protected function multiplySelectors($env)
{
$envs = array();
while (null !== $env) {
if (!empty($env->selectors)) {
$envs[] = $env;
}
$env = $env->parent;
}
$selectors = array();
$parentSelectors = array(array());
while ($env = array_pop($envs)) {
$selectors = array();
foreach ($env->selectors as $selector) {
foreach ($parentSelectors as $parent) {
$selectors[] = $this->joinSelectors($parent, $selector);
}
}
$parentSelectors = $selectors;
}
return $selectors;
}