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  • Perl XML SAX parser emulating XML::Simple record for record

    - by DVK
    Short Q summary: I am looking a fast XML parser (most likely a wrapper around some standard SAX parser) which will produce per-record data structure 100% identical to those produced by XML::Simple. Details: We have a large code infrastructure which depends on processing records one-by-one and expects the record to be a data structure in a format produced by XML::Simple since it always used XML::Simple since early Jurassic era. An example simple XML is: <root> <rec><f1>v1</f1><f2>v2</f2></rec> <rec><f1>v1b</f1><f2>v2b</f2></rec> <rec><f1>v1c</f1><f2>v2c</f2></rec> </root> And example rough code is: sub process_record { my ($obj, $record_hash) = @_; # do_stuff } my $records = XML::Simple->XMLin(@args)->{root}; foreach my $record (@$records) { $obj->process_record($record) }; As everyone knows XML::Simple is, well, simple. And more importantly, it is very slow and a memory hog - due to being a DOM parser and needing to build/store 100% of data in memory. So, it's not the best tool for parsing an XML file consisting of large amount of small records record-by-record. However, re-writing the entire code (which consist of large amount of "process_record"-like methods) to work with standard SAX parser seems like an big task not worth the resources, even at the cost of living with XML::Simple. What I'm looking for is an existing module which will probably be based on a SAX parser (or anything fast with small memory footprint) which can be used to produce $record hashrefs one by one based on the XML pictured above that can be passed to $obj->process_record($record) and be 100% identical to what XML::Simple's hashrefs would have been. I don't care much what the interface of the new module is - e.g whether I need to call next_record() or give it a callback coderef accepting a record.

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  • Please suggest me the ( Interaction model of view model) MVVM design in the simple scenario discusse

    - by Jack
    Data Layer I have an Order class as an entity. This Order entity is my model object. Order can be different types, let it be A B C D Also Order class may have common properties like Name, Time of creation, etc. Also based on the order type there are different fields that are not common. View Layer The view contains the following Main Menu ListView The Main Menu contains the drop down menu button which is used to create the order based on the type selected from the drop down. The drop down contains the Order types ( A ,B , C and D). There are different user control based on the order type. Like for example if user chooses to create an order of type A then different view with different inputs field is popped up. Hence, there are four user control for each order type. If user selects A option from the drop down then Order of type A is created and vica versa. Now below is the List View that contains the List of orders so far created by the user. To Edit any particular order user may double click the list view row. Based on the order type clicked by the user in the listview, the view of that order type opens in edit mode. For example if user selects an order type A from the list view then view for order type A open in edit mode. Please suggest me interaction model for view model's in the scenario discussed above. Please excume me if the query is very basic, since I am new new to MVVM and WPF ,

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  • C# File IO with Streams - Best Memory Buffer Size

    - by AJ
    Hi, I am writing a small IO library to assist with a larger (hobby) project. A part of this library performs various functions on a file, which is read / written via the FileStream object. On each StreamReader.Read(...) pass, I fire off an event which will be used in the main app to display progress information. The processing that goes on in the loop is vaired, but is not too time consuming (it could just be a simple file copy, for example, or may involve encryption...). My main question is: What is the best memory buffer size to use? Thinking about physical disk layouts, I could pick 2k, which would cover a CD sector size and is a nice multiple of a 512 byte hard disk sector. Higher up the abstraction tree, you could go for a larger buffer which could read an entire FAT cluster at a time. I realise with today's PC's, I could go for a more memory hungry option (a couple of MiB, for example), but then I increase the time between UI updates and the user perceives a less responsive app. As an aside, I'm eventually hoping to provide a similar interface to files hosted on FTP / HTTP servers (over a local network / fastish DSL). What would be the best memory buffer size for those (again, a "best-case" tradeoff between perceived responsiveness vs. performance). Thanks in advance for any ideas, Adam

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  • How do I pass a cookie to a Sinatra app using curl?

    - by Brandon Toone
    I'm using the code from the example titled "A Slightly Bigger Example" from this tutorial http://rubylearning.com/blog/2009/09/30/cookie-based-sessions-in-sinatra/ to figure out how to send a cookie to a Sinatra application but I can't figure out how to set the values correctly When I set the name to be "brandon" in the application it creates a cookie with a value of BAh7BiIJdXNlciIMYnJhbmRvbg%3D%3D%0A which is a url encoding (http://ostermiller.org/calc/encode.html) of the value BAh7BiIJdXNlciIMYnJhbmRvbg== Using that value I can send a cookie to the app correctly curl -b "rack.session=BAh7BiIJdXNlciIMYnJhbmRvbg==" localhost:9393 I'm pretty sure that value is a base64 encoding of the ruby hash for the session since the docs (http://rack.rubyforge.org/doc/classes/Rack/Session/Cookie.html) say The session is a Ruby Hash stored as base64 encoded marshalled data set to :key (default: rack.session). I thought that meant all I had to do was base64 encode {"user"=>"brandon"} and use it in the curl command. Unfortunately that creates a different value than BAh7BiIJdXNlciIMYnJhbmRvbg==. Next I tried taking the base64 encoded value and decoding it at various base64 decoders online but that results in strange characters (a box symbol and others) so I don't know how to recreate the value to even encode it. So my question is do you know what characters/format I need to get the proper base64 encoding and/or do you know of another way to pass a value using curl such that it will register as a proper cookie for a Sinatra app?

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  • Rails 3 - yield return or callback won't call in view <%= yield(:sidebar) || render('shared/sidebar'

    - by rzar
    Hey folks, I'm migrating a Website from Rails 2 (latest) to Rails 3 (beta2). Testing with Ruby 1.9.1p378 and Ruby 1.9.2dev (2010-04-05 trunk 27225) Stuck in a situation, i don't know which part will work well. Suspect yield is the problem, but don't know exactly. In my Layout Files I use the following technique quite often: app/views/layouts/application.html.erb: <%= yield(:sidebar) || render('shared/sidebar') %> For Example the partial look like: app/views/shared/_sidebar.html.erb: <p>Default sidebar Content. Bla Bla</p> Now it is time for the key part! In any view, I want to create a content_for block (optional). This can contain a pice of HTML etc. example below. If this block is set, the pice HTML inside should render in application.html.erb. If not, Rails should render the Partial at shared/_sidebar.html.erb on the right hand side. app/views/books/index.html.erb: <% content_for :sidebar do %> <strong>You have to read REWORK, a book from 37signals!</strong> <% end %> So you've got the idea. Hopefully. This technique worked well in any Rails 2.x Application. Now, in Rails 3 (beta2) only the yield Part is working. || render('shared/sidebar') The or side will not process by rails or maybe ruby. Thanks for input and time!

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  • why does text from socket server erase previously written text?

    - by mix
    This is strange enough I'm not sure how to search for an answer. I have a program in Python that communicates via TCP/IP sockets to a telnet-based server. If I telnet in manually and type commands like this: SET MDI G0 X0 Y0 the server will spit back a line like this: SET MDI ACK Pretty standard stuff. Here's the weird part. If, in my code, I precede my printing of each of these lines with some text, the returned line erases what I'm trying to print before it. So for example, if I write the code so it should look like this: SENT: SET MDI G0 X0 Y0 READ: SET MDI ACK What I get instead is: SENT: SET MDI G0 X0 Y0 SET MDI ACK Now, if I make the "READ: " text a bit longer, I can get a better idea of what's happening. Let's say I change READ: to 12345678901234567890, so that it should read as: 12345678901234567890: SET MDI ACK What I get instead is: SET MDI ACK234567890: So it seems like whatever text I'm getting back from the server is somehow deleting what I'm trying to precede it with. I tried saving all of my saved lines in a list, and then printing them out at the end, but it does exactly the same thing. Any ideas on what's going on, or even on how to debug this? Is there a way to get Python to show me any hidden chars in a string, for example? thx!

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  • Dynamic if statement evaluation problem with string comparison

    - by Mani
    I tried the example given in this thread to create if statement dynamically using BeanShell. But it is not working fine. Instead of using "age" variable as integer, i have used string in the below example. I am getting "fail" as answer instead of "success". Can anyone help me? /* To change this template, choose Tools | Templates and open the template in the editor. */ import java.lang.reflect.*; import bsh.Interpreter; public class Main { public static String d; public static void main(String args[]) { try { String age = "30"; String cond = "age==30"; Interpreter i = new Interpreter(); i.set("age", age); System.out.println(" sss" + i.get("age")); if((Boolean)i.eval(cond)) { System.out.println("success"); } else { System.out.println("fail"); } } catch (Throwable e) { System.err.println(e); } } } Thanks, Mani

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  • REST API Best practice: How to accept as input a list of parameter values

    - by whatupwilly
    Hi All, We are launching a new REST API and I wanted some community input on best practices around how we should have input parameters formatted: Right now, our API is very JSON-centric (only returns JSON). The debate of whether we want/need to return XML is a separate issue. As our API output is JSON centric, we have been going down a path where our inputs are a bit JSON centric and I've been thinking that may be convenient for some but weird in general. For example, to get a few product details where multiple products can be pulled at once we currently have: http://our.api.com/Product?id=["101404","7267261"] Should we simplify this as: http://our.api.com/Product?id=101404,7267261 Or is having JSON input handy? More of a pain? We may want to accept both styles but does that flexibility actually cause more confusion and head aches (maintainability, documentation, etc.)? A more complex case is when we want to offer more complex inputs. For example, if we want to allow multiple filters on search: http://our.api.com/Search?term=pumas&filters={"productType":["Clothing","Bags"],"color":["Black","Red"]} We don't necessarily want to put the filter types (e.g. productType and color) as request names like this: http://our.api.com/Search?term=pumas&productType=["Clothing","Bags"]&color=["Black","Red"] Because we wanted to group all filter input together. In the end, does this really matter? It may be likely that there are so many JSON utils out there that the input type just doesn't matter that much. I know our javascript clients making AJAX calls to the API may appreciate the JSON inputs to make their life easier. Thanks, Will

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  • cannot receive UDP broadcast packets

    - by user292792
    Hello I have 2 boxes: - an embedded device (ARM Omap with linux) which I'll call "Omap". - a PC (can either be Windows or linux). Scenario 1 Both boxes are in the same network (example: my office). The Omap gets its address from a DHCP server (ex: 192.168.10.110). The PC has always the same address (ex. 192.168.10.104). I can successfully exchange UDP broadcast packets on any port. Success. Scenario 2 The 2 boxes are in a network withOUT a DHCP server. The PC has a static IP address (example: 10.10.10.20). The Omap boots, looks for a DHCP server, doesn't find it, and is in what I call "bad IP address" state. Now... Broadcasting UDP packets from the Omap works: the PC can see them. The opposite doesn't work: UDP packets broadcasted by the PC are not seen by the Omap. I am using Wireshark on another PC to verify that the packets are being sent. Failure. I tried to change the Omap ip address (with ifconfig)... no luck. What am I missing? To complete the picture, when the Omap is in Scenario 2, if I run udhcpc ... it can communicate with the DHCP server and get an IP address. I also see the packets with Wireshark. So this means that the DHCP client is able to broadcast UDP packets. (Yes, I tried to use DHCP ports 67/68 but it doesn't work). I am using Boost C++ Asio UDP sockets. Specifically, I took the multicast examples and changed them to do broadcasting. Any help is appreciated. Thanks, Benedetto

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  • How to test IO code in JUnit?

    - by add
    I'm want to test two services: service which builds file name service which writes some data into file provided by 1st service In first i'm building some complex file structure (just for example {user}/{date}/{time}/{generatedId}.bin) In second i'm writing data to the file passed by first service (1st service calls 2nd service) How can I test both services using mocks without making any real IO interractions? Just for example: 1st service: public class DefaultLogService implements LogService { public void log(SomeComplexData data) { serializer.write(new FileOutputStream(buildComplexFileStructure()), data); or serializer.write(buildComplexFileStructure(), data); or serializer.write(new GenericInputEntity(buildComplexFileStructure()), data); } private ComplextDataSerializer serializer; // mocked in tests } 2nd service: public class DefaultComplexDataSerializer implements ComplexDataSerializer { void write(InputStream stream, SomeComplexData data) {...} or void write(File file, SomeCompexData data) {...} or void write(GenericInputEntity entity, SomeComplexData data) {...} } In first case i need to pass FileOutputStream which will create a file (i.e. i can't test 1st service) In second case i need to pass File. What can i do in 2nd service test if I need to test data which will be written to specified file? (i can't test 2nd service) In third case i think i need some generic IO object which will wrap File. Maybe there is some ready-to-use solution for this purpose?

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  • Average function without overflow exception

    - by Ron Klein
    .NET Framework 3.5. I'm trying to calculate the average of some pretty large numbers. For instance: using System; using System.Linq; class Program { static void Main(string[] args) { var items = new long[] { long.MinValue + 100, long.MinValue + 200, long.MinValue + 300 }; try { var avg = items.Average(); Console.WriteLine(avg); } catch (OverflowException ex) { Console.WriteLine("can't calculate that!"); } Console.ReadLine(); } } Obviously, the mathematical result is 9223372036854775607 (long.MaxValue - 200), but I get an exception there. This is because the implementation (on my machine) to the Average extension method, as inspected by .NET Reflector is: public static double Average(this IEnumerable<long> source) { if (source == null) { throw Error.ArgumentNull("source"); } long num = 0L; long num2 = 0L; foreach (long num3 in source) { num += num3; num2 += 1L; } if (num2 <= 0L) { throw Error.NoElements(); } return (((double) num) / ((double) num2)); } I know I can use a BigInt library (yes, I know that it is included in .NET Framework 4.0, but I'm tied to 3.5). But I still wonder if there's a pretty straight forward implementation of calculating the average of integers without an external library. Do you happen to know about such implementation? Thanks!! UPDATE: The previous example, of three large integers, was just an example to illustrate the overflow issue. The question is about calculating an average of any set of numbers which might sum to a large number that exceeds the type's max value. Sorry about this confusion. I also changed the question's title to avoid additional confusion. Thanks all!!

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  • LaTeX limitation?

    - by Jayen
    Hi, I've hit an annoying problem in LaTeX. I've got a tex file of about 1000 lines. I've already got a few figures, but when I try to add another figure, It barfs with: ! Undefined control sequence. <argument> ... \sf@size \z@ \selectfont \@currbox l.937 \begin{figure}[t] If I move the figure to other parts of the file, I can get similar errors on different lines: ! Undefined control sequence. <argument> ... \sf@size \z@ \selectfont \@currbox l.657 \paragraph {A Centering Algorithm} If I comment out the figure, all is ok. %\begin{figure}[t] % \caption{Example decision tree, from Reiter and Dale [2000]} % \label{fig:relation-decision-tree} % \centering % \includegraphics[keepaspectratio=true]{./relation-decision-tree.eps} %\end{figure} If I keep just the begin and end like: \begin{figure}%[t] % \caption{Example decision tree, from Reiter and Dale [2000]} % \label{fig:relation-decision-tree} % \centering % \includegraphics[keepaspectratio=true]{./relation-decision-tree.eps} \end{figure} I get: ! Undefined control sequence. <argument> ... \sf@size \z@ \selectfont \@currbox l.942 \end {figure} At first, I thought maybe LaTeX has hit some limit, and I tried playing with the ulimits, but that didn't help. Any ideas? i've got other figures with graphics already. my preamble looks like: \documentclass[acmcsur,acmnow]{acmtrans2n} \usepackage{array} \usepackage{lastpage} \usepackage{pict2e} \usepackage{amsmath} \usepackage{varioref} \usepackage{epsfig} \usepackage{graphics} \usepackage{qtree} \usepackage{rotating} \usepackage{tree-dvips} \usepackage{mdwlist} \makecompactlist{quote*}{quote} \usepackage{verbatim} \usepackage{ulem}

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  • An alternative to reading input from Java's System.in

    - by dvanaria
    I’m working on the UVa Online Judge problem set archive as a way to practice Java, and as a way to practice data structures and algorithms in general. They give an example input file to submit to the online judge to use as a starting point (it’s the solution to problem 100). Input from the standard input stream (java.lang.System.in) is required as part of any solution on this site, but I can’t understand the implementation of reading from System.in they give in their example solution. It’s true that the input file could consist of any variation of integers, strings, etc, but every solution program requires reading basic lines of text input from System.in, one line at a time. There has to be a better (simpler and more robust) method of gathering data from the standard input stream in Java than this: public static String readLn(int maxLg) { byte lin[] = new byte[maxLg]; int lg = 0, car = -1; String line = “”; try { while (lg < maxLg) { car = System.in.read(); if ((car < 0) || (car == ‘\n’)) { break; } lin[lg++] += car; } } catch (java.io.IOException e) { return (null); } if ((car < 0) && (lg == 0)) { return (null); // eof } return (new String(lin, 0, lg)); } I’m really surprised by this. It looks like something pulled directly from K&R’s “C Programming Language” (a great book regardless), minus the access level modifer and exception handling, etc. Even though I understand the implementation, it just seems like it was written by a C programmer and bypasses most of Java’s object oriented nature. Isn’t there a better way to do this, using the StringTokenizer class or maybe using the split method of String or the java.util.regex package instead?

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  • Using Mapping Models to migrate between Core Data Object Models

    - by westsider
    I have a fairly simply scheme. Essentially, Run <-- Data (where a Run holds a data, e.g., Temperature, sampled from some sort of sensor). Now, it seems that sensors can have more than one measurement (e.g., Temperature and Humidity). So, a single Run could have multiple data samples. Hence, Run <-- Sample and Sample <-- Data. (And for simplicity I am leaving Run <-- Data in place, for now.) If I create a new mapping model, then things generally work - except that no new Samples are created, no relationships are established between Runs and Samples nor between Samples and Datas. I am trying to get mapping model to migrate my model but even the slightest change to the generated mapping model results in Cocoa error 134110. For example, if I take the "Sample" mapping (which has no Source) and set its Source to 'Run' (so that I can set Sample's inverse relationship 'run' appropriately) then the mapping changes its name to "RunToSample". There are two relationships handled in this mapping: data and run. The data property gets set automatically to FUNCTION($manager, "destinationInstancesForEntityMappingNamed:sourceInstances:" , "DataToData", $source.dataSet) Following this example, I set the run property to FUNCTION($manager, "destinationInstancesForEntityMappingNamed:sourceInstances:" , "RunToRun", $source) Similarly, I set the 'sample' property mapping in RunToRun to FUNCTION($manager, "destinationInstancesForEntityMappingNamed:sourceInstances:" , "RunToSample", $source) and the 'sample' property in DataToData to FUNCTION($manager, "destinationInstancesForEntityMappingNamed:sourceInstances:" , "RunToSample", $source.run) So, what, I wonder, is going wrong? I have tried various permutations, such as leaving the 'inverse' relationships unspecified. But I continue to get the same error (134110) regardless. I imagine that this is a lot easier than it seems and that I am missing some fundamental but minor piece. I have also tried subclassing NSEntityMigrationPolicy and overriding -createDestinationInstancesForSourceInstance: but these efforts have met with much the same results. Thanks in advance for any pointers or (relevant :-) advice.

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  • Dojo: dojo onblur events

    - by Jane Wilkie
    Hi guys, I have a form setup with dojo 1.5. I am using a dijit.form.ComboBox and a dijit.form.TextBox The Combobox has values like "car","bike","motorcycle" and the textbox is meant to be an adjective to the Combobox. So it doesn't matter what is in the Combobox but if the ComboBox does have a value then something MUST be filled in the TextBox. Optionally, if nothing is in the ComboBox, then nothing can be in the TextBox and that is just fine. In fact if something isn't in the Combobox then nothing MUST be in the text box. In regular coding I would just use an onBlur event on the text box to go to a function that checks to see if the ComboBox has a value. I see in dojo that this doesn't work... Code example is below... Vehicle: <input dojoType="dijit.form.ComboBox" store="xvarStore" value="" searchAttr="name" name="vehicle_1" id="vehicle_1" /> Descriptor: <input type="text" dojoType="dijit.form.TextBox" value="" class=lighttext style="width:350px;height:19px" id="filter_value_1" name="filter_value_1" /> My initial attempt was to add an onBlur within the Descriptor's <input> tag but discovered that that doesn't work. How does Dojo handle this? Is it via a dojo.connect parameter? Even though in the example above the combobox has an id of "vehicle_1" and the text box has an id of "filter_value_1", there can be numerous comboboxes and textboxes numbering sequentially upward. (vehicle_2, vehicle_3, etc) Any advice or links to resources would be greatly appreciated. Janie

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  • How to group strings by prefix

    - by namenlos
    I am writing a Winform UI in which the user must select a single customer. (For reasons beyond my control I am limited to a UI that uses dropdown lists, text fields, checkboxes, radiobuttons only -i.e. no fancy special UI controls) The situation There are a lot of customers (a thousand for example) If i put all the customers in a single dropdown there's no way it will be easy for a customer to even see all the customers. Also the it will take too long to retireve all the customers from the DB to populate the dropdown My thought is to have two combo box, the first lists groups of the customers by their last name something like a phone book "Aa-Ac", "Ad-Ade", "Adf-B", when selecting the first combo box, it scope the second one to a managable set customer names (no more than for example 40 names) The question I need a reasonable way of grouping their names such that it will be clear to customer which group contains the name. I.e. given a group of names I need to bucketize then int "Aa-Ac". Comments I don't need to solve the general problem of an immense number of names - we know based on our data that 1000 names is the max our users will encounter. If there are other techniques please do share, but I am interested specifically in an answer to my specific question around how to determine the buckets ("Aa-Ac", etc.)

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  • How to deal with calculated values with Dependency Properties on a custom WPF control

    - by jpierson
    To summarize what I'm doing, I have a custom control that looks like a checked listbox and that has two dependency properties one that provides a list of available options and the other that represents a enum flag value that combines the selection options. So as I mentioned my custom control exposes two different DependencyProperties, one of which is a list of options called Options and the other property called SelectedOptions is of a specific Enum type that uses the [Flags] attribute to allow combinations of values to be set. My UserControl then contains an ItemsControl similar to a ListBox that is used to display the options along with a checkbox. When the check box is checked or unchecked the SelectedOptions property should be updated accordingly by using the corresponding bitwise operation. The problem I'm experiencing is that I have no way other than resorting to maintaining private fields and handling property change events to update my properties which just feels unatural in WPF. I have tried using ValueConverters but have run into the problem that I can't really using binding with the value converter binding so I would need to resort to hard coding my enum values as the ValueConverter parameter which is not acceptable. If anybody has seen a good example of how to do this sanely I would greatly appreciate any input. Side Note: This has been a problem I've had in the past too while trying to wrap my head around how dependency properties don't allow calculated or deferred values. Another example is when one may want to expose a property on a child control as a property on the parent. Most suggest in this case to use binding but that only works if the child controls property is a Dependency Property since placing the binding so that the target is the parent property it would be overwritten when the user of the parent control wants to set their own binding for that property.

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  • How to provide stl like container with public const iterator and private non-const iterator?

    - by WilliamKF
    Hello, I am deriving a class privately from std::list and wish to provide public begin() and end() for const_iterator and private begin() and end() for just plain iterator. However, the compiler is seeing the private version and complaining that it is private instead of using the public const version. I understand that C++ will not overload on return type (in this case const_iterator and iterator) and thus it is choosing the non-const version since my object is not const. Short of casting my object to const before calling begin() or not overloading the name begin is there a way to accomplish this? I would think this is a known pattern that folks have solved before and would like to follow suit as to how this is typically solved. class myObject; class myContainer : private std::list<myObject> { public: typedef std::list<myObject>::const_iterator myContainer::const_iterator; private: typedef std::list<myObject>::iterator myContainer::iterator; public: myContainer::const_iterator begin() const { return std::list<myObject>::begin(); } myContainer::const_iterator end() const { return std::list<myObject>::end(); } private: myContainer::iterator begin() { return std::list<myObject>::begin(); } myContainer::iterator end() { return std::list<myObject>::end(); } }; void myFunction(myContainer &container) { myContainer::const_iterator aItr = container.begin(); myContainer::const_iterator aEndItr = container.end(); for (; aItr != aEndItr; ++aItr) { const myObject &item = *aItr; // Do something const on container's contents. } } The error from the compiler is something like this: ../../src/example.h:447: error: `std::_List_iterator<myObject> myContainer::begin()' is private caller.cpp:2393: error: within this context ../../src/example.h:450: error: `std::_List_iterator<myObject> myContainer::end()' is private caller.cpp:2394: error: within this context Thanks. -William

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  • identation control while developing a small python like language

    - by sap
    Hello, Im developing a small python like language using flex, byacc (for lexical and parsing) and C++, but i have a few questions regarding scope control. just as python it uses white spaces (or tabs) for identation, not only that but i want to implement index breaking like for instance if you type "break 2" inside a while loop thats inside another while loop it would not only break from the last one but from the first loop as well (hence the number 2 after break) and so on. example: while 1 while 1 break 2 end end #after break 2 it would jump right here but since i dont have an "anti" tab character to check when a scope ends (like C for example i would just use the '}' char) i was wondering if this method would the the best: i would define a global variable, like "int tabIndex" on my yacc file that i would access in my lex file using extern. then everytime i find a tab character on my lex file i would increment that variable by 1. when parsing on my yacc file if i find a "break" keyword i would decrement by the amount typed after it from the tabIndex variable, and when i reach and EOF after compiling and i get a tabIndex != 0 i would output compilation error. now the problem is, whats the best way to see if the identation got reduced, should i read \b (backspace) chars from lex and then reduce the tabIndex variable (when the user doesnt use break)? another method to achieve this? also just another small question, i want every executable to have its starting point on the function called start() should i hardcode this onto my yacc file? sorry for the long question any help is greatly appretiated. also if someone can provide an yacc file for python would be nice as a guideline (tried looking on google and had no luck). thanks in advance.

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  • What purpose does “using” serve when used the following way

    - by user287745
    What purpose does “using” serve when used the following way:- ONE EXAMPLE IS THIS, (AN ANSWERER- @richj - USED THIS CODE TO SOLVE A PROBLEM THANKS) private Method(SqlConnection connection) { using (SqlTransaction transaction = connection.BeginTransaction()) { try { // Use the connection here .... transaction.Commit(); } catch { transaction.Rollback(); throw; } } } OTHER EXAMPLE I FOUND WHILE READING ON MICROSOFT SUPPORT SITE public static void ShowSqlException(string connectionString) { string queryString = "EXECUTE NonExistantStoredProcedure"; StringBuilder errorMessages = new StringBuilder(); using (SqlConnection connection = new SqlConnection(connectionString)) { SqlCommand command = new SqlCommand(queryString, connection); try { command.Connection.Open(); command.ExecuteNonQuery(); } catch (SqlException ex) { for (int i = 0; i < ex.Errors.Count; i++) { errorMessages.Append("Index #" + i + "\n" + "Message: " + ex.Errors[i].Message + "\n" + "LineNumber: " + ex.Errors[i].LineNumber + "\n" + "Source: " + ex.Errors[i].Source + "\n" + "Procedure: " + ex.Errors[i].Procedure + "\n"); } Console.WriteLine(errorMessages.ToString()); } } } I AM doing at top of page as using system.data.sqlclient etc so why this using thing in middle of code, What if I omit it (I know the code will work) but what functionality will I be losing

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  • How to include multiple tables programmaticaly into a Sweave document using R

    - by PaulHurleyuk
    Hello, I want to have a sweave document that will include a variable number of tables in. I thought the example below would work, but it doesn't. I want to loop over the list foo and print each element as it's own table. % \documentclass[a4paper]{article} \usepackage[OT1]{fontenc} \usepackage{longtable} \usepackage{geometry} \usepackage{Sweave} \geometry{left=1.25in, right=1.25in, top=1in, bottom=1in} \listfiles \begin{document} <<label=start, echo=FALSE, include=FALSE>>= startt<-proc.time()[3] library(RODBC) library(psych) library(xtable) library(plyr) library(ggplot2) options(width=80) #Produce some example data, here I'm creating some dummy dataframes and putting them in a list foo<-list() foo[[1]]<-data.frame(GRP=c(rep("AA",10), rep("Aa",10), rep("aa",10)), X1=rnorm(30), X2=rnorm(30,5,2)) foo[[2]]<-data.frame(GRP=c(rep("BB",10), rep("bB",10), rep("BB",10)), X1=rnorm(30), X2=rnorm(30,5,2)) foo[[3]]<-data.frame(GRP=c(rep("CC",12), rep("cc",18)), X1=rnorm(30), X2=rnorm(30,5,2)) foo[[4]]<-data.frame(GRP=c(rep("DD",10), rep("Dd",10), rep("dd",10)), X1=rnorm(30), X2=rnorm(30,5,2)) @ \title{Docuemnt to test putting a variable number of tables into a sweave Document} \author{"Paul Hurley"} \maketitle \section{Text} This document was created on \today, with \Sexpr{print(version$version.string)} running on a \Sexpr{print(version$platform)} platform. It took approx \input{time} sec to process. <<label=test, echo=FALSE, results=tex>>= cat("Foo") @ that was a test, so is this <<label=table1test, echo=FALSE, results=tex>>= print(xtable(foo[[1]])) @ \newpage \subsection{Tables} <<label=Tables, echo=FALSE, results=tex>>= for(i in seq(foo)){ cat("\n") cat(paste("Table_",i,sep="")) cat("\n") print(xtable(foo[[i]])) cat("\n") } #cat("<<label=endofTables>>= ") @ <<label=bye, include=FALSE, echo=FALSE>>= endt<-proc.time()[3] elapsedtime<-as.numeric(endt-startt) @ <<label=elapsed, include=FALSE, echo=FALSE>>= fileConn<-file("time.tex", "wt") writeLines(as.character(elapsedtime), fileConn) close(fileConn) @ \end{document} Here, the table1test chunk works as expected, and produced a table based on the dataframe in foo[[1]], however the loop only produces Table(underscore)1.... Any ideas what I'm doing wrong ?

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  • Is ASP.NET MVC destined to replace Webforms?

    - by johnny
    I found these questions, but a couple of them were a little old: http://stackoverflow.com/questions/191556/should-i-pursue-asp-net-webforms-or-asp-net-mvc http://stackoverflow.com/questions/88787/do-you-think-asp-net-mvc-will-compete-with-asp-net-webforms http://stackoverflow.com/questions/722637/asp-net-mvc-asp-net-webforms-why I do not believe these are duplicates and might be old enough that new light can be shed. If not please close this. I know that no one framework or language is necessarily the only tool for every job. But, do you see MVC eclipsing webforms or webforms going lower on the priority list for Microsoft? They will have to keep webforms for a long time because so many have invested in it, but they don't have to keep adding new functionality for it. I don't know if this is a good example, but it reminds me of web parts. I never saw much improvement in it from Microsoft. It works and I thought it was great until I started to really try and get a lot out of it. Then from what I could see it just wasn't being pursued by Microsoft that much, though it stayed in Visual Studio. Maybe that's a bad example; just what I remembered. EDIT: Also, if anyone has any statements from Microsoft on this subject it is appreciated. No offense to anyone. I was only hoping for something official.

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  • Java Memory Model: reordering and concurrent locks

    - by Steffen Heil
    Hi The java meomry model mandates that synchronize blocks that synchronize on the same monitor enforce a before-after-realtion on the variables modified within those blocks. Example: // in thread A synchronized( lock ) { x = true; } // in thread B synchronized( lock ) { System.out.println( x ); } In this case it is garanteed that thread B will see x==true as long as thread A already passed that synchronized-block. Now I am in the process to rewrite lots of code to use the more flexible (and said to be faster) locks in java.util.concurrent, especially the ReentrantReadWriteLock. So the example looks like this: // in thread A synchronized( lock ) { lock.writeLock().lock(); x = true; lock.writeLock().unlock(); } // in thread B synchronized( lock ) { lock.readLock().lock(); System.out.println( x ); lock.readLock().unlock(); } However, I have not seen any hints within the memory model specification that such locks also imply the nessessary ordering. Looking into the implementation it seems to rely on the access to volatile variables inside AbstractQueuedSynchronizer (for the sun implementation at least). However this is not part of any specification and moreover access to non-volatile variables is not really condsidered covered by the memory barrier given by these variables, is it? So, here are my questions: Is it safe to assume the same ordering as with the "old" synchronized blocks? Is this documented somewhere? Is accessing any volatile variable a memory barrier for any other variable? Regards, Steffen

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  • Linq to NHibernate wrapper issue using where statement

    - by Jacob
    I'am using wrapper to get some data from table users IQueryable<StarGuestWrapper> WhereQuery = session.Linq<User>().Where(u => u.HomeClub.Id == clubId && u.IsActive).Select( u => new StarGuestWrapper() { FullName = u.Name + " " + u.LastName, LoginTime = DateTime.Now, MonthsAsMember = 2, StarRating = 1, UserPicture = u.Photo.PhotoData, InstructorFullName = "Someone Xyz", TalkInteractionDuringSession = true, GoalInteractionDuringSession = false }); I use this without a problem as a IQueryable so I can do useful things before actually running the query. Like : WhereQuery.Skip(startRowIndex).Take(maximumRows).ToList(); and so on. The problem occurs using 'where' statement on query. For example: WhereQuery.Where(s => s.StarRating == 1) will throw an exception in runtime that 'StarRating' doesn't exist in User table - of course it doesn't it's a wrappers property. I will work if I materialize query by WhereQuery.AsEnumerable().Where(s => s.StarRating == 1) but then it loses all the sens of using IQueryable and I don't want to do this. What is strange and interesting that not all properties from wrapper throw error, all the bool values can be used in where statement. Example : WhereQuery.Where(s => s.TalkInteractionDuringSession) It works in EntityFramework , why do I get this error in NHibernate and how to get it working the way I want it to ?

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  • CSS - Inheriting layered background images

    - by NNN
    CSS3 supports multiple background images, for example: foo { background-image: url(/i/image1.jpg), url(/i/image2.jpg); } I'd like to be able to add a secondary image to an element with a class though. So for example, say you have a nav menu. And each item has a background image. When a nav item is selected you want to layer on another background image. I do not see a way to 'add' a background image instead of redeclaring the whole background property. This is a pain because in order to do this with multi-backgrounds, you would have to write the base bg image over and over for each item if the items have unique images. Ideally I'd be able to do something like this: li { background: url(baseImage.jpg); } li.selected { background: url(selectedIndicator.jpg); } And have li.selected's end result appear the same if I did: li.selected { background: url(baseImage.jpg), url(selectedIndicator.jpg); } Update: I also tried the following with no luck (I believe backgrounds are not inherited..) li { background: url(baseImage.jpg), none; } li.selected { background: inherit, url(selectedIndicator.jpg); }

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