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• In SICP exercise 2.26 using DrScheme, why does cons return a list, instead of a pair of lists?

  - by limist

  In SICP exercise 2.26, this Scheme code is given: (define x (list 1 2 3)) (define y (list 4 5 6)) Then this cons call is given: (cons x y) I expected a pair of lists would result, ((1 2 3) (4 5 6)) but the interpreter gives, ((1 2 3) 4 5 6) ...a list with 4 elements, the first being a list. Why is y treated differently? I've tried looking up other SICP answers for an explanation, but couldn't find something satisfactory. So could any Scheme/Lisp experts please shed some light on this aspect of cons? Thanks in advance for any insight.

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• how do i claim a low-numbered port as non-root the "right way"

  - by qbxk

  I have a script that I want to run as a daemon listening on a low-numbered port (< 1024) Script is in python, though answers in perl are also acceptable. The script is being daemonized using start-stop-daemon in a startup script, which may complicate the answer What I really (think) don't want is to type ps -few and see this process running with a "root" on it's line. How do I do it? ( from my less-than-fully-educated-about-system-calls perspective, I can see 3 avenues, Run the script as root (no --user/--group/--chuid to start-stop-daemon), and have it de-escalate it's user after it claims the port Setuid root on the script (chmod u+s), and run the script as the running user, (via --user/--group/--chuid to start-stop-daemon, the startup script still has to be called as root), in the script, acquire root privileges, claim the port, and then revert back to normal user something else i'm unaware of )

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• How Can I Create Reports in a Custom C#.NET Windows Application? - General Question

  - by user311509

  Assume i have a custom Windows application written in C#. This application has only the following functionalists, add, edit, delete and view. For example, a user can add a sale, change sales record, delete a sale record or view the whole sales record. I need to add some reporting functionalists e.g. i want a user to print the sales of a certain customer from 2008 to 2009 into pdf, what all products a certain customer has purchased from us and so on. I will only include the basic common report requests that are usually needed in the office. Any other kind of reports that are requested inconsistently, i would do it manually from my side at the back end and send the results manually to the requester. What i would do is: If a user wants more info of a certain customer, a special window box appears for that customer. This window box will have different controls that allows user to request more info such as, print customer purchases from ..... to ..... (user chooses the dates) and user will view results in pdf or so. Of course, at the back scene i will write an appropriate SQL Query with parameters that meets a certain function. Is this how it should be done? I have heard about SQL Reporting, i don't know anything about it yet. I will check it out. Anyhow, your suggestions won't harm. I'm still a student, so i don't have practical experience yet. I hope my question is clear enough. Thank you.

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• Upload a file to SharePoint through the built-in web services

  - by Andy McCluggage

  What is the best way to upload a file to a Document Library on a SharePoint server through the built-in web services that version WSS 3.0 exposes? Following the two initial answers... We definitely need to use the Web Service layer as we will be making these calls from remote client applications. The WebDAV method would work for us, but we would prefer to be consistent with the web service integration method. There is additionally a web service to upload files, painful but works all the time. Are you referring to the “Copy” service? We have been successful with this service’s CopyIntoItems method. Would this be the recommended way to upload a file to Document Libraries using only the WSS web service API? I have posted our code as a suggested answer.

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• Tough question on WPF, Win32, MFC

  - by Mack

  Let's suppose you're an IT student with a basic knowledge of C++ and C#. Let's suppose that you want to design apps that: need to deliver some performance like archivers, cryptographic algorithms, codecs make use of some system calls have a gui and you want to learn an Api that will enable you to write apps like those described earlier and: is mainstream is future proof entitles you to find a decent job is easy enough - I mean easy like VCL, not easy like winapi So, making these assumptions, what Api will you choose? MFC, WPF, other? I really like VCL and QT, but they're not mainstream and I think few employers will want you to write apps in QT or Visual C++ Builder... Thanks for answers.

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• Is it possible to host a website in the 'ether' of the Internet -- not on a server -- so that it can

  - by Christopher Altman

  This is a theoretical problem I am curious about. Websites are hosted on servers. Servers can be taken offline. Is it possible to host a website in the 'ether' of the Internet -- not on a server -- so that it cannot be taken down? One example, is that the website is hosted on other websites, like a parasite. Another is that it is assembled through storing pieces on DNS machines, routers, etc., so that it get assembled on the fly. The purpose is that this website could live forever because no one person can remove it. The answers I am looking for are plausible idea/approaches on technically how this could be built.

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• GKPeerStateAvailable for non existing peers?

  - by Ernest

  Hi, used this website for the long time to find answers, now need to ask on myself! :) I have implemented multi player for my game using GKSession and client/server approach, not using peer picker (up to 4 player allowed). I have one big problem which I can't find solution for. If you disconnect/reconnect server peer quickly enough, client peer will "remember" that host and will show it in the list of all available peers permanently, only turning wifi/bluetooth off resets this. So if I do this 5 times in a row, my client will show 5 available hosts with the same name! Anyone had experience with this? Any idea of workarounds? I should note that requirements for my game is iPhone SDK 3.0 for Bluetooth and 3.1 for Wifi as GKSession supports both now.

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• .net 4 Chart Control - Hide labels in pie chart

  - by Ricardo Deano

  Hello all. Am I going mad/blind? Probably a combination of the two. How does one go about removing the data labels from a pie chart with the new chart control in .net 4? I can get these to display as tooltips absolutely fine, but ultiamtely I'd like the labels not to be present as it looks rather busy. I've searched previous answers and seen code behind resolutions but surely there must be some sort of code infront option to turn these labels off? Apologies for being thick/blind.

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• Can I specify which VCS module or adaptor is used by a Luntbuild buiulder or schedule?

  - by pkaeding

  I have luntbuild set up and working great for my project, with several different builder schedules running on trunk. Now, I just created a branch, and I want to add at least one schedule (and corresponding builder, if necessary) to build that branch (I want the branch built separately from trunk). Is this possible? Some others in my company have just created separate projects in Luntbuild for their branches, but I feel like that might not be the ideal solution. So, to reiterate, I want to build this branch continuously. If I just add a second module to the current setup, it tries to build both trunk and the branch together. I want them build separately. Thanks for any insight! EDIT: The bounty is about to end, and still no answers. I have worked around the original problem by creating a new project in LB, but I feel like there must be a better way.

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• JavaScript setInterval loop not holding variable

  - by Ryan

  Here is my code: var showNo = 1; window.setInterval(function() { console.log(showNo); if(showNo === 1) { var nextNo = 2; } else if(showNo === 2) { var nextNo = 3; } else if(showNo === 3) { var nextNo = 4; } else if(showNo === 4) { var nextNo = 5; } else if(showNo === 5) { var nextNo = 1; } else { var showNo = 1; var nextNo = 2; } var showNo = nextNo; }, 500); My question is, why is the showNo variable not holding when the setInterval loop starts? The console displays 'undefined' in the above example. This may be a simple question, but I am trying to teach myself query and this has me stuck.. Any answers would be great. Thanks.

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• What design pattern do you use the most?

  - by spoon16

  I'm interested in understanding what design patterns people find themselves using often. Hopefully this list will help other recognize common scenarios and the associated design pattern that can be used to solve them. Please describe a common problem you find yourself solving and the design pattern(s) you use to solve it. Links to blogs or documentation describing the pattern are also appreciated. Edit: Please expand on your answers a bit, I would like this to be a useful reference for someone who wants to learn more about design patterns and is curious on what situations a specific design pattern might be used. Nobody has linked to any "more learning" resources.

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• Recommended way to manage persistent PHP script processes?

  - by BigglesZX

  First off - hello, this is my first Stack Overflow question so I'll try my best to communicate properly. The title of my question may be a bit ambiguous so let me expand upon it immediately: I'm planning a project which involves taking data inputs from several "streaming" APIs, Twitter being one example. I've got a basic script coded up in PHP which runs indefinitely from the command line, taking input from the Twitter streaming API and doing very basic things with it. My eventual objective is to have several such processes running (perhaps daemonized using the System Daemon PEAR class), and I would like to be able to manage them from some governing process (also a PHP script). By manage I mean basic operations such as stop/start and (most crucially) automatically restarting a process that crashes. I would appreciate any pointers on how best to approach this process management angle. Again, apologies if this question is too expansive - tips on more tightly focused lines of enquiry would be appreciated if necessary. Thanks for reading and I look forward to your answers.

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• Ruby Methods: how to return an usage string when insufficient arguments are given

  - by Shyam

  Hi, After I have created a serious bunch of classes (with initialize methods), I am loading these into IRb to test each of them. I do so by creating simple instances and calling their methods to learn their behavior. However sometimes I don't remember exactly what order I was supposed to give the arguments when I call the .new method on the class. It requires me to look back at the code. However, I think it should be easy enough to return a usage message, instead of seeing: ArgumentError: wrong number of arguments (0 for 9) So I prefer to return a string with the human readable arguments, by example using "puts" or just a return of a string. Now I have seen the rescue keyword inside begin-end code, but I wonder how I could catch the ArgumentError when the initialize method is called. Thank you for your answers, feedback and comments!

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• Zero division does not throw exception in nunit

  - by Boris

  Running the following C# code through NUnit yields Test.ControllerTest.TestSanity: Expected: <System.DivideByZeroException> But was: null So either no DivideByZeroException is thrown, or NUnit does not catch it. Similar to this question, but the answers he got, do not seem to work for me. This is using NUnit 2.5.5.10112, and .NET 4.0.30319. [Test] public void TestSanity() { Assert.Throws<DivideByZeroException>(new TestDelegate(() => DivideByZero())); } private void DivideByZero() { // Parse "0" to make sure to get an error at run time, not compile time. var a = (1 / Double.Parse("0")); } Any ideas?

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• Detecting if Excel file has been closed

  - by Charlie

  Hi StackOverflow, I've spent the past 3 hours trawling the web for answers to no avail, so I hope you can help me. I'm writing an application which automates Excel. The application has an option to "show/hide the excel sheet" so you can look at it, make any final changes and so forth. Closing the application will naturally close the instance of Excel, however, there is a small chance that someone may exit out of Excel directly, without thinking. This breaks my application and I can't seem to find anyway of "checking if the same workbook is still open, and if not, re-opening it", before saving it I've tried all sorts of things: checking if the Excel Application is null (when it's !=null it will save correctly, but when it "is" null (or at least, something other than !=null it won't even hit the breakpoint so I'm completely lost :( Help please?

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• How to correctly calculate address spaces?

  - by user337308

  Below is an example of a question given on my last test in a Computer Engineering course. Anyone mind explaining to me how to get the start/end addresses of each? I have listed the correct answers at the bottom... The MSP430F2410 device has an address space of 64 KB (the basic MSP430 architecture). Fill in the table below if we know the following. The first 16 bytes of the address space (starting at the address 0x0000) is reserved for special function registers (IE1, IE2, IFG1, IFG2, etc.), the next 240 bytes is reserved for 8-bit peripheral devices, and the next 256 bytes is reserved for 16-bit peripheral devices. The RAM memory capacity is 2 Kbytes and it starts at the address 0x1100. At the top of the address space is 56KB of flash memory reserved for code and interrupt vector table. What Start Address End Address Special Function Registers (16 bytes) 0x0000 0x000F 8-bit peripheral devices (240 bytes) 0x0010 0x00FF 16-bit peripheral devices (256 bytes) 0x0100 0x01FF RAM memory (2 Kbytes) 0x1100 0x18FF Flash Memory (56 Kbytes) 0x2000 0xFFFF

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• Handling Custom Protocols

  - by nomad311

  I'm looking to respond to an event from a web browser, hopefully any web browser. I'm working solely on windows and I came to the conclusion a custom protocol (I.E. myprot://collection/of/strings) is the best approach here (any objections?). But, handling an instance of this protocol seems to be a little less straight-forward. All I need is that collection of strings auto-magically passed to my already running application! (the app will only respond to these links while in a specific waiting state) So answer me this, if you can, Whats the 'popular' method of handling them or better yet Whats the 'best' (subjective - I know) way to do it? Although your answers don't need to be specific to my language, I am using Delphi for development. Thanks!

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• Is There Any Good Way To Create Mobile Website

  - by Shivam Pandya

  I want to make some simple mobile website. can any one help me out from give some answers of following questions? 1] Is there any good framework, which help me to create one? 2] How to design simple mobile site template? 3] IS there any site available, which allowed me to download free mobile template? 4] Is There any software for develop mobile site? Thanks a lot if you manage to give at-list one answer of above questions.

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• web developer editor ubuntu

  - by madphp

  Hi, I know theres hundred of questions and answers out there, but cant find one to specifically answer this. I need a web editor that will let me choose a dark themed editor. I understand gvim is one, but im not totally ready to let go of my mouse. I would like something like sublime text editor for windows, but open to other suggestions. The less bloat the best. I dont need a full IDE like eclipse, but willing to compromise, as long as the themes can easily be added. I've tried bluefish, kompozer and not happy with them. Just need a basic text editor that will highlight php syntax on a dark background.

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• How do I use .NET to find an orange ball in an image?

  - by JohnS

  I'm getting images from a C328R camera attached to a small arduino robot. I want the robot to drive towards orange ping-pong balls and pick them up. I'm using the C# code supplied by funkotron76 at http://www.codeproject.com/KB/recipes/C328R.aspx. Is there a library I can use to do this, or do I need to iterate over every pixel in the image looking for orange? If so, what kind of tolerance would I need to compensate for various lighting conditions? I could probably test to figure out these numbers, but I'm hoping someone out there knows the answers.

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• getting mysql_insert_id() while using ON DUPLICATE KEY UPDATE with PHP

  - by julio

  Hi-- I've found a few answers for this using mySQL alone, but I was hoping someone could show me a way to get the ID of the last inserted or updated row of a mysql DB when using PHP to handle the inserts/updates. Currently I have something like this, where column3 is a unique key, and there's also an id column that's an autoincremented primary key: $query ="INSERT INTO TABLE (column1, column2, column3) VALUES (value1, value2, value3) ON DUPLICATE KEY UPDATE SET column1=value1, column2=value2, column3=value3"; mysql_query($query); $my_id = mysql_insert_id(); $my_id is correct on INSERT, but incorrect when it's updating a row (ON DUPLICATE KEY UPDATE). I have seen several posts with people advising that you use something like INSERT INTO table (a) VALUES (0) ON DUPLICATE KEY UPDATE id=LAST_INSERT_ID(id) to get a valid ID value when the ON DUPLICATE KEY is invoked-- but will this return that valid ID to the PHP "mysql_insert_id()" function? Thanks for any advice.

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• Vectorizing sums of different diagonals in a matrix

  - by reve_etrange

  I want to vectorize the following MATLAB code. I think it must be simple but I'm finding it confusing nevertheless. r = some constant less than m or n [m,n] = size(C); S = zeros(m-r,n-r); for i=1:m-r for j=1:n-r S(i,j) = sum(diag(C(i:i+r-1,j:j+r-1))); end end The code calculates a table of scores, S, for a dynamic programming algorithm, from another score table, C. The diagonal summing is to generate scores for individual pieces of the data used to generate C, for all possible pieces (of size r). Thanks in advance for any answers! Sorry if this one should be obvious...

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• Performance optimization strategies of last resort?

  - by jerryjvl

  There are plenty of performance questions on this site already, but it occurs to me that almost all are very problem-specific and fairly narrow. And almost all repeat the advice to avoid premature optimization. Let's assume: the code already is working correctly the algorithms chosen are already optimal for the circumstances of the problem the code has been measured, and the offending routines have been isolated all attempts to optimize will also be measured to ensure they do not make matters worse What I am looking for here is strategies and tricks to squeeze out up to the last few percent in a critical algorithm when there is nothing else left to do but whatever it takes. Ideally, try to make answers language agnostic, and indicate any down-sides to the suggested strategies where applicable. I'll add a reply with my own initial suggestions, and look forward to whatever else the SO community can think of.

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• Screen capture doesn't work on MFC application in Vista

  - by David Thornley

  We've got some in-house applications built in MFC, with OpenGL drawing routines. They all use the same code to draw on the screen and either print the screen or save it to a JPEG file. Everything's been working fine in Windows XP, and I need to find a way to make them work on Vista. In three of our applications, everything works. In the remaining one, I can get the window border, title bar, menus, and task bar, but the interior never shows up. As I said, these applications use the exact same code to write to the screen and capture the window image, and the only difference I see that looks like it might be relevant is that the problem application uses the MFC multiple document interface, while the ones that work use the single document interface. Either the answer isn't on the net, or I'm worse at Googling than I thought. I asked on the MSDN forums, and the only practical suggestion I got was to use GDI+ rather than GDI, and that did nothing different. I have tried different things with every part of the code that captures and prints or save, given a pointer to the window, so apparently it's a matter of the window itself. I haven't rebuilt the offending application using SDI yet, and I really don't have any other ideas. Has anybody seen anything like this?

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• ZendFramework integration with other frameworks

  - by St.Woland

  I want to make this question a guide for those interested in ZendFramework integration with other libraries/frameworks. Searching over StackOverflow doesn't give a broad view on the subject. The question is: which libraries/frameworks do you use in your current ZF-based project? what are the best practices for ZF-based project architecture? I don't mean any components that are already a part of ZF. Please give a description of aditional frameworks you have integrated (like RuckUsing, Smarty, or Doctrine). It also applies to any GUI frameworks (perhaps you use a CSS framework), as well as JS frameworks (not just jQuery or prototype, but rather some advanced structures). The main requirement: it has to be a ZendFramework project. Additional bonus will be given to answers that describe performance optimization.

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