[ExpressionLanguage] added ExpressionFunction and ExpressionFunctionProviderInterface

src/Symfony/Component/ExpressionLanguage/CHANGELOG.md

@@ -1,6 +1,11 @@
 CHANGELOG
 =========
 
+2.6.0
+-----
+
+ * Added ExpressionFunction and ExpressionFunctionProviderInterface
+
 2.4.0
 -----
 

src/Symfony/Component/ExpressionLanguage/ExpressionFunction.php

@@ -0,0 +1,65 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\ExpressionLanguage;
+
+/**
+ * Represents a function that can be used in an expression.
+ *
+ * A function is defined by two PHP callables. The callables are used
+ * by the language to compile and/or evaluate the function.
+ *
+ * The "compiler" function is used at compilation time and must return a
+ * PHP representation of the function call (it receives the function
+ * arguments as arguments).
+ *
+ * The "evaluator" function is used for expression evaluation and must return
+ * the value of the function call based on the values defined for the
+ * expression (it receives the values as a first argument and the function
+ * arguments as remaining arguments).
+ *
+ * @author Fabien Potencier <fabien@symfony.com>
+ */
+class ExpressionFunction
+{
+    private $name;
+    private $compiler;
+    private $evaluator;
+
+    /**
+     * Constructor.
+     *
+     * @param string   $name      The function name
+     * @param callable $compiler  A callable able to compile the function
+     * @param callable $evaluator A callable able to evaluate the function
+     */
+   public function __construct($name, $compiler, $evaluator)
+   {
+       $this->name = $name;
+       $this->compiler = $compiler;
+       $this->evaluator = $evaluator;
+   }
+
+   public function getName()
+   {
+       return $this->name;
+   }
+
+   public function getCompiler()
+   {
+       return $this->compiler;
+   }
+
+   public function getEvaluator()
+   {
+       return $this->evaluator;
+   }
+}

src/Symfony/Component/ExpressionLanguage/ExpressionFunctionProviderInterface.php

@@ -0,0 +1,23 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\ExpressionLanguage;
+
+/**
+ * @author Fabien Potencier <fabien@symfony.com>
+ */
+interface ExpressionFunctionProviderInterface
+{
+    /**
+     * @return ExpressionFunction[] An array of Function instances
+     */
+    public function getFunctions();
+}

src/Symfony/Component/ExpressionLanguage/ExpressionLanguage.php

@@ -31,10 +31,17 @@ class ExpressionLanguage
 
     protected $functions = array();
 
-    public function __construct(ParserCacheInterface $cache = null)
+    /**
+     * @param ParserCacheInterface $cache
+     * @param ExpressionFunctionProviderInterface[] $providers
+     */
+    public function __construct(ParserCacheInterface $cache = null, array $providers = array())
     {
         $this->cache = $cache ?: new ArrayParserCache();
         $this->registerFunctions();
+        foreach ($providers as $provider) {
+            $this->registerProvider($provider);
+        }
     }
 
     /**
@@ -92,27 +99,29 @@ class ExpressionLanguage
     /**
      * Registers a function.
      *
-     * A function is defined by two PHP callables. The callables are used
-     * by the language to compile and/or evaluate the function.
-     *
-     * The first function is used at compilation time and must return a
-     * PHP representation of the function call (it receives the function
-     * arguments as arguments).
-     *
-     * The second function is used for expression evaluation and must return
-     * the value of the function call based on the values defined for the
-     * expression (it receives the values as a first argument and the function
-     * arguments as remaining arguments).
-     *
      * @param string   $name      The function name
      * @param callable $compiler  A callable able to compile the function
      * @param callable $evaluator A callable able to evaluate the function
+     *
+     * @see ExpressionFunction
      */
     public function register($name, $compiler, $evaluator)
     {
         $this->functions[$name] = array('compiler' => $compiler, 'evaluator' => $evaluator);
     }
 
+    public function addFunction(ExpressionFunction $function)
+    {
+        $this->register($function->getName(), $function->getCompiler(), $function->getEvaluator());
+    }
+
+    public function registerProvider(ExpressionFunctionProviderInterface $provider)
+    {
+        foreach ($provider->getFunctions() as $function) {
+            $this->addFunction($function);
+        }
+    }
+
     protected function registerFunctions()
     {
         $this->register('constant', function ($constant) {

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

@@ -12,6 +12,7 @@
 namespace Symfony\Component\ExpressionLanguage\Tests;
 
 use Symfony\Component\ExpressionLanguage\ExpressionLanguage;
+use Symfony\Component\ExpressionLanguage\Tests\Fixtures\TestProvider;
 
 class ExpressionLanguageTest extends \PHPUnit_Framework_TestCase
 {
@@ -54,6 +55,13 @@ class ExpressionLanguageTest extends \PHPUnit_Framework_TestCase
         $this->assertEquals('constant("PHP_VERSION")', $expressionLanguage->compile('constant("PHP_VERSION")'));
     }
 
+    public function testProviders()
+    {
+        $expressionLanguage = new ExpressionLanguage(null, array(new TestProvider));
+        $this->assertEquals('foo', $expressionLanguage->evaluate('identity("foo")'));
+        $this->assertEquals('"foo"', $expressionLanguage->compile('identity("foo")'));
+    }
+
     /**
      * @dataProvider shortCircuitProviderEvaluate
      */

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

@@ -0,0 +1,29 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\ExpressionLanguage\Tests\Fixtures;
+
+use Symfony\Component\ExpressionLanguage\ExpressionFunction;
+use Symfony\Component\ExpressionLanguage\ExpressionFunctionProviderInterface;
+
+class TestProvider implements ExpressionFunctionProviderInterface
+{
+    public function getFunctions()
+    {
+        return array(
+            new ExpressionFunction('identity', function ($input) {
+                return $input;
+            }, function (array $values, $input) {
+                return $input;
+            }),
+        );
+    }
+}