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• java.lang.NoSuchMethodError: main when starting HelloWorld with Eclipse Scala plugin

  - by Matt Sheppard

  I've just been playing with Scala, and installed the Eclipse plugin as described at http://www.scala-lang.org/node/94, but after entering the "Hello World" test example and setting up the run configuration as described, I get the following error Exception in thread "main" java.lang.NoSuchMethodError: main For reference the code is package hello object HelloWorld extends Application { println("Hello World!") } I've tinkered a bit with the obvious solutions (adding a main method, adding a singleton object with a main method) but I'm clearly doing something wrong. Can anyone get their test example to work, or point out what I am doing wrong?

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• processing: convert int to byte

  - by inspectorG4dget

  Hello SO, I'm trying to convert an int into a byte in Processing 1.0.9. This is the snippet of code that I have been working with: byte xByte = byte(mouseX); byte yByte = byte(mouseY); byte setFirst = byte(128); byte resetFirst = byte(127); xByte = xByte | setFirst; yByte = yByte >> 1; port.write(xByte); port.write(yByte); According to the Processing API, this should work, but I keep getting an error at xByte = xByte | setFirst; that says: cannot convert from int to byte I have tried converting 128 and 127 to they respective hex values (0x80 and 0x7F), but that didn't work either. I have tried everything mentioned in the API as well as some other blogs, but I feel like I'm missing something very trivial. I would appreciate any help. Thank you.

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• perl regex groups

  - by Aaron Moodie

  I've currenly trying to pull out dates from a file and feed them directly into an array. My regex is working, but I have 6 groups in it, all of which are being added to the array, when I only want the first one. @dates = (@dates, ($line =~ /((0[1-9]|[12][0-9]|3[01])(\/|\-)(0[1-9]|1[0-2])(\/|\-)([0-9][0-9][0-9][0-9]|[0-9][0-9]))/g )); is there a simple way to grab the $1 group of a perl regex? my output is looking like this: 13/04/2009, 13, /, 04, /, 2009, 14-12-09, 14, -, 12, -, 09

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• Usage of ||, OR in PHP

  - by shin

  I have the following code which redirect pages depends on $path. ... $path = $this->uri->segment(3); $pathid = $this->uri->segment(4); if($path=='forsiden'){ redirect('','refresh'); }elseif($path =='contact'){ redirect('welcome/kontakt','refresh'); }elseif($path =='illustration'){ $this->_gallery($path,$pathid); }elseif($path =='webdesign'){ redirect('welcome/webdesign','refresh'); }elseif($path==('web_tjenester' || 'webdesigndetails' || 'vismahjemmeside' || 'joomla' || 'vismanettbutikk' || 'vpasp' || 'artportfolio')){ ... CODE A ... }else{ ... CODE B ... } I am not getting right results with $path==('web_tjenester' || 'webdesigndetails' || 'vismahjemmeside' || 'joomla' || 'vismanettbutikk' || 'vpasp' || 'artportfolio') contact, illustration, gallery and webdesign are redirected and working alright. However all other pages are added CODE A. I am expecting CODE A only when $path is web_tjenester', 'webdesigndetails', 'vismahjemmeside', 'joomla', 'vismanettbutikk', 'vpasp' or 'artportfolio'. Could anyone point out my mistake and correct me please? Thanks in advance. --UPDATE-- The following works, but is there any ways shorten the code? I am repeating ($path==..). elseif(($path=='web_tjenester') || ($path=='webdesigndetails') || ($path=='vismahjemmeside') || ($path=='joomla') || ($path=='vismanettbutikk') || ($path=='vpasp') || ($path=='artportfolio')){

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• lwjgl 101: How can I write the basics?

  - by Vuntic

  This ought to be really simple, but I cannot for the life of me figure out how to compile anything with lwjgl and have it work. I can write something like package gwison; import org.lwjgl.Sys; public class G { public static void main(String[] args) { System.out.println(Sys.getTime()); } } and I can easily compile a program with several classes in different packages, as long as I wrote all the classes myself. But I have no clue how to make G work. I think it has something to do with classpathes? Maybe? Help?

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• Google App Engine (python): TemplateSyntaxError: 'for' statements with five words should end in 'rev

  - by Phil

  This is using the web app framework, not Django. The following template code is giving me an TemplateSyntaxError: 'for' statements with five words should end in 'reversed' error when I try to render a dictionary. I don't understand what's causing this error. Could somebody shed some light on it for me? {% for code, name in charts.items %} <option value="{{code}}">{{name}}</option> {% endfor %} I'm rendering it using the following: class GenerateChart(basewebview): def get(self): values = {"datepicker":True} values["charts"] = {"p3": "3D Pie Chart", "p": "Segmented Pied Chart"} self.render_page("generatechart.html", values) class basewebview(webapp.RequestHandler): ''' Base class for all webapp.RequestHandler type classes ''' def render_page(self, filename, template_values=dict()): filename = "%s/%s" % (_template_dir, filename) path = os.path.join(os.path.dirname(__file__), filename) self.response.out.write(template.render(path, template_values))

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• Scheme implementations - what does it mean?

  - by JDelage

  Hi, I'm a beginning student in CS, and my classes are mostly in Java. I'm currently going through "Little Schemer" as a self study, and in the process of finding out how to do that I have found numerous references to "implementations" of Scheme. My question is, what are implementations? Are they sub-dialects of Scheme, or is that something else (DrScheme seem to allow for different "flavors" of the language)? Is it just the name given to any given ecosystem incorporating an IDE, interpreter, interactive tool and the like? Do all other languages (e.g., Java) also have a variety of "implementations", or is it something reserved to "open" languages? Thank you, Joss Delage

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• Python for a hobbyist programmer ( a few questions)

  - by Matt

  I'm a hobbyist programmer (only in TI-Basic before now), and after much, much, much debating with myself, I've decided to learn Python. I don't have a ton of free time to teach myself a hundred languages and all programming I do will be for personal use or for distributing to people who need them, so I decided that I needed one good, strong language to be good at. My questions: Is python powerful enough to handle most things that a typical programmer might do in his off-time? I have in mind things like complex stat generators based on user input for tabletop games, making small games, automate install processes, and build interactive websites, but probably a hundred things along those lines Does python handle networking tasks fairly well? Can python source be obscufated (mispelled I think), or is it going to be open-source by nature? The reason I ask this is because if I make something cool and distribute it, I don't want some idiot script kiddie to edit his own name in and say he wrote it And how popular is python, compared to other languages. Ideally, my language would be good and useful with help found online without extreme difficulty, but not so common that every idiot with computer knows python. I like the idea of knowing a slightly obscure language. Thanks a ton for any help you can provide.

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• Python MySQLdb placeholders syntax

  - by ensnare

  I'd like to use placeholders as seen in this example: cursor.execute (""" UPDATE animal SET name = %s WHERE name = %s """, ("snake", "turtle")) Except I'd like to have the query be its own variable as I need to insert a query into multiple databases, as in: query = """UPDATE animal SET name = %s WHERE name = %s """, ("snake", "turtle")) cursor.execute(query) cursor2.execute(query) cursor3.execute(query) What would be the proper syntax for doing something like this?

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• Can I avoid explicit 'self'?

  - by bguiz

  I am fairly new to Python and trying to pick it up, so please forgive if this question has a very obvious answer! I have been learning Python by following some pygame tutorials. Therein I found extensive use of the keyword self, and coming from a primarily Java background, I find that I keep forgetting to type self. For example, instead of self.rect.centerx I would type rect.centerx, because, to me, rect is already a member variable of the class. The Java parallel I can think of for this situation is having to prefix all references to member variables with this. Am I stuck prefixing all member variables with self, or is there a way to declare them that would allow me to avoid having to do so? Even if what I am suggesting isn't "pythonic", I'd still like to know if it is possible. I have taken a look at these related SO questions, but they don't quite answer what I am after: Python - why use “self” in a class? Why do you need explicitly have the “self” argument into a Python method?

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• Textmate RSpec Run Example fails

  - by Barb

  When I try to run an RSpec example from within Textmate. I get "Rails requires RubyGems = 1.3.2 (you have 1.3.1). Please gem update --system and try again." I run gem update and I get nothing to update. I think the RSpec bundle is running from the built in directories rather than /local/. How do I change where the bundle looks? Thanks! :)

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• Modifying Bresenham's line algorithm

  - by sphennings

  I'm trying to use Bresenham's line algorithm to compute Field of View on a grid. The code I'm using calculates the lines without a problem but I'm having problems getting it to always return the line running from start point to endpoint. What do I need to do so that all lines returned run from (x0,y0) to (x1,y1) def bresenham_line(self, x0, y0, x1, y1): steep = abs(y1 - y0) > abs(x1 - x0) if steep: x0, y0 = y0, x0 x1, y1 = y1, x1 if x0 > x1: x0, x1 = x1, x0 y0, y1 = y1, y0 if y0 < y1: ystep = 1 else: ystep = -1 deltax = x1 - x0 deltay = abs(y1 - y0) error = -deltax / 2 y = y0 line = [] for x in range(x0, x1 + 1): if steep: line.append((y,x)) else: line.append((x,y)) error = error + deltay if error > 0: y = y + ystep error = error - deltax return line

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• Difficulty getting Saxon into XQuery mode instead of XSLT

  - by Rosarch

  I'm having difficulty getting XQuery to work. I downloaded Saxon-HE 9.2. It seems to only want to work with XSLT. When I type: java -jar saxon9he.jar I get back usage information for XSLT. When I use the command syntax for XQuery, it doesn't recognize the parameters (like -q), and gives XSLT usage information. Here are some command line interactions: >java -jar saxon9he.jar No source file name Saxon-HE 9.2.0.6J from Saxonica Usage: see http://www.saxonica.com/documentation/using-xsl/commandline.html Options: -a Use xml-stylesheet PI, not -xsl argument -c:filename Use compiled stylesheet from file -config:filename Use configuration file -cr:classname Use collection URI resolver class -dtd:on|off Validate using DTD -expand:on|off Expand defaults defined in schema/DTD -explain[:filename] Display compiled expression tree -ext:on|off Allow|Disallow external Java functions -im:modename Initial mode -ief:class;class;... List of integrated extension functions -it:template Initial template -l:on|off Line numbering for source document -m:classname Use message receiver class -now:dateTime Set currentDateTime -o:filename Output file or directory -opt:0..10 Set optimization level (0=none, 10=max) -or:classname Use OutputURIResolver class -outval:recover|fatal Handling of validation errors on result document -p:on|off Recognize URI query parameters -r:classname Use URIResolver class -repeat:N Repeat N times for performance measurement -s:filename Initial source document -sa Use schema-aware processing -strip:all|none|ignorable Strip whitespace text nodes -t Display version and timing information -T[:classname] Use TraceListener class -TJ Trace calls to external Java functions -tree:tiny|linked Select tree model -traceout:file|#null Destination for fn:trace() output -u Names are URLs not filenames -val:strict|lax Validate using schema -versionmsg:on|off Warn when using XSLT 1.0 stylesheet -warnings:silent|recover|fatal Handling of recoverable errors -x:classname Use specified SAX parser for source file -xi:on|off Expand XInclude on all documents -xmlversion:1.0|1.1 Version of XML to be handled -xsd:file;file.. Additional schema documents to be loaded -xsdversion:1.0|1.1 Version of XML Schema to be used -xsiloc:on|off Take note of xsi:schemaLocation -xsl:filename Stylesheet file -y:classname Use specified SAX parser for stylesheet --feature:value Set configuration feature (see FeatureKeys) -? Display this message param=value Set stylesheet string parameter +param=filename Set stylesheet document parameter ?param=expression Set stylesheet parameter using XPath !option=value Set serialization option >java -jar saxon9he.jar -q:"..\w3xQueryTut.xq" Unknown option -q:..\w3xQueryTut.xq Saxon-HE 9.2.0.6J from Saxonica Usage: see http://www.saxonica.com/documentation/using-xsl/commandline.html Options: -a Use xml-stylesheet PI, not -xsl argument // etc... >java net.sf.saxon.Query -q:"..\w3xQueryTut.xq" Exception in thread "main" java.lang.NoClassDefFoundError: net/sf/saxon/Query Caused by: java.lang.ClassNotFoundException: net.sf.saxon.Query // etc... Could not find the main class: net.sf.saxon.Query. Program will exit. I'm probably making some stupid mistake. Do you know what it could be?

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• Short Python alphanumeric hash with minimal collisions

  - by ensnare

  I'd like to set non-integer primary keys for a table using some kind of hash function. md5() seems to be kind of long (32-characters). What are some alternative hash functions that perhaps use every letter in the alphabet as well as integers that are perhaps shorter in string length and have low collision rates? Thanks!

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• How to include text files with Executable Jar

  - by Jake

  Hi guys rookie Java question. I have a Java project and I want to include a text file with the executable jar. Right now the text file is in the default package. InputFlatFile currentFile = new InputFlatFile("src/theFile.txt"); I grab the file with that line as you can see using src. However this doesn't work with the executable jar. Can someone please let me know how to keep this file with the executable jar so someone using the program can just click a single icon and run the program. Thanks!

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• command CHOICE in DOS batch replacement/reproduction in python

  - by LtPinback

  I want to reproduce the behavior of the command CHOICE in DOS batch but with python. raw_input requires the user to type whatever then press the ENTER/RETURN key. What I really want is for the user to press a single key and the script to continue from there.

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• Mercurial: how to apply the hg forget command to an entire directory

  - by SaM

  My directory structure is as follows Project -- .hg -- src -- tests When I ran hg init on the Project path, everything got added into the repo. However, inside src, there are directories like bin and obj which I'd not like to track. How do I exclude them now? I've tried hg forget src\bin - it says path not found. Please guide.

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• bitwise OR on strings

  - by mr.bio

  How can i do a Bitwise OR on strings? A: 10001 01010 ------ 11011 Why on strings? The Bits can have length of 40-50.Maybe this could be problematic on int ? Any Ideas ?

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• Difference between char *foo vs (char *)foo in Objective-C

  - by iWalter

  What is the difference between char *foo and (char*) foo in Objective-C?

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• Foreign keys with Rails' ActiveRecord::Migration?

  - by Earlz

  Hello, I'm new to Ruby on Rails (I know Ruby just decently though) and looking at the Migration tools, it sounds really awesome. Database schemas can finally (easily) go in source control. Now my problem with it. When using Postgres as the database, it does not setup foreign keys. I would like the benefits of foreign keys in my schema such as referential integrity. So how do I apply foreign keys with Migrations?

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• How can I save form input to a database, I'm having trouble sending the values to my controller.

  - by Sergio Tapia

  Here's my RegisterController: public function saveforminformationAction(){ $request = $this->getRequest(); if($request->isPost()){ //I NEED HELP WITH THE getFormValues() METHOD. $formResults = $this->getFormValues(); $db = $this->_getParam('db'); $data = array( 'user' => $formResults['username'], 'email' => $formResults['email'], 'password' => $formResults['password'], 'passwordc' => $formResults['passwordc'], 'name' => $formResults['name'], 'avatar' => $formResults['avatar'], ); $db->insert('Usuario',$data); } } And here's my registration view: <body> <h1>Thanks for signing up!</h1> <?php $this->form->setAction($this->url(array('controller' => 'registration','action'=>'saveforminformation'))); $this->form->setMethod('post'); echo $this->form; ?> <img alt="signupimg" src="/img/signup.png"> </body> I'm fairly new to Zend, but I'm eager to learn. How can I get the values sent in the form?

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• ZSH: why error using array: "illegal character: ^M"?

  - by HH

  $ values=( 300 400 ) $ echo "scale=20; $values[1]-$values[2]" | bc (standard_in) 1: illegal character: ^M // Why does it not print -100? $ echo $values // no ^M sign found! 300 400

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• Decompiling Java class files

  - by abson

  Can one decompile .class files to source code in java?

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• could I know which file is altered using fsevent?

  - by Frost Li

  I get the directory path from fsevent, such as "/User/Data/" But what I really want is "/User/Data/change.txt" I have read the programming guide, it said typedef void ( *FSEventStreamCallback )( ConstFSEventStreamRef streamRef, void *clientCallBackInfo, size_t numEvents, void *eventPaths, const FSEventStreamEventFlags eventFlags[], const FSEventStreamEventId eventIds[]); eventPaths An array of paths to the directories in which event(s) occurred. is there any method to find out which file is altered? thanks!!!! I have stuck to it for so long..

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• jQuery changing fields to substring of related field

  - by Katherine

  Another jquery calculation question. I've this, which is sample code from the plugin site that I am playing with to get this working: function recalc(){ $("[id^=total_item]").calc( "qty * price", { qty: $("input[name^=qty_item_]"), price: $("input[name^=price_item_]"), }, function (s){ return s.toFixed(2);}, function ($this){ var sum = $this.sum(); $("#grandTotal").val( // round the results to 2 digits sum.toFixed(2) ); } ); } Changes in the price fields cause the totals to update: $("input[name^=price_item_]").bind("keyup", recalc); recalc(); Problem is I won't know the value of the price fields, they will be available to me only as a substring of values entered by the user, call it 'itemcode'. There will be a variable number of items, based on a php query. I've come up with this to change the price based on the itemcode: $("input[name^='itemcode_item_1']").keyup(function () { var codeprice = this.value.substring(2,6); $("input[name^='price_item_1']").val(codeprice); }); $("input[name^='itemcode_item_2']").keyup(function () { var codeprice = this.value.substring(2,6); $("input[name^='price_item_2']").val(codeprice); }); However while it does that, it also stops the item_total from updating. Also, I feel there must be a way to not need to write a numbered function for each item on the list. However when I just use $("input[name^='itemcode_item_']") updating any itemcode field updates all price fields, which is not good. Can anyone point me in the right direction? I know I am a bit clueless here, but javascript of any kind is not my thing.

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