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• How can a language be interpreted by itself (like Rubinius)?

  - by japancheese

  I've been programming in Ruby for a while now with just the standard MRI implementation of Ruby, but I've always been curious about the other implementations I hear so much about. I was reading about Rubinius the other day, a Ruby interpreter written in Ruby. I tried looking it up in various places, but I was having a hard time figuring out exactly how something like this works. I've never had much experience in compilers or language writing but I'm really interested to figure it out. How exactly can a language be interpreted by itself? Is there a basic step in compiling that I don't understand where this makes sense? Can someone explain this to me like I'm an idiot (because that wouldn't be too far off base anyways)

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• Are frameworks really necessary for beginners/intermediates? (PHP)

  - by ggfan

  I have been programming for around 6months and currently learning PHP/Mysql. I can create basic functionally sites starting from a plain sheet of paper. Is it necessary I use frameworks to create sites? Currently, everything I do is from scratch. I'll borrow codes from old codes, ask people for help, etc. Are frameworks going to help me much more? Is it alright if I put a site public without using a framework? (I have not looked a lot into frameworks, so my knowledge is limited, but I'm just curious)

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• Searching for a complex and well-designed PHP OOP application to learn from

  - by Raveren

  Basically, I am diving ever deeper into complex programming practices. I've almost no friends that are experienced (or more experienced than me) programmers to learn from, so I am looking for the next best thing - learning from the work of strangers. Can anyone recommend a real world finished and working application written well and OOP-centered. I'd like to take and analyze its source. Bonus if it's based on Zend Framework. What I am interested most in is objects that unlike desktop applications, have only one real operation done to them (or to their representation in DB or session) during their lifetime (or pageload), like user-logIn(). I'm interested in optimal and reusable design patterns and their real life implementations.

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• GoTo statements and alternatives in VB.NET

  - by qais

  I've posted a code snippet on another forum asking for help and people pointed out to me that using GoTo statements is very bad programming practice. I'm wondering: why is it bad? What alternatives to GoTo are there to use in VB.NET that would be considered generally more of a better practice? Consider this snippet below where the user has to input their date of birth. If the month/date/year are invalid or unrealistic(using if statements checking the integer inputs size, if there's a better way to do this, I'd appreciate if you could tell me that also :D) How would I be able to loop back to ask the user again? retryday: Console.WriteLine("Please enter the day you were born : ") day = Console.ReadLine If day > 31 Or day < 1 Then Console.WriteLine("Please enter a valid day") GoTo retryday End If

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• How does exactly Qt works?

  - by Somebody still uses you MS-DOS

  I have seen that you can write your application in Qt, and it can be run in different operating systems. And - correct me if I'm wrong - you don't need to have Qt already installed in all of these platforms. How exactly this approach works? Does Qt compiles to the desired platform, does it bundle some "dlls" (libs), how does it do it? Is different from programming a Java application for the sake of cross-platform? If you use Python to write a Qt application with Python bindings, does the final user needs to have Python installed?

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• Java: How can I create good looking class docs with Javadoc?

  - by Cheeso

  I'd like to create HTNML documentation for a Java class library that includes programming guide information - beyond just a class reference code examples in the reference doc collapsible regions I want it to look well-styled. Something like this: I think that Javadoc exposes a doclet API that allows other parties to provide doc generation integrated in Javadoc. Is there a doclet option that I can use (for free) that does something a little nicer than the standard javadoc output? I tried googling for this but no luck. Suggestions?

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• Django: Data corrupted after loading? (possible programmer error)

  - by Rosarch

  I may be loading data the wrong way. excerpt of data.json: { "pk": "1", "model": "myapp.Course", "fields": { "name": "Introduction to Web Design", "requiredFor": [9], "offeringSchool": 1, "pre_reqs": [], "offeredIn": [1, 5, 9] } }, I run python manage.py loaddata -v2 data: Installed 36 object(s) from 1 fixture(s) Then, I go to check the above object using the Django shell: >>> info = Course.objects.filter(id=1) >>> info.get().pre_reqs.all() [<Course: Intermediate Web Programming>] # WRONG! There should be no pre-reqs >>> from django.core import serializers >>> serializers.serialize("json", info) '[{"pk": 1, "model": "Apollo.course", "fields": {"pre_reqs": [11], "offeredIn": [1, 5, 9], "offeringSchool": 1, "name": "Introduction to Web Design", "requiredFor": [9]}}]' The serialized output of the model is not the same as the input that was given to loaddata. The output has a non-empty pre_req list, whereas the input's pre_reqs field is empty. What am I doing wrong?

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• C# (With .NET & Visual Studio) WebForms - How can I get the title of a page ..?

  - by Ashley Davies

  Prety long question; How can I do the following in C#: Open a webpage (Prefferably not visible) Check whether the page redirects to a different page (Site is down, 404, etc.) Check if the title is not equal to a said string Then seperately, (They need to click a confirm button) open their browser, and go to the adress of the first (It'll be the only one) hyperlink on the site. I literally have been looking on google for ages and haven't found anything similar to what I need. Whether you give me a link to a site with a tutorial on this area of programming or actual source code doesn't make a difference to me.

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• I need to pad IP addresses with Zeroes for each octet

  - by Felipe Alvarez

  Starting with a string of an unspecified length, I need to make it exactly 43 characters long (front-padded with zeroes). It is going to contain IP addresses and port numbers. Something like: ### BEFORE # Unfortunately includes ':' colon 66.35.205.123.80-137.30.123.78.52172: ### AFTER # Colon removed. # Digits padded to three (3) and five (5) # characters (for IP address and port numbers, respectively) 066.035.05.123.00080-137.030.123.078.52172 This is similar to the output produced by tcpflow. Programming in Bash. I can provide copy of script if required. If it's at all possible, it would be nice to use a bash built-in, for speed. Is printf suitable for this type of thing?

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• Conditionally setting the font color of an item in a drop down box in JSF

  - by Greg

  I'm a newbie to web programming, so please bear with me. I am using JSF 1.2 and I want to conditionally set the color of the items in my drop down list. In other words, I have a collection of items that, along with a key and a value, also have a boolean property, warning, that is dynamically set by user action. I want the drop down to show all of the items, but those whose warning property is set to true should be displayed in red. I assume I have to extend the SelectItem class to add in the boolean property. How do I then conditionally set the color of the font of those items whose warning property is set to true in my JSP pages? Thanks in advance

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• How is fseek() implemented in the filesystem?

  - by pajton

  This is not a pure programming question, however it impacts the performance of programs using fseek(), hence it is important to know how it works. A little disclaimer so that it doesn't get closed. I am wondering how efficient it is to insert data in the middle of the file. Supposing I have a file with 1MB data and then I insert something at the 512KB offset. How efficient would that be compared to appending my data at the end of the file? Just to make the example complete lets say I want to insert 16KB of data. I understand the answer varies depending on the filesystem, however I assume that the techniques used in common filesystems are quite similar and I just want to get the right notion of it.

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• What is the most idiomatic way to emulating Perl's Test::More::done_testing?

  - by DVK

  I have to build unit tests for in environment with a very old version of Test::More (perl5.8 with $Test::More::VERSION being '0.80') which predates the addition of done_testing(). Upgrading to newer Test::More is out of the question for practical reasons. And I am trying to avoid using no_tests - it's generally a bad idea not catching when your unit test exits prematurely - say due to some logic not executing when you expected it to. What is the most idiomatic way of running a configurable amount of tests, assuming no no_tests or done_testing() is used? Details: My unit tests usually take the form of: use Test::More; my @test_set = ( [ "Test #1", $param1, $param2, ... ] ,[ "Test #1", $param1, $param2, ... ] # ,... ); foreach my $test (@test_set) { run_test($test); } sub run_test { # $expected_tests += count_tests($test); ok(test1($test)) || diag("Test1 failed"); # ... } The standard approach of use Test::More tests => 23; or BEGIN {plan tests => 23} does not work since both are obviously executed before @tests is known. My current approach involves making @tests global and defining it in the BEGIN {} block as follows: use Test::More; BEGIN { our @test_set = (); # Same set of tests as above my $expected_tests = 0; foreach my $test (@tests) { my $expected_tests += count_tests($test); } plan tests = $expected_tests; } our @test_set; # Must do!!! Since first "our" was in BEGIN's scope :( foreach my $test (@test_set) { run_test($test); } # Same sub run_test {} # Same I feel this can be done more idiomatically but not certain how to improve. Chief among the smells is the duplicate our @test_test declarations - in BEGIN{} and after it. Another approach is to emulate done_testing() by calling Test::More->builder->plan(tests=>$total_tests_calculated). I'm not sure if it's any better idiomatically-wise.

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• Is there a c++ library that provides functionality to execute an external program and read its outpu

  - by BD at Rivenhill

  Basically, I'm looking for something that will allow me to replicate the following Perl code: my $fh = new FileHandle; $fh->open("foo |"); while (<$fh>) { # Do something with this line of data. } This is in the context of Linux, so a library that is specific to Windows will not help. I know how to write a program that does fork/exec/dup2 and all that basic shell-type jazz, but there are some fiddly details involving terminals that I don't feel like messing around with (and I don't have a copy of "Advanced Programming in the UNIX Environment" or a similar reference handy), so I'm hoping that someone has already solved this problem.

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• Convert a string representation of a hex dump to a byte array using Java?

  - by ravigad

  I am looking for a way to convert a long string (from a dump), that represents hex values into a byte array. I couldn't have phrased it better than the person that posted the same question here: http://www.experts-exchange.com/Programming/Programming_Languages/Java/Q_21062554.html But to keep it original, I'll phrase it my own way: suppose I have a string "00A0BF" that I would like interpreted as the byte[] {0x00,0xA0,0xBf} what should I do? I am a Java novice and ended up using BigInteger and watching out for leading hex zeros. But I think it is ugly and I am sure I am missing something simple...

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• What are the things Java got right?

  - by hamletdarcy

  What are the things that Java (the language and platform) got categorically right? In other words, what things are more recent programming languages preserving and carrying forward? Some easy answer are: garbage collection, a VM, lack of pointers, classloaders, reflection(?) What about language based answers? Please don't list the things Java did wrong, just right. (note by Mark Harrison) This is an interesting and useful question, especially for those of us who don't use java regularly. I'm voting for reopening. Please don't close as argumentative, as it doesn't seem to be causing any arguments.

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• In Flash Actionscript 3.0 how do I create smooth keyboard controls for player movement?

  - by Reid

  I am a beginner in Flash Actionscript 3.0 programming. I am trying to create smooth keyboard controls for player movement in a game. I'm currently using addEventListener(KeyboardEvent.KEY_DOWN) listening for a keyboard key press and then within the handler function moving a graphic by adding a number to its .x or .y property. This creates a slow, sluggish jerk at the beginning. I know there's a smoother, more responsive way to do this but have no idea where to begin. Any help would be appreciated!

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• Convert Yes/No/Null from SQL to True/False in a DataTable

  - by Scott Chamberlain

  I have a Sql Database (which I have no control over the schema) that has a Column that will have the varchar value of "Yes", "No", or it will be null. For the purpose of what I am doing null will be handled as No. I am programming in c# net 3.5 using a data table and table adapter to pull the data down. I would like to directly bind the column using a binding source to a check box I have in my program however I do not know how or where to put the logic to convert the string Yes/No/null to boolean True/False; Reading a null from the SQL server and writing back a No on a update is acceptable behavior. Any help is greatly appreciated. EDIT -- This is being developed for windows.

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• Xcode 3.2 not recompiling changed files

  - by Jason

  I've been programming a new iPhone application and everything has been chugging along fine, until this afternoon when I noticed that any changes I was making were not being reflected in the actual app! Even code that throws errors isn't getting picked up by the compiler. To get around this, I have taken to the following procedure: Finish making my edits, and add code to the file which will always throw a compiler error. Right-click the file I have just edited, and hit "Compile" to just compile that one file; it will throw the error. Remove the error-producing code, and again right-click and "Compile" the one file. Build the whole project This is quite annoying, and I can't figure out why this would suddenly happen to my Xcode project. Any thoughts on what could be causing this, and how to fix it?

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• Assign value to list

  - by Kenneth B

  Hello First and foremost. I'm totally new to "programming" in Excel. I'm trying to make a price calculator, that calculates the price when I use my printer. I have made some lists so it's easy to perform the calculations. Single or duplex: Singlex/Duplex Format: SRA3 / A4 / SRA3 High Gloss The idea is that if I type in an amount of 100 prints, choose SRA3 format on the list, and choose Duplex on the other list. the calculation would look like this: This is how it's calculated: Paper + (print x sides) = Price of the print job Print prices Per page (singlex or duplex): 0,6 Paper format and price: A4 reg. paper: 0,2 SRA3 High Gloss: 1,25 SRA3 reg. paper: 1 Does anyone know about this???

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• iPhone/iPad fatal error in C++ code produces no output in the log

  - by morgancodes

  I'm trying to move away from Objective-C to C++ for audio in my iPad programming, due to the a few reports I've heard of Objective-C selectors sometimes causing audio glitches. So I'm starting to use pure C++ files. When a fatal error happens in one of the C++ files, I get no output from the log. The app just crashes. For example, if I do this in my C++ file: env = new ADSR(); cout << "setting env to null\n"; env = NULL; env->setSustainLevel(1); cout << "called function on non-initialized env\n"; I get the following output: setting env to null After that, there's a method called on NULL, which apparently kills the app, but absolutely nothing to that effect is reported. What do I need to do to have useful information logged when there's an error in my C++ code?

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• How to program a connection pool?

  - by the_drow

  Is there a known algorithm for implementing a connection pool? If not what are the known algorithms and what are their trade-offs? What design patterns are common when designing and programming a connection pool? Are there any code examples implement a connection pool using boost.asio? Is it a good idea to use a connection pool for presisting connections (not http)? How is threading related to connection pooling? When do you need a new thread?

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• C++ -- return x,y; The point?

  - by Earlz

  Hello, I have been programming in C and C++ for a few years and now I'm taking a college course in it and our book had a function like this int foo(){ int x=0; int y=20; return x,y; //y is always returned } I have never seen such syntax. In fact, I never see the , operator used outside of parameter lists. If y is always returned though, then what is the point? Is there a case where a return statement would need to be created like this? (Also, I tagged C as well because it applies to both, though my book specifically is C++)

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• Best Online C++ Refresher

  - by Bill

  It's been a longtime since I've done any C++ (probably about 13 years, since I graduated college). I've developing in various others languages since then. My new gig uses a fair bit of C++. Any recommendations for getting bootstrapped? To clarify -- I don't need an "into to programming" book. E.g., what's a variable, flow control, etc. I understand the concepts of OO having implemented them, etc. I'm looking for the best way to get to the specifics of C++.

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• databind a DropDownList control with a list of all sub directories that exist in a particular direct

  - by sushant

  I am wanting to databind a DropDownList control with a list of all sub directories that exist in a particular directory on the server. The directory I want to search is in the root of the application. I am fairly new to programming and I'm not sure where to even start. I found this code on a website: Dim root As String = "C;\" Dim folders() As String = Directory.GetDirectories(root) Dim sb As New StringBuilder(2048) Dim f As String For Each f In folders Dim foldername As String = Path.GetFileName(f) sb.Append("<option>") sb.Append(foldername) sb.Append("</option>") Next Label3.Text = "<select runat=""sever"" id=""folderlist""" & sb.ToString() & "</select>" I guess this is vb. but my tool is in asp, so is their something similar in vbscript so that I can use it.

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• Which is faster in memory, ints or chars? And file-mapping or chunk reading?

  - by Nick

  Okay, so I've written a (rather unoptimized) program before to encode images to JPEGs, however, now I am working with MPEG-2 transport streams and the H.264 encoded video within them. Before I dive into programming all of this, I am curious what the fastest way to deal with the actual file is. Currently I am file-mapping the .mts file into memory to work on it, although I am not sure if it would be faster to (for example) read 100 MB of the file into memory in chunks and deal with it that way. These files require a lot of bit-shifting and such to read flags, so I am wondering that when I reference some of the memory if it is faster to read 4 bytes at once as an integer or 1 byte as a character. I thought I read somewhere that x86 processors are optimized to a 4-byte granularity, but I'm not sure if this is true... Thanks!

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