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-rw-r--r--php.html.markdown135
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diff --git a/php.html.markdown b/php.html.markdown
index c6c70cbb..33bf2859 100644
--- a/php.html.markdown
+++ b/php.html.markdown
@@ -4,17 +4,18 @@ author: Malcolm Fell
author_url: http://emarref.net/
---
-# PHP
-
This document describes PHP 5+.
## [Basic Syntax](http://www.php.net/manual/en/language.basic-syntax.php)
-All statements must end with a semi-colon; All PHP code must be between <?php and ?> tags. PHP can also be configured to respect the [short open tags](http://www.php.net/manual/en/ini.core.php#ini.short-open-tag) <? and ?>.
+All statements must end with a semi-colon; All PHP code must be between <?php and ?> tags. PHP can also be
+configured to respect the [short open tags](http://www.php.net/manual/en/ini.core.php#ini.short-open-tag) <? and ?>.
## [Comments](http://www.php.net/manual/en/language.basic-syntax.comments.php)
```php
+<?php
+
// Two forward slashes start a one-line comment.
# So will a hash (aka pound symbol) but // is more common
@@ -27,11 +28,14 @@ All statements must end with a semi-colon; All PHP code must be between <?php an
## [Types](http://www.php.net/manual/en/language.types.php)
-Types are [weakly typed](http://en.wikipedia.org/wiki/Strong_and_weak_typing) and begin with the $ symbol. A valid variable name starts with a letter or underscore, followed by any number of letters, numbers, or underscores.
+Types are [weakly typed](http://en.wikipedia.org/wiki/Strong_and_weak_typing) and begin with the $ symbol.
+A valid variable name starts with a letter or underscore, followed by any number of letters, numbers, or underscores.
### Scalars
```php
+<?php
+
// Boolean values are case-insensitive
$boolean = true; // or TRUE or True
$boolean = false; // or FALSE or False
@@ -54,20 +58,29 @@ $product = $number * $float;
$quotient = $number / $float;
// Shorthand arithmetic
-$number += 1; // Will add 1 to $number
-$number++; // Will add 1 to $number after it is used
-++$number; // Will add 1 to $number before it is used.
-$number /= $float // Will divide $number $float, and assign the quotient to $number
-
-// Strings
-$sgl_quotes = 'String'; // Strings should be enclosed in single quotes;
-$dbl_quotes = "This is a $sgl_quotes." // Avoid using double quotes to embed other variables
-$escaped = "This contains a \t tab character."; // Escape special characters with backslash
-$money = "I have $${integer} in the bank." // Enclose a variable in curly braces if needed
+$number += 1; // Add 1 to $number
+$number++; // Add 1 to $number after it is used
+++$number; // Add 1 to $number before it is used.
+$number /= $float // Divide and assign the quotient to $number
+
+// Strings should be enclosed in single quotes;
+$sgl_quotes = '$String'; // => '$String'
+
+// Avoid using double quotes except to embed other variables
+$dbl_quotes = "This is a $sgl_quotes." // => 'This is a $String'
+
+// Escape special characters with backslash
+$escaped = "This contains a \t tab character.";
+
+// Enclose a variable in curly braces if needed
+$money = "I have $${integer} in the bank."
+
+// Since PHP 5.3, nowdocs can be used for uninterpolated multi-liners
$nowdoc = <<<'END'
Multi line
string
END;
+
$heredoc = <<<END
Multi line
$sgl_quotes
@@ -80,6 +93,8 @@ $concatenated = $sgl_quotes . $dbl_quotes;
### Compound
```php
+<?php
+
// Arrays
$array = array(1, 2, 3);
$array = [1, 2, 3]; // As of PHP 5.4
@@ -94,15 +109,24 @@ $associative["One"]; // Holds the value 1
## Output
```php
-echo('Hello World!'); // Prints Hello World! to stdout. Stdout is the web page if running in a browser.
+<?php
+
+echo('Hello World!');
+// Prints Hello World! to stdout.
+// Stdout is the web page if running in a browser.
+
print('Hello World!'); // The same as echo
-echo 'Hello World!'; // echo is actually a language construct, so you can drop the parentheses.
+
+// echo is actually a language construct, so you can drop the parentheses.
+echo 'Hello World!';
print 'Hello World!'; // So is print
+
echo 100;
echo $variable;
-echo function_result(); // Output the result of a function call that returns a value. More on functions later.
+echo function_result();
-// If [short open tags](http://www.php.net/manual/en/ini.core.php#ini.short-open-tag) are configured, or your PHP version is 5.4.0 or greater, you can use the short echo syntax
+// If short open tags are configured, or your PHP version is
+// 5.4.0 or greater, you can use the short echo syntax
<?= $variable ?>
```
@@ -111,15 +135,21 @@ echo function_result(); // Output the result of a function call that returns a v
### Assignment
```php
+<?php
+
$x = 1;
$y = 2;
$x = $y; // A now contains the same value sa $y
-$x = &$y; // A now contains a reference to $y. Changing the value of $x will change the value of $y also, and vice-versa.
+$x = &$y;
+// $x now contains a reference to $y. Changing the value of
+// $x will change the value of $y also, and vice-versa.
```
### Comparison
```php
+<?php
+
// These comparisons will always be true, even if the types aren't the same.
$a == $b // TRUE if $a is equal to $b after type juggling.
$a != $b // TRUE if $a is not equal to $b after type juggling.
@@ -141,14 +171,18 @@ $a !== $b // TRUE if $a is not equal to $b, or they are not of the same type.
Variables can be converted between types, depending on their usage.
```php
+<?php
+
$integer = 1;
echo $integer + $integer; // Outputs 2;
$string = '1';
-echo $string + $string; // Also outputs 2 because the + operator converts the strings to integers
+echo $string + $string;
+// Also outputs 2 because the + operator converts the strings to integers
$string = 'one';
-echo $string + $string; // Outputs 0 because the + operator cannot cast the string 'one' to a number
+echo $string + $string;
+// Outputs 0 because the + operator cannot cast the string 'one' to a number
```
Type casting can be used to treat a variable as another type temporarily by using cast operators in parentheses.
@@ -160,7 +194,8 @@ $zero = 0;
$boolean = (boolean) $zero; // $boolean is false
$integer = 5;
-$string = strval($integer); // There are also dedicated functions for casting most types
+$string = strval($integer);
+// There are also dedicated functions for casting most types
$var = null; // Null value
```
@@ -170,6 +205,8 @@ $var = null; // Null value
### If Statements
```php
+<?php
+
if (/* test */) {
// Do something
}
@@ -193,6 +230,7 @@ if (/* test */) {
} else {
// Do something default
}
+?>
<?php if (/* test */): ?>
This is displayed if the test is truthy.
@@ -204,6 +242,8 @@ This is displayed otherwise.
### Switch statements
```php
+<?php
+
switch ($variable) {
case 'one':
// Do something if $variable == 'one'
@@ -221,6 +261,8 @@ switch ($variable) {
### Loops
```php
+<?php
+
$i = 0;
while ($i < 5) {
echo $i++;
@@ -247,7 +289,6 @@ while ($i < 5) {
if ($i == 3) {
break; // Exit out of the while loop and continue.
}
-
echo $i++;
}
@@ -257,7 +298,6 @@ while ($i < 5) {
if ($i == 3) {
continue; // Skip this iteration of the loop
}
-
echo $i++;
}
```
@@ -267,6 +307,8 @@ while ($i < 5) {
Functions are created with the ```function``` keyword.
```php
+<?php
+
function my_function($my_arg) {
$my_variable = 1;
}
@@ -277,16 +319,21 @@ function my_function($my_arg) {
Functions may be invoked by name.
```php
+<?php
+
my_function_name();
$variable = get_something(); // A function may return a value
```
-A valid function name starts with a letter or underscore, followed by any number of letters, numbers, or underscores. There are three ways to declare functions.
+A valid function name starts with a letter or underscore, followed by any
+number of letters, numbers, or underscores. There are three ways to declare functions.
### [User-defined](http://www.php.net/manual/en/functions.user-defined.php)
```php
+<?php
+
function my_function_name ($arg_1, $arg_2) { // $arg_1 and $arg_2 are required
// Do something with $arg_1 and $arg_2;
}
@@ -320,6 +367,8 @@ $bar('C');
### [Variable](http://www.php.net/manual/en/functions.variable-functions.php)
```php
+<?php
+
$function_name = 'my_function_name';
$function_name(); // will execute the my_function_name() function
@@ -330,6 +379,8 @@ $function_name(); // will execute the my_function_name() function
Similar to variable functions, functions may be anonymous.
```php
+<?php
+
function my_function($callback) {
$callback('My argument');
}
@@ -351,6 +402,8 @@ $my_function();
Classes are defined with the ```class``` keyword.
```php
+<?php
+
class MyClass {
const MY_CONST = 'value';
static $staticVar = 'something';
@@ -363,20 +416,20 @@ final class YouCannotExtendMe {
}
```
-Classes are insantiated with the ```new``` keyword. Functions are referred to as methods if they belong to a class.
+Classes are insantiated with the ```new``` keyword. Functions are referred to as
+methods if they belong to a class.
```php
+<?php
+
class MyClass {
- function myFunction()
- {
+ function myFunction() {
}
- final function youCannotOverrideMe()
- {
+ final function youCannotOverrideMe() {
}
- public static function myStaticMethod()
- {
+ public static function myStaticMethod() {
}
}
@@ -392,6 +445,8 @@ MyClass::myStaticMethod(); // myStaticMethod cannot be run on $cls
PHP offers some [magic methods](http://www.php.net/manual/en/language.oop5.magic.php) for classes.
```php
+<?php
+
class MyClass {
private $property;
@@ -407,14 +462,16 @@ class MyClass {
}
$x = new MyClass();
-echo $x->property; // Will use the __get() method to retrieve the value of $property
-$x->property = 'Something'; // Will use the __set() method to set the value of property
+echo $x->property; // Will use the __get() method
+$x->property = 'Something'; // Will use the __set() method
```
Classes can be abstract (using the ```abstract``` keyword), extend other classes (using the ```extends``` keyword) and
implement interfaces (using the ```implements``` keyword). An interface is declared with the ```interface``` keyword.
```php
+<?php
+
interface InterfaceOne
{
public function doSomething();
@@ -444,10 +501,14 @@ class SomeOtherClass implements InterfaceOne, InterfaceTwo
By default, classes exist in the global namespace, and can be explicitly called with a backslash.
```php
+<?php
+
$cls = new \MyClass();
```
```php
+<?php
+
namespace My\Namespace;
class MyClass
@@ -460,6 +521,8 @@ $cls = new My\Namespace\MyClass;
Or from within another namespace.
```php
+<?php
+
namespace My\Other\Namespace;
use My\Namespace\MyClass;
@@ -470,6 +533,8 @@ $cls = new MyClass();
Or you can alias the namespace;
```php
+<?php
+
namespace My\Other\Namespace;
use My\Namespace as SomeOtherNamespace;
@@ -482,6 +547,8 @@ $cls = new SomeOtherNamespace\MyClass();
Traits are available since PHP 5.4.0 and are declared using the ```trait``` keyword.
```php
+<?php
+
trait MyTrait {
public function myTraitMethod()
{