Add {unset …} (#29)

src/Fenom.php

@@ -228,6 +228,10 @@ class Fenom {
             'type' => self::BLOCK_COMPILER,
             'open' => 'Fenom\Compiler::autoescapeOpen',
             'close' => 'Fenom\Compiler::autoescapeClose'
+        ),
+        'unset' => array(
+            'type' => self::INLINE_COMPILER,
+            'parser' => 'Fenom\Compiler::tagUnset'
         )
     );
 

src/Fenom/Compiler.php

@@ -914,4 +914,23 @@ class Compiler {
     public static function autoescapeClose(Tokenizer $tokens, Scope $scope) {
         $scope->tpl->escape = $scope["escape"];
     }
+
+    /**
+     * Unset present variables
+     *
+     * @param Tokenizer $tokens
+     * @param Template $tpl
+     * @return string
+     * @throws InvalidUsageException
+     */
+    public static function tagUnset(Tokenizer $tokens, Template $tpl) {
+        $vars = array();
+        while($tokens->valid()) {
+            $vars[] = $tpl->parseVar($tokens);
+        }
+        if(!$vars) {
+            throw new InvalidUsageException("Unset must accept variable(s)");
+        }
+        return 'unset('.implode(', ', $vars).')';
+    }
 }