Tutorial by Examples: re

main = do input <- getContents putStr input Input: This is an example sentence. And this one is, too! Output: This is an example sentence. And this one is, too! Note: This program will actually print parts of the output before all of the input has been fully read in. This m...

main = do line <- getLine putStrLn line Input: This is an example. Output: This is an example.

Like in several other parts of the I/O library, functions that implicitly use a standard stream have a counterpart in System.IO that performs the same job, but with an extra parameter at the left, of type Handle, that represents the stream being handled. For instance, getLine :: IO String has a cou...

A bit counter-intuitive to the way most other languages' standard I/O libraries do it, Haskell's isEOF does not require you to perform a read operation before checking for an EOF condition; the runtime will do it for you. import System.IO( isEOF ) eofTest :: Int -> IO () eofTest line = do ...

Docker commands which take the name of a container accept three different forms: TypeExampleFull UUID9cc69f11a0f76073e87f25cb6eaf0e079fbfbd1bc47c063bcd25ed3722a8cc4aShort UUID9cc69f11a0f7Nameberserk_wozniak Use docker ps to view these values for the containers on your system. The UUID is generat...

Docker commands which take the name of an image accept four different forms: TypeExampleShort ID693bce725149Namehello-world (defaults to :latest tag)Name+taghello-world:latestDigesthello-world@sha256:e52be8ffeeb1f374f440893189cd32f44cb166650e7ab185fa7735b7dc48d619 Note: You can only refer to an im...

WiredTiger supports LSM trees to store indexes. LSM trees are faster for write operations when you need to write huge workloads of random inserts. In WiredTiger, there is no in-place updates. If you need to update an element of a document, a new document will be inserted while the old document will...

This uses the Dropbox .NET SDK to download a file from the Dropbox API at the remote path to the local file "Test", while tracking progress: var response = await client.Files.DownloadAsync(path); ulong fileSize = response.Response.Size; const int bufferSize = 1024 * 1024; var buffer ...

To create a UIImageView programmatically, all you need to do is create an instance of UIImageView: //Swift let imageView = UIImageView() //Objective-C UIImageView *imageView = [[UIImageView alloc] init]; You can set the size and position of the UIImageView with a CGRect: //Swift imageView...

We use Notification.requestPermission to ask the user if he/she wants to receive notifications from our website. Notification.requestPermission(function() { if (Notification.permission === 'granted') { // user approved. // use of new Notification(...) syntax will now be succe...

5 Using property descriptors we can make a property read only, and any attempt to change it's value will fail silently, the value will not be changed and no error will be thrown. The writable property in a property descriptor indicates whether that property can be changed or not. var a = { }; ...

The following queries will return a list of all Stored Procedures in the database, with basic information about each Stored Procedure: SQL Server 2005 SELECT * FROM INFORMATION_SCHEMA.ROUTINES WHERE ROUTINE_TYPE = 'PROCEDURE' The ROUTINE_NAME, ROUTINE_SCHEMA and ROUTINE_DEFINITION columns are...

Note that these only work in the developer tools of certain browsers. $_ gives you the value of whatever expression was evaluated last. "foo" // "foo" $_ // "foo" $0 refers to the DOM element currently selected in the Inspector. So if &l...

In this type of image addition, one image can be used several times without duplicating its URL, making it a good choice when using one image multiple times in a document. Markdown Source Picture of Duck: ![Duck][1] Same picture of Duck: ![Same Duck][1] [1]: http://i.stack.imgur.com/uk...

While object property notation is usually written as myObject.property, this will only allow characters that are normally found in JavaScript variable names, which is mainly letters, numbers and underscore (_). If you need special characters, such as space, ☺, or user-provided content, this is poss...

Disclaimer: Creating array-like objects is not recommend. However, it is helpful to understand how they work, especially when working with DOM. This will explain why regular array operations don't work on DOM objects returned from many DOM document functions. (i.e. querySelectorAll, form.elements)...

When you start a thread, it will execute until it is finished. Often, at some point, you need to (possibly - the thread may already be done) wait for the thread to finish, because you want to use the result for example. int n; std::thread thread{ calculateSomething, std::ref(n) }; //Doing some...

You cannot pass a reference (or const reference) directly to a thread because std::thread will copy/move them. Instead, use std::reference_wrapper: void foo(int& b) { b = 10; } int a = 1; std::thread thread{ foo, std::ref(a) }; //'a' is now really passed as reference thread.join()...

In C++, threads are created using the std::thread class. A thread is a separate flow of execution; it is analogous to having a helper perform one task while you simultaneously perform another. When all the code in the thread is executed, it terminates. When creating a thread, you need to pass somet...

std::this_thread is a namespace which has functions to do interesting things on the current thread from function it is called from. FunctionDescriptionget_idReturns the id of the threadsleep_forSleeps for a specified amount of timesleep_untilSleeps until a specific timeyieldReschedule running threa...