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• Are there any suggestions for these new assembly mnemonics?

  - by Noctis Skytower

  Greetings! Last semester in college, my teacher in the Computer Languages class taught us the esoteric language named Whitespace. In the interest of learning the language better with a very busy schedule (midterms), I wrote an interpreter and assembler in Python. An assembly language was designed to facilitate writing programs easily, and a sample program was written with the given assembly mnemonics. Now that it is summer, a new project has begun with the objective being to rewrite the interpreter and assembler for Whitespace 0.3, with further developments coming afterwards. Since there is so much extra time than before to work on its design, you are presented here with an outline that provides a revised set of mnemonics for the assembly language. This post is marked as a wiki for their discussion. Have you ever had any experience with assembly languages in the past? Were there some instructions that you thought should have been renamed to something different? Did you find yourself thinking outside the box and with a different paradigm than in which the mnemonics were named? If you can answer yes to any of those questions, you are most welcome here. Subjective answers are appreciated! Stack Manipulation (IMP: [Space]) Stack manipulation is one of the more common operations, hence the shortness of the IMP [Space]. There are four stack instructions. hold N Push the number onto the stack copy Duplicate the top item on the stack copy N Copy the nth item on the stack (given by the argument) onto the top of the stack swap Swap the top two items on the stack drop Discard the top item on the stack drop N Slide n items off the stack, keeping the top item Arithmetic (IMP: [Tab][Space]) Arithmetic commands operate on the top two items on the stack, and replace them with the result of the operation. The first item pushed is considered to be left of the operator. add Addition sub Subtraction mul Multiplication div Integer Division mod Modulo Heap Access (IMP: [Tab][Tab]) Heap access commands look at the stack to find the address of items to be stored or retrieved. To store an item, push the address then the value and run the store command. To retrieve an item, push the address and run the retrieve command, which will place the value stored in the location at the top of the stack. save Store load Retrieve Flow Control (IMP: [LF]) Flow control operations are also common. Subroutines are marked by labels, as well as the targets of conditional and unconditional jumps, by which loops can be implemented. Programs must be ended by means of [LF][LF][LF] so that the interpreter can exit cleanly. L: Mark a location in the program call L Call a subroutine goto L Jump unconditionally to a label if=0 L Jump to a label if the top of the stack is zero if<0 L Jump to a label if the top of the stack is negative return End a subroutine and transfer control back to the caller halt End the program I/O (IMP: [Tab][LF]) Finally, we need to be able to interact with the user. There are IO instructions for reading and writing numbers and individual characters. With these, string manipulation routines can be written. The read instructions take the heap address in which to store the result from the top of the stack. print chr Output the character at the top of the stack print int Output the number at the top of the stack input chr Read a character and place it in the location given by the top of the stack input int Read a number and place it in the location given by the top of the stack Question: How would you redesign, rewrite, or rename the previous mnemonics and for what reasons?

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• WCF DataContractSerializer Behavior

  - by sbanwart

  I'm seeing some unusual behavior when using the DataContractSerializer. I have defined a message contract like so: namespace MyNamespace.DataContracts { [MessageContract(WrapperName = "order", WrapperNamespace = @"http://example.com/v1/order")] public class MyOrder { [MessageBodyMember(Namespace = @"http://http://example.com/v1/order", Order = 1)] public MyStore store; [MessageBodyMember(Namespace = @"http://http://example.com/v1/order", Order = 2)] public MyOrderHeader orderHeader; [MessageBodyMember(Namespace = @"http://example.com/v1/order", Order = 3)] public List<MyPayment> payments; [MessageBodyMember(Namespace = @"http://example.com/v1/order", Order = 4)] public List<MyShipment> shipments; } . . I'm sending it an XML message that looks like this: <?xml version="1.0" encoding="utf-8"?> <order xmlns="http://example.com/v1/order> <store> ... </store> <orderHeader> ... </orderHeader> <payments> <payment> ... </payment> </payments> <shipments> <shipment> ... </shipment> </shipments> </order> My service deserializes this XML as expected. Inside my service, I'm using the DataContractSerializer to create an XML string and that's where things get weird. I'm using the serializer like this: DataContractSerializer serializer = new DataContractSerializer(typeof(MyOrder)); using (MemoryStream ms = new MemoryStream()) { serializer.WriteObject(ms, order); ms.Position = 0; StreamReader sr = new StreamReader(ms); string outputMessage = sr.ReadToEnd(); } Once this finishes, the outputMessage contains the following XML: <?xml version="1.0" encoding="utf-8"?> <MyOrder xmlns="http://example.com/v1/order" xmlns:i="http://www.w3.org/2001/XMLSchema-instance"> <order> <store> ... </store> <orderHeader> ... </orderHeader> <payments> <payment> ... </payment> </payments> <shipments> <shipment> ... </shipment> </shipments> </order> </MyOrder> Needless to say, anything expecting to receive the original XML message will fail to parse this. So I guess I have two questions: Why is the DataContractSerializer adding the extra outer node to my XML output? Is there a way to stop it from doing this? Thanks.

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• Longest Path in Boost Graph

  - by TheTSPSolver

  Hi, Sorry if this is a very basic questions for some of you but I'm new to C++ (let alone Boost Graph Library) and couldn't figure out this problem. So far I've been able to formulate/gather code to create a graph using the code below. Now I'm trying to figure out the code to find the longest path in this graph. Can someone please help with what would the code be? I was having trouble trying to figure out if/how to traverse through each node and/or edge when trying to find the path? I have to try to return all the nodes and edges in the longest path. Any help will be greatly appreciated. P.S. does anyone know if C++ has organized documentation like Javadoc?? #include <boost/graph/dag_shortest_paths.hpp> #include <boost/graph/adjacency_list.hpp> #include <windows.h> #include <iostream> int main() { using namespace boost; typedef adjacency_list<vecS, vecS, directedS, property<vertex_distance_t, double>, property<edge_weight_t, double> > graph_t; graph_t g(6); enum verts { stationA, stationB, stationC, stationD, stationE, stationF }; char name[] = "rstuvx"; add_edge(stationA, stationB, 5000.23, g); add_edge(stationA, stationC, 3001, g); add_edge(stationA, stationD, 2098.67, g); add_edge(stationA, stationE, 3298.84, g); add_edge(stationB, stationF, 2145, g); add_edge(stationC, stationF, 4290, g); add_edge(stationD, stationF, 2672.78, g); add_edge(stationE, stationF, 11143.876, g); add_edge(stationA, stationF, 1, g); //Display all the vertices typedef property_map<graph_t, vertex_index_t>::type IndexMap; IndexMap index = get(vertex_index, g); std::cout << "vertices(g) = "; typedef graph_traits<graph_t>::vertex_iterator vertex_iter; std::pair<vertex_iter, vertex_iter> vp; for (vp = vertices(g); vp.first != vp.second; ++vp.first) std::cout << index[*vp.first] << " "; std::cout << std::endl; // ... // Display all the edges // ... std::cout << "edges(g) = " << std::endl; graph_traits<graph_t>::edge_iterator ei, ei_end; for (tie(ei, ei_end) = edges(g); ei != ei_end; ++ei) std::cout << "(" << index[source(*ei, g)] << "," << index[target(*ei, g)] << ") \n"; std::cout << std::endl; // ...

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• Are their any suggestions for this new assembly language?

  - by Noctis Skytower

  Greetings! Last semester in college, my teacher in the Computer Languages class taught us the esoteric language named Whitespace. In the interest of learning the language better with a very busy schedule (midterms), I wrote an interpreter and assembler in Python. An assembly language was designed to facilitate writing programs easily, and a sample program was written with the given assembly mnemonics. Now that it is summer, a new project has begun with the objective being to rewrite the interpreter and assembler for Whitespace 0.3, with further developments coming afterwards. Since there is so much extra time than before to work on its design, you are presented here with an outline that provides a revised set of mnemonics for the assembly language. This post is marked as a wiki for their discussion. Have you ever had any experience with assembly languages in the past? Were there some instructions that you thought should have been renamed to something different? Did you find yourself thinking outside the box and with a different paradigm than in which the mnemonics were named? If you can answer yes to any of those questions, you are most welcome here. Subjective answers are appreciated! Stack Manipulation (IMP: [Space]) Stack manipulation is one of the more common operations, hence the shortness of the IMP [Space]. There are four stack instructions. hold N Push the number onto the stack copy Duplicate the top item on the stack copy N Copy the nth item on the stack (given by the argument) onto the top of the stack swap Swap the top two items on the stack drop Discard the top item on the stack drop N Slide n items off the stack, keeping the top item Arithmetic (IMP: [Tab][Space]) Arithmetic commands operate on the top two items on the stack, and replace them with the result of the operation. The first item pushed is considered to be left of the operator. add Addition sub Subtraction mul Multiplication div Integer Division mod Modulo Heap Access (IMP: [Tab][Tab]) Heap access commands look at the stack to find the address of items to be stored or retrieved. To store an item, push the address then the value and run the store command. To retrieve an item, push the address and run the retrieve command, which will place the value stored in the location at the top of the stack. save Store load Retrieve Flow Control (IMP: [LF]) Flow control operations are also common. Subroutines are marked by labels, as well as the targets of conditional and unconditional jumps, by which loops can be implemented. Programs must be ended by means of [LF][LF][LF] so that the interpreter can exit cleanly. L: Mark a location in the program call L Call a subroutine goto L Jump unconditionally to a label if=0 L Jump to a label if the top of the stack is zero if<0 L Jump to a label if the top of the stack is negative return End a subroutine and transfer control back to the caller exit End the program I/O (IMP: [Tab][LF]) Finally, we need to be able to interact with the user. There are IO instructions for reading and writing numbers and individual characters. With these, string manipulation routines can be written. The read instructions take the heap address in which to store the result from the top of the stack. print chr Output the character at the top of the stack print int Output the number at the top of the stack input chr Read a character and place it in the location given by the top of the stack input int Read a number and place it in the location given by the top of the stack Question: How would you redesign, rewrite, or rename the previous mnemonics and for what reasons?

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• Variable mysteriously changing value

  - by Eitan

  I am making a simple tcp/ip chat program for practicing threads and tcp/ip. I was using asynchronous methods but had a problem with concurrency so I went to threads and blocking methods (not asynchronous). I have two private variables defined in the class, not static: string amessage = string.Empty; int MessageLength; and a Thread private Thread BeginRead; Ok so I call a function called Listen ONCE when the client starts: public virtual void Listen(int byteLength) { var state = new StateObject {Buffer = new byte[byteLength]}; BeginRead = new Thread(ReadThread); BeginRead.Start(state); } and finally the function to receive commands and process them, I'm going to shorten it because it is really long: private void ReadThread(object objectState) { var state = (StateObject)objectState; int byteLength = state.Buffer.Length; while (true) { var buffer = new byte[byteLength]; int len = MySocket.Receive(buffer); if (len <= 0) return; string content = Encoding.ASCII.GetString(buffer, 0, len); amessage += cleanMessage.Substring(0, MessageLength); if (OnRead != null) { var e = new CommandEventArgs(amessage); OnRead(this, e); } } } Now, as I understand it only one thread at a time will enter BeginRead, I call Receive, it blocks until I get data, and then I process it. The problem: the variable amessage will change it's value between statements that do not touch or alter the variable at all, for example at the bottom of the function at: if (OnRead != null) "amessage" will be equal to 'asdf' and at if (OnRead != null) "amessage" will be equal to qwert. As I understand it this is indicative of another thread changing the value/running asynchronously. I only spawn one thread to do the receiving and the Receive function is blocking, how could there be two threads in this function and if there is only one thread how does amessage's value change between statements that don't affect it's value. As a side note sorry for spamming the site with these questions but I'm just getting a hang of this threading story and it's making me want to sip cyanide. Thanks in advance. EDIT: Here is my code that calls the Listen Method in the client: public void ConnectClient(string ip,int port) { client.Connect(ip,port); client.Listen(5); } and in the server: private void Accept(IAsyncResult result) { var client = new AbstractClient(MySocket.EndAccept(result)); var e = new CommandEventArgs(client, null); Clients.Add(client); client.Listen(5); if (OnClientAdded != null) { var target = (Control) OnClientAdded.Target; if (target != null && target.InvokeRequired) target.Invoke(OnClientAdded, this, e); else OnClientAdded(this, e); } client.OnRead += OnRead; MySocket.BeginAccept(new AsyncCallback(Accept), null); } All this code is in a class called AbstractClient. The client inherits the Abstract client and when the server accepts a socket it create's it's own local AbstractClient, in this case both modules access the functions above however they are different instances and I couldn't imagine threads from different instances combining especially as no variable is static.

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• Can a conforming C implementation #define NULL to be something wacky

  - by janks

  I'm asking because of the discussion that's been provoked in this thread: http://stackoverflow.com/questions/2597142/when-was-the-null-macro-not-0/2597232 Trying to have a serious back-and-forth discussion using comments under other people's replies is not easy or fun. So I'd like to hear what our C experts think without being restricted to 500 characters at a time. The C standard has precious few words to say about NULL and null pointer constants. There's only two relevant sections that I can find. First: 3.2.2.3 Pointers An integral constant expression with the value 0, or such an expression cast to type void * , is called a null pointer constant. If a null pointer constant is assigned to or compared for equality to a pointer, the constant is converted to a pointer of that type. Such a pointer, called a null pointer, is guaranteed to compare unequal to a pointer to any object or function. and second: 4.1.5 Common definitions <stddef.h> The macros are NULL which expands to an implementation-defined null pointer constant; The question is, can NULL expand to an implementation-defined null pointer constant that is different from the ones enumerated in 3.2.2.3? In particular, could it be defined as: #define NULL __builtin_magic_null_pointer Or even: #define NULL ((void*)-1) My reading of 3.2.2.3 is that it specifies that an integral constant expression of 0, and an integral constant expression of 0 cast to type void* must be among the forms of null pointer constant that the implementation recognizes, but that it isn't meant to be an exhaustive list. I believe that the implementation is free to recognize other source constructs as null pointer constants, so long as no other rules are broken. So for example, it is provable that #define NULL (-1) is not a legal definition, because in if (NULL) do_stuff(); do_stuff() must not be called, whereas with if (-1) do_stuff(); do_stuff() must be called; since they are equivalent, this cannot be a legal definition of NULL. But the standard says that integer-to-pointer conversions (and vice-versa) are implementation-defined, therefore it could define the conversion of -1 to a pointer as a conversion that produces a null pointer. In which case if ((void*)-1) would evaluate to false, and all would be well. So what do other people think? I'd ask for everybody to especially keep in mind the "as-if" rule described in 2.1.2.3 Program execution. It's huge and somewhat roundabout, so I won't paste it here, but it essentially says that an implementation merely has to produce the same observable side-effects as are required of the abstract machine described by the standard. It says that any optimizations, transformations, or whatever else the compiler wants to do to your program are perfectly legal so long as the observable side-effects of the program aren't changed by them. So if you are looking to prove that a particular definition of NULL cannot be legal, you'll need to come up with a program that can prove it. Either one like mine that blatantly breaks other clauses in the standard, or one that can legally detect whatever magic the compiler has to do to make the strange NULL definition work. Steve Jessop found an example of way for a program to detect that NULL isn't defined to be one of the two forms of null pointer constants in 3.2.2.3, which is to stringize the constant: #define stringize_helper(x) #x #define stringize(x) stringize_helper(x) Using this macro, one could puts(stringize(NULL)); and "detect" that NULL does not expand to one of the forms in 3.2.2.3. Is that enough to render other definitions illegal? I just don't know. Thanks!

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• Function signature-like expressions as C++ template arguments

  - by Jeff Lee

  I was looking at Don Clugston's FastDelegate mini-library and noticed a weird syntactical trick with the following structure: TemplateClass< void( int, int ) > Object; It almost appears as if a function signature is being used as an argument to a template instance declaration. This technique (whose presence in FastDelegate is apparently due to one Jody Hagins) was used to simplify the declaration of template instances with a semi-arbitrary number of template parameters. To wit, it allowed this something like the following: // A template with one parameter template<typename _T1> struct Object1 { _T1 m_member1; }; // A template with two parameters template<typename _T1, typename _T2> struct Object2 { _T1 m_member1; _T2 m_member2; }; // A forward declaration template<typename _Signature> struct Object; // Some derived types using "function signature"-style template parameters template<typename _Dummy, typename _T1> struct Object<_Dummy(_T1)> : public Object1<_T1> {}; template<typename _Dummy, typename _T1, typename _T2> struct Object<_Dummy(_T1, _T2)> : public Object2<_T1, _T2> {}; // A. "Vanilla" object declarations Object1<int> IntObjectA; Object2<int, char> IntCharObjectA; // B. Nifty, but equivalent, object declarations typedef void UnusedType; Object< UnusedType(int) > IntObjectB; Object< UnusedType(int, char) > IntCharObjectB; // C. Even niftier, and still equivalent, object declarations #define DeclareObject( ... ) Object< UnusedType( __VA_ARGS__ ) > DeclareObject( int ) IntObjectC; DeclareObject( int, char ) IntCharObjectC; Despite the real whiff of hackiness, I find this kind of spoofy emulation of variadic template arguments to be pretty mind-blowing. The real meat of this trick seems to be the fact that I can pass textual constructs like "Type1(Type2, Type3)" as arguments to templates. So here are my questions: How exactly does the compiler interpret this construct? Is it a function signature? Or, is it just a text pattern with parentheses in it? If the former, then does this imply that any arbitrary function signature is a valid type as far as the template processor is concerned? A follow-up question would be that since the above code sample is valid code, why doesn't the C++ standard just allow you to do something like the following, which is does not compile? template<typename _T1> struct Object { _T1 m_member1; }; // Note the class identifier is also "Object" template<typename _T1, typename _T2> struct Object { _T1 m_member1; _T2 m_member2; }; Object<int> IntObject; Object<int, char> IntCharObject;

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• Authlogic OpenID integration

  - by Craig

  I'm having difficulty getting OpenId authentication working with Authlogic. It appears that the problem arose with changes to the open_id_authentication plugin. From what I've read so far, one needs to switch from using gems to using plugins. Here's what I done thus far to get Authlogic-OpenID integration working: Removed relevant gems: authlogic authlogic-oid rack-openid ruby-openid * Installed, configured, and started the authlogic sample application (http://github.com/binarylogic/authlogic_example)--works as expected. This required: installing the authlogic (2.1.3) gem ($ sudo gem install authlogic) adding a dependency (config.gem "authlogic") to the environment.rb file. added migration to add open-id support to User model; ran migration; columns added as expected made changes to the UsersController and UserSessionsController to use blocks to save each. made changes to new user-sessions view to support open id (f.text_field :openid_identifier) installed open_id_authentication plugin ($ script/plugin install git://github.com/rails/open_id_authentication.git) installed the authlogic-oid plugin ($ script/plugin install git://github.com/binarylogic/authlogic_openid.git) installed the plugin ($ script/plugin install git://github.com/glebm/ruby-openid.git) restarted mongrel (CTRL-C; $ script/server) Mogrel failed to start, returning the following error: /Library/Ruby/Site/1.8/rubygems/custom_require.rb:31:in `gem_original_require': no such file to load -- rack/openid (MissingSourceFile) from /Library/Ruby/Site/1.8/rubygems/custom_require.rb:31:in `require' from /Users/craibuc/NetBeansProjects/authlogic_example/vendor/rails/activesupport/lib/active_support/dependencies.rb:156:in `require' from /Users/craibuc/NetBeansProjects/authlogic_example/vendor/rails/activesupport/lib/active_support/dependencies.rb:521:in `new_constants_in' from /Users/craibuc/NetBeansProjects/authlogic_example/vendor/rails/activesupport/lib/active_support/dependencies.rb:156:in `require' from /Users/craibuc/NetBeansProjects/authlogic_example/vendor/plugins/open_id_authentication/lib/open_id_authentication.rb:3 from /Library/Ruby/Site/1.8/rubygems/custom_require.rb:31:in `gem_original_require' from /Library/Ruby/Site/1.8/rubygems/custom_require.rb:31:in `require' from /Users/craibuc/NetBeansProjects/authlogic_example/vendor/rails/activesupport/lib/active_support/dependencies.rb:156:in `require' from /Users/craibuc/NetBeansProjects/authlogic_example/vendor/rails/activesupport/lib/active_support/dependencies.rb:521:in `new_constants_in' from /Users/craibuc/NetBeansProjects/authlogic_example/vendor/rails/activesupport/lib/active_support/dependencies.rb:156:in `require' from /Users/craibuc/NetBeansProjects/authlogic_example/vendor/plugins/open_id_authentication/init.rb:5:in `evaluate_init_rb' from ./script/../config/../vendor/rails/railties/lib/rails/plugin.rb:146:in `evaluate_init_rb' from /Users/craibuc/NetBeansProjects/authlogic_example/vendor/rails/activesupport/lib/active_support/core_ext/kernel/reporting.rb:11:in `silence_warnings' from ./script/../config/../vendor/rails/railties/lib/rails/plugin.rb:142:in `evaluate_init_rb' from ./script/../config/../vendor/rails/railties/lib/rails/plugin.rb:48:in `load' from ./script/../config/../vendor/rails/railties/lib/rails/plugin/loader.rb:38:in `load_plugins' from ./script/../config/../vendor/rails/railties/lib/rails/plugin/loader.rb:37:in `each' from ./script/../config/../vendor/rails/railties/lib/rails/plugin/loader.rb:37:in `load_plugins' from ./script/../config/../vendor/rails/railties/lib/initializer.rb:348:in `load_plugins' from ./script/../config/../vendor/rails/railties/lib/initializer.rb:163:in `process' from ./script/../config/../vendor/rails/railties/lib/initializer.rb:113:in `send' from ./script/../config/../vendor/rails/railties/lib/initializer.rb:113:in `run' from /Users/craibuc/NetBeansProjects/authlogic_example/config/environment.rb:13 from /Library/Ruby/Site/1.8/rubygems/custom_require.rb:31:in `gem_original_require' from /Library/Ruby/Site/1.8/rubygems/custom_require.rb:31:in `require' from /Users/craibuc/NetBeansProjects/authlogic_example/vendor/rails/activesupport/lib/active_support/dependencies.rb:156:in `require' from /Users/craibuc/NetBeansProjects/authlogic_example/vendor/rails/activesupport/lib/active_support/dependencies.rb:521:in `new_constants_in' from /Users/craibuc/NetBeansProjects/authlogic_example/vendor/rails/activesupport/lib/active_support/dependencies.rb:156:in `require' from /Users/craibuc/NetBeansProjects/authlogic_example/vendor/rails/railties/lib/commands/server.rb:84 from /Library/Ruby/Site/1.8/rubygems/custom_require.rb:31:in `gem_original_require' from /Library/Ruby/Site/1.8/rubygems/custom_require.rb:31:in `require' from script/server:3 I suspect this is related the rack-openid gem, but as it was dependent upon the ruby-openid gem, it was removed when the ruby-openid gem was removed. Perhaps this can be installed as a plugin. Any assistance with this matter is greatly appreciated--I'm just about to give up on OpenId integration. * ruby-openid (2.1.2) is installed at /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/gems/1.8. I'm not certain if this is affecting anything. In any case, I'm not sure how to uninstall it or if I should. ** edit ** It appears that there are a number of gems in the /Library/Ruby/Gems/1.8/gems directory that may be causing an issue: authlogic-oid (1.0.4) rack-openid (1.0.3) ruby-openid (2.1.7) Questions: - why doesn't the gem list command list these gems? - Why doesn't the gem uninstall command remove these gems?

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• Why are there so many man-made edge cases in IT, and is there any hope for simplification / unificat

  - by Hamish Grubijan

  This question is meant to generate discussion and so it is marked as community wiki. My observation is that the field of information technology grows so rapidly and randomly, that for many it takes a lot of time to learn many intricacies of some tools that will be obsolete in just short 3 years. If you look at the questions asked on StackOverflow ... at least half of them stem from the fact that some language / tool / API / protocol was poorly designed, is backwards and has gotchas. There are so many things which distract developers from converting English into machine code; instead they spend their time configuring stuff and gluing together things that do not really fit. How many times do you pick up somebody else's project (or someone picks up yours :) ) and realize that this program does not need half of the dialogs that it has, and that the logic can be simplified a great deal? But, it had to be made and sold here before a better thing is made and sold elsewhere, and hence all this rush. I often wish that things would just slow down. I do not want Microsoft Windows to run on my car's computer, my watch, my table, my toaster oven, and my toilet seat. I'd rather have Windows that DOES NOT HAVE WINDOWS REGISTRY, I'd rather have Windows that allows two different programs to work on the same file at the same time, the way it works on Unix systems. Microsoft is just an example. I am looking forward to the day when I do not have to worry about Windows vs Unix new line break, when System32 actually means that this directory contains 32-bit binaries, and not 64-bit ones, the day when dll hell and manifest hell are no longer an issue, the day when it takes me a lot less than 3 months on a new job to learn the system. I do not mean learning the entire code base of a product (depending on the size of it, it can take a long time). I mean - remembering which build-assisting scripts are written in Perl and which version of it, and which ones are done through .bat files, when do I need to manually make every file in some directory writable before running a script, or else a critical step of a database maintenance home-grown tool will bomb, and it will take 2 days to clean that up. Makes me wonder if humans enslaved computers, or if it is the other way around. The key is that improving those things will not bring extra revenue, and hence those taking the time to fix crap like that are not "business focused". However, these imperfections irritate me immensely, particularly because my memory is limited - I can hold only a small portion of that useless knowledge of a system in my head at any given point in time. I must not be alone. Did you also happen to notice that a programmer can waste a lot of time on things that should have been a lot more straight-forward? Is there hope? Will things get better/simpler in the future, or will there be a lot more IT crap floating around? I suppose I see diversity of tools, protocols, etc. as a bad thing. Thank you for participation.

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• Design Question - how do you break the dependency between classes using an interface?

  - by Seth Spearman

  Hello, I apologize in advance but this will be a long question. I'm stuck. I am trying to learn unit testing, C#, and design patterns - all at once. (Maybe that's my problem.) As such I am reading the Art of Unit Testing (Osherove), and Clean Code (Martin), and Head First Design Patterns (O'Reilly). I am just now beginning to understand delegates and events (which you would see if you were to troll my SO questions of recent). I still don't quite get lambdas. To contextualize all of this I have given myself a learning project I am calling goAlarms. I have an Alarm class with members you'd expect (NextAlarmTime, Name, AlarmGroup, Event Trigger etc.) I wanted the "Timer" of the alarm to be extensible so I created an IAlarmScheduler interface as follows... public interface AlarmScheduler { Dictionary<string,Alarm> AlarmList { get; } void Startup(); void Shutdown(); void AddTrigger(string triggerName, string groupName, Alarm alarm); void RemoveTrigger(string triggerName); void PauseTrigger(string triggerName); void ResumeTrigger(string triggerName); void PauseTriggerGroup(string groupName); void ResumeTriggerGroup(string groupName); void SetSnoozeTrigger(string triggerName, int duration); void SetNextOccurrence (string triggerName, DateTime nextOccurrence); } This IAlarmScheduler interface define a component that will RAISE an alarm (Trigger) which will bubble up to my Alarm class and raise the Trigger Event of the alarm itself. It is essentially the "Timer" component. I have found that the Quartz.net component is perfectly suited for this so I have created a QuartzAlarmScheduler class which implements IAlarmScheduler. All that is fine. My problem is that the Alarm class is abstract and I want to create a lot of different KINDS of alarm. For example, I already have a Heartbeat alarm (triggered every (int) interval of minutes), AppointmentAlarm (triggered on set date and time), Daily Alarm (triggered every day at X) and perhaps others. And Quartz.NET is perfectly suited to handle this. My problem is a design problem. I want to be able to instantiate an alarm of any kind without my Alarm class (or any derived classes) knowing anything about Quartz. The problem is that Quartz has awesome factories that return just the right setup for the Triggers that will be needed by my Alarm classes. So, for example, I can get a Quartz trigger by using TriggerUtils.MakeMinutelyTrigger to create a trigger for the heartbeat alarm described above. Or TriggerUtils.MakeDailyTrigger for the daily alarm. I guess I could sum it up this way. Indirectly or directly I want my alarm classes to be able to consume the TriggerUtils.Make* classes without knowing anything about them. I know that is a contradiction, but that is why I am asking the question. I thought about putting a delegate field into the alarm which would be assigned one of these Make method but by doing that I am creating a hard dependency between alarm and Quartz which I want to avoid for both unit testing purposes and design purposes. I thought of using a switch for the type in QuartzAlarmScheduler per here but I know it is bad design and I am trying to learn good design. If I may editorialize a bit. I've decided that coding (predefined) classes is easy. Design is HARD...in fact, really hard and I am really fighting feeling stupid right now. I guess I want to know if you really smart people took a while to really understand and master this stuff or should I feel stupid (as I do) because I haven't grasped it better in the couple of weeks/months I have been studying. You guys are awesome and thanks in advance for your answers. Seth

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• Linq2XML: Get the count of elements where candidate has won2

  - by user287798

  I had an XML Document in the format below <Pronvice_Data> <Pronvice>PronviceA</Pronvice> <Registered_Voters>115852</Registered_Voters> <Sam_Kea>100</Sam_Kea> <Jeje>500</Jeje> <John_Doe>400</John_Doe> </Pronvice_Data> <Pronvice_Data> <Pronvice>PronviceA</Pronvice> <Registered_Voters>25852</Registered_Voters> <Sam_Kea>200</Sam_Kea> <Jeje>100</Jeje> <John_Doe>300</John_Doe> </Pronvice_Data> <Pronvice_Data> <Pronvice>PronviceC</Pronvice> <Registered_Voters>317684</Registered_Voters> <Sam_Kea>1000</Sam_Kea> <Jeje>1200</Jeje> <John_Doe>190</John_Doe> </Pronvice_Data> As suggested by help here,I used the code below to give me this format below C# Code: void Main() { XDocument xmlVectors2 = XDocument.Load(@"C:\\Province_Data.xml"); var elemList= from elem in xmlVectors2.Descendants("Province_Data") where elem.Elements().Count() > 1 select elem; foreach(XElement element in elemList) { XElement elem1= new XElement("Candidates", new XElement(element.Element("Sam_Kea").Name), new XElement(element.Element("Jeje").Name), new XElement(element.Element("John_Doe").Name) ); XElement elem2 = new XElement("Provinces", new XAttribute("Province", (string)element.Element("Province").Value), new XAttribute("Registered_Voters",element.Element("Registered_Voters").Value), new XElement ("Candidate", new XAttribute("Name",element.Element("Sam_Kea").Name), new XAttribute("Votes",element.Element("Sam_Kea").Value) ), new XElement ("Candidate", new XAttribute("Name",element.Element("Jeje").Name), new XAttribute("Votes",element.Element("Jeje").Value) ), new XElement ("Candidate", new XAttribute("Name",element.Element("John_Doe").Name), new XAttribute("Votes",element.Element("John_Doe").Value) )); } } New Format: <root> <Candidates> <Sam_Kea/> <Jeje/> <John_Doe/> </Candidates> <Provinces> <Province name='ProvinceA' Registered_Voters='115852'> <Candidate name='Sam_Kea' votes='100'/> <Candidate name='Jeje' votes='500'/> <Candidate name='John_Doe' votes='400'/> </Province> <Province name='ProvinceB' Registered_Voters='25852'> <Candidate name='Sam_Kea' votes='200'/> <Candidate name='Jeje' votes='100'/> <Candidate name='John_Doe' votes='300'/> </Province> <Province name='ProvinceC' Registered_Voters='317684'> <Candidate name='Sam_Kea' votes='1000'/> <Candidate name='Jeje' votes='1200'/> <Candidate name='John_Doe' votes='190'/> </Province> </Provinces> </root> How can i use the "foreach" in in my code to get the result in this link. http://stackoverflow.com/questions/2396203/get-the-count-of-elements-where-candidate-has-won

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• XSLT Select all nodes containing a specific substing

  - by Mike

  I'm trying to write an XPath that will select certain nodes that contain a specific word. In this case the word is, "Lockwood". The correct answer is 3. Both of these paths give me 3. count(//*[contains(./*,'Lockwood')]) count(BusinessLetter/*[contains(../*,'Lockwood')]) But when I try to output the text of each specific node //*[contains(./*,'Lockwood')][1] //*[contains(./*,'Lockwood')][2] //*[contains(./*,'Lockwood')][3] Node 1 ends up containing all the text and nodes 2 and 3 are blank. Can some one please tell me what's happening or what I'm doing wrong. Thanks. <?xml version="1.0" encoding="UTF-8"?> <?xml-stylesheet type="text/xsl" href="XPathFunctions.xsl"?> <BusinessLetter> <Head> <SendDate>November 29, 2005</SendDate> <Recipient> <Name Title="Mr."> <FirstName>Joshua</FirstName> <LastName>Lockwood</LastName> </Name> <Company>Lockwood &amp; Lockwood</Company> <Address> <Street>291 Broadway Ave.</Street> <City>New York</City> <State>NY</State> <Zip>10007</Zip> <Country>United States</Country> </Address> </Recipient> </Head> <Body> <List> <Heading>Along with this letter, I have enclosed the following items:</Heading> <ListItem>two original, execution copies of the Webucator Master Services Agreement</ListItem> <ListItem>two original, execution copies of the Webucator Premier Support for Developers Services Description between Lockwood &amp; Lockwood and Webucator, Inc.</ListItem> </List> <Para>Please sign and return all four original, execution copies to me at your earliest convenience. Upon receipt of the executed copies, we will immediately return a fully executed, original copy of both agreements to you.</Para> <Para>Please send all four original, execution copies to my attention as follows: <Person> <Name> <FirstName>Bill</FirstName> <LastName>Smith</LastName> </Name> <Address> <Company>Webucator, Inc.</Company> <Street>4933 Jamesville Rd.</Street> <City>Jamesville</City> <State>NY</State> <Zip>13078</Zip> <Country>USA</Country> </Address> </Person> </Para> <Para>If you have any questions, feel free to call me at <Phone>800-555-1000 x123</Phone> or e-mail me at <Email>[email protected]</Email>.</Para> </Body> <Foot> <Closing> <Name> <FirstName>Bill</FirstName> <LastName>Smith</LastName> </Name> <JobTitle>VP of Operations</JobTitle> </Closing> </Foot> </BusinessLetter>

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• Kindle Fire: PopupMenu$OrientationChangeListener leak

  - by dokkaebi

  I have a little popup menu that anchors on a button in the action bar. This works well on 3.0/3.1 Xoom and Galaxy tabs, and a 4.1 Nexus 7. However, on a 7" Fire HD (this one), I get an error about a leaked intent receiver when exiting the application. The error occurs only if the menu was not opened during that run. There is no mention of OrientationChangeListener in the one copy of the source I've found; I suspect Amazon has a different implementation. Questions: Has anyone encountered this? Does anyone know of a workaround or a fix? (Where) can I find Amazon's source code? Finally, (shudder) how important is it that I don't leak a receiver on application exit? Here is the menu xml: <?xml version="1.0" encoding="utf-8"?> <menu xmlns:android="http://schemas.android.com/apk/res/android"> <item android:id="@+id/menu_profile" android:title="@string/menu_item_profile" ></item> <item android:id="@+id/menu_logout" android:title="@string/menu_item_logout" ></item> </menu> This is where I register it: @Override public boolean onCreateOptionsMenu(Menu menu) { super.onCreateOptionsMenu(menu); MenuInflater inflater = getMenuInflater(); inflater.inflate(R.menu.main_menu, menu); MenuItem login = menu.findItem(R.id.menu_login); Button button = (Button) login.getActionView().findViewById(R.id.login); button.setOnClickListener(new View.OnClickListener() { public void onClick(View v) { profileMenu.show(); } }); // profileMenu is an instance field profileMenu = new PopupMenu(this, button); inflater.inflate(R.menu.profile_menu, profileMenu.getMenu()); profileMenu.setOnMenuItemClickListener(new PopupMenu.OnMenuItemClickListener() { public boolean onMenuItemClick(MenuItem item) { // there was code here, but I removed it all and the problem persists return false; } }); return true; } Here is the full stack trace: 10-21 20:55:28.461: E/ActivityThread(4526): Activity **.app.ListActivity has leaked IntentReceiver android.widget.PopupMenu$OrientationChangeListener@422d77e0 that was originally registered here. Are you missing a call to unregisterReceiver()? 10-21 20:55:28.461: E/ActivityThread(4526): android.app.IntentReceiverLeaked: Activity **.app.ListActivity has leaked IntentReceiver android.widget.PopupMenu$OrientationChangeListener@422d77e0 that was originally registered here. Are you missing a call to unregisterReceiver()? 10-21 20:55:28.461: E/ActivityThread(4526): at android.app.LoadedApk$ReceiverDispatcher.<init>(LoadedApk.java:826) 10-21 20:55:28.461: E/ActivityThread(4526): at android.app.LoadedApk.getReceiverDispatcher(LoadedApk.java:621) 10-21 20:55:28.461: E/ActivityThread(4526): at android.app.ContextImpl.registerReceiverInternal(ContextImpl.java:1072) 10-21 20:55:28.461: E/ActivityThread(4526): at android.app.ContextImpl.registerReceiver(ContextImpl.java:1059) 10-21 20:55:28.461: E/ActivityThread(4526): at android.app.ContextImpl.registerReceiver(ContextImpl.java:1053) 10-21 20:55:28.461: E/ActivityThread(4526): at android.content.ContextWrapper.registerReceiver(ContextWrapper.java:357) 10-21 20:55:28.461: E/ActivityThread(4526): at android.widget.PopupMenu.<init>(PopupMenu.java:81) 10-21 20:55:28.461: E/ActivityThread(4526): at **.app.ListActivity.onCreateOptionsMenu(ListActivity.java:350) 10-21 20:55:28.461: E/ActivityThread(4526): at android.app.Activity.onCreatePanelMenu(Activity.java:2558) 10-21 20:55:28.461: E/ActivityThread(4526): at com.android.internal.policy.impl.PhoneWindow.preparePanel(PhoneWindow.java:398) 10-21 20:55:28.461: E/ActivityThread(4526): at com.android.internal.policy.impl.PhoneWindow.invalidatePanelMenu(PhoneWindow.java:883) 10-21 20:55:28.461: E/ActivityThread(4526): at com.android.internal.policy.impl.PhoneWindow$2.run(PhoneWindow.java:3008) 10-21 20:55:28.461: E/ActivityThread(4526): at android.os.Handler.handleCallback(Handler.java:605) 10-21 20:55:28.461: E/ActivityThread(4526): at android.os.Handler.dispatchMessage(Handler.java:92) 10-21 20:55:28.461: E/ActivityThread(4526): at android.os.Looper.loop(Looper.java:137) 10-21 20:55:28.461: E/ActivityThread(4526): at android.app.ActivityThread.main(ActivityThread.java:4491) 10-21 20:55:28.461: E/ActivityThread(4526): at java.lang.reflect.Method.invokeNative(Native Method) 10-21 20:55:28.461: E/ActivityThread(4526): at java.lang.reflect.Method.invoke(Method.java:511) 10-21 20:55:28.461: E/ActivityThread(4526): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784) 10-21 20:55:28.461: E/ActivityThread(4526): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551) 10-21 20:55:28.461: E/ActivityThread(4526): at dalvik.system.NativeStart.main(Native Method)

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• Is this a right way to use NHibernate?

  - by Venemo

  I spent the rest of the evening reading StackOverflow questions and also some blog entries and links about the subject. All of them turned out to be very helpful, but I still feel that they don't really answer my question. So, I'm developing a simple web application. I'd like to create a reusable data access layer which I can later reuse in other solutions. 99% of these will be web applications. This seems to be a good excuse for me to learn NHibernate and some of the patterns around it. My goals are the following: I don't want the business logic layer to know ANYTHING about the inner workings of the database, nor NHibernate itself. I want the business logic layer to have the least possible number of assumptions about the data access layer. I want the data access layer as simplistic and easy-to-use as possible. This is going to be a simple project, so I don't want to overcomplicate anything. I want the data access layer to be as non-intrusive as possible. Will all this in mind, I decided to use the popular repository pattern. I read about this subject on this site and on various dev blogs, and I heard some stuff about the unit of work pattern. I also looked around and checked out various implementations. (Including FubuMVC contrib, and SharpArchitecture, and stuff on some blogs.) I found out that most of these operate with the same principle: They create a "unit of work" which is instantiated when a repository is instantiated, they start a transaction, do stuff, and commit, and then start all over again. So, only one ISession per Repository and that's it. Then the client code needs to instantiate a repository, do stuff with it, and then dispose. This usage pattern doesn't meet my need of being as simplistic as possible, so I began thinking about something else. I found out that NHibernate already has something which makes custom "unit of work" implementations unnecessary, and that is the CurrentSessionContext class. If I configure the session context correctly, and do the clean up when necessary, I'm good to go. So, I came up with this: I have a static class called NHibernateHelper. Firstly, it has a static property called CurrentSessionFactory, which upon first call, instantiates a session factory and stores it in a static field. (One ISessionFactory per one AppDomain is good enough.) Then, more importantly, it has a CurrentSession static property, which checks if there is an ISession bound to the current session context, and if not, creates one, and binds it, and it returns with the ISession bound to the current session context. Because it will be used mostly with WebSessionContext (so, one ISession per HttpRequest, although for the unit tests, I configured ThreadStaticSessionContext), it should work seamlessly. And after creating and binding an ISession, it hooks an event handler to the HttpContext.Current.ApplicationInstance.EndRequest event, which takes care of cleaning up the ISession after the request ends. (Of course, it only does this if it is really running in a web environment.) So, with all this set up, the NHibernateHelper will always be able to return a valid ISession, so there is no need to instantiate a Repository instance for the "unit of work" to operate properly. Instead, the Repository is a static class which operates with the ISession from the NHibernateHelper.CurrentSession property, and exposes some functionality through that. I'm curious, what do you think about this? Is it a valid way of thinking, or am I completely off track here?

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• swf listens to XML, AS3

  - by VideoDnd

  My swf listens to XML from a socket and document. How do I get 'my variables' to grab XML from the socket instead of the XML document? PURPOSE My purpose is to control variables with a XML Socket Server. I hope my question is clear, but ask if there's any questions. EXAMPLE Flash File import flash.net.*; import flash.display.*; import flash.events.*; import flash.system.Security; import flash.utils.Timer; import flash.events.TimerEvent; //MY VARIABLES, LINE 8-12 var timer:Timer = new Timer(10); var myString:String = ""; var count:int = 0; var myStg:String = ""; var fcount:int = 0; var xml_s=new XMLSocket(); xml_s.addEventListener(Event.CONNECT, socket_event_catcher);//OnConnect// xml_s.addEventListener(Event.CLOSE, socket_event_catcher);//OnDisconnect// xml_s.addEventListener(IOErrorEvent.IO_ERROR, socket_event_catcher);//Unable To Connect// xml_s.addEventListener(DataEvent.DATA, socket_event_catcher);//OnDisconnect// xml_s.connect("localhost", 1999); function socket_event_catcher(Event):void { switch (Event.type) { case 'ioError' : trace("ioError: " + Event.text);//Unable to Connect :(// break; case 'connect' : trace("Connection Established!");//Connected :)// break; case 'data' : trace("Received Data: " + Event.data); //var myXML:XML=new XML(Event.data); //trace("myXML.body.file: " + myXML.body.file); //var myLoader:String=myXML.body.file; //var urlReq:URLRequest=new URLRequest(myLoader); //trace("file to load URL: " + urlReq); break; case 'close' : trace("Connection Closed!");//OnDisconnect :( // xml_s.close(); break; } } //LOAD XML var myXML:XML; var myLoader:URLLoader = new URLLoader(); myLoader.load(new URLRequest("time.xml")); myLoader.addEventListener(Event.COMPLETE, processXML); //var myXML:XML=new XML(Event.data); //trace("myXML.body.file: " + myXML.body.file); //var DOINK:String=myXML.body.file; //var urlReq:URLRequest=new URLRequest(DOINK); //trace("file to load URL: " + urlReq); //PARSE XML function processXML(e:Event):void { myXML = new XML(e.target.data); trace(myXML.COUNT.text()); //-77777 //grab the data as a string myString = myXML.COUNT.text() //grab the data as an int count = int(myXML.COUNT.text()); //grab the data as a string myString = myXML.COUNT.text() //grab the data as an int count = int(myXML.COUNT.text()); //grab the data as a string myStg = myXML.COUNT.text() //grab the data as an int fcount = int(myXML.COUNT.text()); //grab the data as a string myStg = myXML.COUNT.text() //grab the data as an int fcount = int(myXML.COUNT.text()); trace("String: ", myString); trace("Int: ", count); trace(count - 1); //just to show you that it's a number that you can do math with (-77778) //TEXT var text:TextField = new TextField(); text.text = myString; addChild(text); } Ruby Server 'Snippet' msg1 = {"msg" => {"head" => {"type" => "frctl", "seq_no" => seq_no, "version" => 1.0}, "SESSION" => {"text" => "88888", "timer" => -1000, "count" => 10, "fcount" => "10"}}} XML <?xml version="1.0" encoding="utf-8"?> <SESSION> <TIMER TITLE="speed">100</TIMER> <COUNT TITLE="starting position">88888</COUNT> <FCOUNT TITLE="ramp">1000</FCOUNT> </SESSION> ENVIROMENT AS3 Ruby 186-25 PROBLEM Coding errors "coercion of value"

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• Increasing speed of python code

  - by Curious2learn

  Hi, I have some python code that has many classes. I used cProfile to find that the total time to run the program is 68 seconds. I found that the following function in a class called Buyers takes about 60 seconds of those 68 seconds. I have to run the program about 100 times, so any increase in speed will help. Can you suggest ways to increase the speed by modifying the code? If you need more information that will help, please let me know. def qtyDemanded(self, timePd, priceVector): '''Returns quantity demanded in period timePd. In addition, also updates the list of customers and non-customers. Inputs: timePd and priceVector Output: count of people for whom priceVector[-1] < utility ''' ## Initialize count of customers to zero ## Set self.customers and self.nonCustomers to empty lists price = priceVector[-1] count = 0 self.customers = [] self.nonCustomers = [] for person in self.people: if person.utility >= price: person.customer = 1 self.customers.append(person) else: person.customer = 0 self.nonCustomers.append(person) return len(self.customers) self.people is a list of person objects. Each person has customer and utility as its attributes. EDIT - responsed added ------------------------------------- Thanks so much for the suggestions. Here is the response to some questions and suggestions people have kindly made. I have not tried them all, but will try others and write back later. (1) @amber - the function is accessed 80,000 times. (2) @gnibbler and others - self.people is a list of Person objects in memory. Not connected to a database. (3) @Hugh Bothwell cumtime taken by the original function - 60.8 s (accessed 80000 times) cumtime taken by the new function with local function aliases as suggested - 56.4 s (accessed 80000 times) (4) @rotoglup and @Martin Thomas I have not tried your solutions yet. I need to check the rest of the code to see the places where I use self.customers before I can make the change of not appending the customers to self.customers list. But I will try this and write back. (5) @TryPyPy - thanks for your kind offer to check the code. Let me first read a little on the suggestions you have made to see if those will be feasible to use. EDIT 2 Some suggested that since I am flagging the customers and noncustomers in the self.people, I should try without creating separate lists of self.customers and self.noncustomers using append. Instead, I should loop over the self.people to find the number of customers. I tried the following code and timed both functions below f_w_append and f_wo_append. I did find that the latter takes less time, but it is still 96% of the time taken by the former. That is, it is a very small increase in the speed. @TryPyPy - The following piece of code is complete enough to check the bottleneck function, in case your offer is still there to check it with other compilers. Thanks again to everyone who replied. import numpy class person(object): def __init__(self, util): self.utility = util self.customer = 0 class population(object): def __init__(self, numpeople): self.people = [] self.cus = [] self.noncus = [] numpy.random.seed(1) utils = numpy.random.uniform(0, 300, numpeople) for u in utils: per = person(u) self.people.append(per) popn = population(300) def f_w_append(): '''Function with append''' P = 75 cus = [] noncus = [] for per in popn.people: if per.utility >= P: per.customer = 1 cus.append(per) else: per.customer = 0 noncus.append(per) return len(cus) def f_wo_append(): '''Function without append''' P = 75 for per in popn.people: if per.utility >= P: per.customer = 1 else: per.customer = 0 numcustomers = 0 for per in popn.people: if per.customer == 1: numcustomers += 1 return numcustomers

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• Java multiple class compositing and boiler plate reduction

  - by h2g2java

  We all know why Java does/should not have multiple inheritance. So this is not questioning about what has already been debated till-cows-come-home. This discusses what we would do when we wish to create a class that has the characteristics of two or more other classes. Probably, most of us would do this to "inherit" from three classes. For simplicity, I left out the constructor.: class Car extends Vehicle { final public Transport transport; final public Machine machine; } So that, Car class directly inherits methods and objects of Vehicle class, but would have to refer to transport and machine explicitly to refer to objects instantiated in Transport and Machine. Car car = new Car(); car.drive(); // from Vehicle car.transport.isAmphibious(); // from Transport car.machine.getCO2Footprint(); // from Machine I thought this was a good idea until when I encounter frameworks that require setter and getter methods. For example, the XML <Car amphibious='false' footPrint='1000' model='Fordstatic999'/> would look for the methods setAmphibious(..), setFootPrint(..) and setModel(..). Therefore, I have to project the methods from Transport and Machine classes class Car extends Vehicle { final public Transport transport; final public Machine machine; public void setAmphibious(boolean b){ this.transport.setAmphibious(b); } public void setFootPrint(String fp){ this.machine.setFootPrint(fp); } } This is OK, if there were just a few characteristics. Right now, I am trying to adapt all of SmartGWT into GWT UIBinder, especially those classes that are not a GWT widget. There are lots of characteristics to project. Wouldn't it be nice if there exists some form of annotation framework that is like this: class Car extends Vehicle @projects {Transport @projects{Machine @projects Guzzler}} { /* No need to explicitly instantiate Transport, Machine or Guzzler */ .... } Where, in case of common names of characteristics exist, the characteristics of Machine would take precedence Guzzler's, and Transport's would have precedence over Machine's, and Vehicle's would have precedence over Transport's. The annotation framework would then instantiate Transport, Machine and Guzzler as hidden members of Car and expand to break-out the protected/public characteristics, in the precedence dictated by the @project annotation sequence, into actual source code or into byte-code. Preferably into byte-code. So that the setFootPrint method is found in both Machine and Guzzler, only that of Machine's would be projected. Questions: Don't you think this is a good idea to have such a framework? Does such a framework already exist? Tell me where/what. Is there an eclipse plugin that does it? Is there a proposal or plan anywhere that you know about such an annotation framework? It would be wonderful too, if the annotation/plugin framework lets me specify that boolean, int, or whatever else needs to be converted from String and does the conversion/parsing for me too. Please advise, somebody. I hope wording of my question was clear enough. Thx. Edited: To avoid OO enthusiasts jumping to conclusion, I have renamed the title of this question.

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• Why is an inverse loop faster than a normal loop (test included)

  - by Saif Bechan

  I have been running some small tests in PHP on loops. I do not know if my method is good. I have found that a inverse loop is faster than a normal loop. I have also found that a while-loop is faster than a for-loop. Setup <?php $counter = 10000000; $w=0;$x=0;$y=0;$z=0; $wstart=0;$xstart=0;$ystart=0;$zstart=0; $wend=0;$xend=0;$yend=0;$zend=0; $wstart = microtime(true); for($w=0; $w<$counter; $w++){ echo ''; } $wend = microtime(true); echo "normal for: " . ($wend - $wstart) . "<br />"; $xstart = microtime(true); for($x=$counter; $x>0; $x--){ echo ''; } $xend = microtime(true); echo "inverse for: " . ($xend - $xstart) . "<br />"; echo "<hr> normal - inverse: " . (($wend - $wstart) - ($xend - $xstart)) . "<hr>"; $ystart = microtime(true); $y=0; while($y<$counter){ echo ''; $y++; } $yend = microtime(true); echo "normal while: " . ($yend - $ystart) . "<br />"; $zstart = microtime(true); $z=$counter; while($z>0){ echo ''; $z--; } $zend = microtime(true); echo "inverse while: " . ($zend - $zstart) . "<br />"; echo "<hr> normal - inverse: " . (($yend - $ystart) - ($zend - $zstart)) . "<hr>"; echo "<hr> inverse for - inverse while: " . (($xend - $xstart) - ($zend - $zstart)) . "<hr>"; ?> Average Results The difference in for-loop normal for: 1.0908501148224 inverse for: 1.0212800502777 normal - inverse: 0.069570064544678 The difference in while-loop normal while: 1.0395669937134 inverse while: 0.99321985244751 normal - inverse: 0.046347141265869 The difference in for-loop and while-loop inverse for - inverse while: 0.0280601978302 Questions My question is can someone explain these differences in results? And is my method of benchmarking been correct?

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• "Attach or Add an entity that is not new...loaded from another DataContext. This is not supported."

  - by sah302

  Similar error as other questions, but not quite the same, I am not trying to attach anything. What I am trying to do is insert a new row into a linking table, specifically UserAccomplishment. Relations are set in LINQ to User and Accomplishment Tables. I have a generic insert function: Public Function insertRow(ByVal entity As ImplementationType) As Boolean If entity IsNot Nothing Then Dim lcfdatacontext As New LCFDataContext() Try lcfdatacontext.GetTable(Of ImplementationType)().InsertOnSubmit(entity) lcfdatacontext.SubmitChanges() lcfdatacontext.Dispose() Return True Catch ex As Exception Return False End Try Else Return False End If End Function If you try and give UserAccomplishment the two appropriate objects this will naturally crap out if either the User or Accomplishment already exist. It only works when both user and accomplishment don't exist. I expected this behavior. What does work is simply giving the userAccomplishment object a user.id and accomplishment.id and populating the rest of the fields. This works but is kind of awkward to use in my app, it would be much easier to simply pass in both objects and have it work out what already exists and what doesn't. Okay so I made the following (please ignore the fact that this is horribly inefficient because I know it is): Public Class UserAccomplishmentDao Inherits EntityDao(Of UserAccomplishment) Public Function insertLinkerObjectRow(ByVal userAccomplishment As UserAccomplishment) Dim insertSuccess As Boolean = False If Not userAccomplishment Is Nothing Then Dim userDao As New UserDao() Dim accomplishmentDao As New AccomplishmentDao() Dim user As New User() Dim accomplishment As New Accomplishment() 'see if either object already exists in db' user = userDao.getOneByValueOfProperty("Id", userAccomplishment.User.Id) accomplishment = accomplishmentDao.getOneByValueOfProperty("Id", userAccomplishment.Accomplishment.Id) If user Is Nothing And accomplishment Is Nothing Then 'neither the user or the accomplishment exist, both are new so insert them both, typical insert' insertSuccess = Me.insertRow(userAccomplishment) ElseIf user Is Nothing And Not accomplishment Is Nothing Then 'user is new, accomplishment is not new, so just insert the user, and the relation in userAccomplishment' Dim userWithExistingAccomplishment As New UserAccomplishment(userAccomplishment.User, userAccomplishment.Accomplishment.Id, userAccomplishment.LastUpdatedBy) insertSuccess = Me.insertRow(userWithExistingAccomplishment) ElseIf Not user Is Nothing And accomplishment Is Nothing Then 'user is not new, accomplishment is new, so just insert the accomplishment, and the relation in userAccomplishment' Dim existingUserWithAccomplishment As New UserAccomplishment(userAccomplishment.UserId, userAccomplishment.Accomplishment, userAccomplishment.LastUpdatedBy) insertSuccess = Me.insertRow(existingUserWithAccomplishment) Else 'both are not new, just add the relation' Dim userAccomplishmentBothExist As New UserAccomplishment(userAccomplishment.User.Id, userAccomplishment.Accomplishment.Id, userAccomplishment.LastUpdatedBy) insertSuccess = Me.insertRow(userAccomplishmentBothExist) End If End If Return insertSuccess End Function End Class Alright, here I basically check if the supplied user and accomplishment already exists in the db, and if so call an appropriate constructor that will leave whatever already exists empty, but supply the rest of the information so the insert can succeed. However, upon trying an insert: Dim result As Boolean = Me.userAccomplishmentDao.insertLinkerObjectRow(userAccomplishment) In which the user already exists, but the accomplishment does not (the 99% typical scenario) I get the error: "An attempt has been made to Attach or Add an entity that is not new, perhaps having been loaded from another DataContext. This is not supported." I have debugged this multiple times now and am not sure why this is occuring, if either User or Accomplishment exist, I am not including it in the final object to try to insert. So nothing appears to be attempted to be added. Even in debug, upon insert, the object was set to empty. So the accomplishment is new and the user is empty. 1) Why is it still saying that and how can I fix it ..using my current structure 2) Pre-emptive 'use repository pattern answers' - I know this way kind of sucks in general and I should be using the repository pattern. However, I can't use that in the current project because I don't have time to refactor that due to my non existence knowledge of it and time constraints. The usage of the app is going to so small that the inefficient use of datacontext's and what have you won't matter so much. I can refactor it once it's up and running, but for now I just need to 'push through' with my current structure. Edit: I also just tested this when having both already exists, and only insert each object's IDs into the table, that works. So I guess I could manually insert whichever object doesn't exist as a single insert, then put the ids only into the linking table, but I still don't know why when one object exists, and I make it empty, it doens't work.

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• Did I find a bug in PHP's `crypt()`?

  - by Nathan Long

  I think I may have found a bug in PHP's crypt() function under Windows. However: I recognize that it's probably my fault. PHP is used by millions and worked on by thousands; my code is used by tens and worked on by me. (This argument is best explained on Coding Horror.) So I'm asking for help: show me my fault. I've been trying to find it for a few days now, with no luck. The setup I'm using a Windows server installation with Apache 2.2.14 (Win32) and PHP 5.3.2. My development box runs Windows XP Professional; the 'production' server (this is an intranet setup) runs Windows Storage Server 2003. The problem happens on both. I don't see anything in php.ini related to crypt(), but will happily answer questions about my config. The problem Several scripts in my PHP app occasionally hang: the page sits there on 'waiting for localhost' and never finishes. Each of these scripts uses crypt to hash a user's password before storing it in the database, or, in the case of the login page, to hash the entered password before comparing it to the version stored in the database. Since the login page is the simplest, I focused on it for testing. I repeatedly logged in, and found that it would hang maybe 4 out of 10 times. As an experiment, I changed the login page to use the plain text password and changed my password in the database to its plain text version. The page stopped hanging. I saw that PHP's latest version lists this bugfix: Fixed bug #51059 (crypt crashes when invalid salt are [sic] given). So I created a very simple test script, as follows, using the same salt given in an official example: $foo = crypt('rasmuslerdorf','r1'); echo $foo; This page, too, will hang, if I reload it like crazy. I only see it hanging in Chrome, but regardless of browser, the effect on Apache is the same. Effect on Apache When these pages hang, Apache's server-status page (which I explained here, regarding a different problem) increments the number of requests being processed and decrements the number of idle workers. The requests being processed almost all have a status of 'Sending Reply,' though sometimes for a moment they will show either 'Reading request' or 'keepalive (read).' Eventually, Apache may crash. When it does, the Windows crash report looks like this: szAppName: httpd.exe szAppVer: 2.2.14.0 szModName: php5ts.dll szModVer: 5.3.1.0 // OK, this report was before I upgraded to PHP 5.3.2, // but that didn't fix it offset: 00a2615 Is it my fault? I'm tempted to file a bug report to PHP on this. The argument against it is, as stated above, that bugs are nearly always my fault. However, my argument in favor of 'it's PHP's fault' is: I'm using Windows, whereas most servers use Linux (I don't get to choose this), so the chances are greater that I've found an edge case There was recently a bug with crypt(), so maybe it still has issues I have made the simplest test case I can, and I still have the problem Can anyone duplicate this? Can you suggest where I've gone wrong? Should I file the bug after all? Thanks in advance for any help you may give.

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• Insert text into a div from a poput form and rewrite the inserted text with javascript

  - by kuswantin

  So I read some related questions here before I asked, but can't find the answer to my problem. Hope some javascript master here can find this and bring the light to me. I created another button for nicEdit, a video button and wanted to insert some formatted text into the editor DIV (note: nicEdit has inline DIV, no iframe, no textarea). This is my button, recreated from the image button: var nicVideoOptions = { buttons : { 'video' : {name : __('Insert Video'), type : 'nicEditorVideoButton'} //, tags : ['VIDEO:'] }, iconFiles : {'video' : '../movie.png'} }; var nicEditorVideoButton = nicEditorAdvancedButton.extend({ addPane : function() { this.vi = this.ne.selectedInstance.selElm().parentTag('A'); this.addForm({ '' : {type : 'title', txt : 'Insert Video URL'}, 'href' : {type : 'text', txt : 'URL', 'value' : 'http://', style : {width: '150px'}} },this.vi); }, submit : function(e) { var vidVal = this.inputs['href'].value; if(vidVal == "" || vidVal == "http://") { alert("Enter the video url"); return false; } this.removePane(); if(!this.vi) { var tmp = 'javascript:nicVidTemp();'; this.ne.nicCommand("insertVideo",tmp); // still nothing works //this.vi = this.findElm('VIDEO:','href',tmp); //this.vi = this.setContent('[video:' + this.inputs['href'].value + ']'); //nicEditors.findEditor('edit-comment').setContent('<strong>Some HTML</strong> here'); //this.vi = this.setContent('<strong>Some HTML</strong> here'); insertAtCaret(this.ne.selectedInstance, vidVal); } if(this.vi) { // still nothing works //this.vi.setAttributes({ //vidVal : this.inputs['href'].value //}); //this.vi = this.setContent('[video:' + this.inputs['href'].value + ']'); //this.vi = this.setContent('<strong>Some HTML</strong> here'); } } }); nicEditors.registerPlugin(nicPlugin,nicVideoOptions); The button is there, the form poput like the image button, so it's okay. But can't insert the text into the DIV. The final output will be taken from this: ('[video:' + this.inputs['href'].value + ']') and displayed in the editor DIV as is: [video:http//some.com/video-url] As you see, I am blindly touching everything :) And this insertion is taken from: http://www.scottklarr.com/topic/425/how-to-insert-text-into-a-textarea-where-the-cursor-is/ function insertAtCaret(areaId,text) { var txtarea = document.getElementById(areaId); var scrollPos = txtarea.scrollTop; var strPos = 0; var br = ((txtarea.selectionStart || txtarea.selectionStart == '0') ? "ff" : (document.selection ? "ie" : false ) ); if (br == "ie") { txtarea.focus(); var range = document.selection.createRange(); range.moveStart ('character', -txtarea.value.length); strPos = range.text.length; } else if (br == "ff") strPos = txtarea.selectionStart; var front = (txtarea.value).substring(0,strPos); var back = (txtarea.value).substring(strPos,txtarea.value.length); txtarea.value=front+text+back; strPos = strPos + text.length; if (br == "ie") { txtarea.focus(); var range = document.selection.createRange(); range.moveStart ('character', -txtarea.value.length); range.moveStart ('character', strPos); range.moveEnd ('character', 0); range.select(); } else if (br == "ff") { txtarea.selectionStart = strPos; txtarea.selectionEnd = strPos; txtarea.focus(); } txtarea.scrollTop = scrollPos; } The flow: I click the button, a form popouts, fill the input text box, hit the query button and the text should appear in the editor DIV. I hope I can make myself clear. Any help would be very much appreaciated Thanks

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• Why does jquery leak memory so badly?

  - by Thomas Lane

  This is kind of a follow-up to a question I posted last week: http://stackoverflow.com/questions/2429056/simple-jquery-ajax-call-leaks-memory-in-ie I love the jquery syntax and all of its nice features, but I've been having trouble with a page that automatically updates table cells via ajax calls leaking memory. So I created two simple test pages for experimenting. Both pages do an ajax call every .1 seconds. After each successful ajax call, a counter is incremented and the DOM is updated. The script stops after 1000 cycles. One uses jquery for both the ajax call and to update the DOM. The other uses the Yahoo API for the ajax and does a document.getElementById(...).innerHTML to update the DOM. The jquery version leaks memory badly. Running in drip (on XP Home with IE7), it starts at 9MB and finishes at about 48MB, with memory growing linearly the whole time. If I comment out the line that updates the DOM, it still finishes at 32MB, suggesting that even simple DOM updates leak a significant amount of memory. The non-jquery version starts and finishes at about 9MB, regardless of whether it updates the DOM. Does anyone have a good explanation of what is causing jquery to leak so badly? Am I missing something obvious? Is there a circular reference that I'm not aware of? Or does jquery just have some serious memory issues? Here is the source for the leaky (jquery) version: <html> <head> <script type="text/javascript" src="http://www.google.com/jsapi"></script> <script type="text/javascript"> google.load('jquery', '1.4.2'); </script> <script type="text/javascript"> var counter = 0; leakTest(); function leakTest() { $.ajax({ url: '/html/delme.x', type: 'GET', success: incrementCounter }); } function incrementCounter(data) { if (counter<1000) { counter++; $('#counter').text(counter); setTimeout(leakTest,100); } else $('#counter').text('finished.'); } </script> </head> <body> <div>Why is memory usage going up?</div> <div id="counter"></div> </body> </html> And here is the non-leaky version: <html> <head> <script type="text/javascript" src="http://yui.yahooapis.com/2.8.0r4/build/yahoo/yahoo-min.js"></script> <script type="text/javascript" src="http://yui.yahooapis.com/2.8.0r4/build/event/event-min.js"></script> <script type="text/javascript" src="http://yui.yahooapis.com/2.8.0r4/build/connection/connection_core-min.js"></script> <script type="text/javascript"> var counter = 0; leakTest(); function leakTest() { YAHOO.util.Connect.asyncRequest('GET', '/html/delme.x', {success:incrementCounter}); } function incrementCounter(o) { if (counter<1000) { counter++; document.getElementById('counter').innerHTML = counter; setTimeout(leakTest,100); } else document.getElementById('counter').innerHTML = 'finished.' } </script> </head> <body> <div>Memory usage is stable, right?</div> <div id="counter"></div> </body> </html>

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• Generics and Performance question.

  - by Tarmon

  Hey Everyone, I was wondering if anyone could look over a class I wrote, I am receiving generic warnings in Eclipse and I am just wondering if it could be cleaned up at all. All of the warnings I received are surrounded in ** in my code below. The class takes a list of strings in the form of (hh:mm AM/PM) and converts them into HourMinute objects in order to find the first time in the list that comes after the current time. I am also curious about if there are more efficient ways to do this. This works fine but the student in me just wants to find out how I could do this better. public class FindTime { private String[] hourMinuteStringArray; public FindTime(String[] hourMinuteStringArray){ this.hourMinuteStringArray = hourMinuteStringArray; } public int findTime(){ HourMinuteList hourMinuteList = convertHMStringArrayToHMArray(hourMinuteStringArray); Calendar calendar = new GregorianCalendar(); int hour = calendar.get(Calendar.HOUR_OF_DAY); int minute = calendar.get(Calendar.MINUTE); HourMinute now = new HourMinute(hour,minute); int nearestTimeIndex = findNearestTimeIndex(hourMinuteList, now); return nearestTimeIndex; } private int findNearestTimeIndex(HourMinuteList hourMinuteList, HourMinute now){ HourMinute current; int position = 0; Iterator<HourMinute> iterator = **hourMinuteList.iterator()**; while(iterator.hasNext()){ current = (HourMinute) iterator.next(); if(now.compareTo(current) == -1){ return position; } position++; } return position; } private static HourMinuteList convertHMStringArrayToHMArray(String[] times){ FindTime s = new FindTime(new String[1]); HourMinuteList list = s.new HourMinuteList(); String[] splitTime = new String[3]; for(String time : times ){ String[] tempFirst = time.split(":"); String[] tempSecond = tempFirst[1].split(" "); splitTime[0] = tempFirst[0]; splitTime[1] = tempSecond[0]; splitTime[2] = tempSecond[1]; int hour = Integer.parseInt(splitTime[0]); int minute = Integer.parseInt(splitTime[1]); HourMinute hm; if(splitTime[2] == "AM"){ hm = s.new HourMinute(hour,minute); } else if((splitTime[2].equals("PM")) && (hour < 12)){ hm = s.new HourMinute(hour + 12,minute); } else{ hm = s.new HourMinute(hour,minute); } **list.add(hm);** } return list; } class **HourMinuteList** extends **ArrayList** implements RandomAccess{ } class HourMinute implements **Comparable** { int hour; int minute; public HourMinute(int hour, int minute) { setHour(hour); setMinute(minute); } int getMinute() { return this.minute; } String getMinuteString(){ if(this.minute < 10){ return "0" + this.minute; }else{ return "" + this.minute; } } int getHour() { return this.hour; } void setHour(int hour) { this.hour = hour; } void setMinute(int minute) { this.minute = minute; } @Override public int compareTo(Object aThat) { if (aThat instanceof HourMinute) { HourMinute that = (HourMinute) aThat; if (this.getHour() == that.getHour()) { if (this.getMinute() > that.getMinute()) { return 1; } else if (this.getMinute() < that.getMinute()) { return -1; } else { return 0; } } else if (this.getHour() > that.getHour()) { return 1; } else if (this.getHour() < that.getHour()) { return -1; } else { return 0; } } return 0; } } If you have any questions let me know. Thanks, Rob

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• JOptionPane opening another JFrame

  - by mike_hornbeck

  So I'm continuing my fight with this : http://stackoverflow.com/questions/2923545/creating-java-dialogs/2926126 task. Now my JOptionPane opens new window with envelope overfiew, but I can't change size of this window. Also I wanted to have sender's data in upper left corner, and receiver's data in bottom right. How can I achieve that ? There is also issue with OptionPane itself. After I click 'OK' it opens small window in the upper left corner of the screen. What is this and why it's appearing ? My code: import java.awt.*; import java.awt.Font; import javax.swing.*; public class Main extends JFrame { private static JTextField nameField = new JTextField(20); private static JTextField surnameField = new JTextField(); private static JTextField addr1Field = new JTextField(); private static JTextField addr2Field = new JTextField(); private static JComboBox sizes = new JComboBox(new String[] { "small", "medium", "large", "extra-large" }); public Main(){ JPanel mainPanel = new JPanel(); mainPanel.setLayout(new BoxLayout(mainPanel, BoxLayout.Y_AXIS)); getContentPane().add(mainPanel); JPanel addrPanel = new JPanel(new GridLayout(0, 1)); addrPanel.setBorder(BorderFactory.createTitledBorder("Receiver")); addrPanel.add(new JLabel("Name")); addrPanel.add(nameField); addrPanel.add(new JLabel("Surname")); addrPanel.add(surnameField); addrPanel.add(new JLabel("Address 1")); addrPanel.add(addr1Field); addrPanel.add(new JLabel("Address 2")); addrPanel.add(addr2Field); mainPanel.add(addrPanel); mainPanel.add(new JLabel(" ")); mainPanel.add(sizes); String[] buttons = { "OK", "Cancel"}; int c = JOptionPane.showOptionDialog( null, mainPanel, "My Panel", JOptionPane.DEFAULT_OPTION, JOptionPane.PLAIN_MESSAGE, null, buttons, buttons[0] ); if(c ==0){ new Envelope(nameField.getText(), surnameField.getText(), addr1Field.getText() , addr2Field.getText(), sizes.getSelectedIndex()); } setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); pack(); setVisible(true); } public static void main(String[] args) { new Main(); } } class Envelope extends JFrame { private final int SMALL=0; private final int MEDIUM=1; private final int LARGE=2; private final int XLARGE=3; public Envelope(String n, String s, String a1, String a2, int i){ Container content = getContentPane(); JPanel mainPanel = new JPanel(); mainPanel.setLayout(new BoxLayout(mainPanel, BoxLayout.Y_AXIS)); mainPanel.add(new JLabel("John Doe")); mainPanel.add(new JLabel("FooBar str 14")); mainPanel.add(new JLabel("Newark, 45-99")); JPanel dataPanel = new JPanel(); dataPanel.setFont(new Font("sansserif", Font.PLAIN, 32)); //set size from i mainPanel.setLayout(new BoxLayout(mainPanel, BoxLayout.Y_AXIS)); mainPanel.setBackground(Color.ORANGE); mainPanel.add(new JLabel("Mr "+n+" "+s)); mainPanel.add(new JLabel(a1)); mainPanel.add(new JLabel(a2)); content.setSize(450, 600); content.setBackground(Color.ORANGE); content.add(mainPanel, BorderLayout.NORTH); content.add(dataPanel, BorderLayout.SOUTH); setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); pack(); setVisible(true); } }

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• Calling system commands from Perl

  - by Dan J

  In an older version of our code, we called out from Perl to do an LDAP search as follows: # Pass the base DN in via the ldapsearch-specific environment variable # (rather than as the "-b" paramater) to avoid problems of shell # interpretation of special characters in the DN. $ENV{LDAP_BASEDN} = $ldn; $lcmd = "ldapsearch -x -T -1 -h $gLdapServer" . <snip> " > $lworkfile 2>&1"; system($lcmd); if (($? != 0) || (! -e "$lworkfile")) { # Handle the error } The code above would result in a successful LDAP search, and the output of that search would be in the file $lworkfile. Unfortunately, we recently reconfigured openldap on this server so that a "BASE DC=" is specified in /etc/openldap/ldap.conf and /etc/ldap.conf. That change seems to mean ldapsearch ignores the LDAP_BASEDN environment variable, and so my ldapsearch fails. I've tried a couple of different fixes but without success so far: (1) I tried going back to using the "-b" argument to ldapsearch, but escaping the shell metacharacters. I started writing the escaping code: my $ldn_escaped = $ldn; $ldn_escaped =~ s/\/\\/g; $ldn_escaped =~ s/`/\`/g; $ldn_escaped =~ s/$/\$/g; $ldn_escaped =~ s/"/\"/g; That threw up some Perl errors because I haven't escaped those regexes properly in Perl (the line number matches the regex with the backticks in). Backticks found where operator expected at /tmp/mycommand line 404, at end of line At the same time I started to doubt this approach and looked for a better one. (2) I then saw some Stackoverflow questions (here and here) that suggested a better solution. Here's the code: print("Processing..."); # Pass the arguments to ldapsearch by invoking open() with an array. # This ensures the shell does NOT interpret shell metacharacters. my(@cmd_args) = ("-x", "-T", "-1", "-h", "$gLdapPool", "-b", "$ldn", <snip> ); $lcmd = "ldapsearch"; open my $lldap_output, "-|", $lcmd, @cmd_args; while (my $lline = <$lldap_output>) { # I can parse the contents of my file fine } $lldap_output->close; The two problems I am having with approach (2) are: a) Calling open or system with an array of arguments does not let me pass > $lworkfile 2>&1 to the command, so I can't stop the ldapsearch output being sent to screen, which makes my output look ugly: Processing...ldap_bind: Success (0) additional info: Success b) I can't figure out how to choose which location (i.e. path and file name) to the file handle passed to open, i.e. I don't know where $lldap_output is. Can I move/rename it, or inspect it to find out where it is (or is it not actually saved to disk)? Based on the problems with (2), this makes me think I should return back to approach (1), but I'm not quite sure how to

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