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With this code: main :: FilePath -> FilePath -> IO () main wrPath rdPath = do x <- readFile rdPath writeFile wrPath x I got the following error: Couldn't match expected type 'IO t0' with actual type 'FilePath -> FilePath -> IO() But the file compiles correctly when I change the name of 'main' to something else. What's so unique about main and why does its type have to be IO t0 ? Because the language spec says so . A Haskell program is a collection of modules, one of which, by convention, must be called Main and must export the value main . The value of the program is the value of the

I've got the following and was wondering if the initial test is overkill: static void Main(string[] args) { if (args.Length == 0 || args == null) { //do X } else { //do Y } } in other words what I'm asking is are there possibilities of args.Length being zero, or args being null....or would just one of these conditions sufficed? Well, Main is defined to never ever ever ever be called with a null parameter. If it does somehow receive a null parameter, then your environment is so broken that all bets are off no matter what you do, so there's really nothing to be gained by checking for null . On

I'm trying to recover an app that I accidentally deleted and managed to do it through the organizer, however, now when I try to run it on the simulator or iphone, it crashes with an error popping up in the main.m file: int main(int argc, char *argv[]) { @autoreleasepool { return UIApplicationMain(argc, argv, nil, NSStringFromClass([AppDelegate class])); } } The error occurs in the "return UIApplicationMain(argc, argv, nil, NSStringFromClass([AppDelegate class]));" section of the file with the SIGABRT error. I am using Xcode 4.2 with ARC on. I am testing it on ios 4.3 and ios 5.0. The app was

I have seen a main() function in some JavaScript files I have come across. Is it the same main function as you use in other languages such as C#, C++?? If you put a main function in your JS file, is that where the code starts executing? Or is it just another name used for a function? I have searched the web but didn't find anything useful regarding this matter. No, main is not the same in JavaScript as in C languages. It's just another function, but the original programmer is probably using the name as a convention to indicate where the code should start running. "Main" function has nothing

i want to set a main page or an index page for my app. i tried adding MAIN_PAGE in settings.py and then creating a main_page view returning a main_page object, but it doesn't work Also, i tries to add in the urls.py a declaration like (r'^$', index), where indexshould be the name of the index.html file on the root (but it obviously does not work) What is the best way to set a main page in a Django website? thanks! If you want to refer to a static page (not have it go through any dynamic processing), you can use the direct_to_template view function from django.views.generic.simple . In your URL

I know that the getName() function on the main thread will return the String main , but this can be changed with setName() . Is there any way to always determine the main thread of an application? It seems that the main thread has an id of 1 as indicated by Thread.getId() : class test{ public static boolean isMainThread(){ return Thread.currentThread().getId() == 1; } public static void main(String[]args){ System.out.println(isMainThread()); new Thread( new Runnable(){ public void run(){ System.out.println(isMainThread()); } }).start(); } } I'm not sure if it is part of the specification or an