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• Boost Include Files in VC++

  - by Dr. K

  For the last few years, I have been exclusively a C# developer. Previously, I developed in C++ and have a C++ application that I built about 3 years ago using VS2005. It made extensive use of the Boost libraries. I recently decided to brush off the old app and rebuild it in VS2008 with the latest version of Boost (the latest version with the "easy" installation program from BoostPro Computing), 1.39. Previously when I had the program running I was at 1.33. Also, the last time the program was running was at least 2 OS installations ago. The Boost installation is located on my machine at: "C:\Program Files\boost\boost_1_39". Anyway, I have done the following: Set the project's "Additional Include Directories" directory to "C:\Program Files\boost\boost_1_39" Added "C:\Program Files\boost\boost_1_39" to VS2008's Tools - Options - Projects and Solutions - VC++ Directories - Include Files I have a number of Boost includes in my stdafx.h file. The compiler fails upon attempting to open the first one - #include <boost/algorithm/string/string.hpp> I have confirmed that the above file is indeed located at "C:\Program Files\boost\boost_1_39\boost\algorithm\string\string.hpp" I continue to get: fatal error C1083: Cannot open include file: 'boost/algorithm/string/string.hpp': No such file or directory Any tips on what else to check would be greatly appreciated. Again, this is an application that compiled fine a few years ago, but the source has now been moved to a new machine/compiler.

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• Isn't an Iterator in c++ a kind of a pointer?

  - by Bilthon

  Ok this time I decided to make a list using the STL. I need to create a dedicated TCP socket for each client. So everytime I've got a connection, I instantiate a socket and add a pointer to it on a list. list<MyTcp*> SocketList; //This is the list of pointers to sockets list<MyTcp*>::iterator it; //An iterator to the list of pointers to TCP sockets. Putting a new pointer to a socket was easy, but now every time the connection ends I should disconnect the socket and delete the pointer so I don't get a huge memory leak, right? well.. I thought I was doing ok by setting this: it=SocketList.begin(); while( it != SocketList.end() ){ if((*it)->getClientId() == id){ pSocket = it; // <-------------- compiler complains at this line SocketList.remove(pSocket); pSocket->Disconnect(); delete pSocket; break; } } But the compiler is saying this: error: invalid cast from type ‘std::_List_iterator<MyTcp*>’ to type ‘MyTcp*’ Can someone help me here? i thought I was doing things right, isn't an iterator at any given time just pointing to one of the elements of the set? how can I fix it?

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• Dynamic Data Extract Tools

  - by Kevin McGovern

  I've been searching around for a few weeks now for a tool that either is fully built or a direction of something I could build for dynamically extracting data via a web interface. Basically, what I'm looking for is a way to give users a list of all available data objects from our database and then let them pick ones from the list they'd like to view and set parameters then export the results to an excel file. Right now we're doing it purely with SQL statements but we have hundreds of objects so as you might imagine, those statements are really complex and prone to errors. It would be great if there was a tool available to do this or if someone had an idea of an easy way to organize this. Any help would be greatly appreciated. We've looked at BI tools like QlikView and Tableau but that is probably overkill for what we're trying to do. The open-source BI tools we've looked at seemed really primitive in their functionality. The other thing we looked at was MSAS (our DB is SQL Server) but I'd prefer something that was more database-agnostic and lived on a web server instead of on the database.

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• JSON onFailure issue

  - by Mikey1980

  I’m having trouble getting a AJAX/JSON function to work correctly. I had this function grabbing value from a drop down box but now I want to use an anchor tag to set it's value. I thought it would be easy to just use the onClick event to pass string to the function I was using for the drop down box but I get the alert in JSON onFailure event even though data gets added to MySQL. I tried removing the alert from onFailure event but then it doesn't add the data. The drop down still continues work work fine, no alerts. (I should note that removing the alert also broke my drop down box) 1st I add an onClick event… <a href="<?php echo Settings::get('app.webroot'); ?>?view=schedule&action=questions" onmouseout="MM_swapImgRestore();" onmouseover="MM_swapImage('bre','','template/images/schedule/bre_f2.gif',1)" onclick="assignCallType('testing')";> 2nd I check main.js.php function assignCallType(type) { alert(type); new Request.JSON({ url: "ajax.php", onSuccess: function(rtndata,txt){ if (rtndata['STATUS'] != 'OK') alert('Status was not okay'); }, onFailure : function () { alert("onFailure") } }).get({ 'action': 'assignCallType', 'call_type': type }); } 3rd Ajax.php: the variable is back in PHP and values get added to MySQL but I get the Alert in the JSON onFailure event if ($_GET['action'] == "assignCallType") { if ($USER->isInsideSales()) { $call_type = $_GET['call_type']; $_SESSION['callinfo']->setCallType($call_type); $_SESSION['callinfo']->save($callid); echo json_encode(array('STATUS'=>'OK')); } else { echo json_encode(array('STATUS'=>'DENIED')); } } Any idea where I am going wrong. The only difference between this and the working drop down is how the function was called, I used onchange="assignCallType(this.value)".

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• Applying drop shadows to divs

  - by CJD

  Hi everyone, I need a bit of help applying a drop shadow image to a range of DIV elements. The elements in question already have a background image so I am wrapping another DIV around them. Things get complicated further because I'm also using the 960gs CSS framework. This is my current HTML for a content box type display: <div class="grid_12 boxout-shadow-920"> <div class="boxout"> <p>planetCJD.co.uk is the personal site and blog of CJD. The site is still a work-in-progress but please do have a look around and let me know what you think! </p> </div> </div> Boxout CSS: .boxout { background:url("../images/overlay.png") repeat-x scroll 0 0 #EEEEEE; -moz-border-radius:4px 4px 4px 4px; border:1px solid #DDDDDD; margin-bottom:15px; padding:5px; } boxout-shadow-920 CSS: .boxout-shadow-920 { background:url("../images/box-shadow-920.png") no-repeat scroll 50% 101% transparent; } Now this works to a degree. The boxshadow image shows at the bottom of the content box which is what I would like. However as I'm using a fixed percentage of 101%, if the content box height is too small, not much of the drop shadow image gets shown, and if the content box is too big, whitespace starts to appear between the box and the shadow image. So anyway, what I'm looking for is a cross-browser CSS based solution for doing this properly. I'm sure there is an easy answer to this - any help is appreciated!

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• How do I check if a scalar has a compiled regex in it with Perl?

  - by Robert P

  Let's say I have a subroutine/method that a user can call to test some data that (as an example) might look like this: sub test_output { my ($self, $test) = @_; my $output = $self->long_process_to_get_data(); if ($output =~ /\Q$test/) { $self->assert_something(); } else { $self->do_something_else(); } } Normally, $test is a string, which we're looking for anywhere in the output. This was an interface put together to make calling it very easy. However, we've found that sometimes, a straight string is problematic - for example, a large, possibly varying number of spaces...a pattern, if you will. Thus, I'd like to let them pass in a regex as an option. I could just do: $output =~ $test if I could assume that it's always a regex, but ah, but the backwards compatibility! If they pass in a string, it still needs to test it like a raw string. So in that case, I'll need to test to see if $test is a regex. Is there any good facility for detecting whether or not a scalar has a compiled regex in it?

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• How do software events work internally?

  - by Duddle

  Hello! I am a student of Computer Science and have learned many of the basic concepts of what is going on "under the hood" while a computer program is running. But recently I realized that I do not understand how software events work efficiently. In hardware, this is easy: instead of the processor "busy waiting" to see if something happened, the component sends an interrupt request. But how does this work in, for example, a mouse-over event? My guess is as follows: if the mouse sends a signal ("moved"), the operating system calculates its new position p, then checks what program is being drawn on the screen, tells that program position p, then the program itself checks what object is at p, checks if any event handlers are associated with said object and finally fires them. That sounds terribly inefficient to me, since a tiny mouse movement equates to a lot of cpu context switches (which I learned are relatively expensive). And then there are dozens of background applications that may want to do stuff of their own as well. Where is my intuition failing me? I realize that even "slow" 500MHz processors do 500 million operations per second, but still it seems too much work for such a simple event. Thanks in advance!

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• How to send java.util.logging to log4j?

  - by matt b

  I have an existing application which does all of its logging against log4j. We use a number of other libraries that either also use log4j, or log against Commons Logging, which ends up using log4j under the covers in our environment. One of our dependencies even logs against slf4j, which also works fine since it eventually delegates to log4j as well. Now, I'd like to add ehcache to this application for some caching needs. Previous versions of ehcache used commons-logging, which would have worked perfectly in this scenario, but as of version 1.6-beta1 they have removed the dependency on commons-logging and replaced it with java.util.logging instead. Not really being familiar with the built-in JDK logging available with java.util.logging, is there an easy way to have any log messages sent to JUL logged against log4j, so I can use my existing configuration and set up for any logging coming from ehcache? Looking at the javadocs for JUL, it looks like I could set up a bunch of environment variables to change which LogManager implementation is used, and perhaps use that to wrap log4j Loggers in the JUL Logger class. Is this the correct approach? Kind of ironic that a library's use of built-in JDK logging would cause such a headache when (most of) the rest of the world is using 3rd party libraries instead.

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• Is it theoretically possible to emulate a human brain on a computer?

  - by JoelK

  Our brain consists of billions of neurons which basically work with all the incoming data from our senses, handle our consciousness, emotions and creativity as well as our hormone system, etc. So I'm completely new to this topic but doesn't each neuron have a fixed function? E.g.: If a signal of strength x enters, if the last signal was x ms ago, redirect it. From what I've learned in biology about our nerves system which includes our brain because both consist of simple neurons, it seems to me as our brain is one big, complicated computer. Maybe so complicated that things such as intelligence and cognition become possible? As the most complicated things about a neuron pretty much are the chemical aspects on generating an electric singal, keeping itself alive, and eventually segmenting itself, it should be pretty easy emulating some on a computer, or? You won't have to worry about keeping your virtual neuron alive, or? If you can emulate a single neuron on a computer, which shouldn't be too hard, could you theoretically emulate more than 1000 billions of them, recreating intelligence, cognition and maybe even creativity? In my question I'm leaving out the following aspects: Speed of our current (super) computers Actually writing a program for emulating neurons I don't know much about this topic, please tell me if I got anything wrong :) (My secret goal: Make a copy of my brain and store it on some 10 million TB HDD and make someone start it up in the future)

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• Methods to see result fo a code change faster

  - by Can't Tell

  This question came to me when developing using Eclipse. I use JBoss Application Server and use hot code replacement. But this option requires that the 'build automatically' option to be enabled. This makes Eclipse build the workspace automatically (periodically or when a file is saved?) and for a large code base this takes too much time and processing which makes the machine freeze for a while. Also sometimes an error message is shown saying that hot code replacement failed. The question that I have is: is there a better way to see the result of a code change? Currently I have the following two suggestions: Have unit tests - this will allow to run a single test and see the result of a code change. ( But for a JavaEE application that uses EJBs is it easy to setup unit tests?) Use OSGi - which allows to add jars to the running system without bringing down the JVM. Any ideas on above suggestions or any other suggestion or a framework that allows to do this is welcome.

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• What's the best practice for handling system-specific information under version control?

  - by Joe

  I'm new to version control, so I apologize if there is a well-known solution to this. For this problem in particular, I'm using git, but I'm curious about how to deal with this for all version control systems. I'm developing a web application on a development server. I have defined the absolute path name to the web application (not the document root) in two places. On the production server, this path is different. I'm confused about how to deal with this. I could either: Reconfigure the development server to share the same path as the production Edit the two occurrences each time production is updated. I don't like #1 because I'd rather keep the application flexible for any future changes. I don't like #2 because if I start developing on a second development server with a third path, I would have to change this for every commit and update. What is the best way to handle this? I thought of: Using custom keywords and variable expansion (such as setting the property $PATH$ in the version control properties and having it expanded in all the files). Git doesn't support this because it would be a huge performance hit. Using post-update and pre-commit hooks. Possibly the likely solution for git, but every time I looked at the status, it would report the two files as being changed. Not really clean. Pulling the path from a config file outside of version control. Then I would have to have the config file in the same location on all servers. Might as well just have the same path to begin with. Is there an easy way to deal with this? Am I over thinking it?

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• Why would one want to use the public constructors on Boolean and similar immutable classes?

  - by Robert J. Walker

  (For the purposes of this question, let us assume that one is intentionally not using auto(un)boxing, either because one is writing pre-Java 1.5 code, or because one feels that autounboxing makes it too easy to create NullPointerExceptions.) Take Boolean, for example. The documentation for the Boolean(boolean) constructor says: Note: It is rarely appropriate to use this constructor. Unless a new instance is required, the static factory valueOf(boolean) is generally a better choice. It is likely to yield significantly better space and time performance. My question is, why would you ever want to get a new instance in the first place? It seems like things would be simpler if constructors like that were private. For example, if they were, you could write this with no danger (even if myBoolean were null): if (myBoolean == Boolean.TRUE) It'd be safe because all true Booleans would be references to Boolean.TRUE and all false Booleans would be references to Boolean.FALSE. But because the constructors are public, someone may have used them, which means that you have to write this instead: if (Boolean.TRUE.equals(myBoolean)) But where it really gets bad is when you want to check two Booleans for equality. Something like this: if (myBooleanA == myBooleanB) ...becomes this: if ( (myBooleanA == null && myBooleanB == null) || (myBooleanA == null && myBooleanA.equals(myBooleanB)) ) I can't think of any reason to have separate instances of these objects which is more compelling than not having to do the nonsense above. What say you?

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• OpenSceneGraph C++ Access Violation reading location 0x00421000

  - by Kobojunkie

  Working with OpenSceneGraph, and I keep running into this violation issue that I would appreciate some help with. The problem is with the particular line below which happens to be the first in my main function. osg::ref_ptr<osg::Node> bench = osgDB::readNodeFile("Models/test.IVE"); I have my models folder right in my directory. The error is as below. Unhandled exception at 0x68630A6C (msvcr100.dll) in OSG3D.exe: 0xC0000005: Access violation reading location 0x00421000. And this is where the problem seems to be coming up. /** Read an osg::Node from file. * Return valid osg::Node on success, * return NULL on failure. * The osgDB::Registry is used to load the appropriate ReaderWriter plugin * for the filename extension, and this plugin then handles the request * to read the specified file.*/ inline osg::Node* readNodeFile(const std::string& filename) { return readNodeFile(filename,Registry::instance()->getOptions()); } I would appreciate details on how best to tackle this kind of exception message in the future. Are there tools that make this easy to debug or are there ways to capture the exact issues and fix them? I would appreciate any help with this. My ultimate goal is to learn how to better debug C++ related issues please. With this, it means reading through the compiler error list http://msdn.microsoft.com/en-us/library/850cstw1(v=vs.71).aspx is not enough

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• Counting a cell up per Objects

  - by Auro

  hey i got a problem once again :D a little info first: im trying to copy data from one table to an other table(structure is the same). now one cell needs to be incremented, beginns per group at 1 (just like a histroy). i have this table: create table My_Test/My_Test2 ( my_Id Number(8,0), my_Num Number(6,0), my_Data Varchar2(100)); (my_Id, my_Num is a nested PK) if i want to insert a new row, i need to check if the value in my_id already exists. if this is true then i need to use the next my_Num for this Id. i have this in my Table: My_Id My_Num My_Data 1 1 'test1' 1 2 'test2' 2 1 'test3' if i add now a row for my_Id 1, the row would look like this: i have this in my Table: My_Id My_Num My_Data 1 3 'test4' this sounds pretty easy ,now i need to make it in a SQL and on SQL Server i had the same problem and i used this: Insert Into My_Test (My_Id,My_Num,My_Data) SELECT my_Id, ( SELECT CASE ( CASE MAX(a.my_Num) WHEN NULL THEN 0 Else Max(A.My_Num) END) + b.My_Num WHEN NULL THEN 1 ELSE ( CASE MAX(a.My_Num) WHEN NULL THEN 0 Else Max(A.My_Num) END) + b.My_Num END From My_Test A where my_id = 1 ) ,My_Data From My_Test2 B where my_id = 1; this Select gives null back if no Rows are found in the subselect is there a way so i could use max in the case? and if it give null back it should use 0 or 1? greets Auro

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• Searching the head of CVS

  - by bobtheowl2

  I'm looking for a 'relatively' easy way to search through cvs to look for a particular string in the HEAD revisions. I realize the way CVS stores versions makes this difficult. But I'm trying to come up with some script to allow this search (performance is not expected here). Currently this command will output the contents of the head files cvs co -r HEAD -p stdout = file contents (to be grepped for the search string) stderr = the file name/header info (to be grepped for the line that signifies file name). Ideally, I want to grep the contents and display the header + a few lines before and after the searched item (the output of this likely directed to some file). I found a way to grep the stdout and stderr using different values. And the resulting stdout/stderr displayed is in the right order. But any attempt to redirect it to a file messes up the order? { { cvs co -r HEAD -p myModule 4>&- | grep 'myString' 2>&4 4>&- } 4>&2 2>&1 >&3 3>&- | grep 'Check' >&2 3>&- } 3>&1 Question 1. Is there an easier way to do this all together? Question 2. If not, how do I get the output of the code above to append to a file in the same order as displayed on the console?

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• Change URL Submitted to Depending on Form Selection

  - by Chris

  I have a form which I need to submit to one of three different URLs depending on a selection made in the form. I suspect the easiest solution is to use jQuery to insert the appropriate path before the rest of the form parameters as the selection is made, but not sure on what the code would be. Any pointers greratly appreciated! <form id="myForm" action='/booking/default-path' accept-charset='utf-8' method='get'> <select name="paramA" id="paramA"> <option id="optionA" value="A" selected="selected">Option A</option> <option id="optionB" value="B">Option B</option> </select> <select name="currency" id="currency"> <option id="GBP" value="GBP" selected="selected">British Pounds</option> <option id="EUR" value="EUR">Euros</option> <option id="USD" value="USD">US Dollars</option> </select> <input type="submit" value="submit" id="submit" name="submit" /> </form> Where the three different URLs would be: ../booking/default-path-gbp?...[params here]... ../booking/default-path-eur?...[params here]... ../booking/default-path-usd?...[params here]... I know it would be a lot easier to incorporate the parameter in the usual way and just use one submission URL root, but unfortunately I'm submitting to an eComms system out of my control and am stuck with having to find a solution to this. Should be easy I think, but not sure where to start, jQuery used elsewhere, so would prefer to use this framework in any solutions.

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• What's a good way to write batch scripts in C#?

  - by Scott Bilas

  I would like to write simple scripts in C#. Stuff I would normally use .bat or 4NT .btm files for. Copying files, parsing text, asking user input, and so on. Fairly simple but doing this stuff right in a batch file is really hard (no exceptions for example). I'm familiar with command line "scripting" wrappers like AxScript so that gets me part of the way there. What I'm missing is the easy file-manipulation framework. I want to be able to do cd(".."), copy(srcFile, destFile) type functionality. Tools I have tried: NANT, which we use in our build process. Not a good scripting tool. Insanely verbose XML syntax and to add a simple function you must write an extension assembly. Can't do it inline. PowerShell. Looks great, but I just haven't been able to switch over to this as my primary shell. Too many differences from 4NT. Whatever I do needs to run from an ordinary command prompt and not require a special shell to run it through. Can PowerShell be used as a script executor? Perl/Python/Ruby. Really hate learning an entirely new language and framework just to do batch file operations. Haven't been able to dedicate the time I need to do this. Plus, we're a 99% .NET shop for our toolchain and I really want to leverage our existing experience and codebase. Are there frameworks out there that are trying to solve this problem of "make a batch file in C#" that you have used? I want the power of C#/.NET with the immediate-mode type functionality of a typical cmd.exe shell language. Am I alone in wanting something like this?

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• How can I pivot these key+values rows into a table of complete entries?

  - by CodexArcanum

  Maybe I demand too much from SQL but I feel like this should be possible. I start with a list of key-value pairs, like this: '0:First, 1:Second, 2:Third, 3:Fourth' etc. I can split this up pretty easily with a two-step parse that gets me a table like: EntryNumber PairNumber Item 0 0 0 1 0 First 2 1 1 3 1 Second etc. Now, in the simple case of splitting the pairs into a pair of columns, it's fairly easy. I'm interested in the more advanced case where I might have multiple values per entry, like: '0:First:Fishing, 1:Second:Camping, 2:Third:Hiking' and such. In that generic case, I'd like to find a way to take my 3-column result table and somehow pivot it to have one row per entry and one column per value-part. So I want to turn this: EntryNumber PairNumber Item 0 0 0 1 0 First 2 0 Fishing 3 1 1 4 1 Second 5 1 Camping Into this: Entry [1] [2] [3] 0 0 First Fishing 1 1 Second Camping Is that just too much for SQL to handle, or is there a way? Pivots (even tricky dynamic pivots) seem like an answer, but I can't figure how to get that to work.

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• Getting a type for a template instantiation?

  - by ebo

  I have the following situation: I have a object of type MyClass, which has a method to cast itself to it's base class. The class includes a typedef for it's base class and a method to do the downcast. template <class T, class B> class BaseClass; template <class T> class NoAccess; template <class T> class MyClass : public BaseClass<T, NoAccess<T> > { private: typedef BaseClass<T, NoAccess<T> > base; public: base &to_base(); }; I need to pass the result of a base call to a functor Operator: template <class Y> class Operator { Operator(Y &x); }; Operator<???> op(myobject.to_base()); Is there a easy way to fill the ??? provided that I do not want to use NoAccess?

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• ASP ListView - Eval() as formatted number, Bind() as unformatted?

  - by chucknelson

  I have an ASP ListView, and have a very simple requirement to display numbers as formatted w/ a comma (12,123), while they need to bind to the database without formatting (12123). I am using a standard setup - ListView with a datasource attached, using Bind(). I converted from some older code, so I'm not using ASP.NET controls, just form inputs...but I don't think it matters for this: <asp:SqlDataSource ID="MySqlDataSource" runat="server" ConnectionString='<%$ ConnectionStrings:ConnectionString1 %>' SelectCommand="SELECT NUMSTR FROM MY_TABLE WHERE ID = @ID" UpdateCommand= "UPDATE MY_TABLE SET NUMSTR = @NUMSTR WHERE ID = @ID"> </asp:SqlDataSource> <asp:ListView ID="MyListView" runat="server" DataSourceID="MySqlDataSource"> <LayoutTemplate> <div id="itemplaceholder" runat="server"></div> </LayoutTemplate> <ItemTemplate> <input type="text" name="NUMSTR" ID="NUMSTR" runat="server" value='<%#Bind("NUMSTR")%>' /> <asp:Button ID="UpdateButton" runat="server" Text="Update" Commandname="Update" /> </ItemTemplate> </asp:ListView> In the example above, NUMSTR is a number, but stored as a string in a SqlServer 2008 database. I'm also using the ItemTemplate as read and edit templates, to save on duplicate HTML. In the example, I only get the unformatted number. If I convert the field to an integer (via the SELECT) and use a format string like Bind("NUMSTR", "{0:###,###}"), it writes the formatted number to the database, and then fails when it tries to read it again (can't convert with the comma in there). Is there any elegant/simple solution to this? It's so easy to get the two-way binding going, and I would think there has to be a way to easily format things as well... Oh, and I'm trying to avoid the standard ItemTemplate and EditItemTemplate approach, just for sheer amount of markup required for that. Thanks!

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• Grab two parts of a single, short string

  - by TankorSmash

  I'm looking to fill a python dict with TAG:definition pairs, and I'm using RegExr http://gskinner.com/RegExr/ to write the regex My first step is to parse a line, from http://www.id3.org/id3v2.3.0, or http://pastebin.com/VJEBGauL and pull out the ID3 tag and the associated definition. For example the first line: 4.20 AENC [#sec4.20 Audio encryption] would look like this myDict = {'AENC' : 'Audio encryption'} To grab the tag name, I've got it looking for at least 3 spaces, then 4 characters, then 4 spaces: {3}[a-zA-Z0-9]{4} {4} That part is easy enough. The second part, the definition, is not working out for me. So far, I've got (?<=(\[#.+?)) A Which should find, but not include the [# as well as an indeterminded set of characters until it finds: _A, but it's failing. If I remove .+? and replace _A with s it works out alright. What is going wrong? *The underscores represent spaces, which don't show up on SO. How do I grab the definition, ie,(Audio encryption) of the ID3v2 tag from the line, using RegEx?

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• Recursive breadth-first travel function in Java or C++?

  - by joejax

  Here is a java code for breadth-first travel: void breadthFirstNonRecursive(){ Queue<Node> queue = new java.util.LinkedList<Node>(); queue.offer(root); while(!queue.isEmpty()){ Node node = queue.poll(); visit(node); if (node.left != null) queue.offer(node.left); if (node.right != null) queue.offer(node.right); } } Is it possible to write a recursive function to do the same? At first, I thought this would be easy, so I came out with this: void breadthFirstRecursive(){ Queue<Node> q = new LinkedList<Node>(); breadthFirst(root, q); } void breadthFirst(Node node, Queue<Node> q){ if (node == null) return; q.offer(node); Node n = q.poll(); visit(n); if (n.left != null) breadthFirst(n.left, q); if (n.right != null) breadthFirst(n.right, q); } Then I found it doesn't work. It is actually does the same thing as this: void preOrder(Node node) { if (node == null) return; visit(node); preOrder(node.left); preOrder(node.right); } Has any one thought about this before?

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• Grails - Where to store properties related to domains

  - by GalmWing

  This is something I have been struggling about for some time now. The thing is: I have many (20 or so) static arrays of values. I say static because that is how I'm actually storing them, as static arrays inside some domains. For example, if I have a list of known websites, I do: class Website { ... static websites = ["web1", "web2" ...] } But I do this just while developing, because I can easily change the arrays if needed, but what I'm going to do when the application is ready for deployment? In my project it is very probable that, at some point, these arrays of values change. I've been researching on that matter, one can store application properties inside an external .properties file, but it will be impossible to store an array, even futile, because if some array gets an additional value, the application can't recognize it until the name of the new property is added where needed. Another approach is to store this information in the database, but for some reason it seems like a waste to add 20 or more tables that will have just two rows, an id and a name. And the last option, as far as I know, would be an XML, but I'm not very experienced with those. It seems groovy has a way of creating and reading XML files relatively easy, but I don't know how difficult would be to modify an XML whose layout is predefined in the application. Needless to say that storing them in the config.groovy is not an option since any change will require to recompile. I haven't come across some "standard" (maybe a best practice?) way of dealing with these. So the questions is: Where to store these arrays?

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• What is the most efficient way to handle points / small vectors in JavaScript?

  - by Chris

  Currently I'm creating an web based (= JavaScript) application thata is using a lot of "points" (= small, fixed size vectors). There are basically two obvious ways of representing them: var pointA = [ xValue, yValue ]; and var pointB = { x: xValue, y: yValue }; So translating my point a bit would look like: var pointAtrans = [ pointA[0] + 3, pointA[1] + 4 ]; var pointBtrans = { x: pointB.x + 3, pointB.y + 4 }; Both are easy to handle from a programmer point of view (the object variant is a bit more readable, especially as I'm mostly dealing with 2D data, seldom with 3D and hardly with 4D - but never more. It'll allways fit into x,y,z and w) But my question is now: What is the most efficient way from the language perspective - theoretically and in real implementations? What are the memory requirements? What are the setup costs of an array vs. an object? ... My target browsers are FireFox and the Webkit based ones (Chromium, Safari), but it wouldn't hurt to have a great (= fast) experience under IE and Opera as well...

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• Which way is preferred when doing asynchronous WCF calls?

  - by Mikael Svenson

  When invoking a WCF service asynchronous there seems to be two ways it can be done. 1. public void One() { WcfClient client = new WcfClient(); client.BegindoSearch("input", ResultOne, null); } private void ResultOne(IAsyncResult ar) { WcfClient client = new WcfClient(); string data = client.EnddoSearch(ar); } 2. public void Two() { WcfClient client = new WcfClient(); client.doSearchCompleted += TwoCompleted; client.doSearchAsync("input"); } void TwoCompleted(object sender, doSearchCompletedEventArgs e) { string data = e.Result; } And with the new Task<T> class we have an easy third way by wrapping the synchronous operation in a task. 3. public void Three() { WcfClient client = new WcfClient(); var task = Task<string>.Factory.StartNew(() => client.doSearch("input")); string data = task.Result; } They all give you the ability to execute other code while you wait for the result, but I think Task<T> gives better control on what you execute before or after the result is retrieved. Are there any advantages or disadvantages to using one over the other? Or scenarios where one way of doing it is more preferable?

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