function compare($a, $b, $negate = false)
{
$schema = new \Fulfil\Schema(['props' => ['a' => true, 'b' => true], 'rules' => [$rule = new Equal(['left' => 'a', 'right' => 'b'])]]);
if ($negate) {
$rule->negate = $negate;
}
$ctx = new \Fulfil\Context(['allowIncomplete' => true]);
$rule->validate(['left' => $a, 'right' => $b], $ctx);
$flat = $ctx->flatten();
return $flat;
}
