public function process()
{
$returnValue = new QtismInteger(0);
$operands = $this->getOperands();
if (count($operands) >= 2) {
$points = $operands[0];
$equation = $operands[1];
if (($points instanceof MultipleContainer || $points instanceof OrderedContainer) && ($points->getBaseType() === BaseType::POINT || $points->getBaseType() === BaseType::STRING) && $equation instanceof QtismString) {
// Check every Point X,Y against the equation...
$math = new \oat\beeme\Parser();
$math->setConstant('#pi', M_PI);
try {
foreach ($points as $point) {
if ($point instanceof QtiPoint) {
$x = floatval($point->getX());
$y = floatval($point->getY());
} else {
$strs = explode(" ", $point->getValue());
if (count($strs) !== 2) {
// Parsing error, the NULL value is returned.
return null;
} else {
$x = floatval($strs[0]);
$y = floatval($strs[1]);
}
}
$result = $math->evaluate($equation->getValue(), array('x' => $x, 'y' => $y));
if ($result === true) {
// The Point X,Y satisfies the equation...
$returnValue->setValue($returnValue->getValue() + 1);
}
}
} catch (\Exception $e) {
// If an error occurs e.g. invalid expression, the NULL value is returned.
return null;
}
} else {
// Not supported operands, return the NULL value.
return null;
}
}
return $returnValue;
}
