Can I extract an associative array into variables? - twig

Question

Lets say I have an associative array like so:
{% set settings = { 'foo':'bar', 'cat':'mouse', 'apple':'banana' } %}
To use this data I would do the following:
{{ settings.foo }}
{{ settings.cat }}
{{ settings.apple }}
However, I wondered if there is a way to extract the keys to variables, and the values to values? Essentially the same as the PHP Extract function. So I can just do this instead:
{{ foo }}
{{ cat }}
{{ apple }}
My very amateurish attempt to do this started out like this:
{% for key,val in settings %}
{% set key = val %}
{% endfor %}
But obviously that doesn't work (or I wouldn't be here). Is there another approach I could take?
Thanks,
Mark

Answer 1

As most things in Twig this can be done by extending Twig
ProjectTwigExtension.php
class ProjectTwigExtension extends Twig_Extension {
public function getFunctions() {
return array(
new Twig_SimpleFunction('extract', array($this, 'extract'), ['needs_context' => true, ]),
);
}
public function extract(&$context, $value) {
foreach($value as $k => $v) $context[$k] = $v;
}
public function getName() {
return 'ProjectTwigExtension';
}
}
Register class in Twig
$twig = new Twig_Environment($loader);
$twig->addExtension(new ProjectTwigExtension());
template.twig
{{ extract({'foo': 'bar', }) }}
{{ foo }} {# output : bar #}
(sidenote) Seems you can't do this by using a closure (see example below) because the compiler of Twig passes the variables in an array, thus creating a copy
With closure
$twig->addFunction(new Twig_SimpleFunction('extract', function (&$context, $value) {
foreach($value as $k => $v) $context[$k] = $v;
}, ['needs_context' => true, ]));
Compiled result
echo twig_escape_filter($this->env, call_user_func_array($this->env->getFunction('extract')->getCallable(), array($context, array("foo" => "bar", "foobar" => "foo"))), "html", null, true);