Search Results

Search found 9133 results on 366 pages for 'global interpreter lock'.

Page 33/366 | < Previous Page | 29 30 31 32 33 34 35 36 37 38 39 40  | Next Page >

  • Event in Global.asax file that fires only for once

    - by fiberOptics
    In MVC Global.asax file, we can see the Application_Start where this event fires only for once. But the session is not yet active/available here. So my question is, is there any event in Global.asax file that fired only for once and session is available also? The reason I ask this is because, I use ExpandoObject e.g.: public static dynamic Data { get { #region FAILSAFE if (HttpContext.Current.Session[datakey] == null) { HttpContext.Current.Session[datakey] = new ExpandoObject(); } #endregion return (ExpandoObject)HttpContext.Current.Session[datakey]; } } I want to initialize all of my ExpandoObject at once with the value of null: MyExpando.Data.UserInformation = null; MyExpando.Data.FolderInformation = null; That's why I'm looking for an event that only fired once.

    Read the article

  • Interpreters: Handling includes/imports

    - by sub
    I've built an interpreter in C++ and everything works fine so far, but now I'm getting stuck with the design of the import/include/however you want to call it function. I thought about the following: Handling includes in the tokenizing process: When there is an include found in the code, the tokenizing function is recursively called with the filename specified. The tokenized code of the included file is then added to the prior position of the include. Disadvantages: No conditional includes(!) Handling includes during the interpreting process: I don't know how. All I know is that PHP must do it this way as conditional includes are possible. Now my questions: What should I do about includes? How do modern interpreters (Python/Ruby) handle this? Do they allow conditional includes?

    Read the article

  • C++: Switching from MSVC to G++: Global Variables

    - by feed the fire
    I recently switched to Linux and wanted to compile my Visual Studio 2010 C++ source code, which uses only the STL, on G++. My Linux machine currently isn't available but I can try to tell you what is going on, first: As I try to compile my project, all global variables I use in main and which perfectly work on MSVC result in myGlobalVar is not defined in this scope errors. My project is built nearly the same as the example below: // myclass.h class myClass { // .... }; extern myClass globalInstance; // myclass.cpp #include "myclass.h" // myClass functions located here myClass globalInstance; // main.cpp #include "myclass.h" int main( ) { // Accessing globalInstance results in an error: Not defined in this scope } What am I doing wrong? Where are the differences between G++ and MSVC in terms of global variables?

    Read the article

  • Codeignitor Global Array Declaration

    - by Ajith
    I have a sequence of number like follows 1 - 25, 2 - 60, 3 - 80, 4 - 100 and so on which means that if input is 1 output will be 25 and so on...I need to store it in global array.I would like to use it in multiple pages also.In codeigniter where i can declare a global array and store all these? I am trying like as follows in constants.php $CONFIDENCEVALUE = array(); $CONFIDENCEVALUE[] = array('1'=>25,'2'=>'60','3'=>80,'4'=>100); If it is correct how can access these array value in required pages.Help me please.I am not an expert with codeignitor.Thanks

    Read the article

  • Error : The Type Initializer of Daemon.Global threw an exception in c#

    - by srk
    I am using the below class file, where some variables are declared to use in the entire application. Now I used that variable BlockLogOut in another class file to make the value true. I just put this below line and getting error in it.. TypeInitializationException Global.BlockLogOut = True; The weird thing is, it was working fine for many months and i am getting this error now on the above line. Of course i was modifying some other stuffs in the application, but surely not this class file. What would have been the problem? namespace Daemon { class Global { public static bool BlockLogOut = false; } }

    Read the article

  • Why is the Python interpreter provided by Django suddenly showing me Python tab completion upon a single Tab press?

    - by ysim
    This issue seems to have just started happening; basically I just noticed that whenever I press the Tab key in the Python interpreter that comes with Django, it gives me the Display all ... possibilities? (y or no) prompt. I opened a similar question just now, where I noticed that removing set show-all-if-ambiguous on from .inputrc fixed the problem in the non-Django Python interpreter that was showing me bash tab completion, but the problem persists with the Django one, only with Python tab completion. It's very odd and it seems to have come out of nowhere. There's nothing else in my .inputrc other than set completion-ignore-case on, which shouldn't be conflicting with the Python interpreter, but I've also tried removing that (leaving my .inputrc blank), but it's still happening. I'm not sure why this is suddenly happening, but it would be great if someone had an idea of why and how to fix it.

    Read the article

  • How to achieve syncronization in loadbalanced multiserver environment

    - by Anoop
    Hi, I have to create a .net web application which would run on more than one front end server which are load balanced. Now I have to use some third party api which is not thread safe so only one thread should call the API at a time so I have to some use syncronization machanism like lock or mutex which provide syncronisation within the process and across the process in machine.Now will lock or mutex work in loadbalanced multiserver environment correctly? If not then is there any mechanism using which I can syncronise all the threads in all the machines??

    Read the article

  • Le W3C travaille sur les applications Web et les terminaux tactiles pour standardiser la manière d'interpréter les actions des utilisateurs

    Le W3C travaille sur les applications Web et les terminaux tactiles Pour standardiser la manière d'interpréter les actions des utilisateurs Le W3C se lance dans la définition d'un nouveau standard (baptisé « Touch Events Specification ») pour les applications Web spécialement conçues pour les téléphones mobiles et autres équipements à écran tactile (dont les tablettes) Les travaux, dont un « brouillon » (une pré-version du document) vient d'être publié par Doug Schepers - membre du W3C, ont pour but de définir une base commune sur la façon dont les navigateurs interprèteront les différentes actions des utilisateurs. Le brouillon présente par exemple comment on peut définir ...

    Read the article

  • [C#] Lock a file and avoid readings while it's writing

    - by vtortola
    Hi, My web application returns a file from the filesystem. These files are dynamic, so I have no way to know the names o how many of them will there be. When this file doesn't exist, the application creates it from the database. I want to avoid that two different threads recreate the same file at the same time, or that a thread try to return the file while other thread is creating it. So I want to lock a file till its recreation is complete, if other thread try to access it ... it will have to wait the file be unlocked. I've been reading about FileStream.Lock, but I have to know the file length and it won't prevent that other thread try to read the file, so it doesn't work for my particular case. I've been reading also about FileAccess.None, but it will throw an exception (which exception type?) if other thread/process try to access the file... so I should develop a "try again while is faulting" ... and I don't like too much that approach, although maybe there is not a better way. How could I archieve this? Kind regards.

    Read the article

  • How to Lock a file and avoid readings while it's writing

    - by vtortola
    My web application returns a file from the filesystem. These files are dynamic, so I have no way to know the names o how many of them will there be. When this file doesn't exist, the application creates it from the database. I want to avoid that two different threads recreate the same file at the same time, or that a thread try to return the file while other thread is creating it. So I want to lock a file till its recreation is complete, if other thread try to access it ... it will have to wait the file be unlocked. I've been reading about FileStream.Lock, but I have to know the file length and it won't prevent that other thread try to read the file, so it doesn't work for my particular case. I've been reading also about FileAccess.None, but it will throw an exception (which exception type?) if other thread/process try to access the file... so I should develop a "try again while is faulting" ... and I don't like too much that approach, although maybe there is not a better way.

    Read the article

  • Lucene.net create+lock errors in ASP.NET

    - by acidzombie24
    I have an issue with Lucene.net. It throws a lock exception. After poking around i notice these things. My code below works in an app bit when calling in Application_Start i get a NoSuchDirectoryException. Not closing the writer (as my code doesnt do below) i WILL get a LockObtainFailedException with the message Lock obtain timed out: SimpleFSLock@<FULL_PATH> from either app or asp.net These thread hinted when spawning threads they get less permissions then i do (but! my main thread has problems as well...) and one solution is to impersonate IIS. I am using visual studios 2010. I am not sure how full blown it is but my attempt to impersonate it failed. So my question is how do i have lucene create the directory and not throw an exception if dont close the writer for some reason (such as power going out)? http://stackoverflow.com/questions/2341163/why-is-my-lucene-index-getting-locked/2499285#2499285 http://stackoverflow.com/questions/1123517/lucene-net-and-i-o-threading-issue/1123981#1123981 static IndexWriter writer = null; static void lucene_init() { bool create = false; //I now use a full path. I still get NoSuchDirectoryException //string dirname = "LuceneIndex_z"; if (System.IO.Directory.Exists(dirname) == false) create = true; var directory = FSDirectory.GetDirectory(dirname); var analyzer = new StandardAnalyzer(); writer = new IndexWriter(directory, analyzer, create); }

    Read the article

  • Lucene.net create+lock errors in ASP.NET

    - by acidzombie24
    I have an issue with Lucene.net. It throws a lock exception. After poking around i notice these things. My code below works in an app bit when calling in Application_Start i get a NoSuchDirectoryException. Not closing the writer (as my code doesnt do below) i WILL get a LockObtainFailedException with the message Lock obtain timed out: SimpleFSLock@<FULL_PATH> from either app or asp.net These thread hinted when spawning threads they get less permissions then i do (but! my main thread has problems as well...) and one solution is to impersonate IIS. I am using visual studios 2010. I am not sure how full blown it is but my attempt to impersonate it failed. So my question is how do i have lucene create the directory and not throw an exception if dont close the writer for some reason (such as power going out)? http://stackoverflow.com/questions/2341163/why-is-my-lucene-index-getting-locked/2499285#2499285 http://stackoverflow.com/questions/1123517/lucene-net-and-i-o-threading-issue/1123981#1123981 static IndexWriter writer = null; static void lucene_init() { bool create = false; string dirname = "LuceneIndex_z"; if (System.IO.Directory.Exists(dirname) == false) create = true; var directory = FSDirectory.GetDirectory(dirname); var analyzer = new StandardAnalyzer(); writer = new IndexWriter(directory, analyzer, create); }

    Read the article

  • OpenGL Calls Lock/Freeze

    - by Necrolis
    I am using some dell workstations(running WinXP Pro SP 2 & DeepFreeze) for development, but something was recenlty loaded onto these machines that prevents any opengl call(the call locks) from completing(and I know the code works as I have tested it on 'clean' machines, I also tested with simple opengl apps generated by dev-cpp, which will also lock on the dell machines). I have tried to debug my own apps to see where exactly the gl calls freeze, but there is some global system hook on ZwQueryInformationProcess that messes up calls to ZwQueryInformationThread(used by ExitThread), preventing me from debugging at all(it causes the debugger, OllyDBG, to go into an access violation reporting loop or the program to crash if the exception is passed along). the hook: ntdll.ZwQueryInformationProcess 7C90D7E0 B8 9A000000 MOV EAX,9A 7C90D7E5 BA 0003FE7F MOV EDX,7FFE0300 7C90D7EA FF12 CALL DWORD PTR DS:[EDX] 7C90D7EC - E9 0F28448D JMP 09D50000 7C90D7F1 9B WAIT 7C90D7F2 0000 ADD BYTE PTR DS:[EAX],AL 7C90D7F4 00BA 0003FE7F ADD BYTE PTR DS:[EDX+7FFE0300],BH 7C90D7FA FF12 CALL DWORD PTR DS:[EDX] 7C90D7FC C2 1400 RETN 14 7C90D7FF 90 NOP ntdll.ZwQueryInformationToken 7C90D800 B8 9C000000 MOV EAX,9C the messed up function + call: ntdll.ZwQueryInformationThread 7C90D7F0 8D9B 000000BA LEA EBX,DWORD PTR DS:[EBX+BA000000] 7C90D7F6 0003 ADD BYTE PTR DS:[EBX],AL 7C90D7F8 FE ??? ; Unknown command 7C90D7F9 7F FF JG SHORT ntdll.7C90D7FA 7C90D7FB 12C2 ADC AL,DL 7C90D7FD 14 00 ADC AL,0 7C90D7FF 90 NOP ntdll.ZwQueryInformationToken 7C90D800 B8 9C000000 MOV EAX,9C So firstly, anyone know what if anything would lead to OpenGL calls cause an infinite lock,and if there are any ways around it? and what would be creating such a hook in kernal memory ? Update: After some more fiddling, I have discovered a few more kernal hooks, a lot of them are used to nullify data returned by system information calls(such as the remote debugging port), I also managed to find out the what ever is doing this is using madchook.dll(by madshi) to do this, this dll is also injected into every running process(these seem to be some anti debugging code). Also, on the OpenGL side, it seems Direct X is fine/unaffected(I ran one of the DX 9 demo's without problems), so could one of these kernal hooks somehow affect OpenGL?

    Read the article

  • Using SQL dB column as a lock for concurrent operations in Entity Framework

    - by Sid
    We have a long running user operation that is handled by a pool of worker processes. Data input and output is from Azure SQL. The master Azure SQL table structure columns are approximated to [UserId, col1, col2, ... , col N, beingProcessed, lastTimeProcessed ] beingProcessed is boolean and lastTimeProcessed is DateTime. The logic in every worker role is: public void WorkerRoleMain() { while(true) { try { dbContext db = new dbContext(); // Read foreach (UserProfile user in db.UserProfile .Where(u => DateTime.UtcNow.Subtract(u.lastTimeProcessed) > TimeSpan.FromHours(24) & u.beingProcessed == false)) { user.beingProcessed = true; // Modify db.SaveChanges(); // Write // Do some long drawn processing here ... ... ... user.lastTimeProcessed = DateTime.UtcNow; user.beingProcessed = false; db.SaveChanges(); } } catch(Exception ex) { LogException(ex); Sleep(TimeSpan.FromMinutes(5)); } } // while () } With multiple workers processing as above (each with their own Entity Framework layer), in essence beingProcessed is being used a lock for MutEx purposes Question: How can I deal with concurrency issues on the beingProcessed "lock" itself based on the above load? I think read-modify-write operation on the beingProcessed needs to be atomic but I'm open to other strategies. Open to other code refinements too.

    Read the article

  • JDBC transaction dead-lock solution required?

    - by user49767
    It's a scenario described my friend and challenged to find solution. He is using Oracle database and JDBC connection with read committed as transaction isolation level. In one of the transaction, he updates a record and executes selects statement and commits the transaction. when everything happening within single thread, things are fine. But when multiple requests are handled, dead-lock happens. Thread-A updates a record. Thread B updates another record. Thread-A issues select statement and waits for Thread-B's transaction to complete the commit operation. Thread-B issues select statement and waits for Thread-A's transaction to complete the commit operation. Now above causes dead-lock. Since they use command pattern, the base framework allows to issue commit only once (at the end of all the db operation), so they are unable to issue commit immediately after select statement. My argument was Thread-A supposed to select all the records which are committed and hence should not be issue. But he said that Thread-A will surely wait till Thread-B commits the record. is that true? What are all the ways, to avoid the above issue? is it possible to change isolation-level? (without changing underlying java framework) Little information about base framework, it is something similar to Struts action, their each and every request handled by one action, transaction begins before execution and commits after execution.

    Read the article

  • MFC/CCriticalSection: Simple lock situation hangs

    - by raph.amiard
    I have to program a simple threaded program with MFC/C++ for a uni assignment. I have a simple scenario in wich i have a worked thread which executes a function along the lines of : UINT createSchedules(LPVOID param) { genProgThreadVal* v = (genProgThreadVal*) param; // v->searcherLock is of type CcriticalSection* while(1) { if(v->searcherLock->Lock()) { //do the stuff, access shared object , exit clause etc.. v->searcherLock->Unlock(); } } PostMessage(v->hwnd, WM_USER_THREAD_FINISHED , 0,0); delete v; return 0; } In my main UI class, i have a CListControl that i want to be able to access the shared object (of type std::List). Hence the locking stuff. So this CList has an handler function looking like this : void Ccreationprogramme::OnLvnItemchangedList5(NMHDR *pNMHDR, LRESULT *pResult) { LPNMLISTVIEW pNMLV = reinterpret_cast<LPNMLISTVIEW>(pNMHDR); if((pNMLV->uChanged & LVIF_STATE) && (pNMLV->uNewState & LVNI_SELECTED)) { searcherLock.Lock(); // do the stuff on shared object searcherLock.Unlock(); // do some more stuff } *pResult = 0; } The searcherLock in both function is the same object. The worker thread function is passed a pointer to the CCriticalSection object, which is a member of my dialog class. Everything works but, as soon as i do click on my list, and so triggers the handler function, the whole program hangs indefinitely.I tried using a Cmutex. I tried using a CSingleLock wrapping over the critical section object, and none of this has worked. What am i missing ?

    Read the article

  • Rails Heroku Gemfile.lock error - push rejected (open source)

    - by KJ50
    I am trying to push my open source RoR application to Heroku but I'm having an issue making the initial push. I have read many similar questions, but none of those answers has helped to solve my problem. I have tried bundle update and bundle install various times. I also have tried removing and then re-committing my Gemfile.lock file, however I get this same error still... $ git push heroku master Counting objects: 5199, done. Compressing objects: 100% (3086/3086), done. Writing objects: 100% (5199/5199), 4.57 MiB | 131 KiB/s, done. Total 5199 (delta 3418), reused 3152 (delta 1962) -----> Removing .DS_Store files -----> Ruby app detected -----> Compiling Ruby/NoLockfile ! ! Gemfile.lock required. Please check it in. ! ! Push rejected, failed to compile Ruby app To [email protected]:frozen-springs-4725.git ! [remote rejected] master -> master (pre-receive hook declined) error: failed to push some refs to '[email protected]:frozen-springs-4725.git' Since my application uses MongoDB with MongoMapper, I suspect that I have some configuration incorrect. My code can be found here on Github (I'm currently working on the heroku branch). Feel free to clone our repository and try it yourself. If anyone has any insight which could help me resolve this issue I would be very thankful!

    Read the article

  • What does the status code of the Perl interpreter mean?

    - by futureelite7
    Hi, This might sound slightly confusing, but please bear with me. I'm trying to execute a copy of the Perl interpreter using Java's Runtime.exec(). However, it returned error code 9. After running the file a few times, the perl interpreter mysteriously started to return code 253 with no changes in my command at all. What does code 253 / code 9 mean? A google search for perl interpreter's exit codes turned up nothing. Where can I find a list of exit codes for the Perl interpreter? Thanks!

    Read the article

  • How do programming languages bind identifiers to functions

    - by sub
    I'm talking about C and/or C++ here as this are the only languages I know used for interpreters where the following could be a problem: If we have an interpreted language X how can a library written for it add functions to the language which can then be called from within programs written in the language? PHP example: substr( $str, 5, 10 ); How is the function substr added to the "function pool" of PHP so it can be called from within scripts? It is easy for PHP storing all registered function names in an array and searching through it as a function is called in a script. However, as there obviously is no eval in C(++), how can the function then be called? I assume PHP doesn't have 100MB of code like: if( identifier == "substr" ) { return PHP_SUBSTR(...); } else if( ... ) { ... } Ha ha, that would be pretty funny. I hope you have understood my question so far. How do interpreters solve this problem? How can I solve this for my own experimental toy interpreter?

    Read the article

  • Win32 -- Object cleanup and global variables

    - by KaiserJohaan
    Hello, I've got a question about global variables and object cleanup in c++. For example, look at the code here; case WM_PAINT: paintText(&hWnd); break; void paintText(HWND* hWnd) { PAINTSTRUCT ps; HBRUSH hbruzh = CreateSolidBrush(RGB(0,0,0)); HDC hdz = BeginPaint(*hWnd,&ps); char s1[] = "Name"; char s2[] = "IP"; SelectBrush(hdz,hbruzh); SelectFont(hdz,hFont); SetBkMode(hdz,TRANSPARENT); TextOut(hdz,3,23,s1,sizeof(s1)); TextOut(hdz,10,53,s2,sizeof(s2)); EndPaint(*hWnd,&ps); DeleteObject(hdz); DeleteObject(hbruzh); // bad? DeleteObject(ps); // bad? } 1)First of all; which objects are good to delete and which ones are NOT good to delete and why? Not 100% sure of this. 2)Since WM_PAINT is called everytime the window is redrawn, would it be better to simply store ps, hdz and hbruzh as global variables instead of re-initializing them everytime? The downside I guess would be tons of global variables in the end _ but performance-wise would it not be less CPU-consuming? I know it won't matter prolly but I'm just aiming for minimalistic as possible for educational purposes. 3) What about libraries that are loaded in? For example: // // Main // int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow) { // initialize vars HWND hWnd; WNDCLASSEX wc; HINSTANCE hlib = LoadLibrary("Riched20.dll"); ThishInstance = hInstance; ZeroMemory(&wc,sizeof(wc)); // set WNDCLASSEX props wc.cbSize = sizeof(WNDCLASSEX); wc.lpfnWndProc = WindowProc; wc.hInstance = ThishInstance; wc.hIcon = LoadIcon(hInstance,MAKEINTRESOURCE(IDI_MYICON)); wc.lpszMenuName = MAKEINTRESOURCE(IDR_MENU1); wc.hCursor = LoadCursor(NULL, IDC_ARROW); wc.hbrBackground = (HBRUSH)COLOR_WINDOW; wc.lpszClassName = TEXT("PimpClient"); RegisterClassEx(&wc); // create main window and display it hWnd = CreateWindowEx(NULL, wc.lpszClassName, TEXT("PimpClient"), 0, 300, 200, 450, 395, NULL, NULL, hInstance, NULL); createWindows(&hWnd); ShowWindow(hWnd,nCmdShow); // loop message queue MSG msg; while (GetMessage(&msg, NULL,0,0)) { TranslateMessage(&msg); DispatchMessage(&msg); } // cleanup? FreeLibrary(hlib); return msg.wParam; } 3cont) is there a reason to FreeLibrary at the end? I mean when the process terminates all resources are freed anyway? And since the library is used to paint text throughout the program, why would I want to free before that? Cheers

    Read the article

  • 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?

    Read the article

  • How do interpreters written in C and C++ bind identifiers to C(++) functions

    - by sub
    I'm talking about C and/or C++ here as this are the only languages I know used for interpreters where the following could be a problem: If we have an interpreted language X how can a library written for it add functions to the language which can then be called from within programs written in the language? PHP example: substr( $str, 5, 10 ); How is the function substr added to the "function pool" of PHP so it can be called from within scripts? It is easy for PHP storing all registered function names in an array and searching through it as a function is called in a script. However, as there obviously is no eval in C(++), how can the function then be called? I assume PHP doesn't have 100MB of code like: if( identifier == "substr" ) { return PHP_SUBSTR(...); } else if( ... ) { ... } Ha ha, that would be pretty funny. I hope you have understood my question so far. How do interpreters written in C/C++ solve this problem? How can I solve this for my own experimental toy interpreter written in C++?

    Read the article

  • How do C and C++ interpreters bind identifiers to functions

    - by sub
    I'm talking about C and/or C++ here as this are the only languages I know used for interpreters where the following could be a problem: If we have an interpreted language X how can a library written for it add functions to the language which can then be called from within programs written in the language? PHP example: substr( $str, 5, 10 ); How is the function substr added to the "function pool" of PHP so it can be called from within scripts? It is easy for PHP storing all registered function names in an array and searching through it as a function is called in a script. However, as there obviously is no eval in C(++), how can the function then be called? I assume PHP doesn't have 100MB of code like: if( identifier == "substr" ) { return PHP_SUBSTR(...); } else if( ... ) { ... } Ha ha, that would be pretty funny. I hope you have understood my question so far. How do C/C++ interpreters solve this problem? How can I solve this for my own experimental toy interpreter?

    Read the article

  • C++ and its type system: How to deal with data with multiple types?

    - by sub
    "Introduction" I'm relatively new to C++. I went through all the basic stuff and managed to build 2-3 simple interpreters for my programming languages. The first thing that gave and still gives me a headache: Implementing the type system of my language in C++ Think of that: Ruby, Python, PHP and Co. have a lot of built-in types which obviously are implemented in C. So what I first tried was to make it possible to give a value in my language three possible types: Int, String and Nil. I came up with this: enum ValueType { Int, String, Nil }; class Value { public: ValueType type; int intVal; string stringVal; }; Yeah, wow, I know. It was extremely slow to pass this class around as the string allocator had to be called all the time. Next time I've tried something similar to this: enum ValueType { Int, String, Nil }; extern string stringTable[255]; class Value { public: ValueType type; int index; }; I would store all strings in stringTable and write their position to index. If the type of Value was Int, I just stored the integer in index, it wouldn't make sense at all using an int index to access another int, or? Anyways, the above gave me a headache too. After some time, accessing the string from the table here, referencing it there and copying it over there grew over my head - I lost control. I had to put the interpreter draft down. Now: Okay, so C and C++ are statically typed. How do the main implementations of the languages mentioned above handle the different types in their programs (fixnums, bignums, nums, strings, arrays, resources,...)? What should I do to get maximum speed with many different available types? How do the solutions compare to my simplified versions above?

    Read the article

< Previous Page | 29 30 31 32 33 34 35 36 37 38 39 40  | Next Page >