PHP Keywords and types should be in lowercase

Follow PSR-12 and use lowercase variants of PHP reserved keywords.
See: https://www.php-fig.org/psr/psr-12/#25-keywords-and-types

Find all uppercase occurrences of "or", "and", "null", "true" and
"false" and change them to the lowercase variant.

22 files changed, 88 insertions, 88 deletions

diff --git a/core/application.php b/core/application.php
index cb2e5b2..80ea1e7 100644
--- a/core/application.php
+++ b/core/application.php
@@ -42,14 +42,14 @@ set_exception_handler(function(Throwable $Exception) {
 #===============================================================================
 # Initialize HTTP class and remove all arrays from $_GET and $_POST
 #===============================================================================
-HTTP::init($_GET, $_POST, $_FILES, TRUE);
+HTTP::init($_GET, $_POST, $_FILES, true);
 
 #===============================================================================
 # Set default configuration
 #===============================================================================
 foreach([
 	'CORE.LANGUAGE' => 'en',
-	'CORE.SEND_304' => FALSE,
+	'CORE.SEND_304' => false,
 	'BLOGMETA.NAME' => 'Example blog',
 	'BLOGMETA.DESC' => 'This is an example blog.',
 	'BLOGMETA.HOME' => 'Home',
@@ -59,7 +59,7 @@ foreach([
 	'DATABASE.BASENAME' => 'blog',
 	'DATABASE.USERNAME' => 'blog',
 	'DATABASE.PASSWORD' => '',
-	'MIGRATOR.ENABLED' => TRUE,
+	'MIGRATOR.ENABLED' => true,
 	'TEMPLATE.NAME' => 'default',
 	'TEMPLATE.LANG' => 'en',
 	'ADMIN.TEMPLATE' => 'admin',
@@ -67,15 +67,15 @@ foreach([
 	'PATHINFO.PROT' => $_SERVER['REQUEST_SCHEME'] ?? 'https',
 	'PATHINFO.HOST' => $_SERVER['HTTP_HOST'] ?? 'localhost',
 	'PATHINFO.BASE' => '',
-	'WRAP_EMOTICONS' => TRUE,
+	'WRAP_EMOTICONS' => true,
 	'CATEGORY.DIRECTORY' => 'category',
 	'PAGE.DIRECTORY' => 'page',
 	'POST.DIRECTORY' => 'post',
 	'USER.DIRECTORY' => 'user',
-	'CATEGORY.SLUG_URLS' => TRUE,
-	'PAGE.SLUG_URLS' => TRUE,
-	'POST.SLUG_URLS' => TRUE,
-	'USER.SLUG_URLS' => TRUE,
+	'CATEGORY.SLUG_URLS' => true,
+	'PAGE.SLUG_URLS' => true,
+	'POST.SLUG_URLS' => true,
+	'USER.SLUG_URLS' => true,
 	'CATEGORY.LIST_SIZE' => 10,
 	'PAGE.LIST_SIZE' => 10,
 	'POST.LIST_SIZE' => 10,
@@ -85,10 +85,10 @@ foreach([
 	'PAGE.DESCRIPTION_SIZE' => 200,
 	'POST.DESCRIPTION_SIZE' => 200,
 	'USER.DESCRIPTION_SIZE' => 200,
-	'CATEGORY.REDIRECT_SINGLE' => FALSE,
-	'PAGE.REDIRECT_SINGLE' => FALSE,
-	'POST.REDIRECT_SINGLE' => FALSE,
-	'USER.REDIRECT_SINGLE' => FALSE,
+	'CATEGORY.REDIRECT_SINGLE' => false,
+	'PAGE.REDIRECT_SINGLE' => false,
+	'POST.REDIRECT_SINGLE' => false,
+	'USER.REDIRECT_SINGLE' => false,
 	'CATEGORY.LIST_SORT' => 'name ASC',
 	'PAGE.LIST_SORT' => 'time_insert DESC',
 	'POST.LIST_SORT' => 'time_insert DESC',
@@ -133,7 +133,7 @@ if(Application::get('MIGRATOR.ENABLED')) {
 #===============================================================================
 # Override configuration if admin
 #===============================================================================
-if(defined('ADMINISTRATION') AND ADMINISTRATION === TRUE) {
+if(defined('ADMINISTRATION') and ADMINISTRATION === true) {
 
 	#===========================================================================
 	# Enable sessions
@@ -143,7 +143,7 @@ if(defined('ADMINISTRATION') AND ADMINISTRATION === TRUE) {
 	#===========================================================================
 	# Authentication check
 	#===========================================================================
-	if(defined('AUTHENTICATION') AND !Application::isAuthenticated()) {
+	if(defined('AUTHENTICATION') and !Application::isAuthenticated()) {
 		HTTP::redirect(Application::getAdminURL('auth.php'));
 	}
 
@@ -164,7 +164,7 @@ $Database = Application::getDatabase();
 #===============================================================================
 # Check if "304 Not Modified" and ETag header should be sent
 #===============================================================================
-if(Application::get('CORE.SEND_304') AND !defined('ADMINISTRATION')) {
+if(Application::get('CORE.SEND_304') and !defined('ADMINISTRATION')) {
 
 	#===========================================================================
 	# Fetch timestamps of the last modified entities
@@ -195,7 +195,7 @@ if(Application::get('CORE.SEND_304') AND !defined('ADMINISTRATION')) {
 	#===========================================================================
 	# Return "304 Not Modified" if the clients ETag value matches
 	#===========================================================================
-	if(strpos($_SERVER['HTTP_IF_NONE_MATCH'] ?? '', $etag) !== FALSE) {
-		Application::exit(NULL, 304);
+	if(strpos($_SERVER['HTTP_IF_NONE_MATCH'] ?? '', $etag) !== false) {
+		Application::exit(null, 304);
 	}
 }
diff --git a/core/functions.php b/core/functions.php
index 15a5318..ffc1e1c 100644
--- a/core/functions.php
+++ b/core/functions.php
@@ -32,7 +32,7 @@ function createPaginationTemplate($current, $last, string $location): Template {
 #===============================================================================
 # Helper function to reduce duplicate code
 #===============================================================================
-function generateCategoryItemTemplate(Category $Category, bool $is_root = FALSE): Template {
+function generateCategoryItemTemplate(Category $Category, bool $is_root = false): Template {
 	$CategoryRepository = Application::getRepository('Category');
 
 	foreach($CategoryRepository->findWithParents($Category->getID()) as $Category) {
@@ -121,8 +121,8 @@ function generateItemTemplateData(EntityInterface $Entity): array {
 		'ARGV' => $arguments,
 		'ATTR' => $attribute,
 
-		'PREV' => FALSE,
-		'NEXT' => FALSE,
+		'PREV' => false,
+		'NEXT' => false,
 
 		'FILE' => [
 			'LIST' => $images,
@@ -292,7 +292,7 @@ function generateSlug($string, $separator = '-') {
 #===========================================================================
 # Callback for (CATEGORY|PAGE|POST|USER) content function
 #===========================================================================
-function getEntityMarkdownLink($ns, $id, $text = NULL, $info = NULL): string {
+function getEntityMarkdownLink($ns, $id, $text = null, $info = null): string {
 	if(!$Entity = Application::getRepository($ns)->find($id)) {
 		return sprintf('`{%s: *Reference error*}`', strtoupper($ns));
 	}
@@ -301,7 +301,7 @@ function getEntityMarkdownLink($ns, $id, $text = NULL, $info = NULL): string {
 	$href = Application::getEntityURL($Entity);
 	$text = $text ?: "»{$title}«";
 
-	if($info === NULL) {
+	if($info === null) {
 		$info = sprintf('%s »%s«',
 			Application::getLanguage()->text(strtolower($ns)),
 			$title);
@@ -399,7 +399,7 @@ foreach(['CATEGORY', 'PAGE', 'POST', 'USER'] as $function) {
 
 	// Get Markdown formatted entity link
 	Application::addContentFunction($function,
-	function($id, $text = NULL, $title = NULL) use($entity) {
+	function($id, $text = null, $title = null) use($entity) {
 		return getEntityMarkdownLink($entity, $id, $text, $title);
 	});
 
diff --git a/core/include/category/list.php b/core/include/category/list.php
index 62881a6..6894801 100644
--- a/core/include/category/list.php
+++ b/core/include/category/list.php
@@ -21,14 +21,14 @@ $lastSite = ceil($count / $site_size);
 $currentSite = HTTP::GET('site') ?? 1;
 $currentSite = intval($currentSite);
 
-if($currentSite < 1 OR ($currentSite > $lastSite AND $lastSite > 0)) {
+if($currentSite < 1 or ($currentSite > $lastSite and $lastSite > 0)) {
 	Application::error404();
 }
 
 #===============================================================================
 # Single redirect
 #===============================================================================
-if(Application::get('CATEGORY.REDIRECT_SINGLE') === TRUE AND $count === 1) {
+if(Application::get('CATEGORY.REDIRECT_SINGLE') === true and $count === 1) {
 	$Category = $CategoryRepository->getLast();
 	HTTP::redirect(Application::getEntityURL($Category));
 }
@@ -42,7 +42,7 @@ $categories = $CategoryRepository->getPaginatedTree(
 );
 
 foreach($categories as $Category) {
-	$templates[] = generateCategoryItemTemplate($Category, TRUE);
+	$templates[] = generateCategoryItemTemplate($Category, true);
 }
 
 #===============================================================================
diff --git a/core/include/category/main.php b/core/include/category/main.php
index 0fcece3..b1741b3 100644
--- a/core/include/category/main.php
+++ b/core/include/category/main.php
@@ -12,7 +12,7 @@ $UserRepository = Application::getRepository('User');
 if(Application::get('CATEGORY.SLUG_URLS')) {
 	if(!$categories = $CategoryRepository->findWithParentsBy('slug', $param)) {
 		if($categories = $CategoryRepository->findWithParents($param)) {
-			$redirect_scheduled = TRUE;
+			$redirect_scheduled = true;
 		}
 	}
 }
@@ -20,7 +20,7 @@ if(Application::get('CATEGORY.SLUG_URLS')) {
 else {
 	if(!$categories = $CategoryRepository->findWithParents($param)) {
 		if($categories = $CategoryRepository->findWithParentsBy('slug', $param)) {
-			$redirect_scheduled = TRUE;
+			$redirect_scheduled = true;
 		}
 	}
 }
@@ -80,7 +80,7 @@ $lastSite = ceil($count / $site_size);
 $currentSite = HTTP::GET('site') ?? 1;
 $currentSite = intval($currentSite);
 
-if($currentSite < 1 OR ($currentSite > $lastSite AND $lastSite > 0)) {
+if($currentSite < 1 or ($currentSite > $lastSite and $lastSite > 0)) {
 	Application::error404();
 }
 
diff --git a/core/include/page/list.php b/core/include/page/list.php
index a02fd33..5fb4706 100644
--- a/core/include/page/list.php
+++ b/core/include/page/list.php
@@ -22,14 +22,14 @@ $lastSite = ceil($count / $site_size);
 $currentSite = HTTP::GET('site') ?? 1;
 $currentSite = intval($currentSite);
 
-if($currentSite < 1 OR ($currentSite > $lastSite AND $lastSite > 0)) {
+if($currentSite < 1 or ($currentSite > $lastSite and $lastSite > 0)) {
 	Application::error404();
 }
 
 #===============================================================================
 # Single redirect
 #===============================================================================
-if(Application::get('PAGE.REDIRECT_SINGLE') === TRUE AND $count === 1) {
+if(Application::get('PAGE.REDIRECT_SINGLE') === true and $count === 1) {
 	$Page = $PageRepository->getLast();
 	HTTP::redirect(Application::getEntityURL($Page));
 }
diff --git a/core/include/post/list.php b/core/include/post/list.php
index c696419..8dfd183 100644
--- a/core/include/post/list.php
+++ b/core/include/post/list.php
@@ -22,14 +22,14 @@ $lastSite = ceil($count / $site_size);
 $currentSite = HTTP::GET('site') ?? 1;
 $currentSite = intval($currentSite);
 
-if($currentSite < 1 OR ($currentSite > $lastSite AND $lastSite > 0)) {
+if($currentSite < 1 or ($currentSite > $lastSite and $lastSite > 0)) {
 	Application::error404();
 }
 
 #===============================================================================
 # Single redirect
 #===============================================================================
-if(Application::get('POST.REDIRECT_SINGLE') === TRUE AND $count === 1) {
+if(Application::get('POST.REDIRECT_SINGLE') === true and $count === 1) {
 	$Post = $PostRepository->getLast();
 	HTTP::redirect(Application::getEntityURL($Post));
 }
diff --git a/core/include/search/main.php b/core/include/search/main.php
index de7be9a..99d43ea 100644
--- a/core/include/search/main.php
+++ b/core/include/search/main.php
@@ -51,7 +51,7 @@ $form_data = [
 
 $search_data = [
 	'TEXT' => $search,
-	'INFO' => isset($message) ? $message : FALSE,
+	'INFO' => isset($message) ? $message : false,
 ];
 
 #===============================================================================
diff --git a/core/include/user/list.php b/core/include/user/list.php
index ec8416d..e0b54a9 100644
--- a/core/include/user/list.php
+++ b/core/include/user/list.php
@@ -21,14 +21,14 @@ $lastSite = ceil($count / $site_size);
 $currentSite = HTTP::GET('site') ?? 1;
 $currentSite = intval($currentSite);
 
-if($currentSite < 1 OR ($currentSite > $lastSite AND $lastSite > 0)) {
+if($currentSite < 1 or ($currentSite > $lastSite and $lastSite > 0)) {
 	Application::error404();
 }
 
 #===============================================================================
 # Single redirect
 #===============================================================================
-if(Application::get('USER.REDIRECT_SINGLE') === TRUE AND $count === 1) {
+if(Application::get('USER.REDIRECT_SINGLE') === true and $count === 1) {
 	$User = $UserRepository->getLast();
 	HTTP::redirect(Application::getEntityURL($User));
 }
diff --git a/core/namespace/Application.php b/core/namespace/Application.php
index 2d5a23c..3dee818 100644
--- a/core/namespace/Application.php
+++ b/core/namespace/Application.php
@@ -29,7 +29,7 @@ class Application {
 	# Get configuration value
 	#===============================================================================
 	public static function get($config) {
-		return self::$configuration[$config] ?? NULL;
+		return self::$configuration[$config] ?? null;
 	}
 
 	#===============================================================================
@@ -42,8 +42,8 @@ class Application {
 	#===============================================================================
 	# Return singleton Database instance
 	#===============================================================================
-	public static function getDatabase($force = FALSE): Database {
-		if(!self::$Database instanceof Database OR $force === TRUE) {
+	public static function getDatabase($force = false): Database {
+		if(!self::$Database instanceof Database or $force === true) {
 			$hostname = self::get('DATABASE.HOSTNAME');
 			$basename = self::get('DATABASE.BASENAME');
 			$username = self::get('DATABASE.USERNAME');
@@ -70,8 +70,8 @@ class Application {
 	#===============================================================================
 	# Return singleton Language instance
 	#===============================================================================
-	public static function getLanguage($force = FALSE): Language {
-		if(!self::$Language instanceof Language OR $force === TRUE) {
+	public static function getLanguage($force = false): Language {
+		if(!self::$Language instanceof Language or $force === true) {
 			$template_name = self::get('TEMPLATE.NAME');
 			$template_lang = self::get('TEMPLATE.LANG');
 
@@ -237,7 +237,7 @@ class Application {
 	#===============================================================================
 	# Exit application with a custom message and status code
 	#===============================================================================
-	public static function exit(?string $message = NULL, int $code = 503): void {
+	public static function exit(?string $message = null, int $code = 503): void {
 		http_response_code($code);
 		exit($message);
 	}
diff --git a/core/namespace/Factory.php b/core/namespace/Factory.php
index 779b890..e30895d 100644
--- a/core/namespace/Factory.php
+++ b/core/namespace/Factory.php
@@ -13,6 +13,6 @@ abstract class Factory implements FactoryInterface {
 	# Gets an instance of a class from the runtime instance cache
 	#===============================================================================
 	protected static function fetchInstance($identifier) {
-		return self::$storage[get_called_class()][$identifier] ?? FALSE;
+		return self::$storage[get_called_class()][$identifier] ?? false;
 	}
 }
diff --git a/core/namespace/HTTP.php b/core/namespace/HTTP.php
index 9145539..90efa44 100644
--- a/core/namespace/HTTP.php
+++ b/core/namespace/HTTP.php
@@ -1,8 +1,8 @@
 <?php
 class HTTP {
-	private static $GET  = NULL;
-	private static $POST = NULL;
-	private static $FILE = NULL;
+	private static $GET  = null;
+	private static $POST = null;
+	private static $FILE = null;
 
 	#===============================================================================
 	# HTTP protocol versions
@@ -76,7 +76,7 @@ class HTTP {
 	#===============================================================================
 	# Initialize $GET, $POST and $FILE
 	#===============================================================================
-	public static function init($GET, $POST, $FILE, $removeArrays = FALSE, $trimValues = TRUE) {
+	public static function init($GET, $POST, $FILE, $removeArrays = false, $trimValues = true) {
 		self::$GET  = $GET;
 		self::$POST = $POST;
 		self::$FILE = $FILE;
@@ -86,8 +86,8 @@ class HTTP {
 			self::$POST = self::removeArrayValues(self::$POST);
 		}
 
-		self::$GET  = ($trimValues === TRUE ? self::trim(self::$GET)  : self::$GET );
-		self::$POST = ($trimValues === TRUE ? self::trim(self::$POST) : self::$POST);
+		self::$GET  = ($trimValues === true ? self::trim(self::$GET)  : self::$GET );
+		self::$POST = ($trimValues === true ? self::trim(self::$POST) : self::$POST);
 	}
 
 	#===============================================================================
@@ -116,38 +116,38 @@ class HTTP {
 	private static function issetData($data, $arguments): bool {
 		foreach($arguments as $key) {
 			if(is_array($key)) {
-				if(!isset($data[key($key)]) OR $data[key($key)] !== $key[key($key)]) {
-					return FALSE;
+				if(!isset($data[key($key)]) or $data[key($key)] !== $key[key($key)]) {
+					return false;
 				}
 			}
 
-			else if(!isset($data[$key]) OR !is_string($data[$key])) {
-				return FALSE;
+			else if(!isset($data[$key]) or !is_string($data[$key])) {
+				return false;
 			}
 		}
 
-		return TRUE;
+		return true;
 	}
 
 	#===============================================================================
 	# Return GET value
 	#===============================================================================
 	public static function GET($parameter) {
-		return self::$GET[$parameter] ?? NULL;
+		return self::$GET[$parameter] ?? null;
 	}
 
 	#===============================================================================
 	# Return POST value
 	#===============================================================================
 	public static function POST($parameter) {
-		return self::$POST[$parameter] ?? NULL;
+		return self::$POST[$parameter] ?? null;
 	}
 
 	#===============================================================================
 	# Return FILE value
 	#===============================================================================
 	public static function FILE($parameter) {
-		return self::$FILE[$parameter] ?? NULL;
+		return self::$FILE[$parameter] ?? null;
 	}
 
 	#===============================================================================
@@ -182,13 +182,13 @@ class HTTP {
 	# Get cookie
 	#===============================================================================
 	public static function getCookie($name) {
-		return $_COOKIE[$name] ?? NULL;
+		return $_COOKIE[$name] ?? null;
 	}
 
 	#===============================================================================
 	# Return HTTP request method or check if request method equals with $method
 	#===============================================================================
-	public static function requestMethod($method = NULL) {
+	public static function requestMethod($method = null) {
 		if(!empty($method)) {
 			return ($_SERVER['REQUEST_METHOD'] === $method);
 		}
@@ -200,7 +200,7 @@ class HTTP {
 	# Return REQUEST_URI
 	#===============================================================================
 	public static function requestURI() {
-		return $_SERVER['REQUEST_URI'] ?? FALSE;
+		return $_SERVER['REQUEST_URI'] ?? false;
 	}
 
 	#===============================================================================
@@ -213,10 +213,10 @@ class HTTP {
 	#===============================================================================
 	# Sends a HTTP redirect to the client
 	#===============================================================================
-	public static function redirect($location, $code = 303, $exit = TRUE) {
+	public static function redirect($location, $code = 303, $exit = true) {
 		http_response_code($code);
 		self::sendHeader("Location: {$location}");
-		$exit AND exit();
+		$exit and exit();
 	}
 
 	#===============================================================================
diff --git a/core/namespace/Language.php b/core/namespace/Language.php
index a2facb0..804f3d5 100644
--- a/core/namespace/Language.php
+++ b/core/namespace/Language.php
@@ -18,7 +18,7 @@ class Language {
 	# Load another language file
 	#===============================================================================
 	public function load($filename) {
-		if(file_exists($filename) AND is_readable($filename)) {
+		if(file_exists($filename) and is_readable($filename)) {
 			require $filename;
 			$this->text = array_merge($this->text, $LANGUAGE ?? []);
 		}
@@ -34,7 +34,7 @@ class Language {
 	#===============================================================================
 	# Return language string with included arguments
 	#===============================================================================
-	public function text($name, $arguments = NULL): string {
+	public function text($name, $arguments = null): string {
 		if(!isset($this->text[$name])) {
 			return "{{$name}}";
 		}
diff --git a/core/namespace/Migrator.php b/core/namespace/Migrator.php
index 7b8d263..607c137 100644
--- a/core/namespace/Migrator.php
+++ b/core/namespace/Migrator.php
@@ -17,7 +17,7 @@ class Migrator {
 			$Statement = $Database->query('SELECT schema_version FROM migration');
 
 			# Explicitly check for FALSE, because result can be "0"
-			if(($this->version = $Statement->fetchColumn()) === FALSE) {
+			if(($this->version = $Statement->fetchColumn()) === false) {
 				throw new Exception('The migration table does exist, but there is
 					no row containing the currently used on-disk schema version!');
 			}
diff --git a/core/namespace/ORM/Entity.php b/core/namespace/ORM/Entity.php
index 61b9371..5462b54 100644
--- a/core/namespace/ORM/Entity.php
+++ b/core/namespace/ORM/Entity.php
@@ -13,7 +13,7 @@ abstract class Entity implements EntityInterface {
 	# Get attribute
 	#===============================================================================
 	public function get(string $attribute) {
-		return $this->{$attribute} ?? NULL;
+		return $this->{$attribute} ?? null;
 	}
 
 	#===============================================================================
diff --git a/core/namespace/ORM/Repositories/CategoryRepository.php b/core/namespace/ORM/Repositories/CategoryRepository.php
index 7c7b3f9..657940c 100644
--- a/core/namespace/ORM/Repositories/CategoryRepository.php
+++ b/core/namespace/ORM/Repositories/CategoryRepository.php
@@ -47,7 +47,7 @@ class CategoryRepository extends Repository {
 			# element. PHP >= 8 will throw a PDOException when the number of
 			# bound variables doesn't matches the number of tokens ("?") in
 			# the SQL query, which is the case here if $value is NULL.
-			is_null($value) ? NULL : [$value]
+			is_null($value) ? null : [$value]
 		);
 
 		# TODO: Virtual column _depth shall not be fetched into the entity class
@@ -128,7 +128,7 @@ class CategoryRepository extends Repository {
 				$UpdateStatement = $this->Database->prepare($query);
 				$UpdateStatement->execute([$_parent, $Entity->get('parent')]);
 				break;
-			} else if($_parent === NULL) {
+			} else if($_parent === null) {
 				break;
 			}
 		}
diff --git a/core/namespace/ORM/Repository.php b/core/namespace/ORM/Repository.php
index e7750cb..ca3690f 100644
--- a/core/namespace/ORM/Repository.php
+++ b/core/namespace/ORM/Repository.php
@@ -23,7 +23,7 @@ abstract class Repository {
 			return $Entity;
 		}
 
-		return NULL;
+		return null;
 	}
 
 	#===============================================================================
@@ -60,7 +60,7 @@ abstract class Repository {
 	# Gets an entity from the runtime cache
 	#===============================================================================
 	protected function fetchInstance($identifier) {
-		return $this->entities[$identifier] ?? FALSE;
+		return $this->entities[$identifier] ?? false;
 	}
 
 	#===============================================================================
@@ -93,7 +93,7 @@ abstract class Repository {
 			return $Statement->execute($params);
 		}
 
-		return FALSE;
+		return false;
 	}
 
 	#===========================================================================
@@ -115,7 +115,7 @@ abstract class Repository {
 			return $Statement->execute($params);
 		}
 
-		return FALSE;
+		return false;
 	}
 
 	#===========================================================================
@@ -199,7 +199,7 @@ abstract class Repository {
 
 		if(!empty($filter)) {
 			foreach($filter as $column => $value) {
-				if($value === NULL) {
+				if($value === null) {
 					$wheres[] = "$column IS NULL";
 				} else {
 					$wheres[] = "$column = ?";
diff --git a/core/namespace/ORM/RepositorySearch.php b/core/namespace/ORM/RepositorySearch.php
index aac46ef..66f27ea 100644
--- a/core/namespace/ORM/RepositorySearch.php
+++ b/core/namespace/ORM/RepositorySearch.php
@@ -8,7 +8,7 @@ trait RepositorySearch {
 	#===============================================================================
 	# Get entities based on search query
 	#===============================================================================
-	public function search(string $search, array $filter = [], int $limit = NULL, int $offset = 0): array {
+	public function search(string $search, array $filter = [], int $limit = null, int $offset = 0): array {
 		if(strlen($filter['year'] ?? '') !== 0) {
 			$extend[] = 'YEAR(time_insert) = ? AND';
 			$params[] = $filter['year'];
@@ -24,12 +24,12 @@ trait RepositorySearch {
 			$params[] = $filter['day'];
 		}
 
-		if(is_numeric($filter['user'] ?? NULL)) {
+		if(is_numeric($filter['user'] ?? null)) {
 			$extend[] = 'user = ? AND';
 			$params[] = $filter['user'];
 		}
 
-		if(is_numeric($filter['category'] ?? NULL)) {
+		if(is_numeric($filter['category'] ?? null)) {
 			$extend[] = 'category = ? AND';
 			$params[] = $filter['category'];
 		}
diff --git a/core/namespace/Parsers/ArgumentParser.php b/core/namespace/Parsers/ArgumentParser.php
index ab32fe1..4ac3b9c 100644
--- a/core/namespace/Parsers/ArgumentParser.php
+++ b/core/namespace/Parsers/ArgumentParser.php
@@ -10,8 +10,8 @@ class ArgumentParser implements ParserInterface {
 		foreach(explode('|', $text) as $delimiter) {
 			$part = explode('=', $delimiter);
 
-			$argumentK = $part[0] ?? NULL;
-			$argumentV = $part[1] ?? TRUE;
+			$argumentK = $part[0] ?? null;
+			$argumentV = $part[1] ?? true;
 
 			if(preg_match('#^[[:word:]]+$#', $argumentK)) {
 				$arguments[strtoupper($argumentK)] = $argumentV;
diff --git a/core/namespace/Parsers/MarkdownParser.php b/core/namespace/Parsers/MarkdownParser.php
index 27a18ad..b9ebc15 100644
--- a/core/namespace/Parsers/MarkdownParser.php
+++ b/core/namespace/Parsers/MarkdownParser.php
@@ -10,7 +10,7 @@ class MarkdownParser implements ParserInterface {
 	#===========================================================================
 	public function __construct() {
 		$this->Parsedown = new Parsedown();
-		$this->Parsedown->setUrlsLinked(FALSE);
+		$this->Parsedown->setUrlsLinked(false);
 	}
 
 	#===========================================================================
diff --git a/core/namespace/Router.php b/core/namespace/Router.php
index 803a8e0..ffb3154 100644
--- a/core/namespace/Router.php
+++ b/core/namespace/Router.php
@@ -34,7 +34,7 @@ class Router {
 	#===============================================================================
 	public static function execute($path) {
 		$path = ltrim($path, '/');
-		$route_found = FALSE;
+		$route_found = false;
 
 		foreach(self::$routes as $route) {
 			if($route['type'] === 'redirect') {
@@ -50,13 +50,13 @@ class Router {
 					# Remove the first element from matches which contains the whole string.
 					array_shift($matches);
 
-					$route_found = TRUE;
+					$route_found = true;
 					call_user_func_array($route['callback'], $matches);
 				}
 			}
 		}
 
-		if($route_found === FALSE) {
+		if($route_found === false) {
 			Application::error404();
 		}
 	}
diff --git a/core/namespace/Template/Template.php b/core/namespace/Template/Template.php
index 25034a2..4967a7f 100644
--- a/core/namespace/Template/Template.php
+++ b/core/namespace/Template/Template.php
@@ -27,7 +27,7 @@ class Template {
 	# Get parameter
 	#===============================================================================
 	public function get($name) {
-		return $this->parameters[$name] ?? NULL;
+		return $this->parameters[$name] ?? null;
 	}
 
 	#===============================================================================
diff --git a/core/script/convert_content_tags.php b/core/script/convert_content_tags.php
index 7b879a3..e11e820 100644
--- a/core/script/convert_content_tags.php
+++ b/core/script/convert_content_tags.php
@@ -42,7 +42,7 @@ function convertContentTags(string $text, &$globalMatches): string {
 				str_replace('"', '\\"', $matches['text'])
 			];
 
-			if($linkTitle = $matches['title'] ?? FALSE) {
+			if($linkTitle = $matches['title'] ?? false) {
 				$q = $matches['qmark'];
 				$format = '{%s: %d, "%s", '.$q.'%s'.$q.'}';
 				$params[] = $linkTitle;
@@ -95,10 +95,10 @@ HTTP::responseHeader(HTTP::HEADER_CONTENT_TYPE, HTTP::CONTENT_TYPE_TEXT);
 #===========================================================================
 # Set "commit" variable based on GET parameter or CLI argument
 #===========================================================================
-$commit = FALSE;
+$commit = false;
 if(isset($_GET['commit']) OR
-	(isset($argv[1]) AND $argv[1] === 'commit')) {
-	$commit = TRUE;
+	(isset($argv[1]) and $argv[1] === 'commit')) {
+	$commit = true;
 }
 
 #===========================================================================
@@ -121,7 +121,7 @@ foreach(['Category', 'Page', 'Post', 'User'] as $entityName) {
 		$content = convertContentTags($content, $matches);
 
 		if($matches) {
-			$foundMatches = TRUE;
+			$foundMatches = true;
 
 			if($commit) {
 				$Entity->set('body', $content);