/**
* @param StackItemInterface $item
* @return $this
*/
public function add(StackItemInterface $item)
{
$this->currentExpression->add($item);
return $this;
}
/**
* @param StackExpression $set
*/
private function validateSet(StackExpression $set)
{
// Set should contain 3 items: "column_name operator value", EG. "level > 200"
if ($set->count() !== 3) {
throw new InvalidExpressionException($set->asString());
}
$arr = $set->get();
if (!$arr[0] instanceof Literal || !$arr[1] instanceof Operator || !$arr[2] instanceof Literal) {
throw new InvalidExpressionException($set->asString());
}
}
