Create a few classes the will be present in the next version

This commit will deprecate some classes in favor of a couple of news
ones. If there are no customisations to `assert()`, `check()`, and other
methods, the migration should be pretty easy on users.

Author: henriquemoody

CONTRIBUTING.md

@@ -62,17 +62,16 @@ declare(strict_types=1);
 
 namespace Respect\Validation\Rules;
 
+use Respect\Validation\Rules\Core\Simple;
+
 /**
  * Explain in one sentence what this rule does.
  *
  * @author Your Name <youremail@yourdomain.tld>
  */
-final class HelloWorld extends AbstractRule
+final class HelloWorld extends Simple
 {
-    /**
-     * {@inheritDoc}
-     */
-    public function validate($input): bool
+    public function isValid(mixed $input): bool
     {
         return $input === 'Hello World';
     }

docs/06-custom-rules.md

@@ -10,11 +10,11 @@ validate method will be executed. Here's how the class should look:
 ```php
 namespace My\Validation\Rules;
 
-use Respect\Validation\Rules\AbstractRule;
+use Respect\Validation\Rules\Core\Simple;
 
-final class Something extends AbstractRule
+final class Something extends Simple
 {
-    public function validate($input): bool
+    public function isValid(mixed $input): bool
     {
         // Do something here with the $input and return a boolean value
     }

library/Rules/AbstractComposite.php

@@ -22,6 +22,8 @@
  * @author Alexandre Gomes Gaigalas <[email protected]>
  * @author Henrique Moody <[email protected]>
  * @author Wojciech Frącz <[email protected]>
+ *
+ * @deprecated This class is deprecated, and will be removed in the next major version. Use {@see \Respect\Validation\Rules\Core\Composite} instead.
  */
 abstract class AbstractComposite extends AbstractRule
 {

library/Rules/AbstractEnvelope.php

@@ -19,6 +19,8 @@
  * having an custom message.
  *
  * @author Henrique Moody <[email protected]>
+ *
+ * @deprecated This class is deprecated, and will be removed in the next major version. Use {@see \Respect\Validation\Rules\Core\Envelop} instead.
  */
 abstract class AbstractEnvelope extends AbstractRule
 {

library/Rules/AbstractRule.php

@@ -18,6 +18,8 @@
  * @author Henrique Moody <[email protected]>
  * @author Nick Lombard <[email protected]>
  * @author Vicente Mendoza <[email protected]>
+ *
+ * @deprecated This class is deprecated, and will be removed in the next major version. Use {@see \Respect\Validation\Rules\Core\Simple} instead.
  */
 abstract class AbstractRule implements Validatable
 {

library/Rules/AbstractWrapper.php

@@ -16,6 +16,8 @@
  *
  * @author Alasdair North <[email protected]>
  * @author Henrique Moody <[email protected]>
+ *
+ * @deprecated This class is deprecated, and will be removed in the next major version. Use {@see \Respect\Validation\Rules\Core\Wrapper} instead.
  */
 abstract class AbstractWrapper extends AbstractRule
 {

library/Rules/Core/Composite.php

@@ -0,0 +1,21 @@
+<?php
+
+/*
+ * Copyright (c) Alexandre Gomes Gaigalas <[email protected]>
+ * SPDX-License-Identifier: MIT
+ */
+
+declare(strict_types=1);
+
+namespace Respect\Validation\Rules\Core;
+
+use Respect\Validation\Rules\AbstractComposite;
+use Respect\Validation\Validatable;
+
+abstract class Composite extends AbstractComposite
+{
+    public function __construct(Validatable $rule1, Validatable $rule2, Validatable ...$rules)
+    {
+        parent::__construct($rule1, $rule2, ...$rules);
+    }
+}

library/Rules/Core/Envelope.php

@@ -0,0 +1,16 @@
+<?php
+
+/*
+ * Copyright (c) Alexandre Gomes Gaigalas <[email protected]>
+ * SPDX-License-Identifier: MIT
+ */
+
+declare(strict_types=1);
+
+namespace Respect\Validation\Rules\Core;
+
+use Respect\Validation\Rules\AbstractEnvelope;
+
+abstract class Envelope extends AbstractEnvelope
+{
+}

library/Rules/Core/Simple.php

@@ -0,0 +1,25 @@
+<?php
+
+/*
+ * Copyright (c) Alexandre Gomes Gaigalas <[email protected]>
+ * SPDX-License-Identifier: MIT
+ */
+
+declare(strict_types=1);
+
+namespace Respect\Validation\Rules\Core;
+
+use Respect\Validation\Rules\AbstractRule;
+
+abstract class Simple extends AbstractRule
+{
+    abstract public function isValid(mixed $input): bool;
+
+    /**
+     * @deprecated Calling `validate()` directly from rules is deprecated. Please use {@see Validator::isValid()} instead.
+     */
+    public function validate($input): bool
+    {
+        return $this->isValid($input);
+    }
+}

library/Rules/Core/Wrapper.php

@@ -0,0 +1,16 @@
+<?php
+
+/*
+ * Copyright (c) Alexandre Gomes Gaigalas <[email protected]>
+ * SPDX-License-Identifier: MIT
+ */
+
+declare(strict_types=1);
+
+namespace Respect\Validation\Rules\Core;
+
+use Respect\Validation\Rules\AbstractWrapper;
+
+abstract class Wrapper extends AbstractWrapper
+{
+}