Concepts adjustments (#552)

concepts/anonymous-functions-closures/about.md

@@ -36,7 +36,7 @@ PHP also has a shorter function syntax called `arrow functions`. They are requir
 fn(arguments) => expression
 ```
 
-In this function style, you do not need to use `use`. It will automatically closed over and capture any values in the parent scope. The expression in these arrow functions is automatically returned without needing to use the `return` keyword. That would allow us to rewrite the `onlyOdds` function above like so:
+In this function style, you do not need to use `use`. It will automatically close over and capture any values in the parent scope. The expression in these arrow functions is automatically returned without needing to use the `return` keyword. That would allow us to rewrite the `onlyOdds` function above like so:
 
 ```php
 function onlyOdds(array $numbers): array
@@ -64,7 +64,7 @@ function positiveAverage(array $numbers): float
     $count = 0;
     return array_walk(
       $numbers, 
-      function($num) use (&$count, %$toal) {
+      function($num) use (&$count, &$total) {
           $total += abs($num);
           $count++;
       }

concepts/foreach-loops/.meta/config.json

@@ -3,5 +3,5 @@
   "authors": [
     "neenjaw"
   ],
-  "contributors": []
+  "contributors": ["vnkmpf"]
 }

concepts/foreach-loops/about.md

@@ -12,13 +12,3 @@ foreach (iterable as $key => $value) {
 }
 ```
 
-When iterating arrays, it is possible to modify the original array by preceding the `$value` with `&`:
-
-```php
-foreach (iterable as &$value) {
-  // statements
-}
-unset($value);
-```
-
-However, `$value` persists after the `foreach` block so it is **strongly** recommended to break the reference using `unset($value)` after the block.

concepts/readonly-properties/about.md

@@ -10,8 +10,8 @@ The property is allowed to be assigned once, but any attempt to re-assign or mod
 class Block
 {
     public function __construct(
-        public readonly int $length;
-        public readonly int $width;
+        public readonly int $length,
+        public readonly int $width,
     ) {
     }
 }
@@ -26,8 +26,8 @@ Additionally it prevents the addition of dynamic properties.
 readonly class Block
 {
     public function __construct(
-        public int $length;
-        public int $width;
+        public int $length,
+        public int $width,
     ) {
     }
 }

concepts/scope-resolution-operator/about.md

@@ -80,7 +80,7 @@ class AnotherClass extends MyClass
 // (new AnotherClass())->getMaximum() => 10
 ```
 
-Most commonly in object oriented programming `parent` is used to call the call the parent constructor when an object is being instantiated:
+Most commonly in object oriented programming `parent` is used to call the parent constructor when an object is being instantiated:
 
 ```php
 class ChildClass extends ParentClass

concepts/ternary-operator/about.md

@@ -40,7 +40,7 @@ The obvious benefit of using a ternary operator is brevity, such that it is shor
   }
 
   $needExactAnswer = false;
-  $estimatedAnswer = 40
+  $estimatedAnswer = 40;
   $answer = $needExactAnswer ? expensiveCalculation() : $estimatedAnswer;
   ```
 

concepts/union-types/.meta/config.json

@@ -3,5 +3,5 @@
   "authors": [
     "neenjaw"
   ],
-  "contributors": ["dstockto"]
+  "contributors": ["dstockto","vnkmpf"]
 }

concepts/union-types/about.md

@@ -11,7 +11,6 @@ function add(int|float $a, int|float $b): int|float
 
 ## Nuances
 
-- `null` cannot be used as a standalone type, but types may be declared _nullable_ by either using `?Type` or `Type1|Type2|null`.
-- `false` cannot be used as a standalone type, and is included for historical reasons, as many legacy functions may return `false` when an error is encountered.
+- `null` types may be declared _nullable_ by either using `?Type` or `Type1|Type2|null`.
 - declared duplicate or redundant types will result in a compile-time error.
 - `void` cannot be used as part of a union type declaration.

docs/INSTALLATION.md

@@ -2,7 +2,7 @@
 
 ## Which version to chose?
 
-We encourage to use a stable PHP release with active support. Currently this is **PHP 7.3, 7.4 and 8.0**. Details on current releases and their timelines can be found at [php.net/supported-versions](https://www.php.net/supported-versions.php). PHP 7.3 is only supported until December 2021, so PHP 7.4 or 8.0 are preferred. Version 8.1 will be available in late November 2021.
+We encourage to use a stable PHP release with active support. Currently this is **PHP 8.0, 8.1 and 8.2**. Details on current releases and their timelines can be found at [php.net/supported-versions](https://www.php.net/supported-versions.php).
 
 ## Install PHP
 
@@ -30,19 +30,19 @@ For further instructions, read the manual on [Installation on Unix systems](http
 
 ### macOS
 
-While PHP is often bundled with macOS, it is often outdated. We recommended installing php through [Homebrew](https://brew.sh/). You can install Homebrew following the instructions [here](https://brew.sh/#install).
+While PHP is often bundled with macOS, it is often outdated. We recommended installing PHP through [Homebrew](https://brew.sh/). You can install Homebrew following the instructions [here](https://brew.sh/#install).
 
 To confirm its installation try the following command, it should output Homebrew `3.2.x` at the time of this writing.
 ```bash
 $ brew --version 
 ```
 
-Install php via homebrew
+Install PHP via homebrew
 ```bash
 $ brew install [email protected]
 ```
 
-This should display the now installed version of php, at least version `8.0.x`.
+This should display the now installed version of PHP, at least version `8.0.x`.
 ```bash
 $ php -v
 ```
@@ -57,6 +57,11 @@ There are pre-built stacks including [WAMP](https://www.wampserver.com/en/) - (W
 
 For further instructions, read the manual on [Installation on Windows systems](https://www.php.net/manual/en/install.windows.php).
 
+### Docker
+
+If you prefer containerized solutions, you can download [official PHP image from Docker Hub](https://hub.docker.com/_/php).
+You will also need [Docker](https://docs.docker.com/engine/install/).
+
 ### Other
 
 If you want to use a different OS, see instruction on [php.net/manual/en/install](https://www.php.net/manual/en/install.php).
@@ -74,7 +79,7 @@ PHPUnit version 9 can be installed globally via [Composer](https://getcomposer.o
 > composer global require phpunit/phpunit ^9
 ```
 
-It you are using PHP 8+ make sure you install at version 9.5 or later.
+If you are using PHP 8+ make sure you install at version 9.5 or later.
 
 #### Manual installation