/**
* Constructs the arithmetic expression with the arithmetic
* operator $op and two operands, $left and $right, which
* are FQLExpressions themselves.
*
* @param $op arithmetic op (+, -, *, /)
* @param $left FQLExpression representing left operand
* @param $right FQLExpression representing right operand
*/
public function __construct($op, $left, $right)
{
$this->op = $op;
parent::__construct($left, $right);
}
/**
* Gets the query expression that the comparison expression
* is enforcing. Currently this supports equality only, so an
* expression like id < 3 will yield ':', which matches all ids.
* An expression like id == 3 will yield the query for the field
* 'id' for the value 3.
*
* Only comparisons between a field and a constant are valid.
*
* @return associative array where the keys are the query expressions
* and they all map to 1.
*/
public function get_queries()
{
if ($this->op != '==') {
// can only index by equality
return parent::get_queries();
}
if ($this->right instanceof FQLConstantExpression && $this->left instanceof FQLFieldExpression) {
// expression is something like "id == 3"
$query = $this->left->field->get_query($this->right->evaluate(null));
} else {
if ($this->left instanceof FQLConstantExpression && $this->right instanceof FQLFieldExpression) {
// expression is something like "3 == id"
$query = $this->right->field->get_query($this->left->evaluate(null));
} else {
return parent::get_queries();
}
}
if (isset($query) && $query) {
return array($query => 1);
} else {
// this means that we're sure there are no matches. e.g. you did a
// search for groups where id == -5 or something.
return array();
}
}
