Merge branch 'master' of https://github.com/adambard/learnxinyminutes-docs

1 files changed, 144 insertions, 14 deletions

diff --git a/php.html.markdown b/php.html.markdown
index 52ea2a95..cf9544b3 100644
--- a/php.html.markdown
+++ b/php.html.markdown
@@ -12,7 +12,7 @@ This document describes PHP 5+.
 <?php // PHP code must be enclosed with <?php tags
 
 // If your php file only contains PHP code, it is best practice
-// to omit the php closing tag.
+// to omit the php closing tag to prevent accidental output.
 
 // Two forward slashes start a one-line comment.
 
@@ -103,6 +103,9 @@ END;
 // String concatenation is done with .
 echo 'This string ' . 'is concatenated';
 
+// Strings can be passed in as parameters to echo
+echo 'Multiple', 'Parameters', 'Valid';  // Returns 'MultipleParametersValid'
+
 
 /********************************
  * Constants
@@ -115,8 +118,10 @@ echo 'This string ' . 'is concatenated';
 // followed by any number of letters, numbers, or underscores.
 define("FOO",     "something");
 
-// access to a constant is possible by direct using the choosen name
-echo 'This outputs '.FOO;
+// access to a constant is possible by calling the choosen name without a $
+echo FOO; // Returns 'something'
+echo 'This outputs '.FOO;  // Returns 'This ouputs something'
+
 
 
 /********************************
@@ -141,6 +146,8 @@ echo $array[0]; // => "One"
 
 // Add an element to the end of an array
 $array[] = 'Four';
+// or
+array_push($array, 'Five');
 
 // Remove element from array
 unset($array[3]);
@@ -155,9 +162,9 @@ echo('Hello World!');
 
 print('Hello World!'); // The same as echo
 
-// echo is actually a language construct, so you can drop the parentheses.
+// echo and print are language constructs too, so you can drop the parentheses
 echo 'Hello World!';
-print 'Hello World!'; // So is print
+print 'Hello World!';
 
 $paragraph = 'paragraph';
 
@@ -215,6 +222,18 @@ assert($a !== $d);
 assert(1 === '1');
 assert(1 !== '1');
 
+// 'Spaceship' operator (since PHP 7)
+// Returns 0 if values on either side are equal
+// Returns 1 if value on the left is greater
+// Returns -1 if the value on the right is greater
+
+$a = 100;
+$b = 1000;
+
+echo $a <=> $a; // 0 since they are equal
+echo $a <=> $b; // -1 since $a < $b
+echo $b <=> $a; // 1 since $b > $a
+
 // Variables can be converted between types, depending on their usage.
 
 $integer = 1;
@@ -264,6 +283,18 @@ if (false) {
 // ternary operator
 print (false ? 'Does not get printed' : 'Does');
 
+// ternary shortcut operator since PHP 5.3
+// equivalent of "$x ? $x : 'Does'""
+$x = false;
+print($x ?: 'Does');
+
+// null coalesce operator since php 7
+$a = null;
+$b = 'Does print';
+echo $a ?? 'a is not set'; // prints 'a is not set'
+echo $b ?? 'b is not set'; // prints 'Does print'
+
+
 $x = 0;
 if ($x === '0') {
     print 'Does not print';
@@ -359,7 +390,7 @@ for ($i = 0; $i < 5; $i++) {
 
 // Define a function with "function":
 function my_function () {
-  return 'Hello';
+    return 'Hello';
 }
 
 echo my_function(); // => "Hello"
@@ -368,8 +399,8 @@ echo my_function(); // => "Hello"
 // number of letters, numbers, or underscores.
 
 function add ($x, $y = 1) { // $y is optional and defaults to 1
-  $result = $x + $y;
-  return $result;
+    $result = $x + $y;
+    return $result;
 }
 
 echo add(4); // => 5
@@ -380,21 +411,21 @@ echo add(4, 2); // => 6
 
 // Since PHP 5.3 you can declare anonymous functions;
 $inc = function ($x) {
-  return $x + 1;
+    return $x + 1;
 };
 
 echo $inc(2); // => 3
 
 function foo ($x, $y, $z) {
-  echo "$x - $y - $z";
+    echo "$x - $y - $z";
 }
 
 // Functions can return functions
 function bar ($x, $y) {
-  // Use 'use' to bring in outside variables
-  return function ($z) use ($x, $y) {
-    foo($x, $y, $z);
-  };
+    // Use 'use' to bring in outside variables
+    return function ($z) use ($x, $y) {
+        foo($x, $y, $z);
+    };
 }
 
 $bar = bar('A', 'B');
@@ -406,6 +437,31 @@ echo $function_name(1, 2); // => 3
 // Useful for programatically determining which function to run.
 // Or, use call_user_func(callable $callback [, $parameter [, ... ]]);
 
+
+// You can get the all the parameters passed to a function
+function parameters() {
+    $numargs = func_num_args();
+    if ($numargs > 0) {
+        echo func_get_arg(0) . ' | ';
+    }
+    $args_array = func_get_args();
+    foreach ($args_array as $key => $arg) {
+        echo $key . ' - ' . $arg . ' | ';
+    }
+}
+
+parameters('Hello', 'World'); // Hello | 0 - Hello | 1 - World |
+
+// Since PHP 5.6 you can get a variable number of arguments
+function variable($word, ...$list) {
+	echo $word . " || ";
+	foreach ($list as $item) {
+		echo $item . ' | ';
+	}
+}
+
+variable("Separate", "Hello", "World") // Separate || Hello | World | 
+
 /********************************
  * Includes
  */
@@ -495,7 +551,9 @@ class MyClass
     }
 }
 
+// Class constants can always be accessed statically
 echo MyClass::MY_CONST;    // Outputs 'value';
+
 echo MyClass::$staticVar;  // Outputs 'static';
 MyClass::myStaticMethod(); // Outputs 'I am static';
 
@@ -671,8 +729,80 @@ use My\Namespace as SomeOtherNamespace;
 
 $cls = new SomeOtherNamespace\MyClass();
 
+
+/**********************
+* Late Static Binding
+*
+* /
+
+class ParentClass {
+    public static function who() {
+        echo "I'm a " . __CLASS__ . "\n";
+    }
+    public static function test() {
+        // self references the class the method is defined within
+        self::who();
+        // static references the class the method was invoked on
+        static::who();
+    }
+}
+
+ParentClass::test();
+/*
+I'm a ParentClass
+I'm a ParentClass
+*/
+
+class ChildClass extends ParentClass {
+    public static function who() {
+        echo "But I'm " . __CLASS__ . "\n";
+    }
+}
+
+ChildClass::test();
+/*
+I'm a ParentClass
+But I'm ChildClass
+*/
+
+
+/**********************
+*  Error Handling
+*  
 */
 
+// Simple error handling can be done with try catch block
+
+try {
+    // Do something
+} catch (Exception $e) {
+    // Handle exception
+}
+
+// When using try catch blocks in a namespaced enviroment use the following
+
+try {
+    // Do something
+} catch (\Exception $e) {
+    // Handle exception
+}
+
+// Custom exceptions
+
+class MyException extends Exception {}
+
+try {
+
+    $condition = true;
+
+    if ($condition) {
+        throw new MyException('Something just happend');
+    }
+
+} catch (MyException $e) {
+    // Handle my exception
+}
+
 ```
 
 ## More Information