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  • Are there any shortcuts/easier(VB) style way for raising events in C#?

    - by Eric
    Example in VB I have a worker class Public Class worker Public Event EventNumber1(ByVal messages As Dictionary(Of Integer, String)) Public Event EventNumber2(ByVal message As String) Public Sub CallEventNumber1() Dim dict As New Dictionary(Of Integer, String) dict.Add(1, "EventNumber1 First message") dict.Add(2, "EventNumber1 Second message") RaiseEvent EventNumber1(dict) End Sub Public Sub CallEventNumber2() RaiseEvent EventNumber2("I am an EventNumber2 Message") End Sub End Class and wire them up in another class with AddHandler _worker.EventNumber1, AddressOf EventNumber1Handler AddHandler _worker.EventNumber2, AddressOf EventNumber2Handler and in C# the worker class class Worker { public delegate void EventNumber1Handler(Dictionary<int, string> messages); public delegate void EventNumber2Handler(string message); public event EventNumber1Handler EventNumber1; public event EventNumber2Handler EventNumber2; public void CallEventNumber1() { Dictionary<int, string> dict = new Dictionary<int, string>(); dict.Add(1, "EventNumber1 First message"); dict.Add(2, "EventNumber1 Second message"); if (EventNumber1 != null) EventNumber1(dict); } public void CallEventNumber2() { if (EventNumber2 != null) EventNumber2("I am an EventNumber2 Message"); } } and wire that up with worker.EventNumber1 += new Worker.EventNumber1Handler(worker_EventNumber1); worker.EventNumber2 += new Worker.EventNumber2Handler(worker_EventNumber2); So I guess my question is do I always need to add the delegate along with the event in c#? Is there any new syntax for c# 3.0/4.0? Regards _Eric

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  • How to reference input elements within a specific scope when there are multiple input elements of same kind?

    - by Will Merydith
    How do I select data for input elements within a specific scope? I have the same form multiple times (class "foo-form), and want to ensure I get the values for the hidden inputs within the scope of the form being submitted. Is the scope "this" implied? If not, what is the syntax for selecting input class "foo-text" within the scope of this? Feel free to point me to examples in the jquery docs - I could not find what I was looking for. $('.foo-form').submit(function() { // Store a reference to this form var $thisForm = $(this); }); <form class="foo-form"> <input type="hidden" class="foo-text"/> <input type="submit" class="button" /> </form> <form class="foo-form"> <input type="hidden" class="foo-text"/> <input type="submit" class="button" /> </form> <form class="foo-form"> <input type="hidden" class="foo-text"/> <input type="submit" class="button" /> // user clicks this submit button </form>

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  • C# Linq Select Problem in Method Chain.

    - by Gnought
    Note that the _src inherit IQueryable<U> and V inherit new(); I wrote the following statement, there is no syntax error. IQueryable<V> a = from s in _src where (s.Right - 1 == s.Left) select new V(); But if i re-wrote it as follows, the Visual Studio editor complains an error in the "Select" IQueryable<V> d = _src.Where(s => s.Right - 1 == s.Left).Select(s=> new V()); The Error is: The type arguments cannot be inferred from the usage. Try specifying the type arguments explicitly. Candidates are: System.Collections.Generic.IEnumerable<V> Select<U,V>(this System.Collections.Generic.IEnumerable<U>, System.Func<U,V>) (in class Enumerable) System.Linq.IQueryable<V> Select<U,V>(this System.Linq.IQueryable<U>, System.Linq.Expressions.Expression<System.Func<U,V>>) (in class Queryable) Could anyone explain this phenomenon, and what the solution is to fix the error?

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  • Performance difference between functions and pattern matching in Mathematica

    - by Samsdram
    So Mathematica is different from other dialects of lisp because it blurs the lines between functions and macros. In Mathematica if a user wanted to write a mathematical function they would likely use pattern matching like f[x_]:= x*x instead of f=Function[{x},x*x] though both would return the same result when called with f[x]. My understanding is that the first approach is something equivalent to a lisp macro and in my experience is favored because of the more concise syntax. So I have two questions, is there a performance difference between executing functions versus the pattern matching/macro approach? Though part of me wouldn't be surprised if functions were actually transformed into some version of macros to allow features like Listable to be implemented. The reason I care about this question is because of the recent set of questions (1) (2) about trying to catch Mathematica errors in large programs. If most of the computations were defined in terms of Functions, it seems to me that keeping track of the order of evaluation and where the error originated would be easier than trying to catch the error after the input has been rewritten by the successive application of macros/patterns.

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  • XPath Query - Select relative top level nodes

    - by John
    I'm trying to iterate over some elements in an XML document that may be nested, but as I iterate over them I may be removing some from the tree. I'm thinking the best way is to do this recursively, so I'm trying to come up with an XPath Query that will select all the top-level nodes relative to the current node. //foo[not(ancestor::foo)] works great at the document level, but I'm trying to figure out how to do this from a relative query. <foo id="1"> <foo id="2" /> <foo id="3"> <foo id="4"> <bar> <foo id="5"> <foo id="6" /> </foo> <foo id="7" /> </bar> </foo> </foo> </foo> If the current node is foo#3, I only want to select foo#4. When the current node is foo#4, I only want to select foo#5 and foo#7. I think I'm trying to select any descendant foo nodes of the current node, but without any ancestor foo nodes between the current node and the node I'm selecting. My conundrum is if we're already inside a foo node, not(ancestor::foo) doesn't help.

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  • Creating independent process!

    - by Neha
    I am trying to create a process from a service in C++. This new process is creating as a child process. I want to create an independent process and not a child process... I am using CreateProcess function for the same. Since the new process i create is a child process when i try to kill process tree at the service level it is killing the child process too... I dont want this to happen. I want the new process created to run independent of the service. Please advice on the same.. Thanks.. Code STARTUPINFO si; PROCESS_INFORMATION pi; ZeroMemory( &si, sizeof(si) ); si.cb = sizeof(si); // Start the child process. ZeroMemory( &pi, sizeof(pi) ); si.dwFlags = STARTF_USESHOWWINDOW; if(bRunOnWinLogonDesktop) { if(csDesktopName.empty()) si.lpDesktop = _T("winsta0\\default"); else _tcscpy(si.lpDesktop, csDesktopName.c_str()); } if(bHide) si.wShowWindow = SW_HIDE; /* maybe even SW_HIDE */ else si.wShowWindow = SW_SHOW; /* maybe even SW_HIDE */ TCHAR szCmdLine[512]; _tcscpy(szCmdLine, csCmdLine.c_str()); if( !CreateProcess( NULL, szCmdLine, NULL, NULL, FALSE, CREATE_NEW_PROCESS_GROUP, NULL, NULL, &si, &pi ) )

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  • How can I pass a hash to a Perl subroutine?

    - by Vishalrix
    In one of my main( or primary) routines,I have two or more hashes. I want the subroutine foo() to recieve these possibly-multiple hashes as distinct hashes. Right now I have no preference if they go by value, or as references. I am struggling with this for the last many hours and would appreciate help, so that I dont have to leave perl for php! ( I am using mod_perl, or will be) Right now I have got some answer to my requirement, shown here From http://forums.gentoo.org/viewtopic-t-803720-start-0.html # sub: dump the hash values with the keys '1' and '3' sub dumpvals { foreach $h (@_) { print "1: $h->{1} 3: $h->{3}\n"; } } # initialize an array of anonymous hash references @arr = ({1,2,3,4}, {1,7,3,8}); # create a new hash and add the reference to the array $t{1} = 5; $t{3} = 6; push @arr, \%t; # call the sub dumpvals(@arr); I only want to extend it so that in dumpvals I could do something like this: foreach my %k ( keys @_[0]) { # use $k and @_[0], and others } The syntax is wrong, but I suppose you can tell that I am trying to get the keys of the first hash ( hash1 or h1), and iterate over them. How to do it in the latter code snippet above?

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  • Shared Git repo syncing to svn causing git svn rebase to pollute repo with a log of no-op merge prob

    - by John K
    This wasn't so bad at the beginning, but now I have hundreds of no-op merge problems (solved by git rebase --skip). I have setup a shared git repo for my group because it is easier to deal with. But the company uses SVN so I have to keep SVN in sync with GIT. Worked like a dream at first, but after weeks of doing this GIT is giving me a lot of the following errors. Applying: * making all config actions work Using index info to reconstruct a base tree... Falling back to patching base and 3-way merge... Auto-merging app/controllers/vulnerabilities_controller.rb CONFLICT (content): Merge conflict in app/controllers/vulnerabilities_controller.rb Auto-merging public/javascripts/network_analysis_vulnerability_config.js CONFLICT (content): Merge conflict in public/javascripts/network_analysis_vulnerability_config.js Failed to merge in the changes. Patch failed at 0046 * making all config actions work My workflow: git co master git pull origin git svn rebase ... deal with no-op merge problems ... git svn dcommit git pull origin git push origin The problem is that what is in SVN is the correct so I use git rebase --skip, but I have to do that hundreds of times before I can dcommit. How do I clear these merge problems permanently?

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  • Does using functional languages help against computing values repeatedly?

    - by sharptooth
    Consider a function f(x,y): f(x,0) = x*x; f(0,y) = y*(y + 1); f(x,y) = f(x,y-1) + f(x-1,y); If one tries to implement that recursively in some language like C++ he will encounter a problem. Suppose the function is first called with x = x0 and y = y0. Then for any pair (x,y) where 0 <= x < x0 and 0 <= y < y0 the intermediate values will be computed multiple times - recursive calls will form a huge tree in which multiple leaves will in fact contain the same pairs (x,y). For pairs (x,y) where x and y are both close to 0 values will be computed numerous times. For instance, I tested a similar function implemented in C++ - for x=20 and y=20 its computation takes about 4 hours (yes, four Earth hours!). Obviously the implementation can be rewritten in such way that repeated computation doesn't occur - either iteratively or with a cache table. The question is: will functional languages perform any better and avoid repeated computations when implementing a function like above recursively?

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  • Make conversion to a native type explicit in C++

    - by Tal Pressman
    I'm trying to write a class that implements 64-bit ints for a compiler that doesn't support long long, to be used in existing code. Basically, I should be able to have a typedef somewhere that selects whether I want to use long long or my class, and everything else should compile and work. So, I obviously need conversion constructors from int, long, etc., and the respective conversion operators (casts) to those types. This seems to cause errors with arithmetic operators. With native types, the compiler "knows" that when operator*(int, char) is called, it should promote the char to int and call operator*(int, int) (rather than casting the int to char, for example). In my case it gets confused between the various built-in operators and the ones I created. It seems to me like if I could flag the conversion operators as explicit somehow, that it would solve the issue, but as far as I can tell the explicit keyword is only for constructors (and I can't make constructors for built-in types). So is there any way of marking the casts as explicit? Or am I barking up the wrong tree here and there's another way of solving this? Or maybe I'm just doing something else wrong...

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  • CakePHP 2.0: how to access properties of the parent object?

    - by PaulJ
    I just started learning CakePHP 2.0 a few days ago, and there's one thing that is leaving me stumped: say I have an User model and a Posts model: class User extends AppModel { public $name = "User"; public $hasMany=array( 'Post' => array( 'className' => 'Post', 'foreignKey' => 'author_id' ) ); } class Post extends AppModel { public $name = 'Post'; public $belongsTo = array( 'className' = 'User', 'foreignKey' = 'author_id', ); } (Where "author_id" is the foreign key in the posts table that references the Users table's primary key). And now, in the PostsController, I want to access the properties of the user that owns the current post (to show his display name, for example). What would be the proper syntax? I tried: $this->Post->User->find('first', array('conditions' => array('User.id' => "$usuario"))) But it didn't work (I guess it's because the User is the parent of the Post object, not its child). Or should CakePHP load everything automatically, once you've declared the $hasMany and $belongsTo relationships?

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  • PHP error T_object_operator

    - by kwek-kwek
    I am getting this error : Parse error: syntax error, unexpected T_OBJECT_OPERATOR in wp-content/themes/phil/page.php on line 104 This is my code: <?php $todaysDate = date ('M d'); $event_query = new WP_Query('showposts=5&category_name=events&meta_key=Date&meta_compare=>=&meta_value='.$todaysDate.'&orderby=meta_value=order=ASC'); ?> <?php if (event_query->have_post()) : while ($event_query->have_post()) : $event_query->the_post(); $eventMeta = get_post_meta($post->ID, 'Date', true); $eventDate = strtotime($eventMeta); $displayDate = date ('M d', $eventDate); ?> <li> <span class="date"><?php echo $displayDate ; ?></span> <span><a href="<?php the_permalink();?>" title="<?php the_title(); ?>"><?php the_title(); ?></a></span></li> <?php endwhile; else:?> <li>No Upcoming events</li> <?php endif;?> I am pretty new to this PHP stuff and WOrdpress so let me know what am I doing wrong. or paste the code to replace. Thank you

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  • SSIS Expressions - EvaluateAsExpression Problem

    - by Randy Minder
    In a Data Flow, I have an Derived Column task. In the expression for one of the columns, I have the following expression: [siteid] == "100" ? "1101" : [siteid] == "110" ? "1001" : [siteid] == "120" ? "2101" : [siteid] == "140" ? "1102" : [siteid] == "210" ? "2001" : [siteid] == "310" ? "3001" : [siteid] This works just fine. However, I intend to reuse this in at least a dozen other places so I want to store this to a variable and use the variable in the Derived Column instead of the hard-coded expression. When I attempt to create a variable, using the expression above, I get a syntax error saying 'siteid' is not defined. I guess this makes sense because it isn't. But how can I get this the expression to work by using a variable? It seems like I need some sort of way to tell it that 'siteid' will be the column containing the data I want to apply the expression to.

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  • Automatically Organize Tags in Tax/Folksonomy

    - by Rob Wilkerson
    I'm working on a process that will perform natural language processing (NLP) on one--and potentially several--of our content rich sites. What I'd like to do once the NLP is complete is to automatically organize the output (generally a set of terms that you might think of as tags given the prevalence of that metaphor) into some kind of standard or generally accepted organizational structure. In a perfect world, I'd really like this to be crowd sourced under the folksonomy concept (as opposed to a taxonomy) since the ultimate goal is to target/appeal to real people rather than "domain experts", but I'm open to ideas and best practices. For the obvious purpose of scalability, I'd like to automate the population of this tax/folksonomy so that "some guy" in the team/organization isn't responsible for looking at a bunch of words (with or without context) and arbitrarily fleshing out the contextual components of the tree. I have a few ideas for doing this that require some research to establish viability, but I have exactly zero practical experience with this sort of thing so the ideas really just boil down to stuff I made up that might perform some role in accomplishing the task. Imagining that others have vastly more experience with this sort of thing, I'm hoping that I can stand on your shoulders. Thanks for your thoughts and insights.

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  • SFTP in Python? (platform independent)

    - by Mark Wilbur
    I'm working on a simple tool that transfers files to a hard-coded location with the password also hard-coded. I'm a python novice, but thanks to ftplib, it was easy: import ftplib info= ('someuser', 'password') #hard-coded def putfile(file, site, dir, user=(), verbose=True): """ upload a file by ftp to a site/directory login hard-coded, binary transfer """ if verbose: print 'Uploading', file local = open(file, 'rb') remote = ftplib.FTP(site) remote.login(*user) remote.cwd(dir) remote.storbinary('STOR ' + file, local, 1024) remote.quit() local.close() if verbose: print 'Upload done.' if __name__ == '__main__': site = 'somewhere.com' #hard-coded dir = './uploads/' #hard-coded import sys, getpass putfile(sys.argv[1], site, dir, user=info) The problem is that I can't find any library that supports sFTP. What's the normal way to do something like this securely? Edit: Thanks to the answers here, I've gotten it working with Paramiko and this was the syntax. import paramiko host = "THEHOST.com" #hard-coded port = 22 transport = paramiko.Transport((host, port)) password = "THEPASSWORD" #hard-coded username = "THEUSERNAME" #hard-coded transport.connect(username = username, password = password) sftp = paramiko.SFTPClient.from_transport(transport) import sys path = './THETARGETDIRECTORY/' + sys.argv[1] #hard-coded localpath = sys.argv[1] sftp.put(localpath, path) sftp.close() transport.close() print 'Upload done.' Thanks again!

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  • C ++ virtual function

    - by user2950788
    masters of C++. I am trying to implement polymorphism in C++. I want to write a base class with a virtual function and then redefine that function in the child class. then demonstrate dynamic binding in my driver program. But I just couldn't get it to work. I know how to do it in C#, so I figured that I might have made some syntactical mistakes where I had used C#'s syntax in my C++ code, but these mistakes are not obvious to me at all. So I'd greatly appreciate it if you would correct my mistakes. class polyTest { public: polyTest(); virtual void type(); virtual ~polyTest(); }; void polyTest::type() { cout << "first gen"; } class polyChild: public polyTest { public: void type(); }; void polyChild::type() { cout << "second gen"; } int main() { polyChild * ptr1; polyChild * ptr2; ptr1 = new polyTest(); ptr2 = new polyChild(); ptr1 -> type(); ptr2 -> type(); }

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  • Project management software, available options

    - by canni
    Hey, sorry for posting this here, I know that this question better suites into SuperUser, but I would like to know answers from developers point of view. I have been using Indefero for project management etc. for some time, but I found that Indefero limitations are too big for my team. I'm searching project-management software that best suites this needs: Open-Source, but I can consider commercial apps GIT integration is mandatory, best if it can support multiple repos per project Time-tracking, good if it can have Gannt chart connected with issues etc. Issue, milestone, task tracking Good if it can be integrated with Gitosis, or have similar repository access control It must have an option, to setup on our own server Markdown syntax support is mandatory (or easy way to install plugin for this etc.) Issue tagging will be and advantage It will be used by developers team by 99% of time, but it has to have some simple interface, that clients can fill up bug reports etc. per project. It does not have to fill all this needs, but good if it can :) What options do You know, and can recommend?

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  • Input html tag not parsing properly in php

    - by Akaash
    I have a database with names that I would like displayed in the form of a table with checkboxes. Everything works until I try to place the html tag into my php code. When I put the input tag in it gives me the error: Parse error: syntax error, unexpected T_STRING, expecting ',' or ';' I can't see where I would put a comma or semi colon. <form> <?php $name = $_POST['name']; $host = "mysql16.000webhost.com"; $user_name = "a1611480_akaash"; $pwd = "****"; $database_name = "a1611480_akaash"; $db = mysql_connect($host, $user_name, $pwd); mysql_select_db($database_name); $result = mysql_query("SELECT name FROM Sort"); $var = array(); while ($row = mysql_fetch_array($result)) { $var[] = $row['name']; } $unique = array_unique($var); foreach ($unique as $value) { echo "<p class = Body_text><label>$value</label> <input type="checkbox" name="name" value="$value" /> </p>\n"; } ?> </form>

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  • Java scripts conflict on my home page

    - by naveen
    <script type="text/javascript" src="jquery-1.js"></script> <script type="text/javascript" src="mootools.js"></script> <script type="text/javascript" src="slideshow.js"></script> <script type="text/javascript"> //<![CDATA[ window.addEvent('domready', function(){ var data = { '1.jpg': { caption: 'Volcano Asención in Ometepe, Nicaragua.' }, '2.jpg': { caption: 'A Ceibu tree.' }, '3.jpg': { caption: 'The view from Volcano Maderas.' }, '4.jpg': { caption: 'Beer and ice cream.' } }; var myShow = new Slideshow('show', data, {controller: true, height: 400, hu: 'images/', thumbnails: true, width: 500}); }); //]]> </script> <script type="text/javascript"> $(document).ready(function() { //slides the element with class "menu_body" when paragraph with class "menu_head" is clicked $("#firstpane p.menu_head").click(function() { $(this).css({backgroundImage:"url(down.png)"}).next("div.menu_body").slideToggle(300).siblings("div.menu_body").slideUp("slow"); $(this).siblings().css({backgroundImage:"url(left.png)"}); }); //slides the element with class "menu_body" when mouse is over the paragraph $("#secondpane p.menu_head").mouseover(function() { $(this).css({backgroundImage:"url(down.png)"}).next("div.menu_body").slideDown(500).siblings("div.menu_body").slideUp("slow"); $(this).siblings().css({backgroundImage:"url(left.png)"}); }); }); </script> <!--[if lt IE 7]> <script type="text/javascript" src="unitpngfix.js"></script> <![endif]-->

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  • Convert IIS / Tomcat Web Application to a multi-server environment.

    - by bill_the_loser
    I have an existing web application built in .Net, running on IIS that leverages a java servlet that we have running on Tomcat 5.5. We need to scale the application and I'm confused about what relates to our situation and what we need to do to get the servlet running on multiple servers. Right now I have 4 servers that can each individually process results, it almost seems like all I should have to do is add the ajp13 worker processes from three additional machines to the machine hosting the load balancer worker. But I can't imagine it should be that easy. What do I need to do to distribute the Tomcat load to the extra three machines? Thanks. Update: The current configuration is using a workers2.properties configuration file. From all of the documentation online I have not been able to determine the distinction between the workers.properties and the workers2.properties. Most of the examples that I have found are configuring the workers.properties and revolve around adding workers and registering them in the worker.list element. The workers2.properties does not appears to have a worker.list element and the syntax is different enough between the workers.properties and the workers2.properties that I'm doubtful that I can add that element. If I just add my multiple AJP workers to the workers2.properties file do I need to worry about the apparent lack of a worker.list element? [ajp13:localhost:8009] channel=channel.socket:localhost:8009 group=lb [ajp13:host2.mydomain.local:8009] channel=channel.socket:host2.mydomain.local:8009 group=lb [ajp13:host3.mydomain.local:8009] channel=channel.socket:host3.mydomain.local:8009 group=lb A couple of side notes... One I've noticed that sometime Tomcat doesn't seem to reload my changes and I don't know why. Also, I have no idea why this configuration has a workers2.properties and not a workers.properties. I've been assuming that it's based on version but I haven't seen anything to back up that assumption.

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  • How to enforce that HTTP client uses conditional requests for updates?

    - by Day
    In a (proper RMM level 3) RESTful HTTP API, I want to enforce the fact that clients should make conditional requests when updating resources, in order to avoid the lost update problem. What would be an appropriate response to return to clients that incorrectly attempt unconditional PUT requests? I note that the (abandoned?) mod_atom returns a 405 Method Not Allowed with an Allow header set to GET, HEAD (view source) when an unconditional update is attempted. This seems slightly misleading - to me this implies that PUT is never a valid method to attempt on the resource. Perhaps the response just needs to have an entity body explaining that If-Match or If-Unmodified-Since must be used to make the PUT request conditional in which case it would be allowed? Or perhaps a 400 Bad Request with a suitable explanation in the entity body would be a better solution? But again, this doesn't feel quite right because it's using a 400 response for a violation of application specific semantics when RFC 2616 says (my emphasis): The request could not be understood by the server due to malformed syntax. But than again, I think that using 400 Bad Request for application specific semantics is becoming a widely accepted pragmatic solution (citation needed!), and I'm just being overly pedantic.

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  • C++ IDE for Linux?

    - by Sven
    I want to expand my programming horizons to Linux. A good, dependable basic toolset is important, and what is more basic than an IDE? I could find these SO topics: Lightweight IDE for linux and What tools do you use to develop C++ applications on Linux? I'm not looking for a lightweight IDE. If an IDE is worth the money, then I will pay for it, so it need not be free. My question, then: What good, C++ programming IDE is available for Linux? The minimums are fairly standard: syntax highlighting, code completion (like intellisense or its Eclipse counterpart) and integrated debugging (e.g., basic breakpoints). I have searched for it myself, but there are so many that it is almost impossible to separate the good from the bads by hand, especially for someone like me who has little C++ coding experience in Linux. I know that Eclipse supports C++, and I really like that IDE for Java, but is it any good for C++ and is there something better? The second post actually has some good suggestions, but what I am missing is what exactly makes the sugested IDE so good for the user, what are its (dis)advantages? Maybe my question should therefore be: What IDE do you propose (given your experiences), and why?

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  • Adding functions to Java class libraries

    - by Eric
    I'm using a Java class library that is in many ways incomplete: there are many classes that I feel ought to have additional member functions built in. However, I am unsure of the best practice of adding these member functions. Lets call the insufficient base class A. class A { public A(/*long arbitrary arguments*/) { //... } public A(/*long even more arbitrary arguments*/) { //... } public int func() { return 1; } } Ideally, I would like to add a function to A. However, I can't do that. My choice is between: class B extends A { //Implement ALL of A's constructors here public int reallyUsefulFunction() { return func()+1; } } and class AddedFuncs { public int reallyUsefulFunction(A a) { return a.func()+1; } } The way I see it, they both have advantages and disadvantages. The first choice gives a cleaner syntax than the second, and is more logical, but has problems: Let's say I have a third class, C, within the class library. class C { public A func() { return new A(/*...*/); } } As I see it, there is no easy way of doing this: C c; int useful = c.func().reallyUsefulFunction(); as the type returned by C.func() is an A, not a B, and you can't down-cast. So what is the best way of adding a member function to a read-only library class?

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  • How to construct objects based on XML code?

    - by the_drow
    I have XML files that are representation of a portion of HTML code. Those XML files also have widget declarations. Example XML file: <message id="msg"> <p> <Widget name="foo" type="SomeComplexWidget" attribute="value"> inner text here, sets another attribute or inserts another widget to the tree if needed... </Widget> </p> </message> I have a main Widget class that all of my widgets inherit from. The question is how would I create it? Here are my options: Create a compile time tool that will parse the XML file and create the necessary code to bind the widgets to the needed objects. Advantages: No extra run-time overhead induced to the system. It's easy to bind setters. Disadvantages: Adds another step to the build chain. Hard to maintain as every widget in the system should be added to the parser. Use of macros to bind the widgets. Complex code Find a method to register all widgets into a factory automatically. Advantages: All of the binding is done completely automatically. Easier to maintain then option 1 as every new widget will only need to call a WidgetFactory method that registers it. Disadvantages: No idea how to bind setters without introducing a maintainability nightmare. Adds memory and run-time overhead. Complex code What do you think is better? Can you guys suggest a better solution?

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  • How to update attributes without validation

    - by Brian Roisentul
    I've got a model with its validations, and I found out that I can't update an attribute without validating the object before. I already tried to add on => :create syntax at the end of each validation line, but I got the same results. My announcement model have the following validations: validates_presence_of :title validates_presence_of :description validates_presence_of :announcement_type_id validate :validates_publication_date validate :validates_start_date validate :validates_start_end_dates validate :validates_category validate :validates_province validates_length_of :title, :in => 6..255, :on => :save validates_length_of :subtitle, :in => 0..255, :on => :save validates_length_of :subtitle, :in => 0..255, :on => :save validates_length_of :place, :in => 0..50, :on => :save validates_numericality_of :vacants, :greater_than_or_equal_to => 0, :only_integer => true validates_numericality_of :price, :greater_than_or_equal_to => 0, :only_integer => true My rake task does the following: task :announcements_expiration => :environment do announcements = Announcement.expired announcements.each do |a| #Gets the user that owns the announcement user = User.find(a.user_id) puts a.title + '...' a.state = 'deactivated' if a.update_attributes(:state => a.state) puts 'state changed to deactivated' else a.errors.each do |e| puts e end end end This throws all the validation exceptions for that model, in the output. Does anybody how to update an attribute without validating the model?

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