Re: Why does using a dynamic binding make a function impure?
On 19 July 2010 19:41, Laurent PETIT laurent.pe...@gmail.com wrote: 2010/7/19 Stuart Halloway stuart.hallo...@gmail.com use = rely on In your example, func relies on a variable which is (presumably, based on its use in other-func) intended for dynamic binding. Therefore, func is impure. It is idiomatic to name such variables with earmuffs, e.g. *forty-two*. Sure. But the OP is somehow true: it is by convention that it is declared pure. Indeed, even func itself could have been rebound dynamically, thus making the content of the result theoretically unpredictable, given only the values of its arguments. I think the point being made here is that, because other-func uses dynamic binding (and hence is impure) you have to be more careful about how you code it. For example, in the absence of impure code, it is perfectly acceptable to name intermediate values freely - so (defn demo1 [] (+ (some-fn) 17)) and (defn demo2 [] (let [res (some-fn)] (+ res 17))) are exactly the same. That doesn't work with the impure other-func: (defn other-func [] (binding [forty-two 6] (func))) vs (defn other-func-2 [] (let [res (func)] (binding [forty-two 6] res))) Transformations like naming intermediate values only work (at least, without analysis) in the definition of pure functions. When coming from an imperative language like Java or C, this seems glaringly obvious - of course you have to be careful when moving code round like that. The point is that in functional languages (and in Clojure when you avoid impure functions) you *don't* have to be careful - you can do as much of that type of refactoring as you want, without worrying. I hope that helps clarify things. Paul. -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en
Re: clojure.contrib.sql does not protect table names?
On 14 July 2010 16:21, Tim McCormack basalgang...@brainonfire.net wrote: Is there some kind of JDBC nonsense that I'm not aware of? Are backticks a special feature of MySQL that can't be read by all JDBC- compatible RDBMSs? I'm not a database person, but it seems to me that either backticks should be placed around all table, database, and column names, or a warning should be added to the docs about only using non-reserved alphabetic table names. Certainly backticks aren't understood by Oracle. Unless JDBC does a translation, I think it's database specific (Oracle uses double quotes instead). Paul -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en
Re: ClojureDocs.org
On 12 July 2010 23:25, j-g-faustus johannes.fries...@gmail.com wrote: The site looks very nice, I especially like the find real world examples functionality and the fact that it collects documentation for common non-core libraries as well. I made my own cheat sheet for private use over the past month or so, core functions only. It's at the 80% stage, I don't expect it will ever be 100%, but I have found it useful: http://faustus.webatu.com/clj-quick-ref.html Can I suggest omitting the Table of contents sidebar when printing? I've not tried printing the document to see how it looks, but removing the sidebar would be an essential starting point... Paul. -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en
Re: Idiomatic Clojure namespace names
On 10 July 2010 09:06, James Reeves jree...@weavejester.com wrote: On 9 July 2010 17:46, Paul Moore p.f.mo...@gmail.com wrote: Is there any benefit to using a name like foo.core (or foo.api) rather than simply foo (beyond sytlistic considerations, that is)? Clojure compiles foo to a package-less class called foo. foo.ciore is compiled to a class called core in the package foo. Package-less classes are a bit problematic if you want to call them from another Java package, IIRC. But if your library isn't intended to be AOT-compiled and used from Java, I don't think it makes a difference. Ah! I hadn't realised the package/class distinction - a result of my having no Java background. Thanks for the explanation, I can now understand the trade-offs better. Paul -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en
Re: Idiomatic Clojure namespace names
On 9 July 2010 17:30, Laurent PETIT laurent.pe...@gmail.com wrote: Indeed, foo.api sounds better than foo.core to me, now than I'm exposed to that (core sounds more like 'internals'). But still I prefer to have the library name at the end of the namespace, it's easier to spot than in the middle (e.g. I prefer net.cgrand.parsley to paredit.core) Is there any benefit to using a name like foo.core (or foo.api) rather than simply foo (beyond sytlistic considerations, that is)? Leiningen creates a foo.core source file as part of its new project skeleton, but I prefer foo. Before I start fighting Leiningen, are there any pitfalls I'll hit (other than the obvious problems of fighting your tools...)? Paul. -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en
Re: -- macro proposal
On 6 July 2010 22:02, Greg g...@kinostudios.com wrote: Greg you're enthusiasm is appreciated. But this ML is filled with talented and smart people who have an equal grasp of logic and reason who have been using Clojure for a couple years now and they aren't clamoring to your nice snippet of code. That's something to consider. It is indeed. I would be surprised though if I was the only person who sees -- as useful, and that brings us to your next sentence... It is interesting that this is not the first time such a feature has been requested. But again, I haven't ever had a need for such a general threading macro. I'll make a list here of the reasons given for Yay/Nay so far: Nay: 1) I haven't had a need for a general threading macro. 2) The response so far is negative (and consists of repeating point #1 above). Sigh. I just *know* I shouldn't get involved in this... - It isn't particularly readable. (I know you disagree with this, but nevertheless, it has been stated as a negative point). - It is perfectly possible to write the macro yourself and use it in your own code. The fact that people haven't done this implies that it's less useful than you claim (you'll say I'm repeating (1) here, but never mind). - It is easy to emulate using the existing macros and anonymous functions like #(fn a % b). - The named variable can be omitted from a form. The implications of this are far from intuitive (and in the previous thread, there was even a suggestion that this should be treated as an error). Yay: 1) This has been requested multiple times. (Which pretty much cancels out Nay #1 #2). I think the statement was that it's been requested twice. Better than just once, but hardly multiple/ 2) -- is a generalized version of - and -, and therefore useful in situations where you can't use - or -. It is the 'nth' to 'first' 'last'. If you use anonymous functions, there are no such situations. It's a convenience rather than a generalisation. 3) It makes code more readable by explicitly indicating where the argument is passed. Your view. I find it very *un*readable. The first time I saw the let- proposal, the named argument completely confused me. First, I misread the forms as expressions rather than templates, then I didn't follow the way the variable was (in effect) updated in each step. At least if I've outlined the positions correctly, it's pretty sad that this is being fought against so hard. You haven't. I'll make the additional points that: - There are plenty of macros and functions in the core that I'm sure you've never used once, yet they are there for others who find them useful. So simply responding to my proposal by saying, I don't think I need it isn't a valid reason against its inclusion. Correct. The argument you are mischaracterising is that there is no evidence that an existing body of code (such as clojure core or clojure contrib) would benefit in any significant way from the proposal. Paul. -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en
Re: -- macro proposal
On 6 July 2010 22:24, Greg g...@kinostudios.com wrote: This would be most likely java interop, ie. -. There the main arguments are 99% of the times the first or the last ones. So - or - will work OK, so what happens when one of the functions takes it in the front, and the other in the back? Or what happens when you're using a piece of code that doesn't follow either convention? Are you saying such code doesn't exist? Use an anonymous function. In both those cases, - and - become useless. Not useless, merely less convenient. Paul. -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en
Re: Documentation and examples (and where is the documentation on reduce)?
On 2 July 2010 15:50, Meikel Brandmeyer m...@kotka.de wrote:
Then there are examples like this one:
(reduce '* '(1 2 3))
Someone who is new to Clojure and tries to understand reduce... Does
he understand why the result is 3? A result which relies on a not very
well-known fact, that you can actually call symbols like keywords for
map lookup with up to two arguments. (I bet there quite a few of
seasoned clojurians who didn't know that) I - if I was a newbie to
the language - would mainly think: wtf?
Even with your explanation, I'm baffled... I can get to
user= ('* ('* 1 2) 3)
3
Ah. This means look '* up in ('* 1 2) and use 3 as the default if you
don't find it. And you don't (for all sorts of odd reasons - why
doesn't this raise a what are you doing, it's not even a map you're
looking up in exception? :-)), so the result is the default, 3.
Uh, yeah.
That example is actually harmful - as it confused me about what does
and doesn't need quoting - something I would probably have got right
instinctively until I read this :-(
Paul.
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Managing the classpath
First, a disclaimer - I don't have any problem with the idea of the classpath in Java. In principle, it's pretty similar to Python's sys.path. And jar files are much like Python having zip files on sys.path. So I'm familiar with the idea. Where I struggle is with the practicalities of managing the classpath. From what I can tell, there is no way of modifying the classpath from a running Java/Clojure program (barring use of a custom classloader which sounds like deep magic). So, assuming that is right, I need to list my dependencies in advance, when I start the JVM (either by setting the CLASSPATH environment variable, or with the -classpath argument). Generally, I avoid using global environment variables like CLASSPATH (except if they are locally set in a wrapper script), so I guess that I have the following options for my Clojure applications: * Use something like lein uberjar to wrap all my dependencies up in one file * Create an application-specific wrapper, which sets CLASSPATH (or uses -cp) and runs my application I have personal reservations about both of these options (I won't elaborate, to avoid boring people with my prejudices - ask if you really want to know) so I guess my question would be - is there another option I have missed? Python doesn't have these issues because (a) conventionally, dependencies are installed into the site-packages directory which is on the standard sys.path - it appears to me that the JVM doesn't have such an always available install location, and (b) for special cases sys.path can be manipulated at runtime (as noted above, the JVM doesn't really have this option). One further question - does having a lot of entries on CLASSPATH slow down JVM code (either at startup time, or in terms of slowing down runtime class loading)? Essentially, is there a cost to including things like clojure-contrib just in case? (I don't imagine that the cost would be significant for just one such case, but I could imagine that if the practice were to become common, it wouldn't be long before there were many extra entries, not just one). I appreciate that this question is only tangentially Clojure-related. If there is a better forum to discuss this type of question, please feel free to direct me there. Thanks, Paul. -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en
Re: Managing the classpath
On 1 July 2010 15:29, Laurent PETIT laurent.pe...@gmail.com wrote: Hello, note that with java 6 you can specify at once to add all the jars located in a directory: java -cp libs/* clojure.main and you can place any jar you want in directory libs. and this is composable: java -cp clojure.jar:libs/* clojure.main My 0.02€, just in case you didn't know this (rather recent) possibility. Thanks. I had actually just discovered this possibility in the last few days. In fact, it is what raised in my mind the question of whether having too many jars on the classpath would hurt performance. I've not yet fully integrated the idea into my thinking. I guess it allows the possibility of bundling all application dependencies into a lib directory, then doing something like java -cp clojure.jar;lib/* clojure.main myapp.clj But in practical terms, I guess that's the equivalent of an uberjar. (My biggest concern about an uberjar is that I end up with each app having a separate bundled copy of all its dependencies. That makes version management a huge pain - imagine a bugfix release of clojure.jar - but is otherwise not an unreasonable option). Paul. -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en
Re: Managing the classpath
On 1 July 2010 16:49, Kevin Livingston kevinlivingston.pub...@gmail.com wrote: Some of the build tools like Maven can help a lot. (Thanks for your other comments, which I've cut. But this one made me think). I've heard comments like this elsewhere (with regard to both Maven and Leiningen), but I'm not quite sure I follow. You say [...] put the jar on ProjB's class path But as I understand it, ProjB doesn't *have* a classpath in its own right - rather, when you run ProjB, you specify a classpath (and if you get it wrong, ProjB won't run). But there's no concrete, discoverable entity that can be considered ProjB's classpath, and referenced from elsewhere. Otherwise, the often-quoted clj.bat driver script could be written as Get %1's classpath into CLASSPATH somehow java clojure.main %1 and nobody would ever worry about classpaths again :-) If Maven (and/or Leiningen) actually do maintain, for each project, metadata including its required classpath, then I'd love to know how to extract that metadata - because I could certainly use it to write a generic driver script (at least for my own purposes, even if it wasn't sufficiently general for every use). Paul. -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en
Re: Clojure's n00b attraction problem
On 30 June 2010 04:02, Jason Smith ja...@lilypepper.com wrote: So I'll say it again, it's just not that simple. Unless you already know Java, and the only learning curve you face is the new features in Clojure. Then it's not bad. But it does give you new ways to cut your foot off more quickly. :-) An interesting alternative not that simple point of view, that it's not Clojure's Lisp-like features that are the hard bit, but the Java integration :-) Based on this comment, maybe I could ask an alternative question - can you suggest where I should go to read some tutorials which would give me a fast start on just enough Java infrastructure to get comfortable in Clojure? Most of the Java tutorials I've seen tend to assume I want to learn Java - I know enough Java to read code samples, and that'll do for what I want. Paul. -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en
Re: Clojure's n00b attraction problem
On 29 June 2010 23:31, Sean Corfield seancorfi...@gmail.com wrote: FWIW, I blogged a short step-by-step post on getting up and running with Leiningen to show some Clojure at the repl, run as a script and compiled to a JAR and run via java: http://corfield.org/blog/post.cfm/getting-started-with-clojure Bear in mind my blog audience is folks with some familiarity with Java... That's nice! I never noticed lein repl before... One thing I've found is that the experience (as described) is a lot simpler on Unix/Linux/Mac than my experience on Windows. Part of the reason may be that lein self-install doesn't work on Windows. I may look into that. I wonder - would a Windows installer package that installed clojure, clojure-contrib and leiningen, and set up some basic paths and start menu shortcuts be of use? I'm not a great fan of installers myself, but I suspect that once I get a clean working environment set up for myself, it wouldn't be a big step to package that up in an installer so that others could use it. Paul. PS What are the standards for jar naming conventions? I have seen some people use clojure.jar and others use clojure-1.1.0.jar. Should I have version numbers in my jar filenames? Is there a Java best practice I should be referring to for things like 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: Newb Question
On 28 June 2010 20:24, Angel Java Lopez ajlopez2...@gmail.com wrote: Hi people! Any way to produce a lazy seq of chars, that prints as a string, based on two parameters, n (number of repeats), text (text to repeat)? Then, something like (myrepeat 100 superdupertext) could be implemented without a big processing or concatenation. The built in repeat is lazy: user= (doc repeat) - clojure.core/repeat ([x] [n x]) Returns a lazy (infinite!, or length n if supplied) sequence of xs. Paul. -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en
Re: Clojure's n00b attraction problem
On 28 June 2010 19:49, Mike Meyer mwm-keyword-googlegroups.620...@mired.org wrote: Yet another set of choices n00bs are faced with is figuring out how to actually compile their source into an executable. Executable? We're talking about Java here. It doesn't do executables - it does jar files. There's little reason to build those as a newb, as it's not noticeably harder to run the source than it is to run a jar file - or to import them if you're building libraries. We're not talking about Java here, we're talking about clojure! A certain proportion of new clojure users are coming from non-Java/non-JVM backgrounds. To them, how do I make an executable is a perfectly valid question. And clojure doesn't do executables isn't a particularly encouraging answer (not even if you blame Java for it :-)) Classpaths, server vs client JVMs, ant/maven, all of these are confusing hurdles to get over if you don't have any Java experience. For such people, introductory clojure material needs to (a) assume no JVM/Java knowledge, and (b) provide some guidance for how to interpret the inevitable Java terminology that a newcomer will encounter. For example: Q: How do I make an executable in clojure? A: Clojure scripts can be executed in a similar manner to scripting languages like Python or Perl - clj myscript.clj. [Note: a standard clj wrapper script should be supplied with clojure!] However, even when executed like this, clojure code is compiled (for more details read up on JVM bytecode, and the Java just in time compilers). You can compile clojure code into a jar file - which is a JVM executable format which can be run using the java command (insert reference to more detailed explanation here). More or less self-contained formats (bundling dependencies, or hiding the invocation of the java command) are possible, but are generally reserved for more specialised applications. Q: What are ant, maven? A: JVM build systems, commonly used in the Java world. The clojure community is beginning to standardise on Leiningen (insert reference here) which uses a more clojure-like language for describing builds, but which works with the existing ant/maven infrastructure (so all of the existing libraries available via these tools are available for free in Leiningen). If these examples are useful, feel free to add them to a FAQ or newbie documentation. Paul. -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en
Re: Life on the bleeding edge
On 29 June 2010 06:47, Mark Engelberg mark.engelb...@gmail.com wrote: Yes, that is disconcerting that clojure-contrib produces errors on Windows (sigh, it often feels like Windows is a second-class citizen when it comes to clojure), but that did the trick and allowed the build to complete. Thanks for the tip. Is there anything a clojure newbie with little JVM development experience (but a willingness to learn) can do to help with the Windows situation? From what I understand, Java itself is fine on Windows, so I assume this is a clojure-specific issue? Paul. -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en
Re: Clojure's n00b attraction problem
On 28 June 2010 23:13, Lee Spector lspec...@hampshire.edu wrote: and more recently I had to figure out about.dotted.names and their meaning with respect to directory structures, in order to get require to find a second clj file. It's not complicated, but it's also not obvious to everyone first coming to Clojure. That's actually far more of a stumbling block than the classpath. In my experience, very few languages/environments tie directory structure and language identifiers (class name in Java, namespace in Clojure) together as closely as the Java/JVM environment. As in, if you change the filename, you have to change the namespace declaration as well - and vice versa. Or Clojure can't find your code, and you have no idea why :-( And yet, there's no reference that I can see to this fact in any of the Clojure tutorials. Not even in Programming Clojure (which is generally a great book). I could have missed something, of course - I wasn't looking for the information - but I've hit the issue a couple of times, so I suspect if I had seen anything, I would have remembered. Paul. -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en
Re: Clojure's n00b attraction problem
On 28 June 2010 22:41, cageface milese...@gmail.com wrote: On Jun 28, 12:16 pm, Martin DeMello martindeme...@gmail.com wrote: It depends. I found the concepts pretty easy, since I have done a lot of functional programming, but when I was new to clojure I had a truly horrible time figuring out the various classpath issues needed to get things working. What is it about the classpath in particular that people find difficult? Is it that different from things like PYTHONPATH or RUBYLIB? The main differences I can see are: For me (and to be honest, I don't have any real problem with the *concept* of the classpath, just with some of the practicalities) it's the fact that by default, Clojure doesn't work. OK, that's overstating it - the issue is that clojure.jar isn't on the *default* classpath. This is hardly surprising, of course, but it does make it harder - you encounter the classpath right at the start, before you even get Clojure running. And unless you write your own wrapper, you keep having to deal with it (hmm, java -cp, now where did I put clojure, D:\Apps\Clojure\clojure.jar, clojure.main, oops no, this is the PC it's on the C drive. Or ...). I know you can set the global CLASSPATH, but that feels a bit too general - what else might it affect? The simple fix to that, of course, is to supply a small wrapper script with clojure. The response it's easy for you to write one yourself misses the point - we're talking about the out of the box experience. If clojure.org included a Download Clojure link that pointed at a zipfile containing clojure.jar, clojure-contrib.jar, and a wrapper script (well, two, one for Unix, one for Windows) which set classpath based on the location of the script and ran Clojure, then people could download that, unzip it anywhere, and go. It doesn't solve all the world's problems, but it sure simplifies the initial experience! For what it's worth, here's a trivial clj.bat for Windows: @echo off setlocal set CLASSPATH=%~dp0clojure.jar;%~dp0clojure-contrib.jar;%CLASSPATH% java clojure.main %* endlocal Add as much extra complexity as you like, but that's enough for a starter. Paul. -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en
Re: Clojure's n00b attraction problem
On 29 June 2010 06:11, cageface milese...@gmail.com wrote: On Jun 28, 9:14 pm, Michael Richter ttmrich...@gmail.com wrote: Ah. The Clojure community has already started down the road to Common Lisp-style, smugness-generated obscurity and disdain. Bravo! Well-played! Not at all. Nothing would make me happier than Clojure for Dummies and Wrox Professional Clojure books on the shelves of every Barnes Noble programming section. It's pained me to watch Python and Ruby far outpace the growth of any functional language in the last ten years. I'd love to stop looking for excuses to sneak things like Clojure under the radar at work and actually have a management mandate to use them. It is very, very hard to get a decent characterisation of newbies. It's too wide a range. You've lumped at least three different possibilities in the paragraph above alone: - Completely new programmers (Clojure for dummies) who need to learn things like what is recursion, how do I do the same thing 10 times, etc. - Experienced programmers in a scripting language (Python/Ruby) who know how to program and need to know how Clojure differs (and there's a whole subrange in here). - People who work in a Java Shop (sneak things like Clojure under the radar - I'm making assumptions here) and who work with the JVM regularly, but maybe have little or no experience with non-traditional languages. And by my own argument, there are many more possibilities. Each of these groups will want something different (or more likely, look for the best fit in what they can find, and ignore the bits they don't need). It's important to look at what people are actually asking for in each case, and not offer a single generic response to everyone (you'd offend me if you suggested I need Clojure for Dummies, but on the other hand, you'd look elitist to someone who had never programmed before if you launched straight into recursion or the advantages of immutability when a new programmer asked for help getting his Hello, World program to write its output 10 times...) The fact remains though that Clojure trades in heavy concepts. The syntax alone will simply be a non-starter for at least half the potential audience. Toss in concurrency and non-mutability and ubiquitous recursion which are tricky concepts no matter how cleanly exposed in the language. Only for certain audiences. And anyone can learn given a sympathetic teacher. What I wouldn't do is expect people to have to pick up multiple things at once. That's why, for people who are new to the language concepts in Clojure, I'd say you want a fast start environment which lets them get straight to writing (simple) code. Writing a hello world program, or your first recursive factorial, shouldn't be hard. java -cp clojure.jar clojure.main myprog.clj isn't hard, but a trivial script that wraps that as clj myprog.clj is a little less intimidating (and as a bonus, matches the expectations of people who have seen Python, Ruby, or any one of many others). And a straightforward if you like IDEs like Visual Studio, grab this package for now and you're off will help people who prefer an IDE. (They can make their own choice from the various options later, when they have more experience). As many posters have said in this thread, you really do have to have a decent grasp on Java to do real work in Clojure so you're already on the hook for two languages, one of which is a baroque and provincial monster. OK, that's a good point. For people who won't have an issue with Clojure's concepts (e.g. Lisp users, people with a wider range of programming experience, etc) this means the message is you want to learn Clojure - presumably because it's a high-level, sophisticated language - so you also need to learn Java (which, frankly, is pretty much the antithesis of a sophisticated language in many such people's minds). Maybe JVM experience can't be avoided. But it's a bitter pill to swallow for a certain class of newbies (and this is where I'd place myself) so why not try to make it easier? As some examples of what could be done: - Build a page of JVM concepts for non-Java programmers - Collect links to tutorial information on the key JVM concepts, looking particularly for material which is as language-agnostic as possible. The Jython, JRuby, Groovy, Scala people presumably also have this problem - why not share any generic links with them? - Promote clojure-like alternatives to Java tools (Leiningen vs Maven) for people with non-Java background. Work with such people to pick out places where the documentation of such tools assumes too much knowledge, and work to improve it (I'll help here!) - Give examples of how to use the more obvious benefits of the JVM-hosted environment: * How to find and use some of the huge range of 3rd party Java code out there (not interop, but finding things on the net, referencing them in your project, etc etc). * How to use the scalability of the JVM (hosting a Clojure app
Re: Newb Question
On 29 June 2010 15:14, Angel Java Lopez ajlopez2...@gmail.com wrote: Hi people! Paul, yes! but... The apply and str evaluations in (apply str (repeat n text)) are lazy? I guess the result could be a big string. Isn't it? So you're looking for a result that behaves like a string, but isn't an actual java.lang.String, rather it's a type that produces characters lazily, on demand somehow? I'm afraid I've no idea if Clojure has such a thing, or even if it could support such a thing. (There's no string abstraction similar to the seq abstraction, as far as I'm aware). But I'm very new at Clojure, so I could easily be wrong... Paul. -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en
Re: Life on the bleeding edge
On 29 June 2010 18:36, Mark Engelberg mark.engelb...@gmail.com wrote: On Tue, Jun 29, 2010 at 12:30 AM, Paul Moore p.f.mo...@gmail.com wrote: Is there anything a clojure newbie with little JVM development experience (but a willingness to learn) can do to help with the Windows situation? From what I understand, Java itself is fine on Windows, so I assume this is a clojure-specific issue? Paul. Tom mentioned to me a few weeks ago that he'd love to have some help getting autodoc to work on Windows, and that he'd be willing to supervise someone who had the time to make the changes. That might be a great way to dive in! OK, I'll take a look. Thanks. Paul -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en
Re: Leiningen documentation review?
On 29 June 2010 21:03, Phil Hagelberg p...@hagelb.org wrote: On Wed, Jun 16, 2010 at 9:24 PM, Phil Hagelberg p...@hagelb.org wrote: Mostly I'd like feedback on the tutorial: http://github.com/technomancy/leiningen/blob/master/TUTORIAL.md But if you've got some time to look over the readme, that would be great too: http://github.com/technomancy/leiningen/blob/master/README.md With all the newbies that have chimed in recently with strong opinions on the newbies thread, I was wondering if I could convince some of them to help the out-of-the-box experience by suggesting improvements to the recently-revised pieces of documentation above. =) I'd read the current versions of the docs. The README seems not to have changed much, but that's OK, it was pretty good before. The tutorial looks pretty good now - it does an excellent job of covering what's needed of the Maven infrastructure without expecting the reader to follow Java-style material or read too many links to source documentation. One thing I would have found useful, although it's not strictly something for Leiningen, is a brief explanation of how namespace declarations need to match filenames. My experience so far is that all my initial code has been single-file scripts (where I could get away with ignoring namespaces and just naming the file whatever I wanted). When I made the leap to proper projects, I moved to Leiningen and at the same time, I encountered namespaces - so a note in the Leiningen documentation on how to define my namespaces to match my project structure would have saved me a significant amount of grief! Paul. -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en
Re: Batch file wrappers on Windows
On 21 June 2010 22:12, Russ Olsen russol...@gmail.com wrote: Paul, One way would be to use the cljw.exe that comes with dejour. This is a windows executable that runs clojure without creating that annoying extra window. Thanks. That's certainly one option - I could probably without too much difficulty put together something similar for Leiningen. It sounds like there isn't a generic answer, so going with a custom launcher sounds viable. Hmm, I wonder whether a stub executable plus a suitable Ant task / Leiningen plugin (see how I use these terms like I know what they mean? :-)) would be an option - add some static data onto the stub, which the stub reads and sets the appropriate variables and command line args, then launches Java. Something to think about... Paul. -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en
Re: Batch file wrappers on Windows
On 22 June 2010 00:11, Rick Moynihan rick.moyni...@gmail.com wrote: On 21 June 2010 18:42, Paul Moore p.f.mo...@gmail.com wrote: 3. Using a bat file to start a GUI application from Explorer causes an unnecessary and ugly console window to appear. You should use javaw instead of java to start the JVM without the console window appearing. This should ship with both the JRE and JDK on Windows. Sorry for not being clear - I know about javaw, but even with that, double clicking on a .bat file flashes up a console window (briefly). I can also set the console to start minimised and it's then a very minor inconvenience. As I said, there are workarounds (and this is the least problematic of the three issues I noted) but I still find it an issue. Clearly others don't get so up tight about these inconveniences as me, which is fine. At least that means I haven't missed a solution that already exists. Thanks for the feedback, Paul. -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en
Re: Batch file wrappers on Windows
On 22 June 2010 15:15, Lars Nilsson chamael...@gmail.com wrote: Maybe Windows Script Host is an option, if you haven't looked at that one yet. Yes, WSH/VBS is a reasonable option. There are some gotchas which you need to be careful of though - there's *still* only one filetype (.vbs) which is executed by cscript or wscript depending on user-settable defaults (cscript //H:wscript) which makes it unreliable. For a really robust solution, I think a custom EXE might be the best (for the user) answer. But this is probably far too Windows-specific for the list now. I'll go off and try to implement something and report back. Thanks for all the feedback, Paul. -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en
Batch file wrappers on Windows
The common way of running Java applications (and hence Clojure code) on Windows seems to be to use a batch file wrapper (for example, lein.bat for Leiningen). It seems to me that there are a number of issues with this: 1. Batch files don't nest well - if I want to call lein.bat from within another batch file, I have to remember to say call lein arg arg... rather than simply lein arg arg... as the latter doesn't return to the calling script. 2. I use JP Software's Take Command, which implements a command language almost, but not precisely, like that of cmd.exe. As a result, lein.bat (in particular, possibly others) fails with syntax errors. I appreciate that this is a Take Command problem (and it's not too hard to work around, in fact) but nevertheless it does routinely trip me up. And presumably other Take Command users have the same problem. 3. Using a bat file to start a GUI application from Explorer causes an unnecessary and ugly console window to appear. Before I spend time trying to solve a problem that the Java community turns out to have solved years ago, is there another solution that people use? Or is it just one of those things that Windows people put up with (I'm not a typical Windows user, I guess :-))? Thanks, Paul -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en
Re: Basic toolset for non-Java programmer
Thanks to Ryan, Rob and Alex for the suggestions. I'll have a deeper look into all of them. Paul -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en
Re: Clojure script in the classpath
On 19 June 2010 07:24, rzeze...@gmail.com rzeze...@gmail.com wrote: On Jun 18, 6:15 pm, Paul Moore p.f.mo...@gmail.com wrote: I've just seen a couple of postings which, if I'm not mistaken, imply that it's possible to have a Clojure script in my classspath. Is that right? Yes, you can have .clj files on your classpath. In fact, you can pretty much have anything on your classpath. Checkout java.lang.ClassLoader http://java.sun.com/j2se/1.5.0/docs/api/java/lang/ClassLoader.html#getResource(java.lang.String) . This is what Clojure uses under the covers. Thanks! (And thanks for the rest of your comments). I'll look into this a bit more. I think that my experiments were failing because I had the namespaces wrong - thanks for the pointer. Paul. -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en
Re: Clojure script in the classpath
On 19 June 2010 17:22, Chas Emerick cemer...@snowtide.com wrote: If you're just looking to run a script that happens to be on the classpath, you can do so by prepending an '@' character to the classpath-relative path to the script. So, if a directory foo is on your classpath, and a clojure file you'd like to run is at foo/bar/script.clj, then you can run it with: java -cp your_classpath_here clojure.main @/bar/script.clj FWIW, this is noted in the documentation for clojure here: http://clojure.org/repl_and_main Nice! Thanks. Paul. -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en
Re: Enhanced Primitive Support
On 18 June 2010 15:08, Stuart Halloway stuart.hallo...@gmail.com wrote: While I enjoy a theoretical debate as much as the next person, it would be nice to see (1) examples of real code that fail on reasonable inputs, if this change were made. And how difficult it would be to fix them. (2) examples of real code that get way faster, and the ease of making those changes (if any). WRT #1, we have tested a few dozen libs, and found only a single trivial breakage in their test suites. But I would say tha is still just plural anecdotes. More data welcome! I'm new to clojure, and while I have an interest in fast number crunching, and in easily using big numbers, I don't have a valid opinion on the whole matter. However, I know that some time back, Python changed in precisely the opposite direction - from separate small and big numbers to a unified numeric type. Their situation is completely different (not least because all Python objects are effectively boxed, so the speed benefit of primitive arithmetic isn't relevant) but there may be real-world examples of code that demonstrates (1) in the Python discussions. If the information might be useful, I'd be happy to do some searching of the archives. Paul. -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en
Basic toolset for non-Java programmer
I'm wondering, what would be a useful basic set of tools for a newcomer to Clojure with no Java background? I'm not really talking about IDEs (everyone has their own opinions about IDEs, and I've seen some discussions elsewhere to give me some pointers on that one). I'm more interested in things like build tools, testing frameworks, debuggers, etc. Also, in terms of deployment, what should I be looking at? To try to clarify what I mean: - Build tools: There seem to be things like ant, maven, leiningen. How do they relate to each other? Is there an obvious best answer or should I be expecting to check them all out depending on my needs? In that case, are there any good comparisons around? - Debuggers: Should I be assuming I use my IDE for debugging? What if I stick to a basic text editor to develop my code? Is there a good standalone debugger? - Profilers: Same sort of question - do IDEs offer this, are there standalone tools? - Testing: I've not really got to the documentation on Clojure's own testing tools, so maybe that's all I need, but are there testing frameworks I should look at, that sort of thing? - Deployment: For simple standalone utilities, am I looking at bat file wrappers (I'm on Windows mainly) to set classpath and the like? Given that there are some annoying limitations with bat files (nasty nesting behaviour, ugly console windows for GUI applications), are there any commonly used better solutions? For web applications, I gather that a servlet container (all that fancy J2EE stuff :-)) and something like compojure is a good place to start. For non-web long-running services, is it still reasonable to use an application server, or should I be looking at something to wrap a Clojure app up as a Windows service (something like Java Service Wrapper (http://wrapper.tanukisoftware.org/doc/english/download.jsp) came up for me on a Google search)? That's a lot of stuff, and I certainly don't need to dive into all of this at once, but any pointers, comments or suggestions would be very gratefully received. Thanks in advance, Paul. -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en
java -server
More of a Java question than a Clojure one, but it's in the context of clojure, and I don't know a better place to ask, so forgive me... I've seen a couple of references in articles about clojure to using java -server. My java executable has a server option, but when I try it, I get told: Error: no `server' JVM at `C:\Program Files\Java\jre6\bin\server\jvm.dll'. I have java version 1.6.0_20 Java(TM) SE Runtime Environment (build 1.6.0_20-b02) Java HotSpot(TM) Client VM (build 16.3-b01, mixed mode, sharing) This is on Windows 7 32 bit. Is there a different download I should be using to have a server VM available? (Is it just a J2EE thing? I've never used J2EE except in enterprise setups, and I'd certainly not expect to use it on my PC). Paul. PS I suppose there's a more general question - does java -server make enough of a difference for me to be bothering about all 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: java -server
On 3 June 2010 21:25, Aaron Cohen aa...@assonance.org wrote: This error indicates that your java executable is coming from the JRE rather than the JDK. On windows, the JRE only includes the client virtual machine. If you have the JDK already installed on your computer, switch your JAVA_HOME and PATH to use it instead, and try it again. Thanks, that was precisely the issue. Regards, Paul. -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en
Re: Multithreading didn't make my program as much faster as I expected...
On 31 May 2010 06:12, Zak Wilson zak.wil...@gmail.com wrote: The trouble with pmap is that it only works well with a slow function and a short sequence. In trivial tests, it seems to be best if the sequence has as many elements as you do cores. I've been experimenting with things that are like pmap, but work better in situations that I care about. I'm having trouble getting full performance out of a quad-core machine, but dual-core is working pretty well so far. Here's some discussion with a link to sample code: http://groups.google.com/group/clojure/browse_thread/thread/963cdb76f0c3c178 And here's my personal utility file containing mostly re- implementations of things I didn't know where to find. The zpmap function is an eager parallel map that works well on large vectors and maps with a fairly fast function: http://github.com/zakwilson/zutil-clj/blob/master/util.clj Interesting! Reducing the number of parallel threads in my test case from 10 to 2 improved the speed of the test from 12 seconds to 10, which is about as good as can be expected. And it immediately steps back up to 12 seconds when I use 3 threads. So for CPU intensive tasks, it seems that having precisely the same number of threads as CPUs gives the best performance. It looks like Java schedules 1 thread per CPU, until it can't, and at that point scheduling overhead kicks in (costing something like 30% performance). How did you arrive at the number of CPUs + 2 approach in zpmap? I'd have thought that the +2 would hurt performance as it did in my case. So even when Clojure makes threading as easy as possible, it's still complicated in subtle ways. Ah, well :-) Thanks for the help. Paul. -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en
Re: Clojure script with shebangoid on windows
On 31 May 2010 07:48, alux alu...@googlemail.com wrote: Hello Glen, good hint. Problem and solution reproduced ;-) Yes, it looks like Clojure's (comment ...) form requires the contents of the comment to be syntactically correct Clojure forms. As Glen says, forward slashes seem to work - although personally, I dislike being forced to use forward slashes on Windows :-( Is there a multi-line comment form in Clojure that can contain arbitrary text? Paul. -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en
Re: Clojure script with shebangoid on windows
On 30 May 2010 12:31, alux alu...@googlemail.com wrote: Small addition, you missed to add the : before eof replace goto eof by goto :eof Thanks, good catch. (goto eof without the colon works on TCC, which I normally use as my command shell). Paul. -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en
Multithreading didn't make my program as much faster as I expected...
I've written a small simulation program, in order to help me learn Clojure. I've reproduced it below. It's quite likely not very idiomatic - any suggestions on how to improve it would be nice. However, my main concern is that it doesn't seem to scale as I would expect when multi-threading. The simulation is a simple test of rolling 3 6-sided dice 1,000,000 times. It uses Sean Luke's Java implementation of the Mersenne Twister RNG. I'm using the fast (non-threadsafe) version, which is why I'm using a separate MT instance in each thread. The non-threaded version takes about 18 seconds to run, with CPU showing at about 50% throughout (on my dual-core PC). The threaded version shows CPU maxed out at 100%, but still takes 12 seconds to run. That's not a bad speedup, but it still implies there's about a 33% overhead for multithreading. Are these plausible sorts of figures to see? Or should I be able to get extra performance by tricks I haven't thought of? Thanks, Paul. (use 'clojure.contrib.accumulators) (defn D [mt n m] (apply + (take n (repeatedly #(+ 1 (.nextInt mt m)) (defn histogram [s] (add-items empty-counter s)) (defn testN [count n m] (let [mt (ec.util.MersenneTwisterFast.)] (histogram (take count (repeatedly #(D mt n m)) (time (pr (testN 100 3 6))) (time (pr (apply combine (pmap #(testN % 3 6) (repeat 100 1) (shutdown-agents) -- 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 script with shebangoid on windows
On 28 May 2010 09:48, alux alu...@googlemail.com wrote: Hello! Short: It works, but is not perfect. (this may need an windows expert to make it better) Try this: --- myscript.bat --- :x (comment @echo off java -cp clojure.jar clojure.main %~f0 %* goto eof ) (println Hi! *command-line-args*) -- The way it works: The line starting with :x is treated as a label by cmd.exe (and so, in effect, ignored). In Clojure, it's treated as a keyword :x followed by the start of a multiline comment - (comment So everything down to the closing ) is ignored by clojure, but executed by cmd.exe The next bits: @echo off - suppress cmd.exe's annoying habit of displaying everything java... Run the clojure script. %~f0 is the script name - I quote it in case it has spaces, and %* is the rest of the command line. Then, goto eof terminates the batch file (goto end of file), ignoring the rest of the file, which can therefore be arbitrary clojure. Paul. -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en
Re: Clojure script with shebangoid on windows
On 28 May 2010 16:17, alux alu...@googlemail.com wrote: Hello Paul, thats much better, many thanks! I've added it to the Wikibooks page, http://en.wikibooks.org/wiki/Clojure_Programming/Tutorials_and_Tips#Shebang_Scripting_in_Clojure Paul. -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en
Newbie (with no Java experience) - how best to learn?
Hi, I'm new to Clojure, and looking for the best way to get going. I've got a pretty broad experience of various programming languages (C, Python, Lua, Factor, JavaScript, Haskell, Perl, ...) including a bit of experience with Lisp-like languages, so the language itself isn't likely to be a huge problem for me. But I've no background with Java (beyond a few toy programs, and knowing the syntax) so the environment (classpaths, compiling, where to find libraries, performance, JVMs, etc) is pretty much a mystery to me. I've browsed a bit online, read some of the wikibook articles, and Mark Volkmann's excellent summary, but I'd like to dig a bit deeper (as I say, particularly around libraries and environment, less on how to program in a lisp-like language). Ideally, in a form that I can read offline (printable/PDF documents, or books) as I've got limited free time I can spend in front of a computer screen. I've got a sample program I have tried porting from Python - the experience was interesting, but limited (the core of the relatively complex multithreaded database monitoring process converted to 47 lines of Clojure...!!!) Has anybody got any good suggestions as to where I should go next? I've considered getting one of the Manning books (The Joy of Clojure or Clojure in Action) but I'm not sure which would be better for me - they seem broadly similar, with Clojure in Action looking like a slightly better fit for my needs, but I'd appreciate any comments/recommendations). Also, I wonder whether there's some Java-based documentation that would be worth my while investigating. I suspect that it'd be very easy to get sucked into a huge amount of detail which is only tangentially related at best, but I'm sure an overview would help. Thanks for any suggestions, Paul. -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en
Re: Newbie (with no Java experience) - how best to learn?
On 27 May 2010 15:16, Sean Devlin francoisdev...@gmail.com wrote: Welcome aboard Paul! Thanks! 1. Pick an IDE and stick with it. I'd recommend ClojureBox if you're interested in Clojure only, or NetBeans + Enclojure if you want to learn some about Java too. In fact, NetBeans is probably a better place to start. I don't really like IDEs, I'm a text editor sort of person, I'm afraid. I'll be using Vim to write my code, unless someone gives me very strong reasons to do otherwise. And to be honest, if I can't code in clojure using Vim, I'd be assuming clojure isn't for me, I'm afraid. 2. If you're looking for a dead tree reference, Halloway's book Programming Clojure is a great start. I'd recommend it to anyone not named Rich Hickey. Also, I strongly recommend Core Java Volumes I II from Horstmann Cornell to get started with Java. Thanks for the references. I'd been under the impression that Programming Clojure was more a language tutorial. Looks like I was wrong - I'll check it out! While the Java books look good, I'm not sure how useful they will be. I have (a fairly old copy of) Java in a Nutshell and a couple of other ones, and I'm really not a fan of Java the language - so I don't want to invest too heavily in Java books unless they are going to be useful from a clojure point of view. I'll keep them in mind, though. (Basically, I'd rather get Java background from something downloadable for free). 3. Once you start to play around with the examples in a REPL, take a look at some of the material here: http://news.ycombinator.com/item?id=1033503 Nice link, thanks! 4. Find a project start playing. The best way to learn is by doing, after all :) Absolutely - I'm planning on building up my database monitoring app as a starter. I also have a couple of other testbed applications I'd like to try. On that note, are there good (java|clojure) libraries I should look at for: - command line argument handling (getopt style option handling) - simple parsing (suitable for something like a small expression parser) Thanks again, Paul. -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en
Re: Newbie (with no Java experience) - how best to learn?
On 27 May 2010 15:38, Base basselh...@gmail.com wrote: Regarding Clojure I got Stuart Halloway's book Programming Clojure Another recommendation! Looks like that's definite then :-) Thanks. Also, I spend a *lot* of time on this site and ask a lot of really dumb questions. Clojure has the best group support by far of any language I have ever seen. The people on this board are truly amazingly helpful and patient - even with us newbies :) Reassuring to know. As I suspect my dumb questions will be heavily JVM-biased (What's a classpath?) I'll probably need all the patience people can muster! Actually here's a JVM sort of question to start off with. To run my little database monitor script on Windows, I use a command line java -cp clojure.jar;clojure-contrib.jar;D:\Oracle\product\10.2.0\client_1\jdbc\lib\classes12.jar clojure.main db.clj That's a pretty hairy command line, just to run a script with no parameters! What's the best way to tidy this up (on the Windows command line)? I'd prefer not to wrap it in a batch file for a couple of reasons - two files to maintain, and batch files have some irritating properties on Windows. For the script, I can associate java -cp clojure.jar clojure.main %* with the .clj extension and that's OK, But is there a way of adding the references to the other jars from within the script, so I don't need to specify the classpath on the command line? The hardest part for me was getting things configured. It is really confusing - particularly if you have no background to java. Most of the users here use emacs for their IDE. If you know emacs you can certainly try that. There is Clojure in a Box that is a self contained package If you do not use emacs ( I do not - it is too damn confusing for me) then i recommend using and IDE that has clojure support. There is one for Netbeans called Enclojure. I use Eclipse and a plugin called CounterClockwise. I really like it. As a non-Java user, I'm strongly averse to the various IDEs. Personally, I'm a Vim user and I like to do my compiling from the command line. Hopefully, the bare metal approach won't get me into too much trouble! Stu Halloway has a great starting tutorial with instructions on how to get up to speed and has a series of tutorials via a web server (integrated into the app). It is located at: http://github.com/relevance/labrepl This is where I would start. It has helped me out immensely. That looks like a great resource! Thanks! Paul. -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en
Re: Newbie (with no Java experience) - how best to learn?
On 27 May 2010 16:39, eyeris drewpvo...@gmail.com wrote: The Full Disclojure video series is targeted more toward the lisp newbie, but it contains a series of videos touring different development environments. http://vimeo.com/channels/fulldisclojure Ta. Any way of downloading these to watch on my iPod? As I say, I have limited opportunities to sit in front of a PC to read/watch training stuff. Paul. -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en
Re: Newbie (with no Java experience) - how best to learn?
On 27 May 2010 18:26, Sean Devlin francoisdev...@gmail.com wrote: I make them available CC BY-NC-SA, so download away. You'll need a vimeo account (free) to download them, though. Ah, I hadn't realised that signing up got a download option. Thanks! Paul. -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en
Mersenne Twister
I want to write a reasonably high-performance simulation program in Clojure. For the random numbers, I'd prefer to use Mersenne Twister (for a number of reasons - it's a well-known, good RNG, and it's commonly used in a number of other languages I use, so it's a good baseline for comparing implementations). The Java RNG, which Clojure uses, is not MT, but Knuth's linear congruential RNG. Can someone recommend a good Mersenne Twister implementation I could use? A web search finds a number of implementations in Java - presumably I can use these via Java interop - is that a sensible thing to do? I'm also looking to parallelise my simulation, so I'd want to have multiple threads all generating random numbers. I'm not an expert in this field, if I just naively generate random numbers in multiple threads is that OK, or could it compromise the randomness? If there is an issue, has anyone got a pointer to a thread-safe MT implementation that I could use? Thanks, Paul. -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en
