class Article
{
public function __get($name)
{
if ('title' == $name) {
return 'The title';
}
// throw some kind of error
}
public function __isset($name)
{
if ('title' == $name) {
return true;
}
return false;
}
}
在嵌套循环中访问父级上下文（Accessing the parent Context in Nested Loops）
$data = array(
'topics' => array(
'topic1' => array('Message 1 of topic 1', 'Message 2 of topic 1'),
'topic2' => array('Message 1 of topic 2', 'Message 2 of topic 2'),
),
);
下面的模板将显示所有主题中的所有消息:
{% for topic, messages in topics %}
* {{ loop.index }}: {{ topic }}
{% for message in messages %}
- {{ loop.parent.loop.index }}.{{ loop.index }}: {{ message }}
{% endfor %}
{% endfor %}
输出:
* 1: topic1
- 1.1: The message 1 of topic 1
- 1.2: The message 2 of topic 1
* 2: topic2
- 2.1: The message 1 of topic 2
- 2.2: The message 2 of topic 2
// auto-register all native PHP functions as Twig functions
// don't try this at home as it's not secure at all!
$twig->registerUndefinedFunctionCallback(function ($name) {
if (function_exists($name)) {
return new Twig_Function($name, $name);
}
return false;
});
try {
$twig->parse($twig->tokenize(new Twig_Source($template)));
// the $template is valid
} catch (Twig_Error_Syntax $e) {
// $template contains one or more syntax errors
}
如果您对一组文件进行迭代，可以将文件名传递给tokenize()方法以获取异常消息中的文件名:
foreach ($files as $file) {
try {
$twig->parse($twig->tokenize(new Twig_Source($template, $file->getFilename(), $file)));
// the $template is valid
} catch (Twig_Error_Syntax $e) {
// $template contains one or more syntax errors
}
}
protected $someTemplateState = array();
public function enterNode(Twig_Node $node, Twig_Environment $env)
{
if ($node instanceof Twig_Node_Module) {
// reset the state as we are entering a new template
$this->someTemplateState = array();
}
// ...
return $node;
}
class DatabaseTwigLoader implements Twig_LoaderInterface
{
protected $dbh;
public function __construct(PDO $dbh)
{
$this->dbh = $dbh;
}
public function getSourceContext($name)
{
if (false === $source = $this->getValue('source', $name)) {
throw new Twig_Error_Loader(sprintf('Template "%s" does not exist.', $name));
}
return new Twig_Source($source, $name);
}
public function exists($name)
{
return $name === $this->getValue('name', $name);
}
public function getCacheKey($name)
{
return $name;
}
public function isFresh($name, $time)
{
if (false === $lastModified = $this->getValue('last_modified', $name)) {
return false;
}
return $lastModified <= $time;
}
protected function getValue($column, $name)
{
$sth = $this->dbh->prepare('SELECT '.$column.' FROM templates WHERE name = :name');
$sth->execute(array(':name' => (string) $name));
return $sth->fetchColumn();
}
}
最后，这里有一个关于如何使用它的例子:
$loader = new DatabaseTwigLoader($dbh);
$twig = new Twig_Environment($loader);
echo $twig->render('index.twig', array('name' => 'Fabien'));