/**
* Sets the imported item's alias. If NULL is passed, the alias is removed.
*
* @param \Pharborist\TokenNode|string|NULL $alias
*
* @return $this
*/
public function setAlias($alias)
{
if (is_string($alias)) {
$alias = new TokenNode(T_STRING, $alias);
}
if ($alias instanceof TokenNode) {
if ($this->hasAlias()) {
$this->alias->replaceWith($alias);
} else {
$this->alias = $alias;
$this->addChild(WhitespaceNode::create(' '));
$this->addChild(Token::_as());
$this->addChild(WhitespaceNode::create(' '));
$this->addChild($alias, 'alias');
}
} elseif ($alias === NULL && $this->hasAlias()) {
$this->alias->previousUntil(Filter::isInstanceOf('\\Pharborist\\Namespaces\\NameNode'))->remove();
$this->alias->remove();
$this->alias = NULL;
} else {
throw new \InvalidArgumentException();
}
return $this;
}