Predicates that produce side effects leave the realm of pure logic. These are for example:
writeq/1
read/1
format/2
Side effects are phenomena that cannot be reasoned about within the program. For example, deletion of a file or output on the system terminal.
In oracle, the difference (in days and/or fractions thereof) between two DATEs can be found using subtraction:
SELECT DATE '2016-03-23' - DATE '2015-12-25' AS difference FROM DUAL;
Outputs the number of days between the two dates:
DIFFERENCE
----------
89
And:
SELECT TO_DATE( '201...
Following code will release the lock. There will be no problem. Behind the scenes lock statement works as try finally
lock(locker)
{
throw new Exception();
}
More can be seen in the C# 5.0 Specification:
A lock statement of the form
lock (x) ...
where x is an expression of a referenc...
Given a C++ source file main.cpp defining a main() function, an accompanying CMakeLists.txt file (with the following content) will instruct CMake to generate the appropriate build instructions for the current system and default C++ compiler.
main.cpp (C++ Hello World Example)
#include <iostream...
A browser's debugging console can be used in order to print simple messages. This debugging or web console can be directly opened in the browser (F12 key in most browsers – see Remarks below for further information) and the log method of the console Javascript object can be invoked by typing the fol...
Begin by including highcharts.js in your index.html
<html>
<head>
<script src="http://code.highcharts.com/highcharts.js"></script>
</head>
Add a <div> to contain your chart
<body>
<div id="chart">
<!...
This example will show you how to create a simple animation using the canvas and the 2D context. It is assumed you know how to create and add a canvas to the DOM and obtain the context
// this example assumes ctx and canvas have been created
const textToDisplay = "This is an example that uses...
There are many situation where you want to draw an image that is rotated, scaled, and translated. The rotation should occur around the center of the image. This is the quickest way to do so on the 2D canvas. These functions a well suited to 2D games where the expectation is to render a few hundred e...
$ pg_dumpall -f backup.sql
This works behind the scenes by making multiple connections to the server once for each database and executing pg_dump on it.
Sometimes, you might be tempted to set this up as a cron job, so you want to see the date the backup was taken as part of the filename:
$ post...
Angular 2.0.0-rc.4
In this example we'll create a "Hello World!" app with only one root component (AppComponent) for the sake of simplicity.
Prerequisites:
Node.js v5 or later
npm v3 or later
Note: You can check versions by running node -v and npm -v in the console/terminal.
...
To convert NSString to const char use -[NSString UTF8String]:
NSString *myNSString = @"Some string";
const char *cString = [myNSString UTF8String];
You could also use -[NSString cStringUsingEncoding:] if your string is encoded with something other than UTF-8.
For the reverse path use...
Think about a situation where we need to callback a function with arguments.
std::function used with std::bind gives a very powerful design construct as shown below.
class A
{
public:
std::function<void(int, const std::string&)> m_CbFunc = nullptr;
void foo()
{
...
Redirect any naked domain to www.[your_domain].tld:
# Start Apache Rewriting engine
RewriteEngine On
# Make sure you're not already using www subdomain
# and that the host string is not empty
RewriteCond %{HTTP_HOST} !^$
RewriteCond %{HTTP_HOST} !^www\.
# We check for http/https connection ...
1. URLByDeletingPathExtension:
If the receiver represents the root path, this property contains a copy of the original URL. If the URL has multiple path extensions, only the last one is removed.
2. URLByAppendingPathExtension:
Returns a new URL made by appending a path extension to the original U...
To create a JAR containing all of its dependencies, it is possible to use the built-in descriptor format jar-with-dependencies. The following example configures an execution of the Assembly Plugin bound to the package phase, using this built-in descriptor and declaring a main class of com.example:
...
Following example illustrate the simplest Hello World in groovy using script, place the following code snippet in a file, say helloWorld.groovy
println 'Hello World!'
How to execute:
In the command line, groovy helloWorld.groovy
Output:
Hello World!
If you want to see the generated bytecode for a Java program, you can use the provided javap command to view it.
Assuming that we have the following Java source file:
package com.stackoverflow.documentation;
import org.springframework.stereotype.Service;
import java.io.IOException;
import j...
It is possible to effectively apply a function (cb) which returns a promise to each element of an array, with each element waiting to be processed until the previous element is processed.
function promiseForEach(arr, cb) {
var i = 0;
var nextPromise = function () {
if (i >= arr.leng...
