[ExpressionLanguage] Add enum expression function

src/Symfony/Component/ExpressionLanguage/CHANGELOG.md

@@ -1,6 +1,11 @@
 CHANGELOG
 =========
 
+6.3
+---
+
+ * Add `enum` expression function
+
 6.2
 ---
 

src/Symfony/Component/ExpressionLanguage/ExpressionLanguage.php

@@ -138,6 +138,22 @@ public function registerProvider(ExpressionFunctionProviderInterface $provider)
     protected function registerFunctions()
     {
         $this->addFunction(ExpressionFunction::fromPhp('constant'));
+
+        $this->addFunction(new ExpressionFunction('enum', function ($str): string {
+            return sprintf('\constant(%1$s)', $str);
+        }, function ($arguments, $str): \UnitEnum {
+            if (!\defined($str)) {
+                throw new \LogicException(sprintf('The enum case "%s" is not defined.', $str));
+            }
+
+            $value = \constant($str);
+
+            if (!$value instanceof \UnitEnum) {
+                throw new \LogicException(sprintf('The string "%s" is not the name of a valid enum case.', $str));
+            }
+
+            return $value;
+        }));
     }
 
     private function getLexer(): Lexer

src/Symfony/Component/ExpressionLanguage/Tests/ExpressionLanguageTest.php

@@ -18,6 +18,8 @@
 use Symfony\Component\ExpressionLanguage\ExpressionLanguage;
 use Symfony\Component\ExpressionLanguage\ParsedExpression;
 use Symfony\Component\ExpressionLanguage\SyntaxError;
+use Symfony\Component\ExpressionLanguage\Tests\Fixtures\FooBackedEnum;
+use Symfony\Component\ExpressionLanguage\Tests\Fixtures\FooEnum;
 use Symfony\Component\ExpressionLanguage\Tests\Fixtures\TestProvider;
 
 class ExpressionLanguageTest extends TestCase
@@ -78,6 +80,36 @@ public function testConstantFunction()
         $this->assertEquals('\constant("PHP_VERSION")', $expressionLanguage->compile('constant("PHP_VERSION")'));
     }
 
+    public function testEnumFunctionWithConstantThrows()
+    {
+        $this->expectException(\LogicException::class);
+        $this->expectExceptionMessage('The string "PHP_VERSION" is not the name of a valid enum case.');
+        $expressionLanguage = new ExpressionLanguage();
+        $expressionLanguage->evaluate('enum("PHP_VERSION")');
+    }
+
+    public function testEnumFunctionWithInvalidEnumCaseThrows()
+    {
+        $this->expectException(\LogicException::class);
+        $this->expectExceptionMessage('The enum case "\Invalid\Enum::Case" is not defined.');
+        $expressionLanguage = new ExpressionLanguage();
+        $expressionLanguage->evaluate('enum("\\\\Invalid\\\\Enum::Case")');
+    }
+
+    public function testEnumFunction()
+    {
+        $expressionLanguage = new ExpressionLanguage();
+        $this->assertSame(FooEnum::Foo, $expressionLanguage->evaluate('enum("Symfony\\\\Component\\\\ExpressionLanguage\\\\Tests\\\\Fixtures\\\\FooEnum::Foo")'));
+    }
+
+    public function testBackedEnumFunction()
+    {
+        $expressionLanguage = new ExpressionLanguage();
+        $this->assertSame(FooBackedEnum::Bar, $expressionLanguage->evaluate('enum("Symfony\\\\Component\\\\ExpressionLanguage\\\\Tests\\\\Fixtures\\\\FooBackedEnum::Bar")'));
+
+        $this->assertSame(FooBackedEnum::Bar->value, $expressionLanguage->evaluate('enum("Symfony\\\\Component\\\\ExpressionLanguage\\\\Tests\\\\Fixtures\\\\FooBackedEnum::Bar").value'));
+    }
+
     public function testProviders()
     {
         $expressionLanguage = new ExpressionLanguage(null, [new TestProvider()]);

src/Symfony/Component/ExpressionLanguage/Tests/Fixtures/FooBackedEnum.php

@@ -0,0 +1,8 @@
+<?php
+
+namespace Symfony\Component\ExpressionLanguage\Tests\Fixtures;
+
+enum FooBackedEnum: string
+{
+    case Bar = 'Foo';
+}

src/Symfony/Component/ExpressionLanguage/Tests/Fixtures/FooEnum.php

@@ -0,0 +1,8 @@
+<?php
+
+namespace Symfony\Component\ExpressionLanguage\Tests\Fixtures;
+
+enum FooEnum
+{
+    case Foo;
+}