax didn't frighten management. I figured I'd share it in case any of the slides can be of use elsewhere. open in browser (no notes):http://public.iwork.com/document/?d=JVM_Languages.keya=p1045023190 src:https://github.com/rcampbell/jvm-languages The talk (w/notes in github .key file) was very important and the slides don't make much sense without it, but it generally went like: -Topic is JVM languages, what they are, why we should care about them -We (as a mostly Java house) have two big problems: bloat and concurrency -Show bloat with examples, try to illustrate a trend -Why are these other languages so concise? -Go back over the examples pulling out a single language feature from each (in bold), explain how it leads to more concise code -Talk a bit about concurrency, No free lunch (R), Ghz wall, cores increasing -Java's answer to concurrency is difficult to work with -Make a token effort to select a JVM language based on books, perceived momentum/maturity/community, etc -Select Clojure and Scala, end with Scala example since that's the one that was approved (replace slide here :-) Rob -- 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
Clojure/JVM languages internal presentation
Hey guys, This past summer I gave a presentation on JVM langauges at our company's worldwide developer summit. I tried to get approval for Clojure but had to settle for Scala because its syntax didn't frighten management. I figured I'd share it in case any of the slides can be of use elsewhere. open in browser (no notes): http://public.iwork.com/document/?d=JVM_Languages.keya=p1045023190 src: https://github.com/rcampbell/jvm-languages The talk (w/notes in github .key file) was very important and the slides don't make much sense without it, but it generally went like: -Topic is JVM languages, what they are, why we should care about them -We (as a mostly Java house) have two big problems: bloat and concurrency -Show bloat with examples, try to illustrate a trend -Why are these other languages so concise? -Go back over the examples pulling out a single language feature from each (in bold), explain how it leads to more concise code -Talk a bit about concurrency, No free lunch (R), Ghz wall, cores increasing -Java's answer to concurrency is difficult to work with -Make a token effort to select a JVM language based on books, perceived momentum/maturity/community, etc -Select Clojure and Scala, end with Scala example since that's the one that was approved (replace slide here :-) Rob -- 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
Why does (.foo (new Bar)) use a different method invocation mechanism than (def bar (new Bar)) (.foo bar)?
I've been trying to understand exactly how these two statements are evaluated by tracing execution through Compiler.java, Reflector.java, etc of tag 1.2.0. The second form - (.foo bar), expanded to (. bar foo) - eventually calls Reflector.invokeNoArgInstanceMember. The first form - (.foo (new Bar)), expanded to (. (new Bar) foo) - doesn't seem to use any Reflector _invocation_ methods. I also added a breakpoint to java.lang.reflect.Method.invoke() and it never hits that breakpoint. It seems that Reflector.getMethods is actually used to resolve Methods for placement in the object expression ObjExpr fexpr on line 5421 of Compiler.java. After that poing I'm unable to trace where the actual invocation takes place. I am trying to understand how the first form gets evaluated because I have a case where JRebel instrumentation causes this to work: (def bar (new foo.core.Bar)) #'user/bar (.sayAhoj bar) Ahoj! but this to fail: (.sayAhoj (new foo.core.Bar)) java.lang.NoSuchMethodError: foo.core.Bar.sayAhojLjava/lang/String; (NO_SOURCE_FILE:0) even though the method appears in the stub and can be invoked fine via reflection. More information here: http://blog.robert-campbell.com/post/2760935713/clojures-gen-class-and-jrebel -- 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: Slides for short (45 minutes) presentation of clojure for java devs
I'd like to resurrect this thread, because I have the exact same requirement Laurent had and I'm hoping there's been some additional progress in this area. I'm set to give a Clojure presentation to our company's Java developers, and I'm looking for a way to excite the audience about FP concepts in general and Clojure in particular. This audience will only care about one thing: how does this improve productivity / help do our job better? Thoughts? What convinced you? On Sat, Apr 24, 2010 at 1:54 AM, Laurent PETIT laurent.pe...@gmail.com wrote: Thanks for the food for thought. I'm concerned with the short introduction not being too much goal oriented (and more tutorial oriented), I'll continue think about it in background mode. Cheers, -- Laurent 2010/4/23 cburroughs chris.burrou...@gmail.com: What I did when I needed to give a shorter talk was to base it on some of the well known presentations and just cut out a lot. I don't think Stuart's intro or Rich's for Java people talk assumes people are already enthusiastic about functional programming. [1] http://github.com/stuarthalloway/clojure-presentations/ or those attached to the file section On Apr 21, 8:14 am, Laurent PETIT laurent.pe...@gmail.com wrote: Hello, I've consulted a lot of already made presentations of clojure. They are great, but I guess they may not suit my needs because it seems to me that either: * they are more 1 1/2 to 2 hours talks than 45 minutes * they assume the public will not be relunctant to some terms like Lisp, Functional Programming and directly present these as advantages My goal is to raise interest into clojure in the mind of a public of people having used java for a long time. They may have Scala already in their radar, but not clojure, or may have seen it and immediately dismissed it for what seemed to them good reasons (mainly aversion for lisp syntax), though we all know this is not true after the normal adaptation period. Say this presentation could be the presentation that leads people, at its end, asking you for giving all those great other presentations already available that I mentioned before ... Any references I missed that already solve my problem ? :-) Thanks in advance, -- Laurent -- 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: The % Schemer Series - are they worth the money?
I love the Little/Seasoned Schemer books. They feel lightweight, both physically and in content, and I managed to work through them fairly quickly. It was surprisingly fun. SICP/HTDP/PAIP, on the other hand, have more of the textbook feel which has so far kept me from working through them. The only thing that's kind of bitten me in the ass is that when I started Clojure, I wrote a lot lower level fns, in the style of the book. By this I mean lots of explicit recursion with cons cells, accumulators, etc. when in fact there were already much higher level constructs (map/reduce/filter/etc) I should have been using. Still, you quickly learn, and it's nice knowing the plumbing. Rob On Tue, Mar 23, 2010 at 6:45 PM, cody koeninger c...@koeninger.org wrote: On Mar 23, 10:37 am, Sean Devlin francoisdev...@gmail.com wrote: Hey folks, I'm looking to add to my bookshelf. I was wondering what this groups experience with the Schemer series of books is? Sean Little, seasoned, + the little MLer are awesome, only thing that comes close in terms of pedagogical quality is How To Design Programs. Haven't read reasoned. A little java isn't that great, that style doesn't really mesh well with java. The little schemer may be very basic, but given some of the job applicants I've seen, we'd all be better off if every programmer had read it at least once. -- 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 To unsubscribe from this group, send email to clojure+unsubscribegooglegroups.com or reply to this email with the words REMOVE ME as the subject. -- 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 To unsubscribe from this group, send email to clojure+unsubscribegooglegroups.com or reply to this email with the words REMOVE ME as the subject.
Re: iterator-seq runs over
Hi Stuart, That fixes the problem, thank you. When I ran the result-set through (type), it showed me that the instance was actually a ResultSetStream. While the Jena ResultSet interface doesn't act as a closable resource, perhaps the stream was being closed once the owning QueryExecution obj was closed via with-open. Rob On Tue, Feb 16, 2010 at 9:55 AM, Stuart Halloway stuart.hallo...@gmail.com wrote: Hi Rob, map is lazy, count and butlast are not lazy. Does adding a doall around your call to map fix this problem? Stu (map handler (iterator-seq result-set)) always throws a NoSuchElementException (map handler (butlast (iterator-seq result-set))) always works. (count (iterator-seq result-set)) is returning the correct number of elements. Calls to first, second, nth, also work correctly. When I manually test a result-set of three elements, [(handler (.next result-set)) (handler (.next result-set)) (handler (.next result-set))] evaluates correctly, while adding one more .next call results in the same NoSuchElementException. Using butlast fixes the problem, but then I obviously lose the last element in the result set. This code is replacing vanilla Java code which used .hasNext() and .next() without problem for a couple of months, so I doubt it's the class (com.hp.hpl.jena.query.ResultSet) incorrectly implementing Iterator. Has anyone else seen this type of behavior? Rob -- 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: Leaning about VM's, JVM in particular
Some good books that we recommend to get you on your way [to understanding the JVM/runtime] are: Java Reflection in Action by Ira R. Forman and Nate Forman. The Java Virtual Machine Specification 2nd edition by Tim Lindholm. Effective Java 2nd edition and Java Puzzlers by Joshua Bloch. And Inside The Java Virtual Machine 2nd edition by Bill Venners. - The Joy of Clojure, by Michael Fogus and Chris Houser who are both active on IRC and this mailing list. http://www.manning.com/fogus/ On Tue, Feb 16, 2010 at 5:29 PM, Andrey Fedorov anfedo...@gmail.com wrote: Hi all, I'm looking for approaches to learn about VM's, the JVM in particular. I noticed some local university courses use Virtual Machines (Smith, Nair) [1]. I'm planning on getting it, but would rather query you guys for opinions first, and recommendations on other books/resources? Cheers, Andrey 1. http://www.amazon.com/gp/product/1558609105/ -- 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
iterator-seq runs over
(map handler (iterator-seq result-set)) always throws a NoSuchElementException (map handler (butlast (iterator-seq result-set))) always works. (count (iterator-seq result-set)) is returning the correct number of elements. Calls to first, second, nth, also work correctly. When I manually test a result-set of three elements, [(handler (.next result-set)) (handler (.next result-set)) (handler (.next result-set))] evaluates correctly, while adding one more .next call results in the same NoSuchElementException. Using butlast fixes the problem, but then I obviously lose the last element in the result set. This code is replacing vanilla Java code which used .hasNext() and .next() without problem for a couple of months, so I doubt it's the class (com.hp.hpl.jena.query.ResultSet) incorrectly implementing Iterator. Has anyone else seen this type of behavior? Rob -- 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
Cartesian product of map pairs w/labels
Imagine a map m {
foo [1 2 3 4]
bar [\a \b \c]
baz [true false]
}
How could I transform that into a seq s (
{foo 1 bar \a baz true}
{foo 1 bar \a baz false}
{foo 1 bar \b baz true}
{foo 1 bar \b baz false}
{foo 1 bar \c baz true}
{foo 1 bar \c baz false}
{foo 2 bar \a baz true}
...
)
I've made a macro to expand the map over a for:
(defmacro cartesian-map [m]
`(for ~(vec (reduce #(concat %1 %2) (map #(identity [(symbol %)
(list 'coordinates %)]) (keys coordinates
~(apply hash-map (flatten (map #(identity [% (symbol %)]) (keys
coordinates))
and expands correctly:
(clojure.core/for [foo (coordinates foo) bar (coordinates bar) baz
(coordinates baz)] {foo foo, bar bar, baz baz})
but when I run it, I only get (), which doesn't make any sense because
if I run the expansion against the map m, it performs correctly.
Why would the macro expand correctly, but no run correctly in the
REPL? Also, are there any ways to simplify my macro?
Rob
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Re: Dutch Clojure users
I'm only 1.5hr flight away in Prague. I'd be happy to host any Clojure users to trade notes over our famous beer. On Sat, Feb 6, 2010 at 12:26 PM, Joop Kiefte iko...@gmail.com wrote: Hello folks! I am from the Netherlands and I am learning Clojure now, using it at work, and loving it so far. Are there any more dutch Clojure programmers on this list so we can meet? I am also interested to know about Clojure-programmers from any country in a reasonable distance from Strasbourg. Joop Kiefte -- Communication is essential. So we need decent tools when communication is lacking, when language capability is hard to acquire... - http://esperanto.net - http://esperanto-jongeren.nl Linux-user #496644 (http://counter.li.org) - first touch of linux in 2004 -- 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: Cartesian product of map pairs w/labels
Hi Michał,
That works perfectly and is much simpler, thank you.
On Sun, Feb 7, 2010 at 4:23 PM, Michał Marczyk michal.marc...@gmail.com wrote:
Ouch, sorry, I misread your specs... Use this instead:
(map #(zipmap (keys coordinates) %)
(apply cartesian-product (vals coordinates)))
With coordinates bound to your example map, this produces
({baz true, bar \a, foo 1}
{baz false, bar \a, foo 1}
...)
(which is your example output with the keys ordered differently in the
small maps).
Sincerely,
Michał
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Re: Clojure + Redis
I think anything which lowers the impedance mismatch between Clojure data structures and a persistent store is worth investigating. I'd love to find an ACID, transactional store which accepts native structures. Right now I'm using CouchDB, and while JSON is close enough, it still requires a mapping between the Clojure and Couch worlds. Not supporting set, and not allowing fields with dashes (JavaScript thinks it's a minus) are some of the annoyances. On Wed, Dec 30, 2009 at 12:52 PM, Gabi bugspy...@gmail.com wrote: On first look, Redis and Clojure seems to be a perfect match. They both handle sets and maps efficiently. If one could find an easy way to store and retrieve Clojure data structures to Redis (even a small subset- just a list or a set), a distributed clojure app could be very easy (and effective?) thing to do - The stateless Clojure nodes would share and operate on the same central data structure which is stored in Redis). What do you thing ? Is it worth investigating further? -- 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: Help with my vec matching function
Thanks ajuc.
I updated the implementation to match your algorithm:
(defn closest-match
Searches the haystack vecs for the closest match to the needle vec
[#^IPersistentVector needle #^IPersistentVector haystack]
(letfn [(matching [candidate]
(reduce + (map #(if (= %1 %2) 1 0) needle candidate)))
(closest [v1 v2]
(if (or ( (matching v1) (matching v2))
(and (= (matching v1) (matching v2))
( (count v1) (count v2 v1 v2))]
(reduce #(closest %1 %2) [] haystack)))
It now factors in the second step, taking the shortest candidate.
(closest-match [1 2 3] #{[1 2 3] [9 8 3] [1 2] [1] [1 0 3 4] [1 2 3 4 5]})
now correctly returns [1 2 3] instead of [1 2 3 4 5]
On Mon, Dec 28, 2009 at 4:23 PM, ajuc aju...@gmail.com wrote:
I don't know if I understan correctly the requirements, but this is my
try.
(def v #{[1 2 3] [9 8 3] [1 2] [1] [1 0 3 4] [1 2 3 4 5]} )
(defn matching [p v]
(reduce + (map #(if (= %1 %2) 1 0) p v)))
(defn better-match [p v1 v2]
(if
(or
( (matching p v1) (matching p v2))
(and
(= (matching p v1) (matching p v2)) ( (count v1) (count
v2
v1
v2))
(reduce #(better-match [1 2 4 4 5] %1 %2) [] v)
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Re: Help with my vec matching function
How might I add a third and final condition, where those candidates
with equal scores AND equal counts are all returned together?
A first try was this:
(defn closest-match
Searches the haystack vecs for the closest match to the needle vec
[#^IPersistentVector needle #^IPersistentVector haystack]
(letfn [(matching [candidate]
(reduce + (map #(if (= %1 %2) 1 0) needle candidate)))
(closest [v1 v2]
(cond
(and (= (matching v1) (matching v2))
(= (count v1) (count v2))) [v1 v2]
(or ( (matching v1) (matching v2))
(and (= (matching v1) (matching v2))
( (count v1) (count v2 v1
:else v2))]
(reduce #(closest %1 %2) [] haystack)))
(closest-match [1 2] #{[1 2 \a] [1 2 \b] [2 1]})
[[1 2 \b] [1 2 \a]]
(closest-match [1 2] #{[1 2] [1 2 \a] [1 2 \b] [2 1]})
[1 2]
It looks good at first, but I quickly noticed that I broke the whole
reduction by introducing a pair where we expend only a vec:
(closest-match [1 2] #{[1 2 \a] [1 2 \b] [2 1] [1 2 \c]})
[1 2 \a]
What we should be getting [[1 2 \a] [1 2 \b] [1 2 \c]] since each of
them is equally close to [1 2 3]
On Mon, Dec 28, 2009 at 5:20 PM, Robert Campbell rrc...@gmail.com wrote:
Thanks ajuc.
I updated the implementation to match your algorithm:
(defn closest-match
Searches the haystack vecs for the closest match to the needle vec
[#^IPersistentVector needle #^IPersistentVector haystack]
(letfn [(matching [candidate]
(reduce + (map #(if (= %1 %2) 1 0) needle candidate)))
(closest [v1 v2]
(if (or ( (matching v1) (matching v2))
(and (= (matching v1) (matching v2))
( (count v1) (count v2 v1 v2))]
(reduce #(closest %1 %2) [] haystack)))
It now factors in the second step, taking the shortest candidate.
(closest-match [1 2 3] #{[1 2 3] [9 8 3] [1 2] [1] [1 0 3 4] [1 2 3 4 5]})
now correctly returns [1 2 3] instead of [1 2 3 4 5]
On Mon, Dec 28, 2009 at 4:23 PM, ajuc aju...@gmail.com wrote:
I don't know if I understan correctly the requirements, but this is my
try.
(def v #{[1 2 3] [9 8 3] [1 2] [1] [1 0 3 4] [1 2 3 4 5]} )
(defn matching [p v]
(reduce + (map #(if (= %1 %2) 1 0) p v)))
(defn better-match [p v1 v2]
(if
(or
( (matching p v1) (matching p v2))
(and
(= (matching p v1) (matching p v2)) ( (count v1) (count
v2
v1
v2))
(reduce #(better-match [1 2 4 4 5] %1 %2) [] v)
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Re: Help with my vec matching function
That makes sense. I updated the function to:
(defn closest-match
Returns the closest matches of needle in the haystack
[#^IPersistentVector needle #^IPersistentVector haystack]
(letfn [(matching [candidate]
(println checking candidate)
(reduce + (map #(if (= %1 %2) 1 0) needle candidate)))
(closest [v1s v2]
(cond (empty? v1s) [v2]
(and (= (matching (first v1s)) (matching v2))
(= (count (first v1s)) (count v2))) (conj v1s v2)
(or ( (matching (first v1s)) (matching v2))
(and (= (matching (first v1s)) (matching v2))
( (count (first v1s)) (count v2 v1s
:else [v2]))]
(reduce #(closest %1 %2) [] haystack)))
This does work now:
(closest-match [1 2 3] #{[1 2 \a] [1 2 \b] [2 1] [1] [1 2 \c] [1 2 3 4 5]})
[[1 2 3 4 5]]
(closest-match [1 2] #{[1 2 \a] [1 2 \b] [2 1] [1] [1 2 \c] [1 2 3 4 5]})
[[1 2 \b] [1 2 \c] [1 2 \a]]
(closest-match [2 1 3] #{[1 2 \a] [1 2 \b] [2 1] [1] [1 2 \c] [1 2 3 4 5]})
[[2 1]]
One place I'm going to try to improve upon is how it reacts when there
are no matches. Right now, it will return the smallest candidate
because the third cond predicate will be true:
(and (= (matching (first v1s)) (matching v2)) ; (= 0 0)
( (count (first v1s)) (count v2 v1s ; basically finds the
smallest candidate
(closest-match [\a \b] #{[1 2 \a] [1 2 \b] [2 1] [1] [1 2 \c] [1 2 3 4 5]})
[[1]]
(closest-match [\a \b] #{[1 2 \a] [1 2 \b] [2 1] [1] [1 2 \c] [1 2 3 4 5] []})
[[]]
I think when matches = 0, or there is literally no intersection
between the needle and the candidates, I will just return [].
Rob
On Mon, Dec 28, 2009 at 6:28 PM, ajuc aju...@gmail.com wrote:
On 28 Gru, 20:57, Robert Campbell rrc...@gmail.com wrote:
How might I add a third and final condition, where those candidates
with equal scores AND equal counts are all returned together?
Reduce can work with functions like
f : x * y - x
So we can modify function closest to be like that (untested):
(closest [ v1s v2]
(if (empty v1s)
v2
(cond
(and (= (matching (first v1s)) (matching v2))
(= (count (first v1s)) (count v2))) (into
v1s v2))
(or ( (matching (first v1s)) (matching v2))
(and (= (matching (first v1s)) (matching v2))
( (count (first v1s)) (count v2
[v1]
:else [v2])))
Also, we use matching on the same arguments a lot, so it would be good
to memoize that function.
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Re: Leiningen Run ?
We have talked about adding a run task; if you're interested we could even get it in for the 1.0.0 release. I'd definitely like to see that. Right now my deployment sequence looks like: lein compile lein uberjar java -jar myapp-standalone.jar I imagine lein run should be able to execute the -main method in the :main namespace or an executable jar. It would also be nice if you could chain the targets/tasks together like in Maven: lein compile uberjar run On Sun, Dec 13, 2009 at 2:54 PM, mac markus.gustavs...@gmail.com wrote: On Dec 6, 12:40 am, Phil Hagelberg p...@hagelb.org wrote: Zach Tellman ztell...@gmail.com writes: If that's what it takes, great. Someone just needs to define what a multi-platform JNI package looks like. I'm willing to go along with whatever is decided upon by technomancy et al. I don't think this is necessarily within the scope ofleiningen itself; it should be able to be implemented within a plugin. I'm happy to provide support for how to write a plugin, but since I'm pretty ignorant of the challenges of native code I'm not sure my input is all that helpful. -Phil I looked at the code of the swank plugin and some other I found but it seems like plugins are just new tasks? In order to AOT compile some clojure code that uses native libraries (e.g. penumbra) they need to be on the java.library.path at compile time (because the native libs are loaded in static blocks so simply importing their java classes causes them to be linked in), which means that the compile task needs to know about java.library.path. I've made a rather ham-fisted attempt at adding this functionality to leiningen. The result can be viewed here: http://github.com/bagucode/leiningen However, when trying to build penumbra with it, it still fails with an UnsatisfiedLinkError. It seems like setting the java.library.path property in the ant task in eval-in-project is ignored..? /Mac -- 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: FileNotFoundException (Access is denied)
Thank you, that was the problem. I wonder if Stuart should change this line: (defn clojure-source? [file] (.endsWith (.toString file) .clj )) to this: (defn clojure-source? [file] (and (.isFile file) (.endsWith (.toString file) .clj ))) just to make sure directories like myproj.clj don't throw an error. I suppose that's being excessively safe for what's meant to be a simple example. On Thu, Nov 26, 2009 at 9:43 AM, Rob Wolfe r...@smsnet.pl wrote: Robert Campbell napisał(a): I'm trying to write a file scanner very similar to the one on page 131 of Stuart's book: (ns user (:use [clojure.contrib.duck-streams :only [reader]])) (defn scan [dir] (for [file (file-seq dir)] (with-open [rdr (reader file)] (count (filter #(re-find #foobar %) (line-seq rdr)) user (scan (java.io.File. C:/SomeValidDir)) java.lang.RuntimeException: java.io.FileNotFoundException: C:\publishing\cosmos\trunk\web (Access is denied) (NO_SOURCE_FILE:0) The strange part: user (file-seq (java.io.File. C:/SomeValidDir)) ( #File C:\SomeValidDir\foo1.clj #File C:\SomeValidDir\foo2.clj) and so on, properly listing the entire contents of the directory. user (for [file (file-seq (java.io.File. C:/publishing/cosmos/trunk/web))] nil) (nil nil) and so on, again working properly. user (for [file (file-seq (java.io.File. C:/publishing/cosmos/trunk/web))] (with-open [rdr (reader file)] nil)) ; Evaluation aborted. (this one finally fails with the same error) So with-open [rdr (reader file)] is the problem, but why? I guess reader does not work for directories. Try to change your for loop like this: (for [file (file-seq dir) :when (.isFile file)] HTH, Rob -- 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
FileNotFoundException (Access is denied)
I'm trying to write a file scanner very similar to the one on page 131 of Stuart's book: (ns user (:use [clojure.contrib.duck-streams :only [reader]])) (defn scan [dir] (for [file (file-seq dir)] (with-open [rdr (reader file)] (count (filter #(re-find #foobar %) (line-seq rdr)) user (scan (java.io.File. C:/SomeValidDir)) java.lang.RuntimeException: java.io.FileNotFoundException: C:\publishing\cosmos\trunk\web (Access is denied) (NO_SOURCE_FILE:0) The strange part: user (file-seq (java.io.File. C:/SomeValidDir)) ( #File C:\SomeValidDir\foo1.clj #File C:\SomeValidDir\foo2.clj) and so on, properly listing the entire contents of the directory. user (for [file (file-seq (java.io.File. C:/publishing/cosmos/trunk/web))] nil) (nil nil) and so on, again working properly. user (for [file (file-seq (java.io.File. C:/publishing/cosmos/trunk/web))] (with-open [rdr (reader file)] nil)) ; Evaluation aborted. (this one finally fails with the same error) So with-open [rdr (reader file)] is the problem, but why? -- 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: FileNotFoundException (Access is denied)
Forgot to mention: running Clojure 1.0.0- and Clojure-Contrib 1.0-SNAPSHOT according to the pom.. On Thu, Nov 26, 2009 at 7:38 AM, Robert Campbell rrc...@gmail.com wrote: I'm trying to write a file scanner very similar to the one on page 131 of Stuart's book: (ns user (:use [clojure.contrib.duck-streams :only [reader]])) (defn scan [dir] (for [file (file-seq dir)] (with-open [rdr (reader file)] (count (filter #(re-find #foobar %) (line-seq rdr)) user (scan (java.io.File. C:/SomeValidDir)) java.lang.RuntimeException: java.io.FileNotFoundException: C:\publishing\cosmos\trunk\web (Access is denied) (NO_SOURCE_FILE:0) The strange part: user (file-seq (java.io.File. C:/SomeValidDir)) ( #File C:\SomeValidDir\foo1.clj #File C:\SomeValidDir\foo2.clj) and so on, properly listing the entire contents of the directory. user (for [file (file-seq (java.io.File. C:/publishing/cosmos/trunk/web))] nil) (nil nil) and so on, again working properly. user (for [file (file-seq (java.io.File. C:/publishing/cosmos/trunk/web))] (with-open [rdr (reader file)] nil)) ; Evaluation aborted. (this one finally fails with the same error) So with-open [rdr (reader file)] is the problem, but why? -- 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: Question about future
If you have this: user (def f (future (Thread/sleep 2) :done)) #'user/f user @f ; this immediate deref blocks for 20 sec, finally returning :block :done user @f ; returns immediately :done What is actually happening when you call the first @f? You are waiting for the function to finish executing and return a value? Or are you waiting for a return value to appear in the ref slot? Is there any way to check if there is a value ready or if the function has returned w/out blocking? On Thu, Nov 26, 2009 at 12:32 AM, Hong Jiang h...@hjiang.net wrote: Thanks. Yeah, after adding a call to shutdown-agents, the process no longer hangs. On Nov 25, 1:15 pm, Kevin Downey redc...@gmail.com wrote: future also uses the same threadpool as agents, so once you call future the threadpool spins up, and just sort of sits around for a while before the jvm decides to exit, which is why the program would sit around for 50 seconds On Wed, Nov 25, 2009 at 10:30 AM, Hong Jiang h...@hjiang.net wrote: Thanks for your replies David and Sean. Yes, I made a mistake thinking that future takes a function and its arguments, so the function was never called in my program. On Nov 25, 8:21 am, David Brown cloj...@davidb.org wrote: On Tue, Nov 24, 2009 at 09:04:38PM -0800, Hong Jiang wrote: Hi all, I'm new to Clojure and playing with small programs. Today I wrote a snippet to figure out how future works: (defn testf [] (let [f (future #(do (Thread/sleep 5000) %) 5) g 7] (+ g @f))) You don't ever evaluate the function containing the sleep, you just create it, and then immediately return 5. Future contains an explicit do, so you can just do the steps in the future: [f (future (Thread/sleep 5000) 5) ... Or, if you want to get the function call in, you'll need to call it: [f (future (#(do (Thread/sleep 5000) %) 5)) ...] 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 -- And what is good, Phaedrus, And what is not good— Need we ask anyone to tell us these things? -- 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: roll call of production use?
I've deployed two small mashup apps which combine OpenCalais and our content repository to annotate documents with metadata (named entities, relationships, etc) and expose the results over the web. Good experiences all around, including with the clojure-http-client and saxon wrapper libs + Compojure. I did miss having a nice Clojure RDF lib, so maybe I'll make a Jena wrapper in the future. Parsing the XML-RDF as pure XML w/xpath was enough for my purposes. On Tue, Nov 24, 2009 at 6:06 AM, John Harrop jharrop...@gmail.com wrote: On Mon, Nov 23, 2009 at 9:47 PM, Richard Newman holyg...@gmail.com wrote: 1- We have this license server, used to control the use of a professional software (this one written using delphi). What are the ethics of using an open source product like Clojure to implement DRM restrictions for some other product? Seems there might be something a bit iffy there -- if not legally, perhaps morally. I don't agree. So long as they abide by the Clojure license, everything is A-OK… and the Clojure license doesn't impose restrictions on its use for this purpose. Hence my if not legally. This use of Clojure is internally consistent, and so I suspect that you're simply slightly offended by the idea of someone making money by using open-source software. In that case, I'd suggest you look first at Red Hat (market cap: $5.09B), and the Linux community's attitude towards them (generally positive). Oh, I have no problem with making money by using open source software, when it's done in the manner that companies like Red Hat do it. It's the use to lock down some piece of proprietary software even more than it already is that seems, at the very least, ironic. -- 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
Transforming a SeqMap to a Map
Hey guys,
I'm having some trouble finding a nice way to perform a map
transformation I need. I need to transform this:
[ {:a 1 :b 2 :c 3} {:a 4 :b 5 :c 6} {:a 7 :b 8 :c 9} ]
into this:
{ {:a 1 :b 2} 3 {:a 4 :b 5} 6 {:a 7 :b 8} 9 }
I wanted to use map, but each f in map only returns one value, so I
couldn't figure it out. Here is what I have now:
(def result (ref {}))
(for [item coll]
(dosync (alter result assoc (dissoc item :c) (item :c
; result should now have correct value
I also wrote a recursive version to build the map without using a ref,
but I feel like I'm missing a simpler way..
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Strange behavior seen when ints have leading zeros
C:\dev\clojurejava -cp clojure.jar clojure.lang.Repl Clojure 1.1.0-alpha-SNAPSHOT user= (def grid1 [01 02 03 04 05 06 07]) #'user/grid1 user= grid1 [1 2 3 4 5 6 7] user= (def grid2 [01 02 03 04 05 06 07 08]) java.lang.NumberFormatException: Invalid number: 08 java.lang.Exception: Unmatched delimiter: ] java.lang.Exception: Unmatched delimiter: ) user= Why does Clojure hate 8's? :-) -- 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: Strange behavior seen when ints have leading zeros
Oh, that's pretty neat. Thanks! On Thu, Nov 12, 2009 at 2:36 PM, Fogus mefo...@gmail.com wrote: Why does Clojure hate 8's? :-) It doesn't. By adding a leading zero you're telling Clojure that you want octal numbers. There is no number 08 in octal, instead to write the base-10 number 8 you would use 010 in octal. -m -- 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
Converting to TCO
I've started reading SICP and I came across the Fermat primality test implemented an Scheme. I reimplemented it in Clojure and was able to switch the recursive call in fast-prime to TCO/recur, but I was unable to do the same for the exp-mod function. (defn exp-mod [base exp m] (cond (zero? exp) 1 (even? exp) (mod (Math/sqrt (exp-mod base (/ exp 2) m)) m) :else (mod (* base (exp-mod base (inc exp) m)) m))) (defn fermat-test [n] (defn try-it [a] (= (exp-mod a n n) a)) (try-it (inc (rand-int (dec n) (defn fast-prime? [n times] (cond (zero? times) true (fermat-test n) (recur n (dec times)) :else false)) Calling (fast-prime? 5 3) blows the stack. How can I change exp-mod to use TCO? --~--~-~--~~~---~--~~ 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: Converting to TCO
One correction: after playing with the functions a bit I noticed I screwed up, putting sqrt where I needed square. On Sun, Nov 8, 2009 at 4:43 PM, Robert Campbell rrc...@gmail.com wrote: I've started reading SICP and I came across the Fermat primality test implemented an Scheme. I reimplemented it in Clojure and was able to switch the recursive call in fast-prime to TCO/recur, but I was unable to do the same for the exp-mod function. (defn exp-mod [base exp m] (cond (zero? exp) 1 (even? exp) (mod (Math/sqrt (exp-mod base (/ exp 2) m)) m) :else (mod (* base (exp-mod base (inc exp) m)) m))) (defn fermat-test [n] (defn try-it [a] (= (exp-mod a n n) a)) (try-it (inc (rand-int (dec n) (defn fast-prime? [n times] (cond (zero? times) true (fermat-test n) (recur n (dec times)) :else false)) Calling (fast-prime? 5 3) blows the stack. How can I change exp-mod to use TCO? --~--~-~--~~~---~--~~ 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: Converting to TCO
Mark: that looks a lot like the collector I learned about in The Little Schemer. I actually do have How to Design Programs, but I wanted to finish Seasoned Schemer first. I was poking around in SICP because of a Project Euler problem. Thanks for the tip! John: good catch. Can you confirm the difference between my original defn and your letfn? Both work, but as I understand it from the documentation, defn would actually define that local function globally, while letfn actually does bind it locally to all the expr which follow in the body.. On Sun, Nov 8, 2009 at 7:01 PM, John Harrop jharrop...@gmail.com wrote: You have a bug: (defn exp-mod [base exp m] (cond (zero? exp) 1 (even? exp) (mod (Math/sqrt (exp-mod base (/ exp 2) m)) m) :else (mod (* base (exp-mod base (inc exp) m)) m))) should be (defn exp-mod [base exp m] (cond (zero? exp) 1 (even? exp) (mod (Math/sqrt (exp-mod base (/ exp 2) m)) m) :else (mod (* base (exp-mod base (dec exp) m)) m))) The recursion depth is logarithmic in exp so TCO is probably unnecessary here. But with the bug, it gets locked into a cycle of exp being alternately 2 and 1 and never reaching zero, the base case, so the recursion continues until the stack blows up. Meanwhile, (defn fermat-test [n] (defn try-it [a] (= (exp-mod a n n) a)) (try-it (inc (rand-int (dec n) should really be (defn fermat-test [n] (letfn [(try-it [a] (= (exp-mod a n n) a))] (try-it (inc (rand-int (dec n)) in Clojure, or even (defn fermat-test Performs the Fermat test on n with a, if specified, or with a random value from 2 to n. ([n a] (= (exp-mod a n n) a)) ([n] (fermat-test n (inc (rand-int (dec n)) --~--~-~--~~~---~--~~ 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 -~--~~~~--~~--~--~---
feedback on this code
Hey guys, I'm looking for _any_ feedback/thoughts on this Clojure code
I wrote. I just feel like the entire thing is way too complex, but I'm
not sure about how to simplify it. I wanted to try something real
world so I made a simple shopping cart ref to put in a session:
(defstruct cart :line-items :total)
(defstruct line-item :product :qty :subtotal)
(defn create-line-item [product qty]
(struct line-item product qty (* qty (product :price
(defn add-line-item [cart line-item]
(assoc cart
:line-items (conj (cart :line-items) line-item)
:total (+ (cart :total) (line-item :subtotal
(defn update-line-item [line-items product qty]
(cond
(empty? line-items) ()
(= ((first line-items) :product) product)
(cons
(assoc (first line-items)
:qty qty
:subtotal (* qty (((first line-items) :product) :price)))
(rest line-items))
:else
(cons (first line-items)
(update-line-item (rest line-items) product qty
(defn remove-line-item [cart line-item]
(assoc cart
:line-items (remove #{line-item} (cart :line-items))
:total (- (cart :total) (line-item :subtotal
(defn add-to-cart [product qty cart]
(dosync
(let [li (create-line-item product qty)]
(alter cart add-line-item li
(defn update-cart-helper [cart product qty]
(let [uli (update-line-item (cart :line-items) product qty)]
(assoc cart
:line-items uli
:total (reduce + (map #(% :subtotal) uli)
(defn update-cart [product qty cart]
(dosync
(alter cart update-cart-helper product qty)))
(defn remove-from-cart [line-item cart]
(dosync
(alter cart remove-line-item line-item)))
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Re: feedback on this code
Wow, thank you very much. That's definitely a lot simpler. I'm going to try reimplementing it via your suggestions and see how it goes. I like your idea about not maintaining cart state on the server, because it would make my functions easier to test and debug (no need to setup teardown a fake session) but I'm not sure it would work well in practice. If a user is browsing Amazon, for example, they might add something to their cart, then visit 10 random pages before they go to checkout. I would need to embed the cart in each of these pages and resubmit the cart to the server for each request. The purpose of sessions are to avoid exactly this hairy situation. I wrapped cart in a Ref in case multiple browser windows are open and there is a concurrent add to cart click. On Tue, Oct 27, 2009 at 12:41 PM, Timothy Pratley timothyprat...@gmail.com wrote: Hi Robert On Oct 27, 9:48 pm, Robert Campbell rrc...@gmail.com wrote: Hey guys, I'm looking for _any_ feedback/thoughts on this Clojure code I wrote. I just feel like the entire thing is way too complex, but I'm not sure about how to simplify it. I wanted to try something real world so I made a simple shopping cart ref to put in a session: Great, an open invitation! structs are really no different from maps except as a performance optimisation (and not a huge one). So dropping the structs would remove some boilerplate if simplicity is your goal. Also why not make the cart a map of products to qty and forget about subtotal... subtotal and total are easily calculated by separate functions for view or checkout... something like (untested at all): (defn add-to-cart [product qty] (if (pos? qty) (dosync (alter cart update-in [product] #(+ qty (if % % 0) (defn update-cart [product qty] (dosync (alter cart assoc product qty))) (defn remove [product] (dosync (alter cart dissoc product))) (defn subtotal [product] (* (@cart product) (price product))) (defn total [] (reduce + (map subtotal @cart))) But in a real-world example I'm not sure a ref would be the best way to deal with the state... wouldn't you have the cart sent up in the request and a new cart returned? ie: you wouldn't need to maintain a ref on the server, just provide the hooks for building a cart and checking out. So the functions might be better if they take a cart as input and return a cart. Doing that pretty much makes them empty functions: (defn remove [cart product] (dissoc cart product)) So do you even need a remove function? Maybe not. Just some thoughts - I'm no web-shop programmer so disclaimer attached. Regards, Tim. Regards, Tim. --~--~-~--~~~---~--~~ 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 -~--~~~~--~~--~--~---
Tricks for transforming a DB ResultSet into XLM?
I am using clojure.contrib.sql which gives me the typical Clojure ResultSet: a set of maps. Are there any tricks you've used in the past to transform this into XML? I was looking at Enlive since I've used it - and loved it - for HTML transformations in the past, but examples are few and I don't see how I'd use it. Thanks! Rob --~--~-~--~~~---~--~~ 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: Why do Enlive template functions return a seq instead of a str?
Thanks guys, that makes perfect sense to me. I have another Enlive question: I need the _exact_ functionality of the sniptest function (which appears to have been removed) in production code. I am trying to create a decorator in compojure that will accept a response body and modify the styling in various ways. I can just use the old sniptest definition: (apply str (emit* ((transformation [:h1] (content hey)) (html-src (:body response) but is there a better way? I'm also not sure what emit* does exactly. Is it breaking :content values out of lists so they stand alone as strings? BTW, I want to thank you Christophe for making this library. It's everything xslt-driven views were supposed to be, but elegant instead of evil. It's also going to be much nicer for the designers than all the custom tags/embedded code frameworks I've used in the past. Rob On Mon, Jul 13, 2009 at 12:37 AM, Christophe Grandchristo...@cgrand.net wrote: Hi ! On Sat, Jul 11, 2009 at 7:31 PM, Jarkko Oranen chous...@gmail.com wrote: On Jul 11, 6:01 pm, Robert Campbell rrc...@gmail.com wrote: Hey guys, I'm just curious why Christophe chose to return seq instead of a str for Enlive for his template functions. Most likely Enlive generates each of those fragments separately; Forcing them into a single string at the end would wasteful in case the user intends to write the output into a stream (which can be done a fragment at a time.) Thus, leaving the choice to the user seems like a good decision. Yes you are spot on: most of the time the resulting html is wrote into a stream (disk/network/pipe). This is also why I modified Ring to accept a seq of string as the body of a http response. Christophe -- Professional: http://cgrand.net/ (fr) On Clojure: http://clj-me.blogspot.com/ (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 -~--~~~~--~~--~--~---
Save current namespace like a Smalltalk image
Hello, Sometimes I have pretty long REPL sessions where I'm trying to flesh out some ideas. When I close my instance of Clojure Box (Emacs based) I lose all the definitions I had worked out over time. Is there any way to dump namespace(s) to an image? It would be great to be able to load up some workspace image and pick up where I left off. Rob --~--~-~--~~~---~--~~ 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: Save current namespace like a Smalltalk image
Thanks Daniel, that makes perfect sense, especially about having random - and forgotten - code in the image. I have a lot of this during my exploration sessions. The main reason this is an issue for me is during development I sometimes find I need another library added to my classpath. Right now the only way I know how to modify the classpath in Emacs is to change the .emacs file with an add-to-list 'swank-clojure-extra-classpaths and reboot. I think my looking for an image solution might be a cop-out itself; I need to learn Emacs better so I can figure out how to modify the classpath without rebooting. Then I wouldn't be rebooting so often and I wouldn't need to be making images to save I'm-in-the-middle-of-a-thought state On Wed, Jul 8, 2009 at 10:57 AM, Daniel Lyonsfus...@storytotell.org wrote: Robert, On Jul 8, 2009, at 2:13 AM, Robert Campbell wrote: Sometimes I have pretty long REPL sessions where I'm trying to flesh out some ideas. When I close my instance of Clojure Box (Emacs based) I lose all the definitions I had worked out over time. Is there any way to dump namespace(s) to an image? It would be great to be able to load up some workspace image and pick up where I left off. Something similar was discussed recently but didn't come to a solid conclusion: http://groups.google.com/group/clojure/browse_thread/thread/4efaee2e67a272c6/f24578bfa06e6b9c?lnk=gstq=printing+and+reading+a+function#f24578bfa06e6b9c This is kind of a cop-out, but in general my advice would be to work from a file. Get your Clojure and Emacs set up so that you can compile your stuff pretty easily and your files are in the namespace- appropriate folder underneath your classpath. For example, I keep my Clojure code in ~/Projects/Languages/Clojure and my Emacs config looks like this: (setq swank-clojure-extra-classpaths (cons /Users/fusion/Projects/Languages/Clojure/classes (cons /Users/fusion/Projects/Languages/Clojure (directory-files ~/.clojure t \.jar$ (eval-after-load 'clojure-mode '(clojure-slime-config)) (setq swank-clojure-extra-vm-args '(-Dclojure.compile.path=/Users/ fusion/Projects/Languages/Clojure/classes)) Now if I want to load or compile a Clojure file, it just works. Next, when I start doodling I make a file in the aforementioned directory and put my stuff in there and open up a slime session in another window. C-c C-c sends the current form over Slime to the running session. Then I do my interactive testing and exploration in the slime session. Whenever I hit on a form I want to keep, I copy and paste it over to the file and make it into a function over there. I might make a function with a dumb name like demo or test and put a bunch of forms in there, and eventually they get refactored into unit tests (or not). If I close Emacs and reopen it on a file that doesn't yet have a namespace and whatnot, I select the stuff I want to evaluate and do C-c C-r to evaluate the region. It's handy, if less transparent. The main advantage to this, apart from keeping the code clean, is that you avoid the dirty image problem that can happen with Common Lisp or (I assume) Smalltalk, where the code seems to work but accidentally depends on cruft in the image that never made it into the source file. I've had this happen in CL and found it very frustrating. I had a tumblog which I tried to make faster by saving images and found one day to my surprise that I couldn't make a fresh image on my server, which was running a different architecture, because the only reason it was able to make images on my box was because the first image had some crap in it that never made it to the source file. Maybe this problem isn't as prevalent in Smalltalk; maybe the JVM can circumvent this by being cross-platform, but it's happened more than once in CL. IIRC, CMU CL for a long time was self-hosting to such a degree it couldn't be built at all without a running binary of a previous version. That kind of thing makes porting to new architectures quite difficult. Just my $0.02, — Daniel Lyons --~--~-~--~~~---~--~~ 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: Save current namespace like a Smalltalk image
Hi Jurjen, That wrapper for defn is something I was looking for in another post; I previously asked how I can inspect the definitions of my functions on the REPL. When I'm exploring stuff I'll be redefining many functions many times and sometimes I lose track things. I basically have to scroll around searching my REPL for the last definition. It sounds like you have a solution to this problem. It seems strange to me that Clojure doesn't support this concept natively. At some point the function definition is compiled into bytecode to run on the JVM, why not just automatically safe the original definition in metadata when this is done? Have you should about adding your wrapper code to Contrib? Rob On Wed, Jul 8, 2009 at 12:30 PM, Jurjenjurjen.hait...@gmail.com wrote: I had the same thought (as posted in the other thread) and haven't come to a final solution yet. The main reason I wanted to achieve it was that I do my developing / tinkering / brainstorming spread over several work boxes spread out through several locations, and a clojure REPL is cheap and easy, whereas maintaining several IDEs in synch (3 locations at work, 2 at home) can be a bit of a nightmare. The compromise I've got at the moment is that I've made a custom wrapper around [defn] that records the code used to create the instance, and stores it in the metadata of the var that points to the function. I can then cycle through the namespace definitions using ns- interns / ns-publics and see the definition of each function, and can save it to a file. I tried to create a print-dup method so that the entire contents of a namespace could be dumped to a file, but as chouser pointed out, print- dup works on the function itself, whereas the code is stored in the metadata of the var that points to the function (and there's no back- link from the function to the var), so now it is a multi-stage process to port current code in its entirety, but as I'm generally only working on fairly limited areas of code it isn't a huge deal. Also, any closures are not captured by capturing the source, so there's still issues there, but for me the function definition is generally good enough. Still have to implement it for macros as well, but haven't needed that as much. Incidentally, I find the easiest way to port my code around is to print it to the repl, then cut-and-paste it to etherpad, which I can then access from anywhere (without having to save). Now if only there was a hosted REPL that integrated an IDE nicely I would really be set. Lord-of-all-repls comes close, but is not pure clojure or JVM. Jurjen On Jul 8, 8:13 pm, Robert Campbell rrc...@gmail.com wrote: Hello, Sometimes I have pretty long REPL sessions where I'm trying to flesh out some ideas. When I close my instance of Clojure Box (Emacs based) I lose all the definitions I had worked out over time. Is there any way to dump namespace(s) to an image? It would be great to be able to load up some workspace image and pick up where I left off. Rob --~--~-~--~~~---~--~~ 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: Help with example from A Field Guide to Genetic Programming
It seems to me you want: user= (list + 1 2) (#core$_PLUS___4006 clojure.core$_plus___4...@1acd47 1 2) That looks like what I'm after. When I run a test, however, it doesn't behave properly: user (def my-func (list + 1 2)) #'user/my-func user (my-func) ; Evaluation aborted. clojure.lang.PersistentList cannot be cast to clojure.lang.IFn On Wed, Jul 8, 2009 at 6:06 AM, Timothy Pratleytimothyprat...@gmail.com wrote: It seems to me you want: user= (list + 1 2) (#core$_PLUS___4006 clojure.core$_plus___4...@1acd47 1 2) As opposed to: user= '(+ 1 2) (+ 1 2) Regarding examining a function, contrib has some helpers written by Chris user= (use 'clojure.contrib.repl-utils) (source func) (show func) In your case source wont be useful as the function is generated not read from source. The output from show is a bit opaque to me so not sure if it is useful to you. I think once it is compiled a function is not easy to examine... so as you alluded to the best alternative would be to keep the AST? Regards, Tim. On Jul 7, 10:18 pm, Robert Campbell rrc...@gmail.com wrote: I'm trying to write the first basic GP example in this free book:http://www.lulu.com/items/volume_63/2167000/2167025/2/print/book.pdf I've gotten a lot of the suppor methods working correctly (like fitness) but I'm having problem convering the pseudocode on page 14 for generating random expressions to make up my initial population. Here's what I have so far: (defn gen-rand-expr [functions terminals max-depth arity method] (if (or (= max-depth 0) (and (= method :grow) ( (rand) (/ (count terminals) (+ (count terminals) (count functions)) (rand-element terminals) (let [arg1 (gen-rand-expr functions terminals (- max-depth 1) arity method) arg2 (gen-rand-expr functions terminals (- max-depth 1) arity method) func (rand-element functions)] (func arg1 arg2 First, how can I print out the definition of a function in clojure? For example, if I do (defn add [x y] (+ x y)) how can inspect this definition, like (show-def add) - (defn add [x y] (+ x y)). This would help a lot in debugging the random programs I'm trying to generate. Second, I believe the last line is the problem in my code. Let's assume the function randomly selected was +, it will run (+ 1 2) and the entire function returns 3 instead of a randomly generated syntax tree like I need. I then tried '(func arg1 arg2) hoping it would prevent evaluation, but then it will always just return (func arg1 arg2) which isn't what I need either. I need it to actually return a syntax tree made up of expressions like (+ 1 2) but unevaluated. I am guessing I need to start reading and using macros at this point? Rob --~--~-~--~~~---~--~~ 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: Save current namespace like a Smalltalk image
Unfortunately this is impossible due to the way the classloaders in the JVM work; you can't modify your classpath at runtime and have it work consistently. Doesn't this seem a little crazy though? My day job is Java dev in Eclipse and a little IntelliJ and both IDEs allow you to modify classpath at any time. It seems like it would be a basic requirement for any IDE. Think of how often you do this. If I had to reboot Eclipse every time I'd go crazy. Then throw in the lack of image support and it becomes a real obstacle. Does anyone know exactly when the JVM is booted for the REPL? Is it from swank or clojure-mode or one of these systems? Couldn't there be a way to reboot this subsystem instead of all Emacs? Maybe from the command line you could execute the (add-to-list 'swank-clojure-extra-classpaths /whatever) then reboot the subsystem which invokes the JVM? Or modify the .emacs file and just reboot the subsystem? It's tough because I'm completely new to Emacs and I'm not clear on how all the pieces fit together yet. On Wed, Jul 8, 2009 at 7:14 PM, mccraigmccraigmccraigmccr...@googlemail.com wrote: what's the problem with adding urls to the current ClassLoader ? i've seen remarks to the effect that it doesn't work well, but i don't understand why... c On 8 Jul 2009, at 17:37, Phil Hagelberg wrote: Robert Campbell rrc...@gmail.com writes: The main reason this is an issue for me is during development I sometimes find I need another library added to my classpath. Right now the only way I know how to modify the classpath in Emacs is to change the .emacs file with an add-to-list 'swank-clojure-extra-classpaths and reboot. I think my looking for an image solution might be a cop-out itself; I need to learn Emacs better so I can figure out how to modify the classpath without rebooting. Unfortunately this is impossible due to the way the classloaders in the JVM work; you can't modify your classpath at runtime and have it work consistently. The solution I've settled on is to have a static classpath; no matter what the project is, my classpath is always the same: src/:target/dependency/:target/classes/:test/ When you need to add a new library, instead of putting the jar on the classpath, just unpack the jar in the target/dependency directory. Then you can access it without restarting the JVM. -Phil --~--~-~--~~~---~--~~ 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: Help with example from A Field Guide to Genetic Programming
That's it, that's exactly what I needed to complete this example. I'm pretty pumped because you guys have shown me a way to do it without macros and without manually managing a quoted tree structure. If it's okay, could somebody explain the difference between what's happening here: user (def my-func (list + 1 2)) #'user/my-func user (my-func) ; Evaluation aborted. and here: user (def my-func (list + 1 2)) #'user/my-func user (eval my-func) 3 I don't really understand how: user(my-func) is NOT eval on my-func in the REPL. My understanding is the first item in the list is treated as a function, with the rest of the list passed as arguments. Wouldn't the REPL just be calling eval internally on everything you type in? On Wed, Jul 8, 2009 at 7:22 PM, Richard Newmanholyg...@gmail.com wrote: That looks like what I'm after. When I run a test, however, it doesn't behave properly: You'll want to either eval the expression, or apply the first item in the list to the rest: user= (eval (list + 1 2)) 3 user= (let [form (list + 1 2)] (when (not (empty? form)) (apply (first form) (rest form 3 --~--~-~--~~~---~--~~ 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: Save current namespace like a Smalltalk image
Phil - got it. It wouldn't be hard at all to write a script to monitor a directory, and any jar you throw in there gets exploded to the classpath dir like you use. That would make it pretty painless. For the record, this is usually termed dribbling in the Lisp world. It's very handy for debugging customer interaction -- just tell them to turn on dribble, and have them send you the file rather than copying and pasting: I hate to go completely off topic, but could you explain what advices are in Lisp? When I was reading a post by Steve Yegge he wrote As far as I know, Lisp had it first, and it's called advice in Lisp. Advice is a mini-framework that provides before, around, and after hooks by which you can programmatically modify the behavior of some action or function call in the system. http://steve-yegge.blogspot.com/2007/01/pinocchio-problem.html Searching turns up some pretty thin results, maybe the better one being details on Emacs Lisp advices: http://www.delorie.com/gnu/docs/elisp-manual-21/elisp_212.html Does Clojure support something like this? I didn't come across it in Stuart's book, website, etc. and AOP certainly helps manage complexity in Java On Wed, Jul 8, 2009 at 7:34 PM, Richard Newmanholyg...@gmail.com wrote: Perhaps instead of saving an image, it should be able to save a transcript of the REPL inputs? Then you could rescue code from this, or find any cruft your image had become dependent on, or whatever. For the record, this is usually termed dribbling in the Lisp world. It's very handy for debugging customer interaction -- just tell them to turn on dribble, and have them send you the file rather than copying and pasting: http://www.franz.com/support/documentation/8.1/doc/introduction.htm#reporting-bugs-1 --~--~-~--~~~---~--~~ 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 box - loading book examples from Programming Clojure
1. Here is my .emacs I use for Clojure Box to load the Jars and add
the proper paths to your classpath:
(setq swank-clojure-extra-classpaths
'())
(add-to-list 'swank-clojure-extra-classpaths
C:/Dev/clojure/clojure.jar)
(add-to-list 'swank-clojure-extra-classpaths
C:/Dev/clojure-contrib/target/clojure-contrib-1.0-SNAPSHOT.jar)
(add-to-list 'swank-clojure-extra-classpaths
C:/Dev/compojure/deps/jetty-6.1.16.jar)
(add-to-list 'swank-clojure-extra-classpaths
C:/Dev/technomancy-clojure-http-client/src)
etc... just add directories and jars as needed
2. Your .emacs file would be here: C:\Documents and Settings\${your
username}\Application Data
3. I don't know about this one, but I had problems setting my home
directory. Even though I did it, it was still looking in C:\Documents
and Settings\${your username}\Application Data. Files there would load
fine.
On Wed, Jul 8, 2009 at 8:02 PM, Shawn Hoovershawn.hoo...@gmail.com wrote:
On Wed, Jul 8, 2009 at 2:55 AM, dumb me dumb...@gmail.com wrote:
Hi All,
I am a dumb around here. my first post among many to come :)
I setup clojurebox to work thru the book. I am a newbie to emacs and
to clojure. I don't mind the learning curve to emacs.
I am completely blank about configuring Clojurebox.
Here's what I want to do:
1) load all the code-examples and the related jar-files of the book -
when I load ClojureBox.
This requires putting the example source directly and all the jars into the
Emacs Lisp variable swank-clojure-extra-classpaths (or writing some code to
scoop them all up and generate a value to put in a variable). See the
Customization section of the README.rtf that installs with Clojure Box.
There should be a shortcut in the Start menu.
2) Where do I find the .emacs for Clojure Box? As I understand that I
will have to modify this file to include the libraries/folder-path. I
don't see one...
C-x C-f ~/.emacs. More info in the Customization section of the README.rtf
that installs with Clojure Box.
3) I have been trying to do (load-file
code.examples.introduction.clj) [my home directory being c:\emacs
and the code folder inside the emacs folder.] and I always get the
File-not-found exception.
Once the classpath is set up correctly using the above techniques, in the
REPL you can type (use 'code.examples.introduction) or leave off code. or
code.examples. depending on what part you actually put on your classpath.
Shawn
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Re: Clojure box - loading book examples from Programming Clojure
Wherever the files goes after C-x C-f ~/.emacs and then C-x C-s is where emacs thinks your home directory is. I would just go with that. It's normally in %appdata%, but it won't be there until you create it and save it. yes, this is better than my #2 Robert? Is that all you have in your .emacs? I am looking to create one from scratch. Here is my entire .emacs file, which is extremely basic but got me up and running at least: -- (setq swank-clojure-extra-classpaths '()) (add-to-list 'swank-clojure-extra-classpaths C:/Program Files/Clojure Box/clojure/clojure.jar) (add-to-list 'swank-clojure-extra-classpaths C:/Program Files/Clojure Box/clojure-contrib/target/clojure-contrib-1.0-SNAPSHOT.jar) (add-to-list 'swank-clojure-extra-classpaths C:/Program Files/Clojure Box/compojure/deps/jetty-6.1.16.jar) (add-to-list 'swank-clojure-extra-classpaths C:/Program Files/Clojure Box/compojure/deps/jetty-util-6.1.16.jar) (add-to-list 'swank-clojure-extra-classpaths C:/Program Files/Clojure Box/compojure/deps/servlet-api-2.5-20081211.jar) (add-to-list 'swank-clojure-extra-classpaths C:/Program Files/Clojure Box/compojure/deps/commons-codec-1.3.jar) (add-to-list 'swank-clojure-extra-classpaths C:/Program Files/Clojure Box/compojure/deps/commons-fileupload-1.2.1.jar) (add-to-list 'swank-clojure-extra-classpaths C:/Program Files/Clojure Box/compojure/deps/commons-io-1.4.jar) (add-to-list 'swank-clojure-extra-classpaths C:/Program Files/Clojure Box/compojure/compojure.jar) (add-to-list 'swank-clojure-extra-classpaths C:/Dev/user/libs/postgresql-8.3-604.jdbc4.jar) (add-to-list 'swank-clojure-extra-classpaths C:/Dev/technomancy-clojure-http-client/src) (custom-set-variables ;; custom-set-variables was added by Custom. ;; If you edit it by hand, you could mess it up, so be careful. ;; Your init file should contain only one such instance. ;; If there is more than one, they won't work right. '(cua-mode t nil (cua-base)) '(show-paren-mode t)) (custom-set-faces ;; custom-set-faces was added by Custom. ;; If you edit it by hand, you could mess it up, so be careful. ;; Your init file should contain only one such instance. ;; If there is more than one, they won't work right. ) -- You'll notice the paths are different (I changed it during my first post) but obviously they aren't relevant. A big problem I had was getting versions of Clojure, Contrib, Compojure, Enlive, HttpClient, etc. that all play well with each other. I'd frequently have a version of Compojure/Enlive/HttpClient that was dependent on one or another Contrib version, etc. A quick trick I learned was to just check out Compojure from git, run the ant deps which downloads the dependencies compatible with that version, and just use those because James of Compojure has done the work syncing them all up, so: (add-to-list 'swank-clojure-extra-classpaths C:/Program Files/Clojure Box/compojure/compojure.jar) (add-to-list 'swank-clojure-extra-classpaths C:/Program Files/Clojure Box/compojure/deps/clojure.jar) (add-to-list 'swank-clojure-extra-classpaths C:/Program Files/Clojure Box/compojure/deps/clojure-contrib.jar) But with 1.0 out now I haven't had as many issues. Rob On Thu, Jul 9, 2009 at 5:35 AM, Shawn Hoovershawn.hoo...@gmail.com wrote: On Wed, Jul 8, 2009 at 2:56 PM, Mani dumb...@gmail.com wrote: Thanks Shawn, Robert. From Robert's post, I am bit confused here. I also read that .emacs is in %appdata% folder (vista), but all I see is .emacs.d folder (which I guess is for the emacs server). I tried creating one C-x C-f ~/.emacs - under my home-directory (C:\emacs). Should i just create a .emacs under %appdata%/.emacs.d OR right under %appdata%? Wherever the files goes after C-x C-f ~/.emacs and then C-x C-s is where emacs thinks your home directory is. I would just go with that. It's normally in %appdata%, but it won't be there until you create it and save it. For ideas for a .emacs from scratch, you can look at http://bitbucket.org/shoover/emacs/src/tip/init.el. Shawn --~--~-~--~~~---~--~~ 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 -~--~~~~--~~--~--~---
Help with example from A Field Guide to Genetic Programming
I'm trying to write the first basic GP example in this free book: http://www.lulu.com/items/volume_63/2167000/2167025/2/print/book.pdf I've gotten a lot of the suppor methods working correctly (like fitness) but I'm having problem convering the pseudocode on page 14 for generating random expressions to make up my initial population. Here's what I have so far: (defn gen-rand-expr [functions terminals max-depth arity method] (if (or (= max-depth 0) (and (= method :grow) ( (rand) (/ (count terminals) (+ (count terminals) (count functions)) (rand-element terminals) (let [arg1 (gen-rand-expr functions terminals (- max-depth 1) arity method) arg2 (gen-rand-expr functions terminals (- max-depth 1) arity method) func (rand-element functions)] (func arg1 arg2 First, how can I print out the definition of a function in clojure? For example, if I do (defn add [x y] (+ x y)) how can inspect this definition, like (show-def add) - (defn add [x y] (+ x y)). This would help a lot in debugging the random programs I'm trying to generate. Second, I believe the last line is the problem in my code. Let's assume the function randomly selected was +, it will run (+ 1 2) and the entire function returns 3 instead of a randomly generated syntax tree like I need. I then tried '(func arg1 arg2) hoping it would prevent evaluation, but then it will always just return (func arg1 arg2) which isn't what I need either. I need it to actually return a syntax tree made up of expressions like (+ 1 2) but unevaluated. I am guessing I need to start reading and using macros at this point? Rob --~--~-~--~~~---~--~~ 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 -~--~~~~--~~--~--~---
What books have helped you wrap your brain around FP and Clojure?
Going beyond the language-specific Programming Clojure book, what other books have best helped you make the (sometimes mind-bending) transition from OOP thinking to FP thinking? My bookshelf is piled high with OOP books like Design Patterns, Domain Driven Design, Analysis Patterns, etc. I've recently ordered: - Concepts, Techniques, and Models of Computer Programming (mentioned on this/compojure's list) - Structure and Interpretation of Computer Programs (highly recommended on Stackoverflow, lectures posted online) Any others? --~--~-~--~~~---~--~~ 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: What books have helped you wrap your brain around FP and Clojure?
Talk about bad timing - reading the Silly question from Programming Clojure it looks like a book thread already got started there. Here were some additional mentions: Laurent PETIT: OOSC: Object Oriented Software Construction, but this is OOP so I'm disinclined to include it for this specific list Paul Stadig: Concepts of Programming Languages by Sebesta, suggested as more general than SICP On Sat, Jun 6, 2009 at 1:12 PM, Robert Campbellrrc...@gmail.com wrote: Going beyond the language-specific Programming Clojure book, what other books have best helped you make the (sometimes mind-bending) transition from OOP thinking to FP thinking? My bookshelf is piled high with OOP books like Design Patterns, Domain Driven Design, Analysis Patterns, etc. I've recently ordered: - Concepts, Techniques, and Models of Computer Programming (mentioned on this/compojure's list) - Structure and Interpretation of Computer Programs (highly recommended on Stackoverflow, lectures posted online) Any others? --~--~-~--~~~---~--~~ 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 -~--~~~~--~~--~--~---
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: clojure-contrib build error
If you're on Windows, please take a look at Clojure Box: http://clojure.bighugh.com/ It comes with an installer which sets you up with an Emac environment running Clojure + contrib. It's everything you need to get up in running in minutes. This is the path I took when I faced similar difficulties as you. Let me know later if you need help adding in more depedencies like Compojure or DB drivers, as I had to struggle through that a tiny bit. Rob On Thu, Apr 30, 2009 at 12:08 PM, Hubert Iwaniuk neo...@kungfoo.pl wrote: Hi All, I'm newcomer to clojure. Downloaded clojure.jar. Decided to go with VimClojure. So I need clojure-contrib. svn co clojure-contrib, and failed to build. svn co clojure, build fine retried building clojure-contrib, went fine. It's fine by me, but I believe that is not really a good user experience to need to build from sources just to start playing around. It might be good to have clojure-contrib released as clojure is released. Cheers, Hubert. --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en -~--~~~~--~~--~--~---
Re: AppEngine in Atlanta this week
Is there any way you could record the presentation and post it on your site? On Mon, Apr 27, 2009 at 1:36 PM, slc sari.conn...@gmail.com wrote: If you are interested in Google AppEngine and live in the Atlanta area ... Tuesday - Clojure * Who: John Hume * What: Clojure on Google AppEngine * When: Tuesday, April 28th at 7pm * Where: Norcross Group — 135 Technology Parkway, Suite 200, Norcross, GA 30092. For more details see Atlanta Clojure User Group (atlclj.org) . Wednesday - Groovy * Who: Vincent Stoessel * What: Google AppEngine and Groovy * When: Wednesday April 29, 2009 - 6:30PM * Where: Matrix Resources, 115 Perimeter Center Place NE, Suite 250, Atlanta, GA PLEASE SIGN UP on the gg-members mail list: gg-members- requ...@www.ajug.org Sari Connard --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en -~--~~~~--~~--~--~---
