adding eval tag for more template fun fun fun

Author: chr-hertel

README.md

@@ -20,6 +20,13 @@ Using the eval function:
 {{ eval('echo 1+1;') }}
 ```
 
+Using the eval tag:
+```twig
+{% eval %}
+    echo file_get_contents("/var/log/system.log");
+{% endeval %}
+```
+
 Tests
 -----
 

src/EvalExtension.php

@@ -15,4 +15,11 @@ public function getFunctions(): array
             new TwigFunction('eval', 'eval'),
         ];
     }
+
+    public function getTokenParsers(): array
+    {
+        return [
+            new EvalTokenParser(),
+        ];
+    }
 }

src/EvalNode.php

@@ -0,0 +1,22 @@
+<?php
+
+declare(strict_types=1);
+
+namespace jæm3l\Twig;
+
+use Twig\Node\Node;
+
+class EvalNode extends Node
+{
+    public function compile(\Twig_Compiler $compiler): void
+    {
+        $code = array_reduce($this->nodes, function(string $code, \Twig_Node $node) {
+            return $code . $node->getAttribute('data');
+        }, '');
+
+        $compiler
+            ->addDebugInfo($this)
+            ->write(sprintf('eval("%s;");', addslashes($code)))
+        ;
+    }
+}

src/EvalTokenParser.php

@@ -0,0 +1,31 @@
+<?php
+
+declare(strict_types=1);
+
+namespace jæm3l\Twig;
+
+use Twig\TokenParser\AbstractTokenParser;
+
+class EvalTokenParser extends AbstractTokenParser
+{
+    public function parse(\Twig_Token $token)
+    {
+        $stream = $this->parser->getStream();
+
+        $stream->expect( \Twig_Token::BLOCK_END_TYPE );
+        $content = $this->parser->subparse([$this, 'decideEvalEnd'], true);
+        $stream->expect( \Twig_Token::BLOCK_END_TYPE );
+
+        return new EvalNode([$content], [], $token->getLine(), $this->getTag());
+    }
+
+    public function decideEvalEnd(\Twig_Token $token): bool
+    {
+        return $token->test( 'endeval' );
+    }
+
+    public function getTag(): string
+    {
+        return 'eval';
+    }
+}

tests/EvalExtensionTest.php

@@ -40,4 +40,19 @@ public function testNestedEval()
 
         $this->assertSame('3', $output);
     }
+
+    public function testEvalTag()
+    {
+        $templates = [
+            'eval_tag' => '{% eval %}echo 1+3;{% endeval %}',
+        ];
+
+        $loader = new ArrayLoader($templates);
+        $twig = new Environment($loader);
+        $twig->addExtension(new EvalExtension());
+
+        $output = $twig->render('eval_tag');
+
+        $this->assertSame('4', $output);
+    }
 }