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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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• 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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• How can I determine file encodings on Windows / IIS ?

  - by Dylan Beattie

  From the answers to this question it appears there's a file somewhere on our server that's been saved with the wrong encoding. I've seen this happen before - most often when pasting from Word into Visual Studio, when "smart quotes" can interfere with Visual Studio's encoding settings when saving the file. Thing is - the problem I'm having involves 20-30 different script files, include files and so on (hey, that was how we kept it modular back in the day...) and I really don't want to open every one of them in Visual Studio and check the file encodings individually. Is there any way I can analyze a folder tree full of files and spit out a list of each filename along with the text encoding used to save the file? (Or - if encodings aren't clearly specified - work out what encoding Microsoft IIS thinks was used to save the file?)

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• Yet another Haskell vs. Scala question

  - by Travis Brown

  I've been using Haskell for several months, and I love it—it's gradually become my tool of choice for everything from one-off file renaming scripts to larger XML processing programs. I'm definitely still a beginner, but I'm starting to feel comfortable with the language and the basics of the theory behind it. I'm a lowly graduate student in the humanities, so I'm not under a lot of institutional or administrative pressure to use specific tools for my work. It would be convenient for me in many ways, however, to switch to Scala (or Clojure). Most of the NLP and machine learning libraries that I work with on a daily basis (and that I've written in the past) are Java-based, and the primary project I'm working for uses a Java application server. I've been mostly disappointed by my initial interactions with Scala. Many aspects of the syntax (partial application, for example) still feel clunky to me compared to Haskell, and I miss libraries like Parsec and HXT and QuickCheck. I'm familiar with the advantages of the JVM platform, so practical questions like this one don't really help me. What I'm looking for is a motivational argument for moving to Scala. What does it do (that Haskell doesn't) that's really cool? What makes it fun or challenging or life-changing? Why should I get excited about writing it?

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• Materialized Query Table in SQL Server 2005

  - by Azho KG

  In DB2 there is a support for Materialized Query Table (MQT). Basicly you write a query and create a MQT. But the difference from View is that the query is pre-executed and resulting data is stored in MQT and there are some options when to refresh/syncronize the MQT with base tables. I want same functionality in SQL Server. Is there a way to achieve same result? I've tables with millions of rows, and I want to show summary (like total # of members, total expense and etc) in dashboard. So I don't want to count every time user gets to dashboard, instead I want to store them in table and I want that table to be refresh each night. Any kind of hints, answers,suggestions and ideas are welcome. Thanks.

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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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• 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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• 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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• Windows batch file to delete folders/subfolders using wildcards

  - by Marco Demaio

  I need to delete all folders in "tomin" folder, which name contains terminates with the ".delme" string. The deletion need to be done recurively: I mean on all directory and SUB directories. I though to do this: FOR /R tomin %%X IN (*.delme) DO (RD /S /Q "%%X") but it does not work, I think /R ignores wildcards. Before asking this quation I searched also in SO and found this: but the answers did not help me in solving my issue, following the suggestion given there I tried: FOR /F tomin "delims=" %%X IN ('dir /b /ad *.delme') DO RD /S /Q "%%X" But it did not work either. Any help aprreciated, thanks!

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• Text message (SMS) verification for signups

  - by Unknown

  I have seen a disturbing trend where websites are starting to require verification sent to cellphones by text message (SMS). Gmail and Facebook are two of them. What I want to know are the following: Is it a good idea to start requiring cellphones instead of emails now? How do I do it on my own website? Edit Here are some of my new questions on the topic in response to the answers: I see that most of you are saying that SMS registrations is ok. But what about the people who don't have cell phones? And why is it accepted to give out your cell phone information freely? Do those big providers really pay per message to a gateway service? Is it not possible to set up a server with the correct SMS software, or at least buy a subscription directly instead of having a middleman?

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• Entity framework : [Set all the entities with internal access specifier]

  - by Vedaantees

  Hi, By virtue of my application, I need to seperate my business entities from the entities created by EF4. I need to restrict the entities to only access the repository from where they are translated (using translator) to business entities shared at business and service layer. I thought of restricting them by specifying them as internal. Now there are more than 40 entities in my application so manually setting them as internal is a difficult job. In one of the forums the answers suggested using the T4 templates. But even those templates read from the entity framework access specifier. When I try to manually try to specify all the properties and class access specifiers as internal it gives me an error saying that the entity set should also be set to internal, but there is no option for the same. I am using VS 2010 and Entity Framework 4. Any suggestions???

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• Netlogo: error when putting variable in table, only constants allowe??

  - by Chantal

  Hello, Currently I am working on a Netlogo program where I need to use nodes and links for vehicle routing problem. (links are called streets in the program) Here I have some practical problems of how to input variable linkspeed in a table with another node. Constants like 200 etc are fine. Online I found some examples where variables are used, but I do not know why I keep getting the following error: Expected a constant. (or why netlogo expects a constant) Here is the relevant piece of code: extensions [table] streets-own [linkspeed linktoll] nodes-own [netw] ;; In another piece of code linkspeed is assigned successfully to the links to cheapcalc ;; start conditions set costs very high 300000 ;; state 3 unsearched state 2 searching state 1 searched (for later purposes) ask nodes [ set i 0 set j count nodes set netw table:make while [i < j][ table:put netw (i) [3000000 3] set i (i + 1)]] set i 0 let k 0 ask node 35 ;; here i use node 35 as an example. ;; node 35 is connected to node 34, 36, 20 and 50 [table:put netw (35) [0 1] ;; node need to search costs to travel to itself ;; putting constants is ok. while [i < j] [ask my-links [ask both-ends [if (who != 35) [set color blue ;; set temp ([linkspeed] of street 35 who) ;; here my real goal is to put this in stat of i. but i is easier than linkspeed. table:put netw (who) [ i 2 ] ] ] ] set i (i + 1)] ] ;; next node for later, no it is just repetition of the same. end I hope somebody knows what is going on... Kind regards, Chantal

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• Qt LGPL licencing for a free application with closed source

  - by Andy M

  Hey everyone, I'm working on an application developped with Qt 4.6.2. I'm linking dynamicaly and I don't want to share my source code. The application is totally free and I don't plan on selling any part of it. I did not make any changes in the Qt library, I'm only using it to develop the application... I just want to share my free application, without having to share the source code... My question is, what would be your advices in choosing the correct licencing ? Thanks in advance for your answers !

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• Scala and the Java Memory Model

  - by Ben Lings

  The Java Memory Model (since 1.5) treats final fields differently to non-final fields. In particular, provided the this reference doesn't escape during construction, writes to final fields in the constructor are guaranteed to be visible on other threads even if the object is made available to the other thread via a data race. (Writes to non-final fields aren't guaranteed to be visible, so if you improperly publish them, another thread could see them in a partially constructed state.) Is there any documentation on how/if the Scala compiler creates final (rather than non-final) backing fields for classes? I've looked through the language specification and searched the web but can't find any definitive answers. (In comparison the @scala.volatile annotation is documented to mark a field as volatile)

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• Is there a way to trace through only project source in Delphi?

  - by Justin

  I'm using Delphi 2010 and I'm wondering if there's a way to trace through code which is in the project without tracing through calls to included VCLs. For example - you put in a breakpoint and then use Shift+F7 to trace through line-by-line. Now you run into a call to some lengthy procedure in a VCL - in my case it's often a Measurement Studio or other component that draws the doodads for a bunch of I/O, OPC, or other bits. At any rate, what happens is that the debugger hops out of the active source file, opens the component source, and traces through that line by line. Often this is hundreds or thousands of lines of code I don't care about - I just want to have it execute and return to the next source line in MY project. Obviously you can do this by setting breakpoints around every instance of an external call, but often there are too many to make this practical - I'd be spending an hour setting a hundred breakpoints every time I wanted to step through a section of code. Is there a setting or a tool somewhere that can do this? Allow one to trace through code within the project while silently executing code which is external to the project? Thanks in advance, Stack Overflow!

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• What is the best approach for creating a Common Information Model?

  - by Kaiser Advisor

  Hi, I would like to know the best approach to create a Common Information Model. Just to be clear, I've also heard it referred to as a canonical information model, semantic information model, and master data model - As far as I can tell, they are all referring to the same concept. I've heard in the past that a combined "top-down" and "bottom-up" approach is best. This has the advantage of incorporating "Ivory tower" architects and developers - The work will meet somewhere in the middle and usually be both logical and practical. However, this involves bringing in a lot of people with different skill sets. I've also seen a couple of references to the Distributed Management Task Force, but I can't glean much on best practices in terms of CIM development. This is something I'm quite interested in getting some feedback on since having a strong CIM is a prerequisite to SOA. Thanks for your help! KA Update I've heard another strategy goes along with overall SOA implementation: Get the business involved, and seek executive sponsorship. This would be part of the "Top-down" effort.

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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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• Pros and Cons of Java HTML to XML cleaners

  - by cjavapro

  I am looking to allow HTML emails (and other HTML uploads) without letting in scripts and stuff. I plan to have a white list of safe tags and attributes as well as a whitelist of CSS tags and value regexes (to prevent automatic return receipt). I asked a question: Parse a badly formatted XML document (like an HTML file) I found there are many many ways to do this. Some systems have built in sanitizers (which I don't care so much about). I will post some answers and say Community Wiki. Please post any other options you like and say Community Wiki so they can be voted on. Also any comments or wiki edits on what part of a certain product is better and what is not would be greatly appreciated. This page is a very nice listing page but I get kinda lost http://java-source.net/open-source/html-parsers

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• Displaying untrusted HTML using PHP

  - by esryl

  I have a read a number of excellent questions and answers today about dealing with user input. I am now using htmlspecialchars() to display user data in the create/edit forms (but accepting the raw input via prepared PDO statements into my database). The main question I know have is, what do you do when you are allowing the user to submit HTML which will then be displayed to the public. Obviously htmlspecialchars() is no longer suitable as it just encodes the tags and renders the content useless for purpose. My application is currently accepting HTML from an admin for product descriptions. This would allow a malicious admin to inject potentially unsafe data into public facing pages. How do people cope with this?

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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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• .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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• 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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• Which version of Grady Booch's OOA/D book should I buy?

  - by jackj

  Grady Booch's "Object-Oriented Analysis and Design with Applications" is available brand new in both the 2nd edition (1993) and the 3rd edition (2007), while many used copies of both editions are available. Here are my concerns: 1) The 2nd edition uses C++: given that I just finished reading my first two C++ books (Accelerated C++ and C++ Primer) I guess practical tips can only help, so the 2nd edition is probably best (I think the 3rd edition has absolutely no code). On the other hand, the C++ books I read insist on the importance of using standard C++, whereas Booch's 2nd edition was published before the 1998 standard. 2) The 2nd edition is shorter (608 pages vs. 720) so, I guess, it will be slightly easier to get through. 3) The 3rd edition uses UML 2.0, whereas the 2nd edition is pre-UML. Some reviews say that the notation in the 2nd edition is close enough to UML, so it doesn't matter, but I don't know if I should be worrying about this or not. 4) The 2nd edition is available in good-shape used copies for considerably less than what the 3rd one goes for. Given all the above factors, do you think I should buy the 2nd or the 3rd edition? Recommendations on other books are also welcome but I would prefer it if whoever answers has read at least one of the versions of Booch's book (preferably both!). I have already bought but not read GoF and Riel's books. I also know that I should practice a lot with real-life code. Thanks.

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• Using the WordPress HTTP_API (wp_remote_get) with GZiped data.

  - by Volmar

  Hi i working on a wordpress plugin where i'm getting data from a remote API. at irst i used cURL, but after reading this blogpost i started using WordPress HTTP_API instead. but i've got onw problem. The API answers are Gziped, and i havn't figured out how to decompress them. The Codex page is talking about an argument called decompress, but i've tried it in alot of ways but i don't get it right. I used this code in cURL: $curl = curl_init(); curl_setopt($curl, CURLOPT_URL, $url); curl_setopt($curl, CURLOPT_RETURNTRANSFER, 1); curl_setopt($curl, CURLOPT_ENCODING, "gzip"); $result = curl_exec($curl); curl_close($curl); anyone knows a way to do the same thing with the HTTP_API?

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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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