Init

src/Option/None.php

@@ -0,0 +1,116 @@
+<?php
+
+namespace Modules\Core\Option;
+
+use EmptyIterator;
+
+/**
+ * @extends Option<mixed>
+ */
+final class None extends Option
+{
+    /** @var None|null */
+    private static $instance;
+
+    /** @return None */
+    public static function create(): self
+    {
+        if (null === self::$instance) {
+            self::$instance = new self();
+        }
+
+        return self::$instance;
+    }
+
+    public function get()
+    {
+        throw new \RuntimeException("None has no value.");
+    }
+
+    public function getOrCall($callable)
+    {
+        return $callable();
+    }
+
+    public function getOrElse($default)
+    {
+        return $default;
+    }
+
+    public function getOrThrow(\Exception $ex)
+    {
+        throw $ex;
+    }
+
+    public function isEmpty(): bool
+    {
+        return true;
+    }
+
+    public function isDefined(): bool
+    {
+        return false;
+    }
+
+    public function orElse(Option $else)
+    {
+        return $else;
+    }
+
+    public function ifDefined($callable)
+    {
+        // no-op
+    }
+
+    public function forAll($callable)
+    {
+        return $this;
+    }
+
+    public function map($callable)
+    {
+        return $this;
+    }
+
+    public function flatMap($callable)
+    {
+        return $this;
+    }
+
+    public function filter($callable)
+    {
+        return $this;
+    }
+
+    public function filterNot($callable)
+    {
+        return $this;
+    }
+
+    public function select($value)
+    {
+        return $this;
+    }
+
+    public function reject($value)
+    {
+        return $this;
+    }
+
+    public function getIterator(): EmptyIterator
+    {
+        return new EmptyIterator();
+    }
+
+    public function foldLeft($initialValue, $callable)
+    {
+        return $initialValue;
+    }
+
+    public function foldRight($initialValue, $callable)
+    {
+        return $initialValue;
+    }
+
+    private function __construct() {}
+}