alan-ps · August 3, 2019 13:44 · Aug 3, 2019 · Aug 3, 2019 · May 30, 2019 · May 30, 2019
diff --git a/php_interested_func_things.md b/php_interested_func_things.md
@@ -67,9 +67,6 @@ $closure = function() use ($string) {
 };
 $closure(); // Hello World!
 ```
-##### Helpful links:
-* [RFC: Lambda functions and closures](https://wiki.php.net/rfc/closures)
-* [Difference between closure parameters and the use keyword](https://stackoverflow.com/questions/10692817/whats-the-difference-between-closure-parameters-and-the-use-keyword)
 
 ##### Early and Late Binding
 ```php
@@ -129,4 +126,7 @@ print_r($test2); // Some another text
 (function() {
   echo 'Hello World!';
 })();
-```
+```
+##### Helpful links:
+* [RFC: Lambda functions and closures](https://wiki.php.net/rfc/closures)
+* [Difference between closure parameters and the use keyword](https://stackoverflow.com/questions/10692817/whats-the-difference-between-closure-parameters-and-the-use-keyword)
diff --git a/php_interested_func_things.md b/php_interested_func_things.md
@@ -67,6 +67,9 @@ $closure = function() use ($string) {
 };
 $closure(); // Hello World!
 ```
+##### Helpful links:
+* [RFC: Lambda functions and closures](https://wiki.php.net/rfc/closures)
+* [Difference between closure parameters and the use keyword](https://stackoverflow.com/questions/10692817/whats-the-difference-between-closure-parameters-and-the-use-keyword)
 
 ##### Early and Late Binding
 ```php

diff --git a/php_interested_func_things.md b/php_interested_func_things.md
@@ -119,3 +119,11 @@ $test2 = Closure::bind($testA->showText(), $testB);
 print_r($test1); // Some another text
 print_r($test2); // Some another text
 ``` 
+##### Self-Executing Closures
+```php
+<?php
+// Displays 'Hello World!'.
+(function() {
+  echo 'Hello World!';
+})();
+```
diff --git a/php_interested_func_things.md b/php_interested_func_things.md
@@ -93,3 +93,29 @@ $b = function() use (&$a) {
 $a = 'Hello World!';
 $b(); // Hello World!
 ```
+##### Binding Closures to Scopes
+```php
+<?php
+
+class test {
+  protected $text = 'Default text';
+
+  public function showText() {
+    return function () { return $this->text; };
+  }
+}
+
+class testA extends test {}
+class testB {
+  protected $text = 'Some another text';
+}
+
+$testA = new testA();
+$testB = new testB();
+
+$test1 = $testA->showText()->bindTo($testB);
+$test2 = Closure::bind($testA->showText(), $testB);
+
+print_r($test1); // Some another text
+print_r($test2); // Some another text
+``` 
diff --git a/php_interested_func_things.md b/php_interested_func_things.md
@@ -66,4 +66,30 @@ $closure = function() use ($string) {
   echo $string;
 };
 $closure(); // Hello World!
-```
+```
+
+##### Early and Late Binding
+```php
+<?php
+
+$a = 'Some string';
+// Early binding (default).
+$b = function() use ($a) {
+  echo $a;
+};
+
+$a = 'Hello World!';
+$b(); // Some string
+```
+```php
+<?php
+
+$a = 'Some string';
+// Late binding (reference).
+$b = function() use (&$a) {
+  echo $a;
+};
+
+$a = 'Hello World!';
+$b(); // Hello World!
+```
diff --git a/php_interested_func_things.md b/php_interested_func_things.md
@@ -48,7 +48,7 @@ function myFunc(): void {
 sayWorld(); // Hello World!
 ```
 
-### Lambda
+### Lambda and Closure
 
 ```php
 <?php
@@ -60,4 +60,10 @@ $lambda = function($a, $b) {
 $lambda(2, 3); // 5
 echo (int) is_callable($lambda); // 1
 echo get_class($lambda); // Closure
+
+$string = 'Hello World!';
+$closure = function() use ($string) {
+  echo $string;
+};
+$closure(); // Hello World!
 ```
diff --git a/php_interested_func_things.md b/php_interested_func_things.md
@@ -46,4 +46,18 @@ function myFunc(): void {
 }
 
 sayWorld(); // Hello World!
+```
+
+### Lambda
+
+```php
+<?php
+
+$lambda = function($a, $b) {
+  echo $a + $b;
+};
+
+$lambda(2, 3); // 5
+echo (int) is_callable($lambda); // 1
+echo get_class($lambda); // Closure
 ```
diff --git a/php_interested_things.md → php_interested_func_things.md b/php_interested_things.md → php_interested_func_things.md
@@ -4,7 +4,7 @@
 <?php
 
 function myFunc(?MyObject $myObj) {
-  echo 'Hello world!';
+  echo 'Hello World!';
 }
 
 myFunc(null); // this is allowed
@@ -34,3 +34,16 @@ function getFullName(string $firstName, string $lastName): string {
 $name = getFullName('Serhii', 'Puchkovskyi');
 echo gettype($name); // string
 ```
+
+### Return Void
+If the function is going to return NULL, we can specify that it will return "void":
+
+```php
+<?php
+
+function myFunc(): void {
+  echo 'Hello World!';
+}
+
+sayWorld(); // Hello World!
+```
diff --git a/php_interested_things.md b/php_interested_things.md
@@ -0,0 +1,36 @@
+### Alternate Null Type Syntax
+
+```php
+<?php
+
+function myFunc(?MyObject $myObj) {
+  echo 'Hello world!';
+}
+
+myFunc(null); // this is allowed
+myFunc(); // this produces a fatal error: Too few arguments
+```
+
+### Variadics
+
+```php
+<?php
+
+function myFunc($required, $optional = NULL, ...$variadicParams) {
+  print_r($variadicParams);
+}
+
+myFunc(1, 2, 3, 4); // array([0] => 3, [1] => 4);
+```
+
+### Return Type Declarations
+```php
+<?php
+
+function getFullName(string $firstName, string $lastName): string {
+  return 100;
+}
+
+$name = getFullName('Serhii', 'Puchkovskyi');
+echo gettype($name); // string
+```