Introduce Class, Trait, and Interface components

composer.json

@@ -28,7 +28,8 @@
     "autoload-dev": {
         "psr-4": {
             "Psl\\Tests\\StaticAnalysis\\": "tests/static-analysis",
-            "Psl\\Tests\\Unit\\": "tests/unit"
+            "Psl\\Tests\\Unit\\": "tests/unit",
+            "Psl\\Tests\\Fixture\\": "tests/fixture"
         }
     },
     "extra": {

src/Psl/Class/defined.php

@@ -0,0 +1,26 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Psl\Class;
+
+use function class_exists;
+
+/**
+ * Checks if the class with the given name has already been defined.
+ *
+ * @param string $class_name
+ *
+ * @psalm-assert-if-true class-string $classname
+ *
+ * @pure
+ */
+function defined(string $class_name): bool
+{
+    /**
+     * @psalm-suppress ImpureFunctionCall - call is pure.
+     *
+     * @var bool
+     */
+    return class_exists($class_name, false);
+}

src/Psl/Class/exists.php

@@ -0,0 +1,20 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Psl\Class;
+
+use function class_exists;
+
+/**
+ * Checks if the class with the given name exists.
+ *
+ * @param string $class_name
+ *
+ * @psalm-assert-if-true class-string $classname
+ */
+function exists(string $class_name): bool
+{
+    /** @var bool */
+    return class_exists($class_name, true);
+}

src/Psl/Class/has_constant.php

@@ -0,0 +1,23 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Psl\Class;
+
+use Psl;
+use ReflectionClass;
+
+/**
+ * Checks if constant is defined in the given class.
+ *
+ * @param class-string $class_name
+ *
+ * @throws Psl\Exception\InvariantViolationException If $class_name does not exist.
+ */
+function has_constant(string $class_name, string $constant_name): bool
+{
+    Psl\invariant(namespace\exists($class_name), 'Classname "%s" does not exist.', $class_name);
+
+    /** @psalm-suppress MissingThrowsDocblock */
+    return (new ReflectionClass($class_name))->hasConstant($constant_name);
+}

src/Psl/Class/has_method.php

@@ -0,0 +1,23 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Psl\Class;
+
+use Psl;
+use ReflectionClass;
+
+/**
+ * Checks if method is defined in the given class.
+ *
+ * @param class-string $class_name
+ *
+ * @throws Psl\Exception\InvariantViolationException If $class_name does not exist.
+ */
+function has_method(string $class_name, string $method_name): bool
+{
+    Psl\invariant(namespace\exists($class_name), 'Classname "%s" does not exist.', $class_name);
+
+    /** @psalm-suppress MissingThrowsDocblock */
+    return (new ReflectionClass($class_name))->hasMethod($method_name);
+}

src/Psl/Class/is_abstract.php

@@ -0,0 +1,23 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Psl\Class;
+
+use Psl;
+use ReflectionClass;
+
+/**
+ * Checks if class is abstract.
+ *
+ * @param class-string $class_name
+ *
+ * @throws Psl\Exception\InvariantViolationException If $class_name does not exist.
+ */
+function is_abstract(string $class_name): bool
+{
+    Psl\invariant(namespace\exists($class_name), 'Classname "%s" does not exist.', $class_name);
+
+    /** @psalm-suppress MissingThrowsDocblock */
+    return (new ReflectionClass($class_name))->isAbstract();
+}

src/Psl/Class/is_final.php

@@ -0,0 +1,23 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Psl\Class;
+
+use Psl;
+use ReflectionClass;
+
+/**
+ * Checks if class is final.
+ *
+ * @param class-string $class_name
+ *
+ * @throws Psl\Exception\InvariantViolationException If $class_name does not exist.
+ */
+function is_final(string $class_name): bool
+{
+    Psl\invariant(namespace\exists($class_name), 'Classname "%s" does not exist.', $class_name);
+
+    /** @psalm-suppress MissingThrowsDocblock */
+    return (new ReflectionClass($class_name))->isFinal();
+}

src/Psl/Interface/defined.php

@@ -0,0 +1,20 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Psl\Interface;
+
+use function interface_exists;
+
+/**
+ * Checks if the interface with the given name has already been defined.
+ *
+ * @param string $interface_name
+ *
+ * @pure
+ */
+function defined(string $interface_name): bool
+{
+    /** @var bool */
+    return interface_exists($interface_name, false);
+}

src/Psl/Interface/exists.php

@@ -0,0 +1,18 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Psl\Interface;
+
+use function interface_exists;
+
+/**
+ * Checks if the interface with the given name exists.
+ *
+ * @param string $interface_name
+ */
+function exists(string $interface_name): bool
+{
+    /** @var bool */
+    return interface_exists($interface_name, true);
+}

src/Psl/Internal/Loader.php

@@ -521,6 +521,16 @@ final class Loader
         'Psl\IO\input_handle',
         'Psl\IO\output_handle',
         'Psl\IO\error_handle',
+        'Psl\Class\exists',
+        'Psl\Class\defined',
+        'Psl\Class\has_constant',
+        'Psl\Class\has_method',
+        'Psl\Class\is_abstract',
+        'Psl\Class\is_final',
+        'Psl\Interface\exists',
+        'Psl\Interface\defined',
+        'Psl\Trait\exists',
+        'Psl\Trait\defined',
     ];
 
     public const INTERFACES = [

src/Psl/Trait/defined.php

@@ -0,0 +1,20 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Psl\Trait;
+
+use function trait_exists;
+
+/**
+ * Checks if the trait with the given name has already been defined.
+ *
+ * @param string $trait_name
+ *
+ * @pure
+ */
+function defined(string $trait_name): bool
+{
+    /** @var bool */
+    return trait_exists($trait_name, false);
+}

src/Psl/Trait/exists.php

@@ -0,0 +1,18 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Psl\Trait;
+
+use function trait_exists;
+
+/**
+ * Checks if the trait with the given name exists.
+ *
+ * @param string $trait_name
+ */
+function exists(string $trait_name): bool
+{
+    /** @var bool */
+    return trait_exists($trait_name, true);
+}

tests/fixture/ExampleTrait.php

@@ -0,0 +1,9 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Psl\Tests\Fixture;
+
+trait ExampleTrait
+{
+}

tests/unit/Class/ClassTest.php

@@ -0,0 +1,57 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Psl\Tests\Unit\Class;
+
+use PHPUnit\Framework\TestCase;
+use Psl\Class;
+use Psl\Collection;
+use Psl\Type;
+
+final class ClassTest extends TestCase
+{
+    /**
+     * @dataProvider provideData
+     */
+    public function test(
+        string $classname,
+        bool $exists,
+        bool $final,
+        bool $abstract,
+        array $methods = [],
+        array $constants = []
+    ): void {
+        static::assertSame($exists, Class\exists($classname));
+        static::assertSame($exists, Class\defined($classname));
+        if (!$exists) {
+            return;
+        }
+
+        static::assertSame($final, Class\is_final($classname));
+        static::assertSame($abstract, Class\is_abstract($classname));
+
+        foreach ($methods as $method) {
+            static::assertTrue(CLass\has_method($classname, $method));
+        }
+
+        static::assertFalse(Class\has_method($classname, 'ImNotAClassMethod'));
+
+        foreach ($constants as $constant) {
+            static::assertTrue(Class\has_constant($classname, $constant));
+        }
+
+        static::assertFalse(Class\has_constant($classname, 'I_AM_NOT_A_CONSTANT'));
+    }
+
+    public function provideData(): iterable
+    {
+        yield [Collection\Vector::class, true, true, false, ['first', 'last'], []];
+        yield [Collection\MutableVector::class, true, true, false, ['first', 'last'], []];
+        yield [Collection\Map::class, true, true, false, ['first', 'last'], []];
+        yield [Collection\MutableMap::class, true, true, false, ['first', 'last'], []];
+        yield [Type\Type::class, true, false, true, ['matches', 'getTrace', 'withTrace', 'isOptional'], []];
+
+        yield ['Psl\\Not\\Class', false, false, false, [], []];
+    }
+}

tests/unit/Interface/InterfaceTest.php

@@ -0,0 +1,41 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Psl\Tests\Unit\Interface;
+
+use PHPUnit\Framework\TestCase;
+use Psl\Collection;
+use Psl\Interface;
+use Psl\Type;
+
+final class InterfaceTest extends TestCase
+{
+    /**
+     * @dataProvider provideData
+     */
+    public function test(
+        string $interface_name,
+        bool $exists,
+    ): void {
+        static::assertSame($exists, Interface\exists($interface_name));
+        static::assertSame($exists, Interface\defined($interface_name));
+    }
+
+    public function provideData(): iterable
+    {
+        yield [Collection\VectorInterface::class, true];
+        yield [Collection\MutableVectorInterface::class, true];
+        yield [Collection\MapInterface::class, true];
+        yield [Collection\MutableMapInterface::class, true];
+        yield [Type\TypeInterface::class, true];
+
+        yield [Collection\Vector::class, false];
+        yield [Collection\MutableVector::class, false];
+        yield [Collection\Map::class, false];
+        yield [Collection\MutableMap::class, false];
+        yield [Type\Type::class, false];
+
+        yield ['Psl\\Not\\Interface', false];
+    }
+}

tests/unit/Trait/TraitTest.php

@@ -0,0 +1,34 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Psl\Tests\Unit\Trait;
+
+use PHPUnit\Framework\TestCase;
+use Psl\Tests\Fixture;
+use Psl\Trait;
+
+final class TraitTest extends TestCase
+{
+    /**
+     * @dataProvider provideData
+     */
+    public function test(
+        string $trait_name,
+        bool $defined,
+        bool $exists,
+    ): void {
+        static::assertSame($defined, Trait\defined($trait_name));
+        static::assertSame($exists, Trait\exists($trait_name));
+
+        if ($exists) {
+            static::assertTrue(Trait\defined($trait_name));
+        }
+    }
+
+    public function provideData(): iterable
+    {
+        yield [Fixture\ExampleTrait::class, false, true];
+        yield ['Psl\\Not\\Trait', false, false];
+    }
+}