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  • Splitting MS Access Database - Front End Part Location

    - by kristof
    One of the best practices as specified by Microsoft for Access Development is splitting Access application into 2 parts; Front End that hold all the object except tables and the Back End that holds the tables. The msdn page links there to the article Splitting Microsoft Access Databases to Improve Performance and Simplify Maintainability that describes the process in details. It is recommended that in multi user environment the Back End is stored on the server/shared folder while the Front End is distributed to each user. That implies that each time there are any changes made to the front end they need to be deployed to every user machine. My question is: Assuming that the users themselves do not have rights to modify the Front End part of the application what would be the drawbacks/dangers of leaving this on the server as well next to the Back End copy? I can see the performance issues here, but are there any dangers here like possible corruptions etc? Thank you EDIT Just to clarify, the scenario specified in question assumes one Front End stored on the server and shared by users. I understand that the recommendation is to have FE deployed to each user machine, but my question is more about what are the dangers if that is not done. E.g. when you are given an existing solution that uses the approach of both FE and BE on the server. Assuming the the performance is acceptable and the customer is reluctant to change the approach would you still push the change? And why exactly? For example the danger of possible data corruption would definitely be the strong enough argument, but is that the case? It is a part of follow up of my previous question From SQL Server to MS Access 2007

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  • Node.js/ v8: How to make my own snapshot to accelerate startup

    - by Anand
    I have a node.js (v0.6.12) application that starts by evaluating a Javascript file, startup.js. It takes a long time to evaluate startup.js, and I'd like to 'bake it in' to a custom build of Node if possible. The v8 source directory distributed with Node, node/deps/v8/src, contains a SconScript that can almost be used to do this. On line 302, we have LIBRARY_FILES = ''' runtime.js v8natives.js array.js string.js uri.js math.js messages.js apinatives.js date.js regexp.js json.js liveedit-debugger.js mirror-debugger.js debug-debugger.js '''.split() Those javascript files are present in the same directory. Something in the build process apparently evaluates them, takes a snapshot of state, and saves it as a byte string in node/out/Release/obj/release/snapshot.cc (on Mac OS). Some customization of the startup snapshot is possible by altering the SconScript. For example, I can change the definition of the builtin Date.toString by altering date.js. I can even add new global variables by adding startup.js to the list of library files, with contents global.test = 1. However, I can't put just any javascript code in startup.js. If it contains Date.toString = 1;, an error results even though the code is valid at the node repl: Build failed: -> task failed (err #2): {task: libv8.a SConstruct -> libv8.a} make: *** [program] Error 1 And it obviously can't make use of code that depends on libraries Node adds to v8. global.underscore = require('underscore'); causes the same error. I'd ideally like a tool, customSnapshot, where customSnapshot startup.js evaluates startup.js with node and then dumps a snapshot to a file, snapshot.cc, which I can put into the node source directory. I can then build node and tell it not to rebuild the snapshot.

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  • What would be the time complexity of counting the number of all structurally different binary trees?

    - by ktslwy
    Using the method presented here: http://cslibrary.stanford.edu/110/BinaryTrees.html#java 12. countTrees() Solution (Java) /** For the key values 1...numKeys, how many structurally unique binary search trees are possible that store those keys? Strategy: consider that each value could be the root. Recursively find the size of the left and right subtrees. */ public static int countTrees(int numKeys) { if (numKeys <=1) { return(1); } else { // there will be one value at the root, with whatever remains // on the left and right each forming their own subtrees. // Iterate through all the values that could be the root... int sum = 0; int left, right, root; for (root=1; root<=numKeys; root++) { left = countTrees(root-1); right = countTrees(numKeys - root); // number of possible trees with this root == left*right sum += left*right; } return(sum); } } I have a sense that it might be n(n-1)(n-2)...1, i.e. n!

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  • Calling a .net webservice from a plain HTML site using jQuery

    - by pwee167
    Hi guys, I wanted to know it is possible to call a hosted .net web service from a HTML page using jQuery? I tried this piece of code, but it doesn't work for me: $('#myForm').click(function() { $.ajax({ type: "POST", data: '{}', url: "http://localhost:49590/Service.asmx?op=HelloWorld", contentType: "application/json; charset=utf-8", dataType: "json", success: function(response) { alert(response.d); }, failure: function(result) { alert(result.status + ' ' + result.statusText); } }); }); And the webservice is as such: [WebService(Namespace = "http://tempuri.org/")] [WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)] [System.ComponentModel.ToolboxItem(false)] // To allow this Web Service to be called from script, using ASP.NET AJAX, uncomment the following line. [System.Web.Script.Services.ScriptService] public class Service : System.Web.Services.WebService { [WebMethod] public string HelloWorld() { return "Hello World"; } } I have searched for this and found only examples where it is done from asp.net or asp.net mvc projects. I am not sure what I am missing but I thought this was possible from a plain HTML site with javascript, so can someone please point me in the right direction. Cheers!

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  • Create chart using dynamic interactive ranges to select the series in Excel 2007

    - by jhc
    I would like to create a non-VBA based solution to the following question: How do I create a multi-series chart that will allow a user to select from a dropdown to change the data being graphed? I can do this already when the data series is contiguous; however, I'd like to be able to do it for non-contiguous data. Is this possible? My data look something like this: ID Salary Sal Min Sal Mid Sal Max Division Job Grade Job Subgrade Job XXX 10000 5000 15000 25000 North 13 1 Programmer XXX 12000 5000 15000 25000 North 13 1 Programmer XXX 14000 5000 15000 25000 South 13 1 Analyst XXX 11000 5000 15000 25000 South 13 1 Analyst XXX 20000 5000 15000 25000 North 14 1 Super Programmer XXX 25000 5000 15000 25000 North 14 1 Super Programmer XXX 22000 5000 15000 25000 North 14 1 Manager XXX 17000 5000 15000 25000 South 14 1 Manager XXX 19000 5000 15000 25000 South 14 1 Manager I would like to display Salary, Sal Min, Sal Mid, and Sal Max using a line graph. I would like the user to be able to select Job Grade, Division, and/or Job to determine what is charted. Is this possible? Would I somehow be able to do this if I used a pivottable or converted my data into a datatable? Thanks.

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  • recursively implementing 'minimum number of coins' in python

    - by user5198
    This problem is same as asked in here. Given a list of coins, their values (c1, c2, c3, ... cj, ...), and the total sum i. Find the minimum number of coins the sum of which is i (we can use as many coins of one type as we want), or report that it's not possible to select coins in such a way that they sum up to S. I"m just introduced to dynamic programming yesterday and I tried to make a code for it. # Optimal substructure: C[i] = 1 + min_j(C[i-cj]) cdict = {} def C(i, coins): if i <= 0: return 0 if i in cdict: return cdict[i] else: answer = 1 + min([C(i - cj, coins) for cj in coins]) cdict[i] = answer return answer Here, C[i] is the optimal solution for amount of money 'i'. And available coins are {c1, c2, ... , cj, ...} for the program, I've increased the recursion limit to avoid maximum recursion depth exceeded error. But, this program gives the right answer only someones and when a solution is not possible, it doesn't indicate that. What is wrong with my code and how to correct it?

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  • Replacing .NET WebBrowser control with a better browser, like Chrome?

    - by Sylverdrag
    Is there any relatively easy way to insert a modern browser into a .NET application? As far as I understand, the WebBrowser control is a wrapper for IE, which wouldn't be a problem except that it looks like it is a very old version of IE, with all that entails in terms of CSS screw-ups, potential security risks (if the rendering engine wasn't patched, can I really expect the zillion buffer overflow problems to be fixed?), and other issues. I am using Visual Studio C# (express edition - does it make any difference here?) I would like to integrate a good web browser in my applications. In some, I just use it to handle the user registration process, interface with some of my website's features and other things of that order, but I have another application in mind that will require more err... control. I need: A browser that can integrate inside a window of my application (not a separate window) A good support for CSS, js and other web technologies, on par with any modern browser Basic browser functions like "navigate", "back", "reload"... Liberal access to the page code and output. I was thinking about Chrome, since it comes under the BSD license, but I would be just as happy with a recent version of IE. As much as possible, I would like to keep things simple. The best would be if one could patch the existing WebBrowser control, which does already about 70% of what I need, but I don't think that's possible. I have found an activeX control for Mozilla (http://www.iol.ie/~locka/mozilla/control.htm) but it looks like it's an old version, so it's not necessarily an improvement. I am open to suggestions

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  • ISP Config 3 - squirrel login error & how to add an smtp server for sending mails

    - by A Prasetyo
    Hi, Case #1: I have ISPConfig3 running, sending email through telnet server.mydomain.com 25 are possible. Receiving email also possible. BUT!! problem occurs when I try to login to squirrel... I've been awaken for 2 days now and still couldn't figured out why logging in into squirrel always having an error: ERROR: Connection dropped by IMAP server. here is the /var/log/mail.log: Jun 3 00:23:27 server-01 imapd: Connection, ip=[::ffff:127.0.0.1] Jun 3 00:23:27 server-01 imapd: chdir /var/vmail/mydomain.com/info: Permission denied Jun 3 00:23:27 server-01 imapd: [email protected]: Permission denied I did chmod 777 & still doesn't work, only another message appeared Jun 3 00:24:28 server-01 imapd: Connection, ip=[::ffff:127.0.0.1] Jun 3 00:24:28 server-01 imapd: [email protected]: Account's mailbox directory is not owned by the correct uid or gid Try to do telnet to IMAP port telnet mydomain.com 143 Trying 63.105.102.48... Connected to mydomain.com. Escape character is '^]'. OK [CAPABILITY IMAP4rev1 UIDPLUS CHILDREN NAMESPACE THREAD=ORDEREDSUBJECT THREAD=REFERENCES SORT QUOTA IDLE ACL ACL2=UNION STARTTLS] Courier-IMAP ready. Copyright 1998-2008 Double Precision, Inc. See COPYING for distribution information. login [email protected] mypassword login NO Error in IMAP command received by server. and give no result... -_- I checked mysql.sock, I checked username and password in mysql db, everything is correct.. anyone can help? PLEASE?! Case #2: Does anyone know how to set or to view SMTP settings in ISPConfig 3? thank you..

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  • Use external datasource with NUnit's TestCaseAttribute

    - by Hamman359
    Is it possible to get the values for a TestCaseAttribute from an external data source such as an Excel Spreadsheet, CSV file or Database? i.e. Have a .csv file with 1 row of data per test case and pass that data to NUnit one at a time. Here's the specific situation that I'd like to use this for. I'm currently merging some features from one system into another. This is pretty much just a copy and paste process from the old system into the new one. Unfortunately, the code being moved not only does not have any tests, but is not written in a testable manner (i.e. tightly coupled with the database and other code.) Taking the time to make the code testable isn't really possible since its a big mess, i'm on a tight schedule and the entire feature is scheduled to be re-written from the ground up in the next 6-9 months. However, since I don't like the idea of not having any tests around the code, I'm going to create some simple Selenium tests using WebDriver to test the page through the UI. While this is not ideal, it's better than nothing. The page in question has about 10 input values and about 20 values that I need to assert against after the calculations are completed, with about 30 valid combinations of values that I'd like to test. I already have the data in a spreadsheet so it'd be nice to simply be able to pull that out rather than having to re-type it all in Visual Studio.

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  • Can I compare a template variable to an integer in App Engine templates?

    - by matt b
    Using Django templates in Google App Engine (on Python), is it possible to compare a template variable to an integer in an {% if %} block? views.py: class MyHandler(webapp.RequestHandler): def get(self): foo_list = db.GqlQuery(...) ... template_values['foos'] = foo_list template_values['foo_count'] = len(foo_list) handler.response.out.write(template.render(...)) My template: {% if foo_count == 1 %} There is one foo. {% endif %} This blows up with 'if' statement improperly formatted. What I was attempting to do in my template was build a simple if/elif/else tree to be grammatically correct to be able to state #foo_count == 0: There are no foos. #foo_count == 1: There is one foo. #else: There are {{ foos|length }} foos. Browsing the Django template documents (this link provided in the GAE documentation appears to be for versions of Django far newer than what is supported on GAE), it appears as if I can only actually use boolean operators (if in fact boolean operators are supported in this older version of Django) with strings or other template variables. Is it not possible to compare variables to integers or non-strings with Django templates? I'm sure there is an easy way to workaround this - built up the message string on the Python side rather than within the template - but this seems like such a simple operation you ought to be able to handle in a template. It sounds like I should be switching to a more advanced templating engine, but as I am new to Django (templates or any part of it), I'd just like some confirmation first.

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  • Object oriented design of game in Java: How to handle a party of NPCs?

    - by Arvanem
    Hi folks, I'm making a very simple 2D RPG in Java. My goal is to do this in as simple code as possible. Stripped down to basics, my class structure at the moment is like this: Physical objects have an x and y dimension. Roaming objects are physical objects that can move(). Humanoid objects are roaming objects that have inventories of GameItems. The Player is a singleton humanoid object that can hire up to 4 NPC Humanoids to join his or her party, and do other actions, such as fight non-humanoid objects. NPC Humanoids can be hired by the Player object to join his or her party, and once hired can fight for the Player. So far I have given the Player class a "party" ArrayList of NPC Humanoids, and the NPC Humanoids class a "hired" Boolean. However, my fight method is clunky, using an if to check the party size before implementing combat, e.g. public class Player extends Humanoids { private ArrayList<Humanoids> party; // GETTERS AND SETTERS for party here //... public void fightEnemy(Enemy eneObj) { if (this.getParty().size() == 0) // Do combat without party issues else if (this.getParty().size() == 1) // Do combat with party of 1 else if (this.getParty().size() == 2) // Do combat with party of 2 // etc. My question is, thinking in object oriented design, am I on the right track to do this in as simple code as possible? Is there a better way?

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  • What libraries will parse a DTD using PHP

    - by Chadwick
    I need to parse DTDs using PHP and am hoping there's a simple library to help out. Each DTD has numerous <!ENTITY... and <!-- Comment... elements, which I need to act upon. Note that I do not need to validate anything against these DTDs, simply parse them as data files themselves. A few options I've looked at: James Clarke's SD, which is an option of last resort, but I'd like to avoid the complexity of building/installing/configuring code external to PHP. I'm not sure it's even possible in my situation. PEAR has an XML_DTD_Parser, which requires installing/configuring PEAR and a number of pear modules, which I'm also not sure is possible, and would rather avoid. Has anyone used it with success? PHP XML Classes has the class_path_parser, which another site suggested, but it fails to read ENTITY elements. It appears to be using PHP's built in XML parsing capabilities, which use EXPAT. PHP's DOMDocument will validate against a DTD, so must be able to read them, though I don't see how to get at the DTD parser directly at first glance.

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  • Applets failing to load

    - by Roy Tang
    While testing our setup for user acceptance testing, we got some reports that java applets in our web application would occasionally fail to load. The envt where it was reported was WinXP/IE6, and there were no errors found in the java console. Obviously we'd like to avoid it. What sort of things should we be checking for here? On our local servers, everything seems fine. There's some turnaround time when sending questions to the on-site guy, so I'd look to cover as many possible causes as possible. Some more info: We have multiple applets, in the instance that they fail loading, all of them fail loading. The applet jar files vary in size from 2MB to 8MB. I'm told it seems more likely to happen if the applet isn't cached yet, i.e. if they've been able to load the applets once on a given machine, further runs on that machine go smoothly. I'm wondering if there's some sort of network transfer error when downloading the applets, but I don't know how to verify that. Any advise is welcome!

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  • What options to parse a DTD using PHP

    - by Chadwick
    I need to parse DTDs using PHP and am hoping there's a simple library to help out. Each DTD has numerous <!ENTITY... and <!-- Comment... elements, which I need to act upon. Note that I do not need to validate anything against these DTDs, simply parse them as data files themselves. A few options I've looked at: James Clarke's SD, which is an option of last resort, but I'd like to avoid the complexity of building/installing/configuring code external to PHP. I'm not sure it's even possible in my situation. PEAR has an XML_DTD_Parser, which requires installing/configuring PEAR and a number of pear modules, which I'm also not sure is possible, and would rather avoid. Has anyone used it with success? PHP XML Classes has the class_path_parser, which another site suggested, but it fails to read ENTITY elements. It appears to be using PHP's built in XML parsing capabilities, which use EXPAT. PHP's DOMDocument will validate against a DTD, so must be able to read them, though I don't see how to get at the DTD parser directly at first glance.

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  • Keyboard input: how to separate keycodes received from user

    - by Iulian Serbanoiu
    Hello, I am writing an application involving user input from the keyboard. For doing it I use this way of reading the input: #include <stdio.h> #include <termios.h> #include <unistd.h> int mygetch( ) { struct termios oldt, newt; int ch; tcgetattr( STDIN_FILENO, &oldt ); newt = oldt; newt.c_lflag &= ~( ICANON | ECHO ); tcsetattr( STDIN_FILENO, TCSANOW, &newt ); ch = getchar(); tcsetattr( STDIN_FILENO, TCSANOW, &oldt ); return ch; } int main(void) { int c; do{ c = mygetch(); printf("%d\n",c); }while(c!='q'); return 0; } Everyting works fine for letters digits,tabs but when hiting DEL, LEFT, CTRL+LEFT, F8 (and others) I receive not one but 3,4,5 or even 6 characters. The question is: Is is possible to make a separation of these characters (to actually know that I only hit one key or key combination). What I would like is to have a function to return a single integer value for any type of input (letter, digit, F1-F12, DEl, PGUP, PGDOWN, CTRL+A, CTRL+ALT+A, ALT+LEFT, etc). Is this possible? I'm interested in an idea to to this, the language doesn't matter much, though I'd prefer perl or c. Thanks, Iulian

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  • Writing fortran robust and "modern" code

    - by Blklight
    In some scientific environments, you often cannot go without FORTRAN as most of the developers only know that idiom, and there is lot of legacy code and related experience. And frankly, there are not many other cross-platform options for high performance programming ( C++ would do the task, but the syntax, zero-starting arrays, and pointers are too much for most engineers ;-) ). I'm a C++ guy but I'm stuck with some F90 projects. So, let's assume a new project must use FORTRAN (F90), but I want to build the most modern software architecture out of it. while being compatible with most "recent" compilers (intel ifort, but also including sun/HP/IBM own compilers) So I'm thinking of imposing: global variable forbidden, no gotos, no jump labels, "implicit none", etc. "object-oriented programming" (modules with datatypes + related subroutines) modular/reusable functions, well documented, reusable libraries assertions/preconditions/invariants (implemented using preprocessor statements) unit tests for all (most) subroutines and "objects" an intense "debug mode" (#ifdef DEBUG) with more checks and all possible Intel compiler checks possible (array bounds, subroutine interfaces, etc.) uniform and enforced legible coding style, using code processing tools C stubs/wrappers for libpthread, libDL (and eventually GPU kernels, etc.) C/C++ implementation of utility functions (strings, file operations, sockets, memory alloc/dealloc reference counting for debug mode, etc.) ( This may all seem "evident" modern programming assumptions, but in a legacy fortran world, most of these are big changes in the typical programmer workflow ) The goal with all that is to have trustworthy, maintainable and modular code. Whereas, in typical fortran, modularity is often not a primary goal, and code is trustworthy only if the original developer was very clever, and the code was not changed since then ! (i'm a bit joking here, but not much) I searched around for references about object-oriented fortran, programming-by-contract (assertions/preconditions/etc.), and found only ugly and outdated documents, syntaxes and papers done by people with no large-scale project involvement, and dead projects. Any good URL, advice, reference paper/books on the subject?

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  • Can Haskell's Parsec library be used to implement a recursive descent parser with backup?

    - by Thor Thurn
    I've been considering using Haskell's Parsec parsing library to parse a subset of Java as a recursive descent parser as an alternative to more traditional parser-generator solutions like Happy. Parsec seems very easy to use, and parse speed is definitely not a factor for me. I'm wondering, though, if it's possible to implement "backup" with Parsec, a technique which finds the correct production to use by trying each one in turn. For a simple example, consider the very start of the JLS Java grammar: Literal: IntegerLiteral FloatingPointLiteral I'd like a way to not have to figure out how I should order these two rules to get the parse to succeed. As it stands, a naive implementation like this: literal = do { x <- try (do { v <- integer; return (IntLiteral v)}) <|> (do { v <- float; return (FPLiteral v)}); return(Literal x) } Will not work... inputs like "15.2" will cause the integer parser to succeed first, and then the whole thing will choke on the "." symbol. In this case, of course, it's obvious that you can solve the problem by re-ordering the two productions. In the general case, though, finding things like this is going to be a nightmare, and it's very likely that I'll miss some cases. Ideally, I'd like a way to have Parsec figure out stuff like this for me. Is this possible, or am I simply trying to do too much with the library? The Parsec documentation claims that it can "parse context-sensitive, infinite look-ahead grammars", so it seems like something like I should be able to do something here.

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  • Enumerating a string

    - by JamesB
    I have a status which is stored as a string of a set length, either in a file or a database. I'm looking to enumerate the possible status' I have the following type to define the possible status' Type TStatus = (fsNormal = Ord('N'),fsEditedOnScreen = Ord('O'), fsMissing = Ord('M'),fsEstimated = Ord('E'),fsSuspect = Ord('s'), fsSuspectFromOnScreen = Ord('o'),fsSuspectMissing = Ord('m'), fsSuspectEstimated = Ord('e')); Firstly is this really a good idea? or should I have a seperate const array storing the char conversions? That would mean more than one place to update. Now convert a string to a status array I have the following, but how can I check if a char is valid without looping through the enumeration? Function StrToStatus(Value : String):TStatusArray; var i: Integer; begin if Trim(Value) = '' then begin SetLength(Result,0); Exit; end; SetLength(Result,Length(Value)); for i := 1 to Length(Value) do begin Result[i] := TStatus(Value[i]); // I don't think this line is safe. end; end; AFAIK this should be fine for converting back again. Function StatusToStr(Value : TStatusArray):String; var i: Integer; begin for i := 0 to Length(Value) - 1 do Result := Result + Chr(Ord(Value[i])) end; I'm using Delphi 2007

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  • A error about "Address 0x0 is not stack'd, malloc'd or (recently) free'd" in c program under linux

    - by MaiTiano
    There is a piece of my program: height = atoi(argv[3]); width = atoi(argv[2]); sprintf(seqName,"%s", argv[1]); // strcpy(seqName, argv[1]); After compiling it, a exe file test is generated, then I use Valgrind to check it. Then I got the following message, however I cannot understand what it tends to tell me. Can anyone provide some kind help, Thanks. 1 contexts (suppressed: 13 from 8) 1 contexts (suppressed: 13 from 8) jl@ubuntu:~/work/dsr_analysis$ valgrind --tool=memcheck --leak-check=yes ./test ==28940== Memcheck, a memory error detector ==28940== Copyright (C) 2002-2009, and GNU GPL'd, by Julian Seward et al. ==28940== Using Valgrind-3.6.0.SVN-Debian and LibVEX; rerun with -h for copyright info ==28940== Command: ./test ==28940== ==28940== Invalid read of size 1 ==28940== at 0x40260CA: strcpy (mc_replace_strmem.c:311) ==28940== by 0x804A5C6: main (me_search.c:1428) ==28940== Address 0x0 is not stack'd, malloc'd or (recently) free'd ==28940== ==28940== ==28940== Process terminating with default action of signal 11 (SIGSEGV) ==28940== Access not within mapped region at address 0x0 ==28940== at 0x40260CA: strcpy (mc_replace_strmem.c:311) ==28940== by 0x804A5C6: main (me_search.c:1428) ==28940== If you believe this happened as a result of a stack ==28940== overflow in your program's main thread (unlikely but ==28940== possible), you can try to increase the size of the ==28940== main thread stack using the --main-stacksize= flag. ==28940== The main thread stack size used in this run was 8388608. ==28940== ==28940== HEAP SUMMARY: ==28940== in use at exit: 0 bytes in 0 blocks ==28940== total heap usage: 0 allocs, 0 frees, 0 bytes allocated ==28940== ==28940== All heap blocks were freed -- no leaks are possible ==28940== ==28940== For counts of detected and suppressed errors, rerun with: -v ==28940== ERROR SUMMARY: 1 errors from 1 contexts (suppressed: 13 from 8)1 contexts (suppressed: 13 from 8) 1 contexts (suppressed: 13 from 8)

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  • inverse relation to multiple inheriting classes in django

    - by Ofri Raviv
    Here are my schematic models: class Law(models.Model): ... class Bill(models.Model): ... # data for a proposed law, or change of an existing law class PrivateBill(Bill): ... # data for a Bill that was initiated by a parliament member class GovernmentBill(Bill): ... # data for a Bill that was initiated by the government It is possible and likely that in the future I (or maybe someone else) would want to add more Bill types. Every Bill should point to a Law (indicating what law this bill is going to change) and my question is: What is the best way to implement this? If I add the ForeignKey(Law) to Bill, I'll have a relation from every Bill to Law, but a Law would only have an inverse relation to Bills (bill_set), and not a different inverse relation to each type of bill. Of course I'll be able to filter each type of bill to get only the ones pointing to a specific Law, but this is something I think I'll need to use often, so I think having privatebill_set, governmentbill_set etc would make the code more readable. Another possible solution is to add the foreign key to each of the inheriting classes (this would give me a privatebill_set, governmentbill_set, futurebill_set), but that seems hairy because I would be relying on future programmers to remember to add that relation. How would you solve this?

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  • Complex derived attributes in Django models

    - by rabidpebble
    What I want to do is implement submission scoring for a site with users voting on the content, much like in e.g. reddit (see the 'hot' function in http://code.reddit.com/browser/sql/functions.sql). My submission model currently keeps track of up and down vote totals. Currently, when a user votes I create and save a related Vote object and then use F() expressions to update the Submission object's voting totals. The problem is that I want to update the score for the submission at the same time, but F() expressions are limited to only simple operations (it's missing support for log(), date_part(), sign() etc.) From my limited experience with Django I can see 4 options here: extend F() somehow (haven't looked at the code yet) to support the missing SQL functions; this is my preferred option and seems to fit within the Django framework the best define a scoring function (much like reddit's 'hot' function) in my database, and have Django use the value of that function for the value of the score field; as far as I can tell, #2 is not possible wrap my two step voting process in a suitably isolated transaction so that I can calculate the voting totals in Python and then update the Submission's voting totals without fear that another vote against the submission could be added/changed in the meantime; I'm hesitant to take this route because it seems overly complex - what is a "suitably isolated transaction" in this case anyway? use raw SQL; I would prefer to avoid this entirely -- what's the point of an ORM if I have to revert to SQL for such a common use case as this! (Note that this coming from somebody who loves sprocs, but is using Django for ease of development.) Before I embark on this mission to extend F() (which I'm not sure is even possible), am I about to reinvent the wheel? Is there a more standard way to do this? It seems like such a common use case and yet in an hour of searching I have yet to find a common solution...

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  • documenting class attributes

    - by intuited
    I'm writing a lightweight class whose attributes are intended to be publicly accessible, and only sometimes overridden in specific instantiations. There's no provision in the Python language for creating docstrings for class attributes, or any sort of attributes, for that matter. What is the accepted way, should there be one, to document these attributes? Currently I'm doing this sort of thing: class Albatross(object): """A bird with a flight speed exceeding that of an unladen swallow. Attributes: """ flight_speed = 691 __doc__ += """ flight_speed (691) The maximum speed that such a bird can attain. """ nesting_grounds = "Raymond Luxury-Yacht" __doc__ += """ nesting_grounds ("Raymond Luxury-Yacht") The locale where these birds congregate to reproduce. """ def __init__(**keyargs): """Initialize the Albatross from the keyword arguments.""" self.__dict__.update(keyargs) Although this style doesn't seem to be expressly forbidden in the docstring style guidelines, it's also not mentioned as an option. The advantage here is that it provides a way to document attributes alongside their definitions, while still creating a presentable class docstring, and avoiding having to write comments that reiterate the information from the docstring. I'm still kind of annoyed that I have to actually write the attributes twice; I'm considering using the string representations of the values in the docstring to at least avoid duplication of the default values. Is this a heinous breach of the ad hoc community conventions? Is it okay? Is there a better way? For example, it's possible to create a dictionary containing values and docstrings for the attributes and then add the contents to the class __dict__ and docstring towards the end of the class declaration; this would alleviate the need to type the attribute names and values twice. edit: this last idea is, I think, not actually possible, at least not without dynamically building the class from data, which seems like a really bad idea unless there's some other reason to do that. I'm pretty new to python and still working out the details of coding style, so unrelated critiques are also welcome.

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  • How to move list items from two lists (from different areas) to one specific list by clicking the li

    - by pschorr
    I've been having some issues setting up a list of items and moving them between each other. Is it possible to have multiple lists, with a link inside each item to move it to a specified list? i.e. List of actions with a plus next to the action, click the plus and move to a specified box? Furthermore, would it be possible to then load a lightbox (code would have to be inline I'd guess) from that page and move those names to the specific list as well? Example Images Thanks much! More broad view of my efforts so far... The initial issue being that I could not use listboxes due to their being rendered natively inside each individual browser. Through listboxes I was able to set this up, but with a trigger via the code below (found on stackoverflow). While it gave me partial functionality it did not get the target I was looking for. document.getElementById('moveTrigger').onclick = function() { var listTwo = document.getElementById('secondList'); var options = document.getElementById('firstList').getElementsByTagName('option'); while(options.length != 0) { listTwo.appendChild(options[0]); } } I then moved onto jqueryui's sortable and it's ability to connect multiple, and most important, style-able lists and to be dragged between each other. This works for the side by side tables, but it does not offer the usability I was looking for overall. So, I've come to where I'm unsure as to where to move forward. While I can get around PHP, I wouldn't know where to start with this one personally. I'm open to any and all options! Thanks much!

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  • Use Objective-C without NSObject?

    - by Alex I
    I am testing some simple Objective-C code on Windows (cygwin, gcc). This code already works in Xcode on Mac. I would like to convert my objects to not subclass NSObject (or anything else, lol). Is this possible, and how? What I have so far: // MyObject.h @interface MyObject - (void)myMethod:(int) param; @end and // MyObject.m #include "MyObject.h" @interface MyObject() { // this line is a syntax error, why? int _field; } @end @implementation MyObject - (id)init { // what goes in here? return self; } - (void)myMethod:(int) param { _field = param; } @end What happens when I try compiling it: gcc -o test MyObject.m -lobjc MyObject.m:4:1: error: expected identifier or ‘(’ before ‘{’ token MyObject.m: In function ‘-[MyObject myMethod:]’: MyObject.m:17:3: error: ‘_field’ undeclared (first use in this function) EDIT My compiler is cygwin's gcc, also has cygwin gcc-objc package: gcc --version gcc (GCC) 4.7.3 I have tried looking for this online and in a couple of Objective-C tutorials, but every example of a class I have found inherits from NSObject. Is it really impossible to write Objective-C without Cocoa or some kind of Cocoa replacement that provides NSObject? (Yes, I know about GNUstep. I would really rather avoid that if possible...)

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  • DatagGridViewColumn.DataPropertyName to an array element?

    - by unknown
    Hi there, I'm using a DataGridView binding its datasource to a List, and specifying the properties for each column. An example would be: DataGridViewTextBoxColumn colConcept = new DataGridViewTextBoxColumn(); DataGridViewCell cell4 = new DataGridViewTextBoxCell(); colConcept.CellTemplate = cell4; colConcept.Name = "concept"; colConcept.HeaderText = "Concept"; colConcept.DataPropertyName = "Concept"; colConcept.Width = 200; this.dataGridViewBills.Columns.Add(colConcept); {... assign other colums...} And finally this.dataGridViewBills.DataSource=billslist; //billslist is List<Bill> Obviously Class Bill has a Property called Concept, as well as one Property for each column. Well, now my problem, is that Bill should have and Array/List/whateverdynamicsizecontainer of strings called Years. Let's assume that every Bill will have the same Years.Count, but this only known at runtime.Thus, I can't specify properties like Bill.FirstYear to obtain Bill.Years[0], Bill.SecondYear to obtain Bills.Years[1]... etc... and bind it to each column. The idea, is that now I want to have a grid with dynamic number of colums (known at runtime), and each column filled with a string from the Bill.Years List. I can make a loop to add columns to the grid at runtime depending of Bill.Years.Count, but is possible to bind them to each of the strings that the Bill.Years List contains??? I'm not sure if I'm clear enough. The result ideally would be something like this, for 2 bills on the list, and 3 years for each bill: --------------------------------------GRID HEADER------------------------------- NAME CONCEPT YEAR1 YEAR2 YEAR3 --------------------------------------GRID VALUES------------------------------- Bill1 Bill1.Concept Bill1.Years[0] Bill1.Years[1] Bill1.Years[2] Bill2 Bill2.Concept Bill2.Years[0] Bill2.Years[1] Bill2.Years[2] I can always forget the datasource, and write each cell manually, as the MSFlexGrid used to like, but if possible, I would like to use the binding capabilities of the DataGridView. Any ideas? Thanks a lot.

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