Re: Multimethods derive
On 08.06.2009, at 04:26, Stuart Sierra wrote: If it is, it would be very useful to have something that is the ancestor of everything (like T in common lisp). This has been thought about, at least: http://clojure.org/todo I think the question is... what should the universal ancestor be? For classes, it's java.lang.Object. But derive allows you to create relationships outside the Java class hierarchy. So for now, defining your own root ancestor is the way to proceed. See also my patch that creates such a universal root type (the keyword :root): http://groups.google.com/group/clojure/browse_thread/thread/ bc5193304c1ab2e3/77e5d53d8ccd6b10?lnk=gstq=%3Aroot#77e5d53d8ccd6b10 Of course, it is not a good idea to write code relying on an unofficial patch, I don't even use it myself for production code. But the patch illustrates that this can be done, and my tests have not shown any undesirable side effects. Konrad. --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en -~--~~~~--~~--~--~---
Re: Multimethods derive
On Jun 8, 3:51 pm, Konrad Hinsen konrad.hin...@laposte.net wrote: See also my patch that creates such a universal root type [...] Nice! That's exactly what I was thinking about Peter --~--~-~--~~~---~--~~ 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: VimClojure v2.1.1 is released
Sure, I sent a private mail because I didn't want to increase noise in is group. I used the mail address you left on vimclojure site to reach you. I just learned about user.home. So I can simplify also the .vim installation of the plugin. Beautiful, when is it coming out? Emeka --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com 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?
Just see http://en.wikibooks.org/wiki/Clojure_Programming/Further_Reading On Jun 6, 3:12 pm, Robert Campbell rrc...@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 -~--~~~~--~~--~--~---
Re: VimClojure v2.1.1 is released
On Sun, Jun 7, 2009 at 6:37 PM, Meikel Brandmeyer m...@kotka.de wrote: Am 07.06.2009 um 17:41 schrieb Emeka: And it took Meikel three weeks to make out time to talk to me. Huh? Did I miss something? Meikel, You've been incredibly open and helpful on this list and we all appreciate it. Thanks for all you've done. Regards, - J. --~--~-~--~~~---~--~~ 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 is this using reflection?
On Fri, Jun 5, 2009 at 5:26 PM, tsuraantsur...@gmail.com wrote:
I have a function to get the path out of a lucene searcher
(documentation at
http://lucene.apache.org/java/2_3_2/api/core/org/apache/lucene/search/IndexSearcher.html).
The searcher has a Reader, which has a Directory. The Directory is
abstract, but in my case I know that it's a FSDirectory, so I declare
fsdir, and then use its getFile and getPath. The actual code I'm
using is:
(defn searcher-path [ #^IndexSearcher searcher ]
(let [fsdir #^FSDirectory (.. searcher getIndexReader directory)
path #^String (.. fsdir getFile getPath) ]
path))
When I compile this with warn-on-reflection, I get that getField and
getPath cannot be resolved. Am I doing the hinting wrong somehow? I
do have imports in my file for IndexSearcher and FSDirectory, so I'm
not sure what I'm missing.
I thought it might be fun to try out the new repl-utils expression-info fn on
this.
So first I had to recreate your 'import' line (you might consider including this
kind of detail next time you post a question):
(import '(org.apache.lucene.search IndexSearcher)
'(org.apache.lucene.store FSDirectory))
Then in order to use expression-info, I had to adjust your code to make it
a stand-alone expression that returns the value I care about. Then I wrapped it
in a call to expression-info:
(expression-info
'(let [#^IndexSearcher searcher nil] ; replaced 'defn' with simple 'let'
(let [fsdir #^FSDirectory (.. searcher getIndexReader directory)
path #^String (.. fsdir getFile getPath)]
path)))
This just returns 'nil', which is what I'd expect since the reflection warning
already told us the compiler doesn't know the type. So lets cut out the parts
producing the warning:
(expression-info
'(let [#^IndexSearcher searcher nil] ; replaced 'defn' with simple 'let'
(let [fsdir #^FSDirectory (.. searcher getIndexReader directory)]
fsdir)))
returns:
{:class org.apache.lucene.store.Directory, :primitive? false}
Now this is interesting. I thought we'd specifically told it fsdir was an
FSDirectory, but the complier seems to think it's just a Directory. It appears
to be taking the actual return type of the directory() method over our type
hint. I don't know if this is a feature or a bug, but perhaps we can be a bit
more insistent. What happens if we type-hint the local directly instead of the
expression?
(expression-info
'(let [#^IndexSearcher searcher nil] ; replaced 'defn' with simple 'let'
(let [#^FSDirectory fsdir (.. searcher getIndexReader directory)]
fsdir)))
returns:
{:class org.apache.lucene.store.FSDirectory, :primitive? false}
Well, that seems to have done it. Using that style in the original expression,
we get:
(defn searcher-path [#^IndexSearcher searcher]
(let [#^FSDirectory fsdir (.. searcher getIndexReader directory)
#^String path (.. fsdir getFile getPath)]
path))
That compiles without reflection warnings.
Note also that hinting 'path' as 'String' doesn't really do any good when all we
do is return it:
user= (expression-info '(searcher-path nil))
nil
If you want to promise that 'searcher-path' will always return a String so that
the compiler can make further type deductions based on that, you need to hint
the function itself:
(defn #^String searcher-path [#^IndexSearcher searcher]
(let [#^FSDirectory fsdir (.. searcher getIndexReader directory)]
(.. fsdir getFile getPath)))
user= (expression-info '(searcher-path nil))
{:class java.lang.String, :primitive? false}
--Chouser
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Re: Artificial Intelligence in Clojure
On Sat, Jun 6, 2009 at 11:10 PM, maxsumax.su...@gmail.com wrote: Hi, i'd like to write some AI in clojure. Reading Russel Norvig's AI: A Modern Approach, which focuses heavily on autonomous intelligence agents. Has anyone worked with these or other AI in clojure? Any libraries/git repos out there? Genetic programming comes up from time to time. I haven't looked at anybody's work on the subject, but there's been relevant discussions in this Google group. Can/should we use clojure agents to encapsulate separate interacting autonomous logical/rational agents? Finally, in which way should we organize an asynchronous simulation of a neural network using clojure concurrency? Are agents a good design idea here as well? This sounds to me like it have many concepts in common with cells implementations, which have been discussed in the group several times. I think there are a couple different implementations that may have useful ideas for you. --Chouser --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en -~--~~~~--~~--~--~---
Re: What books have helped you wrap your brain around FP and Clojure?
Programming Erlang is also good. The syntax and message passing emphasis aren't relevant to Clojure, but Erlang also uses immutable data, and is definitely a functional language. On Sat, 6 Jun 2009 13:12:16 +0200 Robert Campbell rrc...@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 -~--~~~~--~~--~--~---
Spam in file section
Not quite sure what the right way to report this is. There seems to be some spam in the file report. The Mathis-Oberg- Insulating_Guide.pdf seems to be out of place. My apologies if this is a false positive. --~--~-~--~~~---~--~~ 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: What books have helped you wrap your brain around FP and Clojure?
On Jun 8, 2009, at 7:24 AM, Nathan Hawkins wrote: The syntax and message passing emphasis aren't relevant to Clojure I don't have any experience with agents in Clojure, but I wonder if they be used to similar effect? Agents seem more like data in another thread to me than self-recursive functions in another thread, which is what Erlang's processes are like, but your remark piques my curiosity. Can one be implemented trivially via the other? — Daniel Lyons http://www.storytotell.org -- Tell It! --~--~-~--~~~---~--~~ 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 is this using reflection?
I thought it might be fun to try out the new repl-utils expression-info fn
on
this.
Is this just in source control, or is it in a release? I'm using
1.0.0, and I don't seem to have that function.
So first I had to recreate your 'import' line (you might consider including
this
kind of detail next time you post a question):
Yeah, sorry about that. I'll remember next time.
Well, that seems to have done it. Using that style in the original
expression,
we get:
(defn searcher-path [#^IndexSearcher searcher]
(let [#^FSDirectory fsdir (.. searcher getIndexReader directory)
#^String path (.. fsdir getFile getPath)]
path))
That compiles without reflection warnings.
I thought I had tried this and gotten an error for it; I must have
made a typo and assumed it was an invalid thing to do. It's certainly
working now :) Where can I get more info on the expression-info call?
A google search for expression-info and clojure gives a pdf on
multiple dispatch and nothing else.
Note also that hinting 'path' as 'String' doesn't really do any good when
all we
do is return it:
That's really strange. The clojure compiler doesn't put types on
functions when the only value returned from a function has an explicit
type?
user= (expression-info '(searcher-path nil))
nil
If you want to promise that 'searcher-path' will always return a String so
that
the compiler can make further type deductions based on that, you need to
hint
the function itself:
(defn #^String searcher-path [#^IndexSearcher searcher]
(let [#^FSDirectory fsdir (.. searcher getIndexReader directory)]
(.. fsdir getFile getPath)))
user= (expression-info '(searcher-path nil))
{:class java.lang.String, :primitive? false}
In the type hinting page, it says type hits can be applied to function
parameters, let-bound names, var names and expressions. Is the
#^String here being applied to a var name (searcher-path)? It wasn't
obvious to me that one could do that, although I guess functions names
are variables just like any other names in the system.
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In let: unpacking maps with accessors too
I'd love to be able to do this:
(defstruct person-s :name :gender)
(def name-a (accessor person-s :name))
(def gender-a (accessor person-s :gender))
(def person-1 (struct person-s Jane :female))
(let [{name name-a, gender gender-a, :as person} person-1]
(println name gender person))
...instead of having to do this:
(let [person person-1, name (name-a person), gender (gender-a person)]
(println name gender person))
In other words, rather than the rule being that, in a map in a let
binding, the values of symbol keys must be keywords so that the key
symbol is bound to (keyword the-map):
(let [{name :name} person-1] ...) ; name is bound to (:name
person-1)
...I'd love it if the values of symbol keys could be any symbol, not
just keywords, so that the key symbol is bound to (val-symbol
the-map):
(let [{name this-is-a-symbol} person-1] ...) ; name is bound to
(this-is-a-symbol person-1)
It's backwards-compatible. But is this possible? Practical?
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Re: Why is this using reflection?
On Mon, Jun 8, 2009 at 11:41 AM, tsuraan tsur...@gmail.com wrote: I thought it might be fun to try out the new repl-utils expression-info fn on this. Is this just in source control, or is it in a release? I'm using 1.0.0, and I don't seem to have that function. repl-utils is a library in clojure-contrib. Docs here: http://code.google.com/p/clojure-contrib/wiki/ReplUtilsApiDoc Source here: http://code.google.com/p/clojure-contrib/source/browse/trunk/src/clojure/contrib/repl_utils.clj HTH, - J. --~--~-~--~~~---~--~~ 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: VimClojure v2.1.1 is released
Hi, Am 08.06.2009 um 09:15 schrieb Emeka: Sure, I sent a private mail because I didn't want to increase noise in is group. I used the mail address you left on vimclojure site to reach you. Ok. I'm sorry. It must have been stuck in the spam filter. I searched my mails, but only found the question about Jacob and Excel. I just learned about user.home. So I can simplify also the .vim installation of the plugin. Beautiful, when is it coming out? Obviously soon... -.- I introduced more bugs than I fixed with this release. I will iron the bigger ones and will do a 2.1.2 soon For that I will throw another eye on the build process. Sincerely Meikel smime.p7s Description: S/MIME cryptographic signature
Re: In let: unpacking maps with accessors too
On Jun 8, 2009, at 17:46, samppi wrote:
...I'd love it if the values of symbol keys could be any symbol, not
just keywords, so that the key symbol is bound to (val-symbol
the-map):
(let [{name this-is-a-symbol} person-1] ...) ; name is bound to
(this-is-a-symbol person-1)
It's backwards-compatible. But is this possible? Practical?
I don't think it could made to be backwards-compatible. The
documentation states:
Map binding-forms allow you to bind names to parts of associative
things (not just maps), like maps, vectors, string and arrays (the
latter three have integer keys).
The current implementation of destructuring map binding forms uses get:
(destructure '[{name :name} person-1])
- [map__268 person-1 name (clojure.core/get map__268 :name)]
This works as advertised with maps, vectors, strings, etc. Your
proposal would change the expansion to
- [map__268 person-1 name (:name map__268)]
That works fine if person-1 is a map, but destructuring a vector with
a map binding form is no longer possible.
Nothing stops you from defining your own let-like macro with your own
destructuring rules, of course!
Konrad.
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Re: The - . nested usage
On Jun 8, 2009, at 12:38 PM, ronen wrote: user= (- String. String.) java.lang.ClassNotFoundException: String. (NO_SOURCE_FILE:7) expanding the macros involved seems to reveal the issue: user= (macroexpand-1 `(- String. String.)) (java.lang.String. java.lang.String.) the . macro isn't expanded. The trailing dot syntax is used for creating an object given a class name: (String.) creates a String object. Nested macros work fine. What were you hoping the above expressions would expand to? Here's an example of - in action: (- (System/getProperties) (.get java.class.path) .toUpperCase (nth 3) int (* 2)) --Steve smime.p7s Description: S/MIME cryptographic signature
Re: The - . nested usage
I see, using - with . will not create a chain of new invocations, the best solution that iv found is: user= (String. (String.)) user= (macroexpand (String. (String.))) user= (macroexpand `(String. (String.))) (new java.lang.String (java.lang.String.)) Nesting is a must :) Thank you both for your helpful reply On Jun 8, 10:51 pm, Kevin Downey redc...@gmail.com wrote: you need to pass something in. example: = (- foo String. String.) foo = (macroexpand '(- String. String.)) (new String String.) = (macroexpand '(- foo String. String.)) (new String (clojure.core/- foo String.)) = (macroexpand '(- foo String.)) (new String foo) String. is only treated as new String ... when it is placed in the function position (String. ...) in (- String. String.) the first String. is never put in the function position, so effectively you get (String. String.) On Mon, Jun 8, 2009 at 12:38 PM, ronennark...@gmail.com wrote: Following a blog post on building large object graphs I was suggested with the following solution: (def nested-object (- GrandFather. Father. GrandSon.)) this indeed seems to be correct however fails in even in a simple example: user= (- String. String.) java.lang.ClassNotFoundException: String. (NO_SOURCE_FILE:7) expanding the macros involved seems to reveal the issue: user= (macroexpand-1 `(- String. String.)) (java.lang.String. java.lang.String.) the . macro isn't expanded. Is there a way of applying nested macros? (iv searched for applying nested macros with no results). -- 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 -~--~~~~--~~--~--~---
Re: The - . nested usage
Just to be clear, is (String.) a macro? I thought it was just a special form. On Mon, Jun 8, 2009 at 3:47 PM, Stephen C. Gilardi squee...@mac.com wrote: On Jun 8, 2009, at 12:38 PM, ronen wrote: user= (- String. String.) java.lang.ClassNotFoundException: String. (NO_SOURCE_FILE:7) expanding the macros involved seems to reveal the issue: user= (macroexpand-1 `(- String. String.)) (java.lang.String. java.lang.String.) the . macro isn't expanded. The trailing dot syntax is used for creating an object given a class name: (String.) creates a String object. Nested macros work fine. What were you hoping the above expressions would expand to? Here's an example of - in action: (- (System/getProperties) (.get java.class.path) .toUpperCase (nth 3) int (* 2)) --Steve --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en -~--~~~~--~~--~--~---
Re: The - . nested usage
sure it can, you just need to pass in an initial value. (- (String.) String. String.) ; works (- x String. String.) ;works for any x where string has a constructor that takes something of type x for example (- file.txt File. FileReader. BufferedReader.) will return a buffered reader on file.txt (assuming you import those classes from java.io) On Mon, Jun 8, 2009 at 12:59 PM, ronennark...@gmail.com wrote: I see, using - with . will not create a chain of new invocations, the best solution that iv found is: user= (String. (String.)) user= (macroexpand (String. (String.))) user= (macroexpand `(String. (String.))) (new java.lang.String (java.lang.String.)) Nesting is a must :) Thank you both for your helpful reply On Jun 8, 10:51 pm, Kevin Downey redc...@gmail.com wrote: you need to pass something in. example: = (- foo String. String.) foo = (macroexpand '(- String. String.)) (new String String.) = (macroexpand '(- foo String. String.)) (new String (clojure.core/- foo String.)) = (macroexpand '(- foo String.)) (new String foo) String. is only treated as new String ... when it is placed in the function position (String. ...) in (- String. String.) the first String. is never put in the function position, so effectively you get (String. String.) On Mon, Jun 8, 2009 at 12:38 PM, ronennark...@gmail.com wrote: Following a blog post on building large object graphs I was suggested with the following solution: (def nested-object (- GrandFather. Father. GrandSon.)) this indeed seems to be correct however fails in even in a simple example: user= (- String. String.) java.lang.ClassNotFoundException: String. (NO_SOURCE_FILE:7) expanding the macros involved seems to reveal the issue: user= (macroexpand-1 `(- String. String.)) (java.lang.String. java.lang.String.) the . macro isn't expanded. Is there a way of applying nested macros? (iv searched for applying nested macros with no results). -- And what is good, Phaedrus, And what is not good— Need we ask anyone to tell us these things? -- 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 -~--~~~~--~~--~--~---
filechooser
Hello Meikel, I have not been able to resolve this issue. As I mentioned in another thread, I want to use filechooser to select the excel file. My code is in this link http://friendpaste.com/wmX89ywgPhdN5hvVBEAbg Regards, Emeka --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com 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 - . nested usage
Great! that was the missing bit i was looking for. thanks for clearing it out ( it seems that String. is indeed a macro) On Jun 8, 11:05 pm, Kevin Downey redc...@gmail.com wrote: sure it can, you just need to pass in an initial value. (- (String.) String. String.) ; works (- x String. String.) ;works for any x where string has a constructor that takes something of type x for example (- file.txt File. FileReader. BufferedReader.) will return a buffered reader on file.txt (assuming you import those classes from java.io) On Mon, Jun 8, 2009 at 12:59 PM, ronennark...@gmail.com wrote: I see, using - with . will not create a chain of new invocations, the best solution that iv found is: user= (String. (String.)) user= (macroexpand (String. (String.))) user= (macroexpand `(String. (String.))) (new java.lang.String (java.lang.String.)) Nesting is a must :) Thank you both for your helpful reply On Jun 8, 10:51 pm, Kevin Downey redc...@gmail.com wrote: you need to pass something in. example: = (- foo String. String.) foo = (macroexpand '(- String. String.)) (new String String.) = (macroexpand '(- foo String. String.)) (new String (clojure.core/- foo String.)) = (macroexpand '(- foo String.)) (new String foo) String. is only treated as new String ... when it is placed in the function position (String. ...) in (- String. String.) the first String. is never put in the function position, so effectively you get (String. String.) On Mon, Jun 8, 2009 at 12:38 PM, ronennark...@gmail.com wrote: Following a blog post on building large object graphs I was suggested with the following solution: (def nested-object (- GrandFather. Father. GrandSon.)) this indeed seems to be correct however fails in even in a simple example: user= (- String. String.) java.lang.ClassNotFoundException: String. (NO_SOURCE_FILE:7) expanding the macros involved seems to reveal the issue: user= (macroexpand-1 `(- String. String.)) (java.lang.String. java.lang.String.) the . macro isn't expanded. Is there a way of applying nested macros? (iv searched for applying nested macros with no results). -- And what is good, Phaedrus, And what is not good— Need we ask anyone to tell us these things? -- 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 -~--~~~~--~~--~--~---
Re: Exception when reading large quoted form
Hi Jason, I've run into the same thing. This has come up on the group before, more info can be found here: http://groups.google.com/group/clojure/msg/efd607d75d59088e Cheers, Tom On Jun 8, 1:32 pm, Jason Wolfe jawo...@berkeley.edu wrote: I get an exception Invalid method Code length 70026 in class file user$eval__3286 0: java.lang.ClassLoader.defineClass1(Native Method) 1: java.lang.ClassLoader.defineClass(ClassLoader.java:675) 2: java.lang.ClassLoader.defineClass(ClassLoader.java:520) 3: clojure.lang.DynamicClassLoader.defineClass (DynamicClassLoader.java:42) 4: clojure.lang.Compiler$FnExpr.getCompiledClass(Compiler.java:3465) 5: clojure.lang.Compiler$FnExpr.eval(Compiler.java:3476) 6: clojure.lang.Compiler.eval(Compiler.java:4600) 7: clojure.core$eval__4610.invoke(core.clj:1730) 8: swank.commands.basic$eval_region__2568.invoke(basic.clj:36) 9: swank.commands.basic$eval__2583$listener_eval__2585.invoke (basic.clj:50) 10: clojure.lang.Var.invoke(Var.java:346) 11: user$eval__3283.invoke(NO_SOURCE_FILE) 12: clojure.lang.Compiler.eval(Compiler.java:4601) by typing the following large quoted form at the REPL. http://paste.lisp.org/display/81543 Removing the quote or some of the elements fixes the problem. It sounds like this is something to do with a JVM method bytecode size limitation ... I can work around it for now, but it would be nice if this limitation was either documented (i.e., with a descriptive exception), or removed somehow. -Jason --~--~-~--~~~---~--~~ 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: performance concerns (again)
Thanks for the replies. This post is moderately long as it includes responses to most of the replies. Before I reply to replies, I will quickly describe some add'l data that I obtained from further tests. I was lead to a line of investigation by the description at the following URL: http://www.coderanch.com/t/419739/Linux-UNIX/JVM-Memory-Linux I executed a simpler test in Java only, one that prints a simple Sleeping 30sec message then sleeps for 30sec. The 30sec delay is so that I can record the memory allocated by JVM. * on a Windows XP laptop a 2.2GHz dual-core CPU and 2GB RAM * on several Linux v2.6 systems w/ 8 cores of ~2.6GHz and 16GB RAM * on several Linux v2.4 systems w/ the same configs as those w/ the v2.6 kernels All tests were executed w/ a v6 JVM. NOTE - Linux version numbers refer to the kernel's version. In short, only the linux v2.6 kernels showed the exorbitant memory-utilization that I reported previously. On both Windows XP and Linux v2.4, the memory allocated was on the order of MBs, not HUNDREDS of MBs. NOTE - in practice, I consider the 10, 11 and 12MBs that I observed to be on the order of MBs, not TENs of MBs. One would guess then that the overcommit feature of the Linux v2.6 kernel is causing this impression of exorbitant memory-utilization. The question remains then whether the overcommit affects the scalability of the JVM on Linux v2.6 systems. IOW, for a simple program that causes the JVM to allocate hundreds of megs of RAM on a multi-gigabyte system, will the number of JVM instances be severely limited? For example, if the JVM allocates 400MB on a 16GB system, is the total number of JVM instances limited to ~40 (16000/400 or to the ~1300 (16000/12) that I would otherwise expect. I can explore that indepedently and share the results here later if anyone is interested. --- Richard Newman wrote: rlehr Simply stated, given that it stated clearly in this group that Clojure rlehr runs, on average, slower than the JVM, is the JVM's high memory- rlehr utilization a non-issue for the Clojure community as well? In short: yes. First, thanks for the info, Richard. Interesting. I am now left to wonder if your disposition is typical of most JVM developers and deployers. I'll have to continue asking my inquiry. Sure, under load that will increase, but it's still negligible in the context of available memory (only a few percent). Additionally, in my experience the memory profile of Java server applications is better than our C++ applications, which typically experience some bloating or memory leak issues. Is that a positive for Java? Or a negative for the programmers that wrote your C++ apps? I'd take steady-state 300MB memory consumption any day over a startup at 50MB ending up at 1.4GB after a couple of months' uptime (a situation I've seen with C++ server applications). In general, I agree. But I would need to take into account few other variables before I made that decision for a specific application. Consider, for an app that starts at 50MB yet has allocated 1.4GB of leaked memory after a couple months, that application could easily restart itself very quickly; and that's a low-cost operation. I know it seems like a hack. But So, in short: if you're on a low-resource machine, running graphical Java clients: yes, the JVM's memory consumption might concern you, as will its startup time. Errrm - so Java's value is limited to large systems ? That statement does not seem to take into account all of the small systems, including mobile devices, that use Java. What am I missing here? You're probably baffled because your definition of unacceptable is very different to most using Java SE/EE. The JVM is monolithic (something Project Jigsaw is trying to fix, precisely to reduce memory usage in constrained scenarios), ... Good point. However, my definition of acceptable is reasonable in the most general sense. I am familiar w/ cost-to-benefit analysis of the choices that designers make. For any benefit that a system provides, there is a limit on the cost that one is willing to pay. When a comparable C++ progie allocates 40k, I do not consider an initial allocation of 400MB to be acceptable for any system. It's wasteful enough to begin reconsidering whether the benefits of the system in question are worth the cost. IOW, when I see a increase of 4 orders of magnitude of attribute A in exchange for 1 order of magnitude of improvement in attribute B, my alarms are triggered. I do my value calculations, start asking questions and looking for something to kill. In this case, the JVM allocating 400MB instead of 40k; I expected something on the order of MBs, not HUNDREDs of MBs. NOTE that the above comment is a general statement and does not reflect my observations of the v6 JVM on Windows XP and Linux v2.4.x. ...but it doesn't bother most people running Java services on 2008/2009-era servers. If my initial observations were
Macro Design - by example
Dear Clojurians, in the past there were several discussions on the list regarding the one or the other macro. Please let me show some design principles, which I believe are good ideas for macro design. On the occasion of a question in another thread we will write a small helper macro to add an action listener to a Swing component. Let's start with the code we want to produce. (.addActionListener component (proxy [ActionListener] [] (actionPerformed [evt] (do-something-with evt) (do-more-stuff This should be easy to translate into a macro. (defmacro add-action-listener [component body] `(.addActionListener ~component (proxy [ActionListener] [] (~'actionPerformed [~'evt] ~...@body Note the ugly actionPerformed quoting. The invocation looks like: (add-action-listener component (do-something-with evt) (do-more-stuff)) Note that we had to capture evt to get access to the event, which is passed to the handling code. This means we get into trouble, when we want to access an external evt in our handling code. This is ugly. So we specify the name to use explicitly. (defmacro add-action-listener [component evt body] `(.addActionListener ~component (proxy [ActionListener] [] (~'actionPerformed [~evt] ~...@body Note the slightly different quoting of evt. Again the invocation: (add-action-listener component the-evt (do-something-with the-evt) (do-more-stuff)) Hurray. We have a working macro. Time for refactoring. We should ask ourselves: Why do we actually need a macro? Macro writing is hard and one should keep the macros as small as possible if not avoiding them at all. Of course one might argue: Yadda yadda. That's just a style question. So here is another motivation. Suppose we have some-handler-fn which we want to us in our action listener. Using our macro this would look like this: (add-action-listener component the-evt (some-handler-fn the-evt)) Bleh. Now this is ugly and verbose. We have to think about a name for a thing which we just immediately pass on to a function. Why should we bother with such details? So let's write a function for that. (defn add-action-listener* [component handler] (.addActionListener component (proxy [ActionListener] [] (actionPerformed [evt] (handler evt) Now the invocation looks like this: (add-action-listener* component some-handler-fn) Much more concise and to the spot. And note: in the function we didn't have to mess around with strange quotations. We just chose whatever name we liked for the event argument without danger of interference. But wait. Now we implemented the same functionality twice. We should DRY this moisture. As we saw, we can easily achieve the desired effect if we have a handler function. So why not base the macro on the function? (defmacro add-action-listener [component evt body] `(add-action-listener* ~component (fn [~evt] ~...@body))) Note the trick: we created a function which takes the given event name as argument and has body as it's body. So the event parameter is available in the body under the given name. The anonymous fn is then simply passed to the star function. Ah. More yadda yadda. I don't have handler fns! So why would it still be a good idea to have the macro use some driver function? Suppose you are hunting a bug. Your suspicion is that there is some trouble with the event handling. So you want to log some message about the event. You start changing the macro. (defmacro add-action-listener [component evt body] `(.addActionListener ~component (proxy [ActionListener] [] (~'actionPerformed [~evt] (println Got event: ~evt) ~...@body And now you can track the event passing. Eh.. well.. Not quite! First you have to recompile all your code and restart the application. Since a macro gets expanded at compile time, there is no way to change the expansion afterwards. Consider the same change to the function version. Now all you have to do is to just reload the single function in the running application. This can be easily done by environments like SLIME or VimClojure. Et voila. The next time the function is called you already get the benefit. Without recompilation of the whole app... So here the complete macro-function pair + invocation: (defn add-action-listener* [component handler] (.addActionListener component (proxy [ActionListener] [] (actionPerformed [evt] (handler evt) (defmacro add-action-listener [component evt body] `(add-action-listener* ~component (fn [~evt] ~...@body))) (add-action-listener component the-evt (do-something-with the-evt) (do-more-stuff)) (add-action-listener* component some-handler-fn) So to summarise: - write the code which you want in your macro - write a macro which expands into the code with variable parts as macro arguments. - extract the parts which are not required to be a macro as a function - modify the macro to simply call the function
Re: VimClojure v2.1.1 is released
Hi, Am 08.06.2009 um 04:35 schrieb e: That'd be awesome. assume the user doesn't even have vim. they just have jdk. ... and they only care about vim for clojure. Well, I'd want to eventually integrate with svn and git, but I suppose folks just drop to a shell for that stuff, typically. Ok. Here it is: http://bitbucket.org/kotarak/clojure-ball/overview/ Nothing there, yet. But I'll work on it. Sincerely Meikel smime.p7s Description: S/MIME cryptographic signature
Re: performance concerns (again)
First, thanks for the info, Richard. Interesting. I am now left to wonder if your disposition is typical of most JVM developers and deployers. I'll have to continue asking my inquiry. I'm actually not a typical JVM developer -- I come from a Common Lisp background, and I avoid writing Java whenever I can -- and I'm most definitely not a Java fanboy. Java makes up the minority of my work. In fact, I've only started using it for real work in the past couple of years, because it happened to be the best tool for the job. I was responding from the perspective of the times I've deployed Java applications, but that's not the majority of my experience. Sure, under load that will increase, but it's still negligible in the context of available memory (only a few percent). Additionally, in my experience the memory profile of Java server applications is better than our C++ applications, which typically experience some bloating or memory leak issues. Is that a positive for Java? Or a negative for the programmers that wrote your C++ apps? Many of the leaks I've been privy to have been in vendors' binaries or in libraries, which are hard to fix! The rest are 'common or garden' bloat, and would arise in most C++ applications developed under the same circumstances. I certainly don't attribute any exceptional blame to the teams involved. Part of the reason why GC is so fantastic is that writing truly correct memory handling code is actually quite hard, particularly for long-running applications, and getting it right is costly. I view GC as a good thing. I would not write any new applications in C++, and that's been true for several years. Additionally, applications with GC can outperform those with malloc/ free-based approaches, which is fascinating. I'd take steady-state 300MB memory consumption any day over a startup at 50MB ending up at 1.4GB after a couple of months' uptime (a situation I've seen with C++ server applications). In general, I agree. But I would need to take into account few other variables before I made that decision for a specific application. Consider, for an app that starts at 50MB yet has allocated 1.4GB of leaked memory after a couple months, that application could easily restart itself very quickly; and that's a low-cost operation. Unless you have current sessions, and a gentle restart involves rerouting traffic. (I work in a high-availability domain.) I don't like writing bounce the server as a routine recommendation in an ops guide :) So, in short: if you're on a low-resource machine, running graphical Java clients: yes, the JVM's memory consumption might concern you, as will its startup time. Errrm - so Java's value is limited to large systems ? For me, yes. Put another way: there's no way I'd write Unix utilities in Java (because of the startup time). Its applicable domains for me are limited. Other people are much more enthusiastic about its applicability -- they're running Java on televisions, Blu-ray players, mobile handsets, VoIP desk phones, network appliances, cash registers... That statement does not seem to take into account all of the small systems, including mobile devices, that use Java. What am I missing here? There are different profiles of Java: ME, SE, EE. Java ME is a very different beast to an enterprise (*gag*) Java application server. I wouldn't use Java ME either, but that's a different story :) IOW, when I see a increase of 4 orders of magnitude of attribute A in exchange for 1 order of magnitude of improvement in attribute B, my alarms are triggered. I do my value calculations, start asking questions and looking for something to kill. In this case, the JVM allocating 400MB instead of 40k; I expected something on the order of MBs, not HUNDREDs of MBs. I don't see similar measurements to you. My Nailgun server for Clojure development, started with -server and -Xmx512M, is at 19MB RSIZE on my 64-bit Mac. After loading all of my code and its dependencies, that jumps to 37MB. After quite a bit of work, it's at 65MB. I rarely see it rise above 100MB. My Java app server -- actually deployed and handling requests -- on Solaris x86 is at 158MB RSS, which actually impresses me given the amount of code loaded. Those sizes are smaller than some non-Java apps I've deployed recently, one of which is hovering around 500MB RSS right now. Java memory usage no longer enters into the technology choice equation for me. It did a few years ago. ...but it doesn't bother most people running Java services on 2008/2009-era servers. If my initial observations were true for all cases then I suspect that your comment would reflect poorly on your group of most people. Sorry. :( Indeed, which is why I think either your measurements are flawed, or that measuring standalone memory consumption (no matter how accurately) is an irrelevant metric for real-world
Re: What books have helped you wrap your brain around FP and Clojure?
I second most of the book suggestions already mentioned (those that I've read). If you like reading papers, I strongly suggest you take a look at Can Programming Be Liberated from the von Neumann Style?: http://www.stanford.edu/class/cs242/readings/backus.pdf This paper will help you with two things: 1. Motivation to investigate deeper FP; 2. Understanding many core concepts of FP. If you read this paper, I strongly suggest you schedule some time to read at least the first 12 pages of his lecture. The first 7 pages will shed out more light on what’s wrong with imperative languages; then, the next pages will explain how a language can be implemented on top of a very small number of sound and simple concepts that can be used and powerfully combined in all sorts of natural ways to describe computations. (Although it could be argued that some of this paper's ideas go even further than our current FP languages do, they won't hinder your understanding at all.) If you'd like to read about Backus' contribution to our field, I think these are the best links: http://en.wikipedia.org/wiki/John_Backus http://theory.stanford.edu/~aiken/other/backus.pdf http://www-03.ibm.com/ibm/history/exhibits/builders/builders_backus.html Another paper which helped me understand FP in relation with maths is Recursion Equations As A Programming Language. Last time I checked (Jan.), this paper was still not freely available on the web; but you can read most of its message through Google Books. It's a much easier read than Backus, but less complete; nonetheless, it's really, really highly recommended because it's complementary. Next, I've seen the following mentioned in quite a few places, and I think the general opinion is that it's also high-quality stuff. I'm yet to read it. Why Functional Programming Matters: http://www.cs.chalmers.se/~rjmh/Papers/whyfp.html Now, one might argue these papers' goal is more to introduce/motivate FP over traditional imperative programming. I would oppose to this that in order to back FP, these papers need to explain FP in very powerful terms for people; thus, they are great reads for the problem at hand. On Jun 8, 11:10 am, Daniel Lyons fus...@storytotell.org wrote: On Jun 8, 2009, at 7:24 AM, Nathan Hawkins wrote: The syntax and message passing emphasis aren't relevant to Clojure I don't have any experience with agents in Clojure, but I wonder if they be used to similar effect? Agents seem more like data in another thread to me than self-recursive functions in another thread, which is what Erlang's processes are like, but your remark piques my curiosity. Can one be implemented trivially via the other? — Daniel Lyonshttp://www.storytotell.org-- Tell It! --~--~-~--~~~---~--~~ 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: In let: unpacking maps with accessors too
Oh, I didn't know that. It makes me wonder, then, why integers were
not implemented as functions of sequential collections: (3
[:a :b :c]).
Ah, well. I guess since let can't be changed, it's then a choice
between using accessors or being more elegant. Thanks for the reply.
On Jun 8, 9:25 am, Konrad Hinsen konrad.hin...@laposte.net wrote:
On Jun 8, 2009, at 17:46, samppi wrote:
...I'd love it if the values of symbol keys could be any symbol, not
just keywords, so that the key symbol is bound to (val-symbol
the-map):
(let [{name this-is-a-symbol} person-1] ...) ; name is bound to
(this-is-a-symbol person-1)
It's backwards-compatible. But is this possible? Practical?
I don't think it could made to be backwards-compatible. The
documentation states:
Map binding-forms allow you to bind names to parts of associative
things (not just maps), like maps, vectors, string and arrays (the
latter three have integer keys).
The current implementation of destructuring map binding forms uses get:
(destructure '[{name :name} person-1])
- [map__268 person-1 name (clojure.core/get map__268 :name)]
This works as advertised with maps, vectors, strings, etc. Your
proposal would change the expansion to
- [map__268 person-1 name (:name map__268)]
That works fine if person-1 is a map, but destructuring a vector with
a map binding form is no longer possible.
Nothing stops you from defining your own let-like macro with your own
destructuring rules, of course!
Konrad.
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SWT (Cocoa) from Aquamacs+SLIME?
Hi everyone, I've started playing with SWT + Clojure (I know very little about SWT and I've just started out with Clojure, so please bear with me) and I would like to get it going from within Aquamacs Emacs + SLIME. I'm not sure if this is a real Clojure question or more of a Cocoa/Carbon specific thing, but since many are using Aquamacs Emacs as a Clojure IDE someone may have already seen this. I'm using Java 1.6 and I've built swt.jar from Eclipe CVS, using org.eclipse.swt.cocoa.macosx.x86_64 for the platform specific stuff. I'm trying a very simple Hello World which runs fine when started from a terminal REPL, but from Aquamacs Emacs, it creates an empty window (it does't even draw the window borders) and then it just hangs (as if the event processing loop never starts). My *inferior-lisp* buffer spews a lot of complaints about no autorelease pool being present, like this one: 2009-06-09 08:32:01.844 java[4010:20a03] *** _NSAutoreleaseNoPool(): Object 0x1001b1120 of class NSCFArray autoreleased with no pool in place - just leaking Is it possible at all to run SWT Cocoa from Aquamacs+SLIME? This is my script, cobbled together from bits and pieces I found online: (ns main (:import (org.eclipse.swt.widgets Display Shell Label) (org.eclipse.swt SWT))) (defn swt-loop [display shell] (loop [] (if (.isDisposed shell) (.dispose display) (do (if (not (.readAndDispatch display)) (.sleep display)) (recur) (defn do-it [] (let [d (Display.)] (let [s (Shell. d)] (doto (Label. s SWT/CENTER) (.setText Hello World!) (.setBounds (.getClientArea s))) (.open s) (swt-loop s d (do-it) And here's a command that's equivalent to what I run as a clojure- swank-binary: java -cp clojure-1.0.0.jar:clojure-contrib.jar:swt.jar -server -d64 \ -XstartOnFirstThread -Xdebug \ -Xrunjdwp:transport=dt_socket,server=y,suspend=n clojure.main Many thanks! gert --~--~-~--~~~---~--~~ 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 -~--~~~~--~~--~--~---
Thoughts on bags?
The relational operations work on sets. That's often useful, but there are situations in which preserving cardinality is more useful. One such situation bit me today -- I did some relational operations on some spreadsheet-esque data, much as I would in SQL or SPARQL, finally projecting to the two columns I cared about before adding up some numbers. The numbers didn't total correctly. A few minutes of reading my code narrowed it down to the projection, which of course outputs a set, discarding some of my inputs. Has there been any thinking about supporting a 'bag' sibling of 'set', and allowing it to be passed correctly through the relational operators? Right now I have a choice between rephrasing my code in non- relational terms, or adding a unique value to each item to thwart the distinctness semantics. I can't help but think that other people will also encounter this. --~--~-~--~~~---~--~~ 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: Thoughts on bags?
I think I know what you mean by a bag, but I'm not quite sure. How does a bag compare to a set, vector and/or list? On Jun 9, 1:31 am, Richard Newman holyg...@gmail.com wrote: The relational operations work on sets. That's often useful, but there are situations in which preserving cardinality is more useful. One such situation bit me today -- I did some relational operations on some spreadsheet-esque data, much as I would in SQL or SPARQL, finally projecting to the two columns I cared about before adding up some numbers. The numbers didn't total correctly. A few minutes of reading my code narrowed it down to the projection, which of course outputs a set, discarding some of my inputs. Has there been any thinking about supporting a 'bag' sibling of 'set', and allowing it to be passed correctly through the relational operators? Right now I have a choice between rephrasing my code in non- relational terms, or adding a unique value to each item to thwart the distinctness semantics. I can't help but think that other people will also encounter this. --~--~-~--~~~---~--~~ 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: Thoughts on bags?
I think I know what you mean by a bag, but I'm not quite sure. How does a bag compare to a set, vector and/or list? A bag is also known as a multiset: it's an unordered collection in which an item can appear more than once. Think of a set without the distinctness. --~--~-~--~~~---~--~~ 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 -~--~~~~--~~--~--~---
