Go programs end when the main function ends, therefore it is common practice to wait for all goroutines to finish. A common solution for this is to use a sync.WaitGroup object.
package main
import (
"fmt"
"sync"
)
var wg sync.WaitGroup // 1
func routine(i int...
You shouldn't call NSLog without a literal format string like this:
NSLog(variable); // Dangerous code!
If the variable is not an NSString, the program will crash, because NSLog expects an NSString.
If the variable is an NSString, it will work unless your string contains a %. NSLog will pars...
A useful tool in Java Concurrency is ThreadLocal – this allows you to have a variable that will be unique to a given thread. Thus, if the same code runs in different threads, these executions will not share the value, but instead each thread has its own variable that is local to the thread.
For exa...
When two margins are touching each other vertically, they are collapsed. When two margins touch horizontally, they do not collapse.
Example of adjacent vertical margins:
Consider the following styles and markup:
div{
margin: 10px;
}
<div>
some content
</div>
<div>...
We can illustrate this problem with the following pseudo-code
function foo() {
global $bob;
$bob->doSomething();
}
Your first question here is an obvious one
Where did $bob come from?
Are you confused? Good. You've just learned why globals are confusing and considered a bad p...
Bool is a Boolean type with two possible values: true and false.
let aTrueBool = true
let aFalseBool = false
Bools are used in control-flow statements as conditions.
The if statement uses a Boolean condition to determine which block of code to run:
func test(_ someBoolean: Bool) {
if som...
The prefix ! operator returns the logical negation of its argument. That is, !true returns false, and !false returns true.
print(!true) // prints "false"
print(!false) // prints "true"
func test(_ someBoolean: Bool) {
if !someBoolean {
print("someBoolean ...
Table cells can span multiple columns or rows using the colspan and rowspan attributes. These attributes can be applied to <th> and <td> elements.
<table>
<tr>
<td>row 1 col 1</td>
<td>row 1 col 2</td>
<td>row 1 c...
It’s a good practice to declare the primary language of the document in the html element:
<html lang="en">
If no other lang attribute is specified in the document, it means that everything (i.e., element content and attribute text values) is in that language.
If the document con...
The <section> element represents a generic section to thematically group content. Every section, typically, should be able to be identified with a heading element as a child of the section.
You can use the <section> element within an <article> and vice-versa.
Every section shou...
Object initializers are the only way to initialize anonymous types, which are types generated by the compiler.
var album = new { Band = "Beatles", Title = "Abbey Road" };
For that reason object initializers are widely used in LINQ select queries, since they provide a convenie...
The construct (?R) is equivalent to (?0) (or \g<0>) - it lets you recurse the whole pattern:
<(?>[^<>]+|(?R))+>
This will match properly balanced angle brackets with any text in-between the brackets, like <a<b>c<d>e>.
You can recurse into a subpattern using the following constructs (depending on the flavor), assuming n is a capturing group number, and name the name of a capturing group.
(?n)
\g<n>
\g'0'
(?&name)
\g<name>
\g'name'
(?P>name)
The following pattern:
\[(?<angle>&...
The (?(DEFINE)...) construct lets you define subpatterns you may reference later through recursion. When encountered in the pattern it will not be matched against.
This group should contain named subpattern definitions, which will be accessible only through recursion. You can define grammars this w...
Subpatterns can be referenced with their relative group number:
(?-1) will recurse into the previous group
(?+1) will recurse into the next group
Also usable with the \g<N> syntax.
Documentation comments are placed directly above the method or class they describe. They begin with three forward slashes ///, and allow meta information to be stored via XML.
/// <summary>
/// Bar method description
/// </summary>
public void Bar()
{
}
Information in...
You can create a horizontal break to divide your text by placing three (or more) underscores
___
or asterisks
***
or hyphens
---
on their own line.
You can create a horizontal break to divide your text by placing three (or more) underscores
or asterisks
or hyphens
o...
