public function calculate(Token ...$tokenStream)
{
$stack = new Stack();
foreach ($tokenStream as $token) {
if ($token instanceof Operand) {
$stack->push($token);
continue;
}
if ($token instanceof Operator) {
$stack->push($token->bla($stack->pop(), $stack->pop()));
}
}
return $stack->pop()->value();
}
/**
* @param $operators
* @param $token
* @param $output
*/
private function handleOperator(Stack $operators, Operator $token, Stack $output)
{
while ($o2 = $operators->poke()) {
switch (true) {
case $o2 instanceof Parenthesis:
break 2;
case $token->isLeftAssociative() && $token->precedence() <= $o2->precedence():
case $token->isRightAssociative() && $token->precedence() < $o2->precedence():
$output->push($operators->pop());
break;
default:
break 2;
}
}
$operators->push($token);
}