implement Listing support

src/Document.php

@@ -49,6 +49,17 @@ class Document
 
                 break;
 
+                // Listing
+                case Parser\Listing::match($line):
+
+                    $this->_entities[] = new Entity\Listing(
+                        Parser\Listing::getItem(
+                            $line
+                        )
+                    );
+
+                break;
+
                 // Plain
                 default:
 

src/Entity/Listing.php

@@ -0,0 +1,44 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Yggverse\Gemtext\Entity;
+
+class Listing
+{
+    public const TAG = '*';
+
+    private ?string $_item;
+
+    public function __construct(
+        ?string $item = null
+    ) {
+        $this->setItem(
+            $item
+        );
+    }
+
+    public function setItem(
+        ?string $item
+    ): void
+    {
+        if ($item)
+        {
+            $item = trim(
+                $item
+            );
+        }
+
+        $this->_item = $item;
+    }
+
+    public function Item(): ?string
+    {
+        return $this->_item;
+    }
+
+    public function toString(): string
+    {
+        return self::TAG . ' ' . $this->_item;
+    }
+}

src/Parser/Listing.php

@@ -0,0 +1,44 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Yggverse\Gemtext\Parser;
+
+class Listing
+{
+    public static function match(
+        string $line,
+        array &$matches = []
+    ): bool
+    {
+        return (bool) preg_match(
+            '/^\*\s*(?<item>.*)$/m',
+            $line,
+            $matches
+        );
+    }
+
+    public static function getItem(
+        string $line
+    ): ?string
+    {
+        $matches = [];
+
+        if (self::match($line, $matches))
+        {
+            if (isset($matches['item']))
+            {
+                $item = trim(
+                    $matches['item']
+                );
+
+                if ($item)
+                {
+                    return $item;
+                }
+            }
+        }
+
+        return null;
+    }
+}