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This is a type system extension that allows types that are existentially quantified, or, in other words, have type variables that only get instantiated at runtime†. A value of existential type is similar to an abstract-base-class reference in OO languages: you don't know the exact type in contains,...

The following expressions are sequenced: a && b a || b a , b a ? b : c for ( a ; b ; c ) { ... } In all cases, the expression a is fully evaluated and all side effects are applied before either b or c are evaluated. In the fourth case, only one of b or c will be evaluated. In the l...

C11 The following expressions are unsequenced: a + b; a - b; a * b; a / b; a % b; a & b; a | b; In the above examples, the expression a may be evaluated before or after the expression b, b may be evaluated before a, or they may even be intermixed if they correspond to several instruct...

On OS X and MacOS, Elixir can be installed via the common package managers: Homebrew $ brew update $ brew install elixir Macports $ sudo port install elixir

Ajax Get: Solution 1: $.get('url.html', function(data){ $('#update-box').html(data); }); Solution 2: $.ajax({ type: 'GET', url: 'url.php', }).done(function(data){ $('#update-box').html(data); }).fail(function(jqXHR, textStatus){ alert('Error occured: ' + te...

$string = "0| PHP 1| CSS 2| HTML 3| AJAX 4| JSON"; //[0-9]: Any single character in the range 0 to 9 // + : One or more of 0 to 9 $array = preg_split("/[0-9]+\|/", $string, -1, PREG_SPLIT_NO_EMPTY); //Or // [] : Character class // \d : Any digit // + : One or more ...

Server side: import socket serversocket = socket.socket(socket.AF_INET, socket.SOCK_STREAM) serversocket.bind(('localhost', 8089)) serversocket.listen(5) # become a server socket, maximum 5 connections while True: connection, address = serversocket.accept() buf = connection.recv(6...

You can validate request data using the validate method (available in the base Controller, provided by the ValidatesRequests trait). If the rules pass, your code will keep executing normally; however, if validation fails, an error response containing the validation errors will automatically be se...

EXPOSE <port> [<port>...] From Docker's documentation: The EXPOSE instruction informs Docker that the container listens on the specified network ports at runtime. EXPOSE does not make the ports of the container accessible to the host. To do that, you must use either the -p flag to ...

Quote is a special operator that prevents evaluation of its argument. It returns its argument, unevaluated. CL-USER> (quote a) A CL-USER> (let ((a 3)) (quote a)) A

docker exec -it <container id> /bin/bash It is common to log in an already running container to make some quick tests or see what the application is doing. Often it denotes bad container use practices due to logs and changed files should be placed in volumes. This example allows us log in the...

Before Python 3.5+ was released, the asyncio module used generators to mimic asynchronous calls and thus had a different syntax than the current Python 3.5 release. Python 3.x3.5 Python 3.5 introduced the async and await keywords. Note the lack of parentheses around the await func() call. import ...

Note: Uses the Python 3.5+ async/await syntax asyncio supports the use of Executor objects found in concurrent.futures for scheduling tasks asynchronously. Event loops have the function run_in_executor() which takes an Executor object, a Callable, and the Callable's parameters. Scheduling a task f...

<?xml version="1.0" encoding="utf-8"?> <manifest xmlns:android="http://schemas.android.com/apk/res/android" <!-- etc --> > <!-- Internet is required. READ_LOGS are to ensure that the Logcat is transmitted--> <uses-perm...

This will show the user location on the map Objective-C [self.map setShowsUserLocation:YES]; Swift self.map?.showsUserLocation = true This will track the user location on the map, updating regions according Objective-C [self.map setUserTrackingMode:MKUserTrackingModeFollow]; Swift s...

views.py: from django.http import HttpResponse from django.views.generic import View class MyView(View): def get(self, request): # <view logic> return HttpResponse('result') urls.py: from django.conf.urls import url from myapp.views import MyView urlpatterns...

Users of homebrew can install gradle by running brew install gradle

There are different cases where you must Explicitly specify the type parameters for a generic method. In both of the below cases, the compiler is not able to infer all of the type parameters from the specified method parameters. One case is when there are no parameters: public void SomeMethod<T...

The most common and easiest type of centering is that of lines of text in an element. CSS has the rule text-align: center for this purpose: HTML <p>Lorem ipsum</p> CSS p { text-align: center; } This does not work for centering entire block elements. text-align controls onl...

A try/catch block is used to catch exceptions. The code in the try section is the code that may throw an exception, and the code in the catch clause(s) handles the exception. #include <iostream> #include <string> #include <stdexcept> int main() { std::string str("foo&...