http://stackoverflow.com/questions/7304879/make-string-from-sequence-of-characters

 (defn make-str [s c] (let [my-str (ref s)] (dosync (alter my-str str c)))) (defn make-str-from-chars "make a string from a sequence of characters" ([chars] make-str-from-chars chars "") ([chars result] (if (= (count chars) 0) result (recur (drop 1 chars) (make-str result (take 1 chars)))))) 

Thank you!

Given what I've just said, what I'm about to say won't come as a surprise. Your post above, about re-envisioning programs from other languages in Clojure, is a good one. So (and here it comes…) please feel free to do it yourself and send it in. Articles on this website will allow comments, so if somebody else has a different idea of how the program "should" be written and why, they will be able to do so.

As for a Getting Clojure magazine, for the time being, this website is the magazine. Once there's enough content, I'll create an actual magazine (PDF and/or print-on-demand) and make that available. Then when there's enough new content, I'll repeat the process.

You can send me the article directly if you want me to edit it. For instant gratification, do the following:

1. Click the "Home" text link at the top left of this page
2. At the bottom of the Home page, type your article title in the text box and click the "new article" button to its right.

Voila! You now have a wiki page for your article. Type in your text, click "Post it" at the bottom of the page, and your article appears on the "All articles" page, which is http://www.gettingclojure.com/system:all-articles. (Again, I can edit your article if you wish.)

Thanks again for posting—this is what will make GettingClojure.com successful!

As to learning the Java libraries, you'll learn what the Java API does, but you'll be calling it natively from Clojure. From my learning perspective, you can obtain documentation on the Java API all over the place.

I would get one of three books, Programming Clojure and Practical Clojure to start and eventually The Joy of Clojure. O'Reilly is publishing a Clojure book that appears to be geared more towards learning Clojure's LISP-ness.

The Cookbook here is quite good, and there are lots of blogs.

Good Luck.

Installations never go right; this is the inevitable result of non-commercial software (with documentation of varying quality and comprehensiveness) being combined in countless permutations on at least three different OS platforms. Nine months ago, it took me almost two weeks to get SLIME running. Now, things are much better…but these things will still happen.

I've got something older working, and I'm not touching it. I connect via M-x slime-connect, so your error message re. lein-jack-in is unfamiliar to me. So good luck! Google the error message first, and if that doesn't work, try posting on the Clojure Google Group. You can get these things working, but it takes perseverence (ask me how I know).

Who needs puzzle games? I install open-source software!

What am I doing wrong? Should I have gotten swank-clojure directly from github/technomancy instead?

I recommend swank-clojure, which gives you breakpoints *and* the ability to examine and manipulate local variables at the REPL—see http://hugoduncan.org/post/2010/swank_clojure_gets_a_break_with_the_local_environment.xhtml. I use the version of swank-clojure at https://github.com/technomancy, which is where you'll also find leiningen.

If you're interested in even more debugging power, there's swank-clj: https://github.com/hugoduncan/swank-clj. Useful info about it is at http://groups.google.com/group/clojure/browse_thread/thread/a683967fd8aee9e7 . Be warned—it's a newer project that is classified as alpha quality. Good luck!

My old C# habit for trying stuff was to change a dummy unit test and then compile/run. It had all the drama of flipping a big switch and waiting for a lumbering Frankenstein to wake up and do something, all the boiler plate of unit tests, etc. I'm so glad Clojure is a lisp.

I was wondering this about development environments other than emacs: can you navigate/slurp/barf/kill entire sexps in other IDEs like you can in emacs? (If I should ask this someplace else in the forums, let me know!)

I read "Out of the Tar Pit" and found the FRP concept interesting. By all means, proceed! Once you have working code, I can (if you wish) help you outline an article about the code; I've found that doing so makes writing go smoother and produces better articles. Feel free to contact me at "gregg AT-SIGN GettingClojure DOT-SIGN com".

Keep me posted!

One reason I dropped Clojure to go for Scala, after studying it for months, is because I didn't know how to extend existing Java classes using proxy. May be this is a good reason for me to pick Clojure again.

I come this this site from http://www.pragprog.com/magazines/2010-11/getting-clojure
Thanks a lot.

I'd be very interested in reading a Clojure "magazine". I think I'd
be interested in interviews with professional Clojure programmers. It's
usually hard to find good examples of Clojure being used in professional
environments.

I'd like to see some opinion articles, Clojure seems to come with lots
of fascinating philosophy which I'm sure Rich Hickey has plenty more to
share.

Articles with working code sounds good.

How about some code snippets showing off some particularly concise code.
There are plenty of gems around the 'net, not to easy to search through them.
Maybe try and abstract out a pattern (eg. when looping over more than one vector
consider using <pattern>). That's always fun to read.

Workflows are usually interesting. Lots of newbies would love to hear how others
*really* use their IDE/editor. Maybe brief overviews of vimclojure/slime and then
ways to optimize your workflow? Accessibility of clojure tools seems to be a weakness
IMO, at least for the more powerful ones.

If content is needed, I could could write something about genetic programming, Clojure web server performance or computer algebra.

Any opinions?

Ideas for articles:

1) A tour of the Java / JVM ecosystem for clojure programmers with little or no Java background. What are the libraries, frameworks, and tools every clojure programmer should know about, even if he or she never writes a line of java? How do we use them from clojure? Actually this might make for a nice series or even a regular column.

2) Articles about how to arrange your development environment, tailored to begininning, intermediate, and advanced programmers, and exploring a few different styles of workflow. For example, emacs/swank vs other IDE's, leiningen vs other building techniques, git vs hg vs whatever, etc. Obviously some of this is orthogonal to language choice, so a straight git vs hg article probably doesn't make sense.

3) You mentioned code walkthroughs — I'd love to see this for some key, important, popular, clojure libraries or apps. Not sure what to suggest, but reading good code is one of the best ways for me to learn a new language.

I think the preference for short names comes from a mathematical tradition. Many functions are useful on a wide range of values, so the implementers tend to use generic argument names. I find that short names are easier to read when composing nested expressions. Longer, more descriptive names are appropriate when something has a specialized meaning.

usually when I learn a new language I write a chess programm to have something
hands-on and a mission. But I wonder how to do this with clojure.
My problem is:
=> Usually you have a mutable board structure like a Mailbox, 0x88 or a Bitboard. So if I try to use immutable structures it sounds terribly inefficient.
Does someone have a hint here like:

• Well: try it in Clojure. It will optimize and not so much worse then Java. Even in your Chess problem.
• Try the core search in C++, C or D
• Here is another workaround…

On the other hand Clojure looks brilliant for distributed search and the safe writeback of the search-results that the threads will yield.

Thanks in advance
Stefan Edlich

Most of my C# code is heavily FP influenced as-is, so that part isn't a huge learning curve.

Clojure seems like a good modern tool, and I'd like to give it a fair chance, but…

1) I don't know the Java libraries
2) I don't know the Java IDEs
3) I really like Visual Studio and Resharper; emacs just isn't jiving well with me.

Where's a good place to start?

electronic medical record software

I have a string of data and I would like to get a map {:key value, :key value, …}

How can I do that?

I've got:

user> (split (slurp "data") #",")
["0" "2" "1" "5" "2" "8" "3" "15" "4" "9"]

And I would like:
{:0 2, :1 5, :2 8, :3 15, :4 9}

Thanks.

To anyone else reading this, if you've got the passion (and time) to make this a better site for Clojure beginners, let's talk! Write me at "gregg4 at-sign getting clojure dot com". Thanks.

—Gregg Williams, site manager

The syntax for calling a Java class constructor is "(JavaClass. args)" — the classname followed by a dot is the first element.

user=> (float= 0.0001 (- 12.305 12.3049))
true

But I can come up with a use case where it fails:

user=> (float= 12.3049 12.305)
true

Second, 'sort-by' wouldn't help us with the efficiency problem we are trying to handle via the Schwartzian Transform.

(sort-by factor-count int-list)

As an adjunct to that, I think that each recipe should be on a separate page. Pros / cons?

; Clojure has "subs" function, that works just like "substring"
;
(subs "Is this not pung?" 3 7) => "this"

; In the "center" example, you can use (count s) instead of (.length s)
; clojure.contrib.str-utils2 have most of the functions defined here

(apply str (interpose ", " (range 10)))

yields

"0, 1, 2, 3, 4, 5, 6, 7, 8, 9"

and

(apply str (interpose ", " ["Tom" "Jerry"]))

yields

"Tom, Jerry"

(defn play-file [file-name]
(let [absolute-name (.getAbsolutePath (File. file-name))
url (str "file://" absolute-name)]
(play-url url)))

So, what are you having trouble with as a Clojure programmer? I invite you (and anyone else) to write that up in a few paragraphs and submit it, either as an article or a forum topic. BTW, it'll be a *long* time before I have time to write an article like the proxy one!

Thanks again for posting! —Gregg

Thanks,

-Dave

How do you feel about this? Agree or disagree?