/**
* Evaluate a Script.
*
* @param string $expression to parse
* @param Context $context the context in which the expression is evaluated
* @param int $environment the environment in which the expression is evaluated
* @return Literals\Literal parsed value
*/
public function evaluate($expression, $context, $environment = self::DEFAULT_ENV)
{
self::$context = $context;
$operands = [];
$tokens = $this->parse($expression, $context, $environment);
while (count($tokens)) {
$token = array_shift($tokens);
if ($token instanceof ScriptFunction) {
$perform = $token->perform();
array_push($operands, $perform);
} elseif ($token instanceof Literals\Literal) {
if ($token instanceof Literals\SassString) {
$token = new Literals\SassString($this->interpolate($token->toString(), self::$context));
}
array_push($operands, $token);
} else {
$args = [];
for ($i = 0, $c = $token->operandCount; $i < $c; $i++) {
$args[] = array_pop($operands);
}
array_push($operands, $token->perform($args));
}
}
return self::makeSingular($operands);
}
