result

src/Support/Result/Error.php

@@ -0,0 +1,111 @@
+<?php
+
+namespace Lucent\Support\Result;
+
+use PhpOption\None;
+use PhpOption\Option;
+use PhpOption\Some;
+
+/**
+ * @template T
+ * @template E
+ *
+ * @extends Result<T,E>
+ */
+final class Error extends Result
+{
+    /**
+     * @var E
+     */
+    private $value;
+
+    /**
+     * Internal constructor for an error value.
+     *
+     * @param E $value
+     *
+     * @return void
+     */
+    private function __construct($value)
+    {
+        $this->value = $value;
+    }
+
+    /**
+     * Create a new error value.
+     *
+     * @template F
+     *
+     * @param F $value
+     *
+     * @return Result<T,F>
+     */
+    public static function create($value): Result
+    {
+        return new self($value);
+    }
+
+    /**
+     * Get the success option value.
+     *
+     * @return Option<T>
+     */
+    public function success(): Option
+    {
+        return None::create();
+    }
+
+    /**
+     * Map over the success value.
+     *
+     * @template S
+     *
+     * @param callable(T):S $f
+     *
+     * @return Result<S,E>
+     */
+    public function map(callable $f): Result
+    {
+        return self::create($this->value);
+    }
+
+    /**
+     * Flat map over the success value.
+     *
+     * @template S
+     * @template F
+     *
+     * @param callable(T):Result<S,F> $f
+     *
+     * @return Result<S,F>
+     */
+    public function flatMap(callable $f): Result
+    {
+        /* @var Result<S,F> */
+        return self::create($this->value);
+    }
+
+    /**
+     * Get the error option value.
+     *
+     * @return Option<E>
+     */
+    public function error(): Option
+    {
+        return Some::create($this->value);
+    }
+
+    /**
+     * Map over the error value.
+     *
+     * @template F
+     *
+     * @param callable(E):F $f
+     *
+     * @return Result<T,F>
+     */
+    public function mapError(callable $f): Result
+    {
+        return self::create($f($this->value));
+    }
+}