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• Existing parsers in c# (BSD license or similar)

  - by Sylverdrag

  I am looking for parsers (in C#) for a bunch of formats. (PHP, ASP, some XML based formats, HTML,...pretty much anything I can get my hands on.) The purpose is to separate the text from the code and do some edits without messing up the code. I had a look at ANTLR, but while it seems like the "right tool", there is just too much prior knowledge assumed. I have an easier time writing a parser from scratch than understanding how to "easily" generate parsers from ANTLR. (I wrote a small parser for a specific type of RTF files within a couple days, so the task is probably within my reach, but as I have no formal knowledge of parsing/lexing, I am at loss with ANTLR) Then it occurred to me that there must existing parsers for many formats, so before I start writing yet another a brand new and potentially buggy version of the wheel, I figured I would check what parsers already exist and can be reused in a commercial product. I could use parsers for just about every format in existence, so this question would be a good place to make a list of all existing free parsers written in C#, if there are any. Thanks in advance for your suggestions

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• .Net lambda expression-- where did this parameter come from?

  - by larryq

  I'm a lambda newbie, so if I'm missing vital information in my description please tell me. I'll keep the example as simple as possible. I'm going over someone else's code and they have one class inheriting from another. Here's the derived class first, along with the lambda expression I'm having trouble understanding: class SampleViewModel : ViewModelBase { private ICustomerStorage storage = ModelFactory<ICustomerStorage>.Create(); public ICustomer CurrentCustomer { get { return (ICustomer)GetValue(CurrentCustomerProperty); } set { SetValue(CurrentCustomerProperty, value); } } private int quantitySaved; public int QuantitySaved { get { return quantitySaved; } set { if (quantitySaved != value) { quantitySaved = value; NotifyPropertyChanged(p => QuantitySaved); //where does 'p' come from? } } } public static readonly DependencyProperty CurrentCustomerProperty; static SampleViewModel() { CurrentCustomerProperty = DependencyProperty.Register("CurrentCustomer", typeof(ICustomer), typeof(SampleViewModel), new UIPropertyMetadata(ModelFactory<ICustomer>.Create())); } //more method definitions follow.. Note the call to NotifyPropertyChanged(p => QuantitySaved) bit above. I don't understand where the "p" is coming from. Here's the base class: public abstract class ViewModelBase : DependencyObject, INotifyPropertyChanged, IXtremeMvvmViewModel { public event PropertyChangedEventHandler PropertyChanged; protected virtual void NotifyPropertyChanged<T>(Expression<Func<ViewModelBase, T>> property) { MvvmHelper.NotifyPropertyChanged(property, PropertyChanged); } } There's a lot in there that's not germane to the question I'm sure, but I wanted to err on the side of inclusiveness. The problem is, I don't understand where the 'p' parameter is coming from, and how the compiler knows to (evidently?) fill in a type value of ViewModelBase from thin air? For fun I changed the code from 'p' to 'this', since SampleViewModel inherits from ViewModelBase, but I was met with a series of compiler errors, the first one of which statedInvalid expression term '=>' This confused me a bit since I thought that would work. Can anyone explain what's happening here?

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• Using Python to get a CSV output for the following example.

  - by Az

  Hi there, I'm back again with my ongoing saga of Student-Project Allocation questions. Thanks to Moron (who does not match his namesake) I've got a bit of direction for an evaluation portion of my project. Going with the idea of the Assignment Problem and Hungarian Algorithm I would like to express my data in the form of a .csv file which would end up looking like this in spreadsheet form. This is based on the structure I saw here. | | Project 1 | Project 2 | Project 3 | |----------|-----------|-----------|-----------| |Student1 | | 2 | 1 | |----------|-----------|-----------|-----------| |Student2 | 1 | 2 | 3 | |----------|-----------|-----------|-----------| |Student3 | 1 | 3 | 2 | |----------|-----------|-----------|-----------| To make it less cryptic: the rows are the Students/Agents and the columns represent Projects/Task. Obviously ONE project can be assigned to ONE student. That, in short, is what my project is about. The fields represent the preference weights the students have placed upon the projects (ranging from 1 to 10). If blank, that student does not want that project and there's no chance of him/her being assigned such. Anyway, my data is stored within dictionaries. Specifically the students and projects dictionaries such that: students[student_id] = Student(student_id, student_name, alloc_proj, alloc_proj_rank, preferences) where preferences is in the form of a dictionary such that preferences[rank] = {project_id} and projects[project_id] = Project(project_id, project_name) I'm aware that sorted(students.keys()) will give me a sorted list of all the student IDs which will populate the row labels and sorted(projects.keys()) will give me the list I need to populate the column labels. Thus for each student, I'd go into their preferences dictionary and match the applicable projects to ranks. I can do that much. Where I'm failing is understanding how to create a .csv file. Any help, pointers or good tutorials will be highly appreciated.

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• What is wrong with accessing DBI directly?

  - by canavanin

  Hi everyone! I'm currently reading Effective Perl Programming (2nd edition). I have come across a piece of code which was described as being poorly written, but I don't yet understand what's so bad about it, or how it should be improved. It would be great if someone could explain the matter to me. Here's the code in question: sub sum_values_per_key { my ( $class, $dsn, $user, $password, $parameters ) = @_; my %results; my $dbh = DBI->connect( $dsn, $user, $password, $parameters ); my $sth = $dbh->prepare( 'select key, calculate(value) from my_table'); $sth->execute(); # ... fill %results ... $sth->finish(); $dbh->disconnect(); return \%results; } The example comes from the chapter on testing your code (p. 324/325). The sentence that has left me wondering about how to improve the code is the following: Since the code was poorly written and accesses DBI directly, you'll have to create a fake DBI object to stand in for the real thing. I have probably not understood a lot of what the book has so far been trying to teach me, or I have skipped the section relevant for understanding what's bad practice about the above code... Well, thanks in advance for your help!

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• Why would I use Assembly.LoadFile in lieu of Assembly.LoadFrom?

  - by Cheeso

  It's my impression that Assembly.LoadFrom uses the ApplicationBase and PrivateBinPath. It also my impression that Assembly.LoadFile does not. Why would anyone want to use LoadFile? In other words, if my understanding is correct, why would anyone want to NOT use the ApplicationBase and PrivateBinPath? I'm working with some existing code, which uses LoadFile, and I don't understand why it would do so. LoadFile apparently does not load dependencies from the same directory. The LoadFrom method does load dependencies (From the doc: The load-from context...allows dependencies on that path to be found and loaded because the path information is maintained by the context.) I'd like to convert it from using LoadFile, to use LoadFrom. What is likely to break, if anything, if I replace LoadFile with LoadFrom? Even if it iss benign, it may be that I cannot do the replacement, just based on project schedules. If I cannot replace LoadFile with LoadFrom, is there a way to convince assemblies loaded with LoadFile to load dependencies? Is there a packaging trick I can use (embedded assembly, ILMerge, an AssemblyResolve event, something like that) that can allow an assembly loaded with LoadFile to also load its dependencies?

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• Easily (as in WYSIWYG) customize the docbook output

  - by Sukima

  I've used DocBook in the past and I love the idea behind the separation of content from presentation. I am very comfortable editing XML directly. In my extensive search to find the best documenting solution for my needs I am always coming back to this one solution: DocBook - Build system (ant, make, etc.) - Output I have seen lots of information concerning the best WYSIWYG, XML, Text editors for writing DocBook including alternative markup languages like asciidoc. All these solutions focus on the creation of DocBook or the nightmare of the DocBook tool chain. No one ever addresses the Output side other then to say "Just use XSL" or "Custom scripts" When tasked to make a document or manual I don't want to worry about spending countless hours attempting to reprogram, customize, and modify the XSL, CSS, and shell scripts (i.e. O'Riely books). That is a very arduous task. My query: is there a tool that makes the customizing easier? And is there anything that could be similar to say Pages or Word in that the user creates a template and the tool chain does the rest? Attempting to do a visual task like pretty logos and fixing all the broken layouts that the default XSL comes up with (pagination is a mess) is very difficult from a text editor. Content is easy. Editing DocBook XSL was truly a nightmare when I did it in the past. I've searched and I find lots of info on XML editors but nothing on XSL editors. Or am I lacking a key understanding of the process. Thanks.

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• PHP Object References in Frameworks

  - by bigstylee

  Before I dive into the disscusion part a quick question; Is there a method to determine if a variable is a reference to another variable/object? For example $foo = 'Hello World'; $bar = &$foo; echo (is_reference($bar) ? 'Is reference' : 'Is orginal'; I have been using PHP5 for a few years now (personal use only) and I would say I am moderately reversed on the topic of Object Orientated implementation. However the concept of Model View Controller Framework is fairly new to me. I have looked a number of tutorials and looked at some of the open source frameworks (mainly CodeIgnitor) to get a better understanding how everything fits together. I am starting to appreciate the real benefits of using this type of structure. I am used to implementing object referencing in the following technique. class Foo{ public $var = 'Hello World!'; } class Bar{ public function __construct(){ global $Foo; echo $Foo->var; } } $Foo = new Foo; $Bar = new Bar; I was surprised to see that CodeIgnitor and Yii pass referencs of objects and can be accessed via the following method: $this->load->view('argument') The immediate advantage I can see is a lot less code and more user friendly. But I do wonder if it is more efficient as these frameworks are presumably optimised? Or simply to make the code more user friendly? This was an interesting article Do not use PHP references.

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• What happens when value types are created?

  - by Bob

  I'm developing a game using XNA and C# and was attempting to avoid calling new struct() type code each frame as I thought it would freak the GC out. "But wait," I said to myself, "struct is a value type. The GC shouldn't get called then, right?" Well, that's why I'm asking here. I only have a very vague idea of what happens to value types. If I create a new struct within a function call, is the struct being created on the stack? Will it simply get pushed and popped and performance not take a hit? Further, would there be some memory limit or performance implications if, say, I need to create many instances in a single call? Take, for instance, this code: spriteBatch.Draw(tex, new Rectangle(x, y, width, height), Color.White); Rectangle in this case is a struct. What happens when that new Rectangle is created? What are the implications of having to repeat that line many times (say, thousands of times)? Is this Rectangle created, a copy sent to the Draw method, and then discarded (meaning no memory getting eaten up the more Draw is called in that manner in the same function)? P.S. I know this may be pre-mature optimization, but I'm mostly curious and wish to have a better understanding of what is happening.

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• How to learn how to program?

  - by twinbornJoint

  I would like to know the best methods for learning to program. I've been directed towards the Python language because I was told it is good for beginners. I ultimately want to make games for OS X/iPhone. My problem is that I understand what I read but I can't apply my knowledge to anything. I am a programming noob. Should I stick with Python? (is there a better language I should be learning?) Where can I learn programming theory? I get very hyper when reading my book sometimes, any tips on staying calm and focusing? What are effective ways to learn how to program? Are there standard exercises for programming? (I feel solving problems helps my understanding immensely) Ultimately I feel like I am in a never ending tunnel that leads me no where. It feels like I am just completely unable to pursue anything in the world of programming, yet it is something I want to do very much. Thanks.

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• What is happening in this T-SQL code? (Concatenting the results of a SELECT statement)

  - by Ben McCormack

  I'm just starting to learn T-SQL and could use some help in understanding what's going on in a particular block of code. I modified some code in an answer I received in a previous question, and here is the code in question: DECLARE @column_list AS varchar(max) SELECT @column_list = COALESCE(@column_list, ',') + 'SUM(Case When Sku2=' + CONVERT(varchar, Sku2) + ' Then Quantity Else 0 End) As [' + CONVERT(varchar, Sku2) + ' - ' + Convert(varchar,Description) +'],' FROM OrderDetailDeliveryReview Inner Join InvMast on SKU2 = SKU and LocationTypeID=4 GROUP BY Sku2 , Description ORDER BY Sku2 Set @column_list = Left(@column_list,Len(@column_list)-1) Select @column_list ---------------------------------------- 1 row is returned: ,SUM(Case When Sku2=157 Then Quantity Else 0 End) As [157 -..., SUM(Case ... The T-SQL code does exactly what I want, which is to make a single result based on the results of a query, which will then be used in another query. However, I can't figure out how the SELECT @column_list =... statement is putting multiple values into a single string of characters by being inside a SELECT statement. Without the assignment to @column_list, the SELECT statement would simply return multiple rows. How is it that by having the variable within the SELECT statement that the results get "flattened" down into one value? How should I read this T-SQL to properly understand what's going on?

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• How do I return an array from a method?

  - by dwwilson66

  I'm trying to create a deck of cards for my homework. Code is posted below. I need to create four sets of cards (the four suits) and am create a multidimensional array. When I print the results instead of trying to pass the array, I can see that the data in the array is as expected. However, when I try to pass the array card, I get an error cannot find symbol. I've got this modeled after texbook and Java tutorial examples, and I need some help figuring out what I'm missing. I've over-documented to give an idea of how I'm thinking this SHOULD work...please let me know where I've gone horribly wrong in my understanding. import java.util.*; import java.lang.*; // public class CardGame { public static int[][] main(String[] args) { int[][] startDeck = deckOfCards(); /* cast new deck as int[][], calling method deckOfCards System.out.println(" /// from array: " + Arrays.deepToString(startDeck)); } public static int[][] deckOfCards() /* method to return a multi-dimensional array */ { int rank; int suit; for(rank=1;rank<14;rank++) /* cards 1 - 13 .... */ { for(suit=1;suit<5;suit++) /* suits 1 - 4 .... */ { int[][] card = new int[][] /* define a new card... */ { {rank,suit} /* with rank/suit from for... loops */ }; System.out.println(" /// from array: " + Arrays.deepToString(card)); } } return card; /* Error: cannot find symbol } }

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• Tools to document/visualize call graph?

  - by Dave Griffiths

  Hi, having recently joined a project with a vast amount of code to get to grips with, I would like to start documenting and visualizing some of the flows through the call graph to give me a better understanding of how everything fits together. This is what I would like to see in my ideal tool: every node is a function/method nodes are connected if one function can call another optional square box in between detailing conditions under which call is made (or a label icon you can hover over like a tooltip) also icon on edge describing parameters hover over node and description is displayed optional icons for node to display pseudo code scenario/domain view - display subset of complete diagram for particular use-case slide view mode - for each frame, the currently executing function is highlighted plenty of options over what to display to reduce on-screen clutter the interactive use of such a tool is key, I'm not looking for a Graphviz type solution because there would be too much clutter. The ability to form a view of a subset of the entire graph would be very handy (maybe with the unimportant clutter greyed out). Don't need automatic generation from source code, happy to enter it manually. Almost like a mind-map. Does that make sense? If you are not aware of such a tool, do you also think it would be useful? (Just in case I decide to go and scratch that itch one day!)

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• Ideas Related to Subset Sum with 2,3 and more integers

  - by rolandbishop

  I've been struggling with this problem just like everyone else and I'm quite sure there has been more than enough posts to explain this problem. However in terms of understanding it fully, I wanted to share my thoughts and get more efficient solutions from all the great people in here related to Subset Sum problem. I've searched it over the Internet and there is actually a lot sources but I'm really willing to re-implement an algorithm or finding my own in order to understand fully. The key thing I'm struggling with is the efficiency considering the set size will be large. (I do not have a limit, just conceptually large). The two phases I'm trying to implement ideas on is finding two numbers that are equal to given integer T, finding three numbers and eventually K numbers. Some ideas I've though; For the two integer part I'm thing basically sorting the array O(nlogn) and for each element in the array searching for its negative value. (i.e if the array element is 3 searching for -3). Maybe a hash table inclusion could be better, providing a O(1) indexing the element? For the three or more integers I've found an amazing blog post;http://www.skorks.com/2011/02/algorithms-a-dropbox-challenge-and-dynamic-programming/. However even the author itself states that it is not applicable for large numbers. So I was for 2 and 3 and more integers what ideas could be applied for the subset problem. I'm struggling with setting up a dynamic programming method that will be efficient for the large inputs as well.

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• Natural problems to solve using closures

  - by m.u.sheikh

  I have read quite a few articles on closures, and, embarassingly enough, I still don't understand this concept! Articles explain how to create a closure with a few examples, but I don't see any point in paying much attention to them, as they largely look contrived examples. I am not saying all of them are contrived, just that the ones I found looked contrived, and I dint see how even after understanding them, I will be able to use them. So in order to understand closures, I am looking at a few real problems, that can be solved very naturally using closures. For instance, a natural way to explain recursion to a person could be to explain the computation of n!. It is very natural to understand a problem like computing the factorial of a number using recursion. Similarly, it is almost a no-brainer to find an element in an unsorted array by reading each element, and comparing with the number in question. Also, at a different level, doing Object-oriented programming also makes sense. So I am trying to find a number of problems that could be solved with or without closures, but using closures makes thinking about them and solving them easier. Also, there are two types to closures, where each call to a closure can create a copy of the environment variables, or reference the same variables. So what sort of problems can be solved more naturally in which of the closure implementations?

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• postgresql help with php loop....

  - by KnockKnockWhosThere

  I keep getting an "Notice: Undefined index: did" error with this query, and I'm not understanding why... I'm much more used to mysql, so, maybe the syntax is wrong? This is the php query code: function get_demos() { global $session; $demo = array(); $result = pg_query("SELECT DISTINCT(did,vid,iid,value) FROM dv"); if(pg_num_rows($result) > 0) { while($r = pg_fetch_array($result)) { switch($r['did']) { case 1: $demo['a'][$r['vid']] = $r['value']; break; case 2: $demo['b'][$r['vid']] = $r['value']; break; case 3: $demo['c'][$r['vid']] = $r['value']; break; } } } else { $session->session_setMessage(2); } return $demo; } When I run that query at the pg prompt, I get results: "(1,1,1,"A")" "(1,2,2,"B")" "(1,3,3,"C")" "(1,4,4,"D")" "(1,5,5,"E")" "(1,6,6,"F")" "(1,7,7,"G")" "(1,8,8,"H")" "(1,9,9,"I")" "(1,10,A,"J")" "(1,11,B,"K")" "(1,12,C,"L")" "(1,13,D,"M")" "(2,14,1,"A")" "(2,15,2,"B")" "(2,16,0,"C")" "(3,17,1,"A")" "(3,18,2,"B")" "(3,19,3,"C")" "(3,20,4,"D")" "(3,21,5,"E")" "(3,22,6,"F")" "(3,23,7,"G")"

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• How do i write task? (parallel code)

  - by acidzombie24

  I am impressed with intel thread building blocks. I like how i should write task and not thread code and i like how it works under the hood with my limited understanding (task are in a pool, there wont be 100 threads on 4cores, a task is not guaranteed to run because it isnt on its own thread and may be far into the pool. But it may be run with another related task so you cant do bad things like typical thread unsafe code). I wanted to know more about writing task. I like the 'Task-based Multithreading - How to Program for 100 cores' video here http://www.gdcvault.com/sponsor.php?sponsor_id=1 (currently second last link. WARNING it isnt 'great'). My fav part was 'solving the maze is better done in parallel' which is around the 48min mark (you can click the link on the left side). However i like to see more code examples and some API of how to write task. Does anyone have a good resource? I have no idea how a class or pieces of code may look after pushing it onto a pool or how weird code may look when you need to make a copy of everything and how much of everything is pushed onto a pool.

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• Newbie question: When to use extern "C" { //code } ?

  - by Russel

  Hello, Maybe I'm not understanding the differences between C and C++, but when and why do we need to use: extern "C" { ? Apparently its a "linkage convention"? I read about it briefly and noticed that all the .h header files included with MSVS surround their code with it. What type of code exactly is "C code" and NOT "C++ code"? I thought C++ included all C code? I'm guessing that this is not the case and that C++ is different and that standard features/functions exist in one or the other but not both (ie: printf is C and cout is C++), but that C++ is backwards compatible though the extern "C" declaration. Is this correct? My next question depends on the answer to the first, but I'll ask it here anyway: Since MSVS header files that are written in C are surrounded by extern "C" { ... }, when would you ever need to use this yourself in your own code? If your code is C code and you are trying to compile it in a C++ compiler, shouldn't it work without problem because all the standard h files you include will already have the extern "C" thing in them with the C++ compiler? Do you have to use this when compiling in C++ but linking to alteady built C libraries or something? Please help clarify this for me... Thanks! --Keith

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• ListBox selector odd behavior when there are dupes

  - by byte1918

  I'm working on a bigger project atm, but I made this simple example to show you what happens.. using System.Collections.Generic; using System.Windows; namespace txt { public partial class MainWindow { public MainWindow() { InitializeComponent(); } private void Window_Loaded(object sender, RoutedEventArgs e) { var obsLst = new List<Info> { new Info { name = "asd" }, new Info { name = "asd" }, new Info { name = "asd" }, new Info { name = "asd" } }; var temp = new List<Info>(); for (var i = 1; i <= 3; i++) { temp.Add(obsLst[0]); //I add 3 of the same item from obsLst to temp } lst.DataContext = temp; //lst = ListBox } } public class Info { public string name { get; set; } } } The ListBox ItemsSource is set to {Binding}.. When I start the application I get 3 txt.Info objects displayed and if I click any of them, 2 or even all of them get selected aswell. From my understanding the problem relies in the fact that the listbox selector cannot differentiate between the items and therefor doesn't know which one I selected. Here's a picture of what it looks like.. I only clicked on the second txt.Info item. I found a solution where someone said that I have to specify the DisplayMemberPath, but I can't really do that in the other project because I have a datatemplate for the object. Any ideas on how I could fix this would be great.. Thx in advance.

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• can javascript process binary data?

  - by Johnny

  admit me describe my questions in situation-oriented way: assume IE is still the dominate web browser(the firefox have document for binary processing): the XMLHttpRequest.responseText or XMLHttpRequest.responseXML in ie desire txt or xml/xhtml/html,but what about the server response the xmlHttprequest whith MIME TYPE application/octet ? would the response string all little than 256 ?(every char of that string < 256), thanks very much for a straight answer, i have no webserver env,so i don't know how to test it out. because use txt or xml have a issue of character set encode, and i don't know how to process #[[[CDDATA node of one encoded xml(ex : utf-8,ascii,gb18030) with javascript, when i getNodeText, does the docObj return me byte or decoded char ? if it was decoded char which according to the header indicated charSet in the httpresponse , it would be all wrong. to avoid mess up with charSet ,i would like the server to response octet data and force strings data to be encoded as utf-8 but another charSet in the binary format. if the response is octal, so i guess the browser would not try to decode the response"txt" does this weird? or miss understanding the fundamental things? EDIT: I believe the question is asking this: Can Javascript safely process strings that aren't encoded in Unicode? What are the problems with trying to do so? EDIT: no no no , i means if http-header: content-type is "application/octet" , would the ie try to decoded it as (16bits Unicode | ie local setting charset ) when i get XMLHttpRequestobj.responseText use javascript ? or it(ie) just wrap every single byte of the response body as a javascript string, then every char in that string little than or equal 256 (char<=256), am i talking Mars language? sadly, if i were Marsizen,i would come as tourist without fuzzy questions. however i am in a country which share at least one property with Mars : RED

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• Am I making the right choice in choosing Yii as my PHP Framework?

  - by Bara

  I am about to begin development of a new website and have been doing research on PHP Frameworks. I'm not an advanced PHP developer, but I have been developing web sites and apps (in asp.net) for a few years now. My website will primarily be AJAX-based (using jQuery) and making lots of calls to web services. After some research, here's what I came up with: CakePHP: Originally started developing in this, but found it too complex. The fact that it forces you to use and learn all this new stuff just to use it was a bit daunting, so I put it aside for the time being. Zend: The performance of the framework leaves me a bit skeptical, but I heard it has great support for creating web services. I also heard it was a bit complex. CodeIgniter: No real reason for not using this one. Based on what I've read CodeIgniter and Yii are very similar, but Yii is a bit faster and doesn't have un-needed code for PHP4 (since I plan on developing exclusively in PHP5). As far as Yii, the only things that scare me about it are that it is newer than the other frameworks so it has a smaller community. It also doesn't seem to have a ton of web service support (only SOAP, from my understanding) as opposed to Zend. So my questions come down to: Should these things worry me? (not as big of a community, poor web service support) Is there anything else I should look into? Is my choice of Yii over the other frameworks ok for a primarily AJAX-based web app? Bara

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• Any danger in calling flash messages html_safe?

  - by PreciousBodilyFluids

  I want a flash message that looks something like: "That confirmation link is invalid or expired. Click here to have a new one generated." Where "click here" is of course a link to another action in the app where a new confirmation link can be generated. Two drawbacks: One, since link_to isn't defined in the controller where the flash message is being set, I have to put the link html in myself. No big deal, but kind of messy. Number two: In order for the link to actually display properly on the page I have to html_safe the flash display function in the view, so now it looks like (using Haml): - flash.each do |name, message| = content_tag :div, message.html_safe This gives me pause. Everything else I html_safe has been HTML I've written myself in helpers and whatnot, but the contents of the flash hash are stored in a cookie client-side, and could conceivably be changed. I've thought through it, and I don't see how this could result in an XSS attack, but XSS isn't something I have a great understanding of anyway. So, two questions: 1. Is there any danger in always html_safe-ing all flash contents like this? 2. The fact that this solution is so messy (breaking MVC by using HTML in the controller, always html_safe-ing all flash contents) make me think I'm going about this wrong. Is there a more elegant, Rails-ish way to do this? I'm using Rails 3.0.0.beta3.

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• PHP, is_array() generating an "Undefined property: stdClass::$crit " error

  - by Brook Julias

  is_array($src2->crit) is generating an "Undefined property: stdClass::$crit" error. The line throwing the error is: if(is_array($src2->crit) && count($src->crit) > 0){ $src2->crit is initialized here. $src2->crit = array(); $src2->crit[0] = new dataSet(); $src2->crit[0]->tblName = $tbl2; $src2->crit[0]->colName = "ID"; $src2->crit[0]->val = $elm->editID; When testing $src2->crit with this code. print("\$src->crit is a ".$src->crit."<br />"); print_r($src->crit); print("<br />"); This is returned. $src2->crit is a Array Array ( [0] => dataSet Object ( [tblName] => sExam [colName] => ID [val] => 10 ) ) What am I not seeing/understanding correctly? If print("\$src2->crit is a ".$src->crit."<br />") returns that it is an array then why is is_array($src2->$crit) generating an error?

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• Virtual destructor - How does it work?

  - by Prabhu

  Hello All, Few hours back I was fiddling with a Memory Leak issue and it turned out that I really got some basic stuff about virtual destructor wrong!! Let me put explain my class design. class Base { virtual push_elements()<br>{}<br> }; class Derived:public Base { vector<int> x; public: void push_elements(){ for(int i=0;i <5;i++) x.push_back(i); } }; void main() { Base* b = new Derived(); b->push_elements(); delete b; } The bounds checker tool reported a memory leak in the derived class vector. And I figured out that the destructor is not virtual and the derived class destructor is not called.And it surprisingly got fixed when I made the destructor virtual. But my question is "isn't the vector deallocated automatically even if the derived class destructor is not called"? Is that a quirk in BoundsChecker tool or is my understanding of virtual destructor is wrong:)

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• SSL signed certificates for internal use

  - by rogueprocess

  I have a distributed application consisting of many components that communicate over TCP (for examle JMS) and HTTP. All components run on internal hardware, with internal IP addresses, and are not accessible to the public. I want to make the communication secure using SSL. Does it make sense to purchase signed certificates from a well-known certificate authority? Or should I just use self-signed certs? My understanding of the advantage of trusted certs is that the authority is an entity that can be trusted by the general public - but that is only an issue when the general public needs to be sure that the entity at a particular domain is who they say they are. Therefore, in my case, where the same organization is responsible for the components at both ends of the communication, and everything in between, a publicly trusted authority would be pointless. In other words, if I generate and sign a certificate for my own server, I know that it's trustworthy. And no one from outside the organization will ever be asked to trust this certificate. That is my reasoning - am I correct, or is there some potential advantage to using certs from a known authority?

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• Fluent NHibernate Repository with subclasses

  - by reallyJim

  Having some difficulty understanding the best way to implement subclasses with a generic repository using Fluent NHibernate. I have a base class and two subclasses, say: public abstract class Person { public virtual int PersonId { get; set; } public virtual string FirstName { get; set; } public virtual string LastName { get; set; } } public class Student : Person { public virtual decimal GPA { get; set; } } public class Teacher : Person { public virtual decimal Salary { get; set; } } My Mappings are as follows: public class PersonMap : ClassMap { public PersonMap() { Table("Persons"); Id(x => x.PersonId).GeneratedBy.Identity(); Map(x => x.FirstName); Map(x => x.LastName); } } public class StudentMap : SubclassMap<Student> { public StudentMap() { Table("Students"); KeyColumn("PersonId"); Map(x => x.GPA); } } public class TeacherMap : SubclassMap<Teacher> { public TeacherMap() { Table("Teachers"); KeyColumn("PersonId"); Map(x => x.Salary); } } I use a generic repository to save/retreive/update the entities, and it works great--provided I'm working with Repository--where I already know that I'm working with students or working with teachers. The problem I run into is this: What happens when I have an ID, and need to determine the TYPE of person? If a user comes to my site as PersonId = 23, how do I go about figuring out which type of person it is?

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