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• How should I name a native DLL distributed in both 32-bit and 64-bit form?

  - by Spike0xff

  I have a commercial product that's a DLL (native 32-bit code), and now it's time to build a 64-bit version of it. So when installing on 64-bit Windows, the 32-bit version goes into Windows\SysWOW64, and the 64-bit version goes into... Windows\System32! (I'm biting my tongue here...) Or the DLL(s) can be installed alongside the client application. What should I name the 64-bit DLL? Same name as 32-bit: Two files that do the same thing, have the same name, but are totally non-interchangeable. Isn't that a recipe for confusion and support problems? Different names (e.g. product.dll and product64.dll): Now client applications have to know whether they are running 32-bit or 64-bit in order to reference my DLL, and there are languages where that isn't known until run-time - .NET being just one example. And now all the statically compiled clients have to conditionalize the import declarations: IF target=WIN64 THEN import Blah from "product64.dll" ELSE import Blah from "product.dll" ENDIF The product contains massive amounts of C code, and a large chunk of C++ - porting it to C# is not an option. Advice? Suggestions?

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• Examples using Active Directory/LDAP groups for permissions \ roles in Rails App.

  - by Nick Gorbikoff

  Hello. I was wondering how other people implemented this scenario. I have an internal rails app ( inventory management, label printing, shipping,etc). I'm rewriting security on the system, cause the old way got to cumbersome to maintain ( users table, passwords, roles) - I used restful_authentication and roles. It was implemented about 3 years ago. I already implemented AuthLogic with ruby-ldap-net to authenticate users ( actually that was surprisingly easy, compared to how I struggled with other frameworks/languages before). Next step is roles. I already have groups defined in Active Directory - so I don't want to run a separate roles system in my rails app, I just want to reuse Active Directory groups - since that part of the system is already maintained for other purposes ( shared drives, backups, pc access, etc) So I was wondering if others had experience implementing permissions/roles in a rails app based on groups in Active Directory or LDAP. Also the roles requirements are pretty complex. Here is an example: For instance I have users that belong to the supervisors group in AD and to inventory dept, so I was that user to be able to run "advanced" tasks in invetory - adjust qty, run reports, however other "supervisors" from other departmanets, shouldn't be able to do this, also Top Management - should be able to use those reports (regardless weather they belong to the invetory or not), but not Middle Management, unless they are in inventory group. Admins of the system (Domain Admins) should have unrestricted access to the system , except for HR & Finances part unless they are in HR ( like you don't want all system admins (except for one authorized one) to see personal info of other employees). I looked at acl9, cancan, aegis. I was wondering if there are any advantaged/cons to using one versus the other for this particular use of system access based on AD. Suggest other systems if you had good experience. Thank you!!!

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• How do I run NUnit in debug mode from Visual Studio?

  - by Jon Cage

  I've recently been building a test framework for a bit of C# I've been working on. I have NUnit set up and a new project within my workspace to test the component. All works well if I load up my unit tests from Nunit (v2.4), but I've got to the point where it would be really useful to run in debug mode and set some break points. I've tried the suggestions from several guides which all suggest changing the 'Debug' properties of the test project: Start external program: C:\Program Files\NUnit 2.4.8\bin\nunit-console.exe Command line arguments: /assembly: <full-path-to-solution>\TestDSP\bin\Debug\TestDSP.dll I'm using the console version there, but have tried the calling the GUI as well. Both give me the same error when I try and start debugging: Cannot start test project 'TestDSP' because the project does not contain any tests. Is this because I normally load \DSP.nunit into the Nunit GUI and that's where the tests are held? I'm beginning to think the problem may be that VS wants to run it's own test framework and that's why it's failing to find the NUnit tests? [Edit] To those asking about test fixtures, one of my .cs files in the TestDSP project looks roughly like this: namespace Some.TestNamespace { // Testing framework includes using NUnit.Framework; [TestFixture] public class FirFilterTest { /// <summary> /// Tests that a FirFilter can be created /// </summary> [Test] public void Test01_ConstructorTest() { ...some tests... } } } ...I'm pretty new to C# and the Nunit test framework so it's entirely possible I've missed some crucial bit of information ;-) [FINAL SOLUTION] The big problem was the project I'd used. If you pick: Other Languages->Visual C#->Test->Test Project ...when you're choosing the project type, Visual Studio will try and use it's own testing framework as far as I can tell. You should pick a normal c# class library project instead and then the instructions in my selected answer will work.

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• C++ interpreter conceptual problem

  - by Jan Wilkins

  I've built an interpreter in C++ for a language created by me. One main problem in the design was that I had two different types in the language: number and string. So I have to pass around a struct like: class myInterpreterValue { myInterpreterType type; int intValue; string strValue; } Objects of this class are passed around million times a second during e.g.: a countdown loop in my language. Profiling pointed out: 85% of the performance is eaten by the allocation function of the string template. This is pretty clear to me: My interpreter has bad design and doesn't use pointers enough. Yet, I don't have an option: I can't use pointers in most cases as I just have to make copies. How to do something against this? Is a class like this a better idea? vector<string> strTable; vector<int> intTable; class myInterpreterValue { myInterpreterType type; int locationInTable; } So the class only knows what type it represents and the position in the table This however again has disadvantages: I'd have to add temporary values to the string/int vector table and then remove them again, this would eat a lot of performance again. Help, how do interpreters of languages like Python or Ruby do that? They somehow need a struct that represents a value in the language like something that can either be int or string.

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• translate a PHP $string using google translator API

  - by Toni Michel Caubet

  hey there! been google'ing for a while how is the best way to translate with google translator in PHP, found very different ways converting URLS, or using Js but i want to do it only with php (or with a very simple solution JS/JQUery) example: //hopefully with $from_lan and $to_lan being like 'en','de', .. or similar function translate($from_lan, $to_lan, $text){ // do return $translated_text; } can you give me a clue? or maybe you already have this function.. my intention it's to use it only for the languages i have not already defined (or keys i haven't defined), that's why i wan it so simple, will be only temporal.. EDIT thanks for your replies we are now trying this soulutions: function auto_translate($from_lan, $to_lan, $text){ // do $json = json_decode(file_get_contents('https://ajax.googleapis.com/ajax/services/language/translate?v=1.0&q=' . urlencode($text) . '&langpair=' . $from_lan . '|' . $to_lan)); $translated_text = $json->responseData->translatedText; return $translated_text; } (there was a extra 'g' on variables for lang... anyway) it returns: works now :) i don't really understand much the function, so any idea why is not acepting the object? (now i do) OR: unction auto_translate($from_lan, $to_lan, $text){ // do // $json = json_decode(file_get_contents('https://ajax.googleapis.com/ajax/services/language/translate?v=1.0&q=' . urlencode($text) . '&langpair=' . $from_lan . '|' . $to_lan)); // $translated_text = $json['responseData']['translatedText']; error_reporting(1); require_once('GTranslate.php'); try{ $gt = new Gtranslate(); $translated_text = $gt-english_to_german($text); } catch (GTranslateException $ge) { $translated_text= $ge->getMessage(); } return $translated_text; } And this one looks great but it doesn't even gives me an error, the page won't load (error_report(1) :S) thanks in advance!

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• C++ Switch won't compile with externally defined variable used as case

  - by C Nielsen

  I'm writing C++ using the MinGW GNU compiler and the problem occurs when I try to use an externally defined integer variable as a case in a switch statement. I get the following compiler error: "case label does not reduce to an integer constant". Because I've defined the integer variable as extern I believe that it should compile, does anyone know what the problem may be? Below is an example: test.cpp #include <iostream> #include "x_def.h" int main() { std::cout << "Main Entered" << std::endl; switch(0) { case test_int: std::cout << "Case X" << std::endl; break; default: std::cout << "Case Default" << std::endl; break; } return 0; } x_def.h extern const int test_int; x_def.cpp const int test_int = 0; This code will compile correctly on Visual C++ 2008. Furthermore a Montanan friend of mine checked the ISO C++ standard and it appears that any const-integer expression should work. Is this possibly a compiler bug or have I missed something obvious? Here's my compiler version information: Reading specs from C:/MinGW/bin/../lib/gcc/mingw32/3.4.5/specs Configured with: ../gcc-3.4.5-20060117-3/configure --with-gcc --with-gnu-ld --with-gnu-as --host=mingw32 --target=mingw32 --prefix=/mingw --enable-threads --disable-nls --enable-languages=c,c++,f77,ada,objc,java --disable-win32-registry --disable-shared --enable-sjlj-exceptions --enable-libgcj --disable-java-awt --without-x --enable-java-gc=boehm --disable-libgcj-debug --enable-interpreter --enable-hash-synchronization --enable-libstdcxx-debug Thread model: win32 gcc version 3.4.5 (mingw-vista special r3)

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• Primary key/foreign Key naming convention

  - by Jeremy

  In our dev group we have a raging debate regarding the naming convention for Primary and Foreign Keys. There's basically two schools of thought in our group: 1) Primary Table (Employee) Primary Key is called ID Foreign table (Event) Foreign key is called EmployeeID 2) Primary Table (Employee) Primary Key is called EmployeeID Foreign table (Event) Foreign key is called EmployeeID I prefer not to duplicate the name of the table in any of the columns (So I prefer option 1 above). Conceptually, it is consisted with a lot of the recommended practices in other languages, where you don't use the name of the object in its property names. I think that naming the foreign key EmployeeID (or Employee_ID might be better) tells the reader that it is the ID column of the Employee Table. Some others prefer option 2 where you name the primary key prefixed with the table name so that the column name is the same throughout the database. I see that point, but you now can not visually distinguish a primary key from a foreign key. Also, I think it's redundant to have the table name in the column name, because if you think of the table as an entity and a column as a property or attribute of that entity, you think of it as the ID attribute of the Employee, not the EmployeeID attribute of an employee. I don't go an ask my coworker what his PersonAge or PersonGender is. I ask him what his Age is. So like I said, it's a raging debate and we go on and on and on about it. I'm interested to get some new perspective.

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• reading non-english html pages with c#

  - by Gal Miller

  I am trying to find a string in Hebrew in a website. The reading code is attached. Afterward I try to read the file using streamReader but I can't match strings in other languages. what am I suppose to do? // used on each read operation byte[] buf = new byte[8192]; // prepare the web page we will be asking for HttpWebRequest request = (HttpWebRequest) WebRequest.Create("http://www.webPage.co.il"); // execute the request HttpWebResponse response = (HttpWebResponse) request.GetResponse(); // we will read data via the response stream Stream resStream = response.GetResponseStream(); string tempString = null; int count = 0; FileStream fileDump = new FileStream(@"c:\dump.txt", FileMode.Create); do { count = resStream.Read(buf, 0, buf.Length); fileDump.Write(buf, 0, buf.Length); } while (count > 0); // any more data to read? fileDump.Close();

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• PHP Socket Server vs node.js: Web Chat

  - by Eliasdx

  I want to program a HTTP WebChat using long-held HTTP requests (Comet), ajax and websockets (depending on the browser used). Userdatabase is in mysql. Chat is written in PHP except maybe the chat stream itself which could also be written in javascript (node.js): I don't want to start a php process per user as there is no good way to send the chat messages between these php childs. So I thought about writing an own socket server in either PHP or node.js which should be able to handle more then 1000 connections (chat users). As a purely web developer (php) I'm not much familiar with sockets as I usually let web server care about connections. The chat messages won't be saved on disk nor in mysql but in RAM as an array or object for best speed. As far as I know there is no way to handle multiple connections at the same time in a single php process (socket server), however you can accept a great amount of socket connections and process them successive in a loop (read and write; incoming message - write to all socket connections). The problem is that there will most-likely be a lag with ~1000 users and mysql operations could slow the whole thing down which will then affect all users. My question is: Can node.js handle a socket server with better performance? Node.js is event-based but I'm not sure if it can process multiple events at the same time (wouldn't that need multi-threading?) or if there is just an event queue. With an event queue it would be just like php: process user after user. I could also spawn a php process per chat room (much less users) but afaik there are singlethreaded IRC servers which are also capable to handle thousands of users. (written in c++ or whatever) so maybe it's also possible in php. I would prefer PHP over Node.js because then the project would be php-only and not a mixture of programming languages. However if Node can process connections simultaneously I'd probably choose it.

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• Keyboard shortcut to Un/Comment out code in Mathematica 7?

  - by dbjohn

  A keyboard shortcut to comment/uncomment out a piece of code is common in other programming IDE's for languages like Java, .Net. I find it a very useful technique when experimenting through trial and error to temporarily comment out and uncomment lines, words and parts of the code to find out what is and isn't working. I cannot find any such keyboard shortcut on the Mathematica front end in version 7. I know that it is possible to comment out code by selecting the code, right mouse click and select Un/Comment from the menu that appears but this is too slow while coding. I tried to access this using the menu key Menu on the keyboard but Mathematica frontend doesn't respond to or recognise this key unlike other applications, this could have allowed a key combination for commenting. Can someone else verify that this isn't unique to my machine and that the key isn't recognised by mathematica. I looked at this question and looked in the KeyEventTranslations.tr file but I don't think there is any way to create a shortcut to do this(?). Should I just live with it? Any other suggestions? (I have seen there is an Emacs version of mathematica, I have never tried Emacs or this Mma version and imagine that it would have this ability but would prefer not to go to the trouble and uncertainty of installing it. Also I would guess that the Wolfram Workbench could do this, but that may not be worth the investment just for this.)

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• Are there any code critique sites or similar resources?

  - by Ukko

  I have noticed when people post example code illustrating some issue that they are having often they will gather a number of comments addressing the quality of the code they presented and not the actual problem asked. This is very helpful--if not well directed. Often, this is wasted effort since the asker is often not receptive and the code is often chopped down to something small to post leaving lots of rough edges. In the old days you would see people asking questions like this on comp.lang.lisp and other parts of the comp.lang hierarchy. But that bit of the net kind of sank into the sewers of neglect. Is there a comparable one-stop-shop today? I am partially asking for selfish reasons, I know how to write good idiomatic C, Lisp, O'Caml, and Java code. But I learned C++ pre-template and STL, those rusty skills are not really applicable to today's C++. I have picked up languages like Scala in a vacuum and get by, but am I really doing it correctly? There are so many ways you can abuse a language, I am currently working against a codebase of Fortran written in C, and I recognize and loathe the "that guy" who wrote it. I don't want to be someone else's "that guy" if I can help it. Just because it works does not mean that one did not totally miss the boat on how it should have been done. Do you seek out this type of critique? If so how, where and why? What types of benefits do you derive from it? How about abuse and trolls?

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• Design patterns for Agent / Actor based concurrent design.

  - by nso1

  Recently i have been getting into alternative languages that support an actor/agent/shared nothing architecture - ie. scala, clojure etc (clojure also supports shared state). So far most of the documentation that I have read focus around the intro level. What I am looking for is more advanced documentation along the gang of four but instead shared nothing based. Why ? It helps to grok the change in design thinking. Simple examples are easy, but in a real world java application (single threaded) you can have object graphs with 1000's of members with complex relationships. But with agent based concurrency development it introduces a whole new set of ideas to comprehend when designing large systems. ie. Agent granularity - how much state should one agent manage - implications on performance etc or are their good patterns for mapping shared state object graphs to agent based system. tips on mapping domain models to design. Discussions not on the technology but more on how to BEST use the technology in design (real world "complex" examples would be great).

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• Framework or design pattern for mailing all users of a webapp

  - by Todd Owen

  My app takes care of user registration (with the option to receive email announcements), and can easily handle the actual template-based rendering of email for a given user. JavaMail provides the mail transport layer. But how should I design the application layer between the business objects (e.g. User) and the mail transport? The straightforward approach would be a simple, synchronous loop: iterate through the users, queue the emails, and be done with it. "Queue" might mean sending them straight to the MTA (mail server), or to an in-memory queue to be consumed by another thread. However, I also plan to implement features like throttling the rate of emails, processing bounced emails (NDRs), and maintaining status across application restarts. My intuition is that a good design would decouple this from both the business layer and the mail transport layer as much as possible. I wondered if others had solved this problem before, but after much searching I haven't found any Java libraries which seem to fit this problem. Standalone mail apps such as James or list servers are too large in scope; packages like Spring's MailSender or Commons Email are too small in scope (being basically drop-in replacements for JavaMail). For other languages I haven't found anything appropriate either. I'm curious about how other developers have gone about adding bulk mailing to their applications.

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• Java-Eclipse-Spring 3.1 - the fastest way to get familiar with this set

  - by Leron

  I, know almost all of you at some point of your life as a programmer get to the point where you know (more or less) different technologies/languages/IDEs and a times come when you want to get things together and start using them once - more efficient and second - more closely to the real life situation where in fact just knowing Java, or some experience with Eclipse doesn't mean nothing, and what makes you a programmer worth something is the ability to work with the combination of 2 or more combinations. Having this in mind here is my question - what do you think is the optimal way of getting into Java+Eclipse+Spring3.1 world. I've read, and I've read a lot. I started writing real code but almost every step is discovering the wheel again and again, wondering how to do thing you know are some what trivial, but you've missed that one article where this topic was discussed and so on. I don't mind for paying for a good tutorial like for example, after a bit of research I decided that instead of losing a lot of time getting the different parts together I'd rather pay for the videos in http://knpuniversity.com/screencast/starting-in-symfony2-tutorial and save myself a lot of time (I hope) and get as fast as possible to writing a real code instead of wondering what do what and so on. But I find it much more difficult to find such sources of info especially when you want something more specific as me and that's the reason to ask this question. I know a lot of you go through the hard way, and I won't give up if I have to do the same, but to be honest I really hope to get post with good tutorials on the subject (paid or not) because in my situation time is literally money. Thanks Leron

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• How to find an embedded platform?

  - by gmagana

  I am new to the locating hardware side of embedded programming and so after being completely overwhelmed with all the choices out there (pc104, custom boards, a zillion option for each board, volume discounts, devel kits, ahhh!!) I am asking here for some direction. Basically, I must find a new motherboard and (most likely) re-implement the program logic. Rewriting this in C/C++/Java/C#/Pascal/BASIC is not a problem for me. so my real problem is finding the hardware. This motherboard will have several other devices attached to it. Here is a summary of what I need to do: Required: 2 RS232 serial ports (one used all the time for primary UI, the second one not continuous) 1 modem (9600+ baud ok) [Modem will be in simultaneous use with only one of the serial port devices, so interrupt sharing with one serial port is OK, but not both] Minimum permanent/long term storage: Whatever O/S requires + 1 MB (executable) + 512 KB (Data files) RAM: Minimal, whatever the O/S requires plus maybe 1MB for executable. Nice to have: USB port(s) Ethernet network port Wireless network Implementation languages (any O/S I will adapt to): First choice Java/C# (Mono ok) Second choice is C/Pascal Third is BASIC Ok, given all this, I am having a lot of trouble finding hardware that will support this that is low in cost. Every manufacturer site I visit has a lot of options, and it's difficult to see if their offering will even satisfy my must-have requirements (for example they sometimes list 3 "serial ports", but it appears that only one of the three is RS232, for example, and don't mention what the other two are). The #1 constraint is cost, #2 is size. Can anyone help me with this? This little task has left me thinking I should have gone for EE and not CS :-). EDIT: A bit of background: This is a system currently in production, but the original programmer passed away, and the current hardware manufacturer cannot find hardware to run the (currently) DOS system, so I need to reimplement this in a modern platform. I can only change the programming and the motherboard hardware.

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• Mapping one column in a table to multiple tables

  - by user1721814

  I am working on a new product development creating a WMS system. I have done it in past using ASP, VB, and other techniques where we did not hard code the mapping. But now i am working on it using MVC and entity frame work and i am stumped. How can i map one column in transaction table to a column in multiple tables. I have transaction table trans Transid orderref TType productid qty ....(More Columns) now the orderref will hold either Receiptkey, orderkey , movementkey, adjustmentkey and the TType column will tell me which type of transaction i am dealing with and based on that i would know which table to link further. Now how can i achieve this in Entity Frame work. This is the most important step. I have done this many times in my other languages but now using EF i am stuck. Please help. I have checked a lot online but i have not found it. I am new to MVC and entity frame work architecture. Any guidance would be highly appreciated. Ranjit

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• Create swipe controlled simple flipbook style animation in ObjC

  - by eco_bach

  Hi I am a beginner in Obj C development, though quite experienced (over 10 years) with other ECMAscript based languages and OOP development. I want to build a simple flipbook style animation, controlled through swiping motion. I'm sure extremely simple for any advanced ObjC coders. Can anyone with extensive ObjC-CocoaTouch experience give me some higher level recommendations? ie, 1 -general application design, should I start with a simple view based application, or navigation based or? 2 -should I use 3rd party animation frameworks such as Cocos2D, or stick with built in classes and methods? 3 -if using built in methods, classes, what is the recommended way of achieving a animation, that will be controlled via swipe and touch gestures? 4 -I want to eventually have multiple 'flipbooks' that I can 'instantly' swap with one another, ie to give the net effect of an object changing color, etc, but not sure how to approach this from a memory management point of view, related to #1 above Except for point 3 above, I'm not expecting any actual code examples. Just general guidelines to follow and perhaps, what are some next steps I should take in my goal as an ObjC code samurai.

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• Common Lisp condition system for transfer of control

  - by Ken

  I'll admit right up front that the following is a pretty terrible description of what I want to do. Apologies in advance. Please ask questions to help me explain. :-) I've written ETLs in other languages that consist of individual operations that look something like: // in class CountOperation IEnumerable<Row> Execute(IEnumerable<Row> rows) { var count = 0; foreach (var row in rows) { row["record number"] = count++; yield return row; } } Then you string a number of these operations together, and call The Dispatcher, which is responsible for calling Operations and pushing data between them. I'm trying to do something similar in Common Lisp, and I want to use the same basic structure, i.e., each operation is defined like a normal function that inputs a list and outputs a list, but lazily. I can define-condition a condition (have-value) to use for yield-like behavior, and I can run it in a single loop, and it works great. I'm defining the operations the same way, looping through the inputs: (defun count-records (rows) (loop for count from 0 for row in rows do (signal 'have-value :value `(:count ,count @,row)))) The trouble is if I want to string together several operations, and run them. My first attempt at writing a dispatcher for these looks something like: (let ((next-op ...)) ;; pick an op from the set of all ops (loop (handler-bind ((have-value (...))) ;; records output from operation (setq next-op ...) ;; pick a new next-op (call next-op))) But restarts have only dynamic extent: each operation will have the same restart names. The restart isn't a Lisp object I can store, to store the state of a function: it's something you call by name (symbol) inside the handler block, not a continuation you can store for later use. Is it possible to do something like I want here? Or am I better off just making each operation function explicitly look at its input queue, and explicitly place values on the output queue?

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• Hashtable is that fast

  - by Costa

  Hi s[0]*31^(n-1) + s[1]*31^(n-2) + ... + s[n-1]. Is the hash function of the java string, I assume the rest of languages is similar or close to this implementation. If we have hash-Table and a list of 50 elements. each element is 7 chars ABCDEF1, ABCDEF2, ABCDEF3..... ABCDEFn If each bucket of hashtable contains 5 strings (I think this function will make it one string per bucket, but let us assume it is 5). If we call col.Contains("ABCDEFn"); // will do 6 comparisons and discover the difference on the 7th. The hash-table will take around 70 operations (multiplication and additions) to get the hashcode and to compare with 5 strings in bucket. and BANG it found. For list it will take around 300 comparisons to find it. for the case that there is only 10 elements, the list will take around 70 operations but the Hashtable will take around 50 operations. and note that hashtable operations are more time consuming (it is multiplications). I conclude that HybirdDictionary in .Net probably is the best choice for that most cases that require Hashtable with unknown size, because it will let me use a list till the list becomes more than 10 elements. still need something like HashSet rather than a Dictionary of keys and values, I wonder why there is no HybirdSet!! So what do u think? Thanks

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• How do you make life easier for yourself when developing a really large database

  - by Hannes de Jager

  I am busy developing 2 web based systems with MySql databases and the amount of tables/views/stored routines is really becoming a lot and it is more and more challenging to handle the complexity. Now in programming languages we have namespacing e.g. Java packages, C++ namespaces to partition the software, grouping it together to make things more understandable. Databases on the other hand have more of a flat structure (MySql at least) e.g. tables and stored procedures are on the same level. So one have to be more creative, creating naming conventions, perhaps use more than one database or using tools to visualize things. What methods do you use to ease the pain? To be effective while developing your databases? To not get lost in a sea of tables and fields and stored procs? Feel free to mention tools you use also, but try to restrict it to open source and preferably Linux solutions if thats OK. b.t.w How many tables would a database have to be considered large in terms of design?

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• How would I code a complex formula parser manually?

  - by StormianRootSolver

  Hm, this is language - agnostic, I would prefer doing it in C# or F#, but I'm more interested this time in the question "how would that work anyway". What I want to accomplish ist: a) I want to LEARN it - it's about my ego this time, it's for a fun project where I want to show myself that I'm a really good at this stuff b) I know a tiny little bit about EBNF (although I don't know yet, how operator precedence works in EBNF - Irony.NET does it right, I checked the examples, but this is a bit ominous to me) c) My parser should be able to take this: 5 * (3 + (2 - 9 * (5 / 7)) + 9) for example and give me the right results d) To be quite frankly, this seems to be the biggest problem in writing a compiler or even an interpreter for me. I would have no problem generating even 64 bit assembler code (I CAN write assembler manually), but the formula parser... e) Another thought: even simple computers (like my old Sharp 1246S with only about 2kB of RAM) can do that... it can't be THAT hard, right? And even very, very old programming languages have formula evaluation... BASIC is from 1964 and they already could calculate the kind of formula I presented as an example f) A few ideas, a few inspirations would be really enough - I just have no clue how to do operator precedence and the parentheses - I DO, however, know that it involves an AST and that many people use a stack So, what do you think?

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• how does one _model_ data from relational databases in clojure ?

  - by sandeep

  I have asked this question on twitter as well the #clojure IRC channel, yet got no responses. There have been several articles about Clojure-for-Ruby-programmers, Clojure-for-lisp-programmers.. but what is the missing part is Clojure for ActiveRecord programmers . There have been articles about interacting with MongoDB, Redis, etc. - but these are key value stores at the end of the day. However, coming from a Rails background, we are used to thinking about databases in terms of inheritance - has_many, polymorphic, belongs_to, etc. The few articles about Clojure/Compojure + MySQL (ffclassic) - delve right into sql. Of course, it might be that an ORM induces impedence mismatch, but the fact remains that after thinking like ActiveRecord, it is very difficult to think any other way. I believe that relational DBs, lend themselves very well to the object-oriented paradigm because of them being , essentially, Sets. Stuff like activerecord is very well suited for modelling this data. For e.g. a blog - simply put class Post < ActiveRecord::Base has_many :comments end class Comment < ActiveRecord::Base belongs_to :post end How does one model this in Clojure - which is so strictly anti-OO ? Perhaps the question would have been better if it referred to all functional programming languages, but I am more interested from a Clojure standpoint (and Clojure examples)

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• Why can't I simply copy installed Perl modules to other machines?

  - by pistacchio

  Being very new to Perl but not to dynamic languages, I'm a bit surprised at how not straight forward the manage of modules is. Sure, cpan X does theoretically work, but I'm working on the same project from three different machines and OSs (at work, at home, testing in an external environment). At work (Windows 7) I have problem using cpan because of our firewall that makes ftp unusable At home (Mac OS X) it does work In the external environment (Linux CentOs) it worked after hours because I don't have root access and I had to configure cpan to operate as a non-root user I've tried on another server where I have an access. If the previous external environment is a VPS and so I have a shell access, this other one is a cheap shared hosting where I have no way to install new modules other than the ones pre-installed At the moment I still can't install Template under Windows. I've seen that as an alternative I could compile it and I've also tried ActiveState's PPM but the module is not existent there. Now, my perplexity is about Perl being a dynamic language. I've had all these kind of problems while working, for example, with C where I had to compile all the libraries for all the platform, but I thought that with Perl the approach would have been very similar to Python's or PHP's where in 90% of the cases copying the module in a directory and importing it simply works. So, my question: if Perl's modules are written in Perl, why the copy/paste approach will not work? If some (or some part) of the modules have to be compiled, how to see in CPAN if a module is Perl-only or it relies upon compiled libraries? Isn't there a way to download the module (tar, zip...) and use cpan to deploy it? This would solve my problem under Windows.

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• Visual Studio and .NET programming

  - by Vit

  Hi, I just want to ask wheather I am right or not about .NET. So, .NET is new framework that enables you to easily implement new and old windows functions. It is similiar to java in the way that its also compiled into "bytecode", but its name is Common Language Infrastructure, or CLI. This language is interpreted by .NET Framework, so code generated by programming using .NET cannot be executed directly by CPU. Now, few languages can be compiled to CLI. First, it was Microsoft-developed C#, than J#, C++ others. I suspect that this is in general right, at least I hope I understand it right. But, what I am still missing is, can you write to machine code compiled code in C#? And, if using Visual Studio 2005, when I select Win32 project, it is compiled into machine code, so only thing you need to run this apps are windows dynamic-link libraries, since static libraries code is implemented into app durink linking phase. And those dynamic-link libraries are implemented in every windows installation, or provided by DirectX installations. But when I select CLR in Visual Studio 2005, than app is compiled into CLI code, and it first executes .NET framework, and than .NET framework executes that program, since its not in machine code. So, I am right? I ask becouse you can read these infos on the internet, but I have noone to tell me wheather I understand it right or not. Thanks.

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• OOP, Interface Design and Encapsulation

  - by Mau

  C# project, but it could be applied to any OO languages. 3 interfaces interacting: public interface IPublicData {} public /* internal */ interface IInternalDataProducer { string GetData(); } public interface IPublicWorker { IPublicData DoWork(); IInternalDataProducer GetInternalProducer(); } public class Engine { Engine(IPublicWorker worker) {} IPublicData Run() { DoSomethingWith(worker.GetInternalProducer().GetData()); return worker.DoWork(); } } Clearly Engine is parametric in the actual worker that does the job. A further source of parametrization is how we produce the 'internal data' via IInternalDataProducer. This implementation requires IInternalDataProducer to be public because it's part of the declaration of the public interface IPublicWorker. However, I'd like it to be internal since it's only used by the engine. A solution is make the IPublicWorker produce the internal data itself, but that's not very elegant since there's only a couple of ways of producing it (while there are many more worker implementations), therefore it's nice to delegate to a couple of separate concrete classes. Moreover, the IInternalDataProducer is used in more places inside the engine, so it's good for the engine to pass around the actual object. I'm looking for elegant ideas/patterns. Cheers :-)

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