--- /dev/null
+<?php
+
+namespace Drupal\Core\Template;
+
+use Drupal\Component\Utility\Html;
+
+/**
+ * A class that represents most standard HTML attributes.
+ *
+ * To use with the Attribute class, set the key to be the attribute name
+ * and the value the attribute value.
+ * @code
+ * $attributes = new Attribute(array());
+ * $attributes['id'] = 'socks';
+ * $attributes['style'] = 'background-color:white';
+ * echo '<cat ' . $attributes . '>';
+ * // Produces: <cat id="socks" style="background-color:white">.
+ * @endcode
+ *
+ * @see \Drupal\Core\Template\Attribute
+ */
+class AttributeString extends AttributeValueBase {
+
+ /**
+ * Implements the magic __toString() method.
+ */
+ public function __toString() {
+ return Html::escape($this->value);
+ }
+
+}