Result Calculator::run(Expression expr)
{
auto rpn = _parser.toRPN(expr);
RPNStack calcStack;
while (!rpn.empty()) {
auto element = rpn.top();
if (!_parser.isOperator(element)) {
calcStack.push(element);
rpn.pop();
continue;
}
auto rhs = BigInteger(calcStack.top());
calcStack.pop();
auto lhs = BigInteger(calcStack.top());
calcStack.pop();
BigInteger result;
if (element == "*") {
result = lhs * rhs;
} else if (element == "+") {
result = lhs + rhs;
} else if (element == "-") {
result = lhs - rhs;
}
calcStack.push(result.value());
rpn.pop();
}
return calcStack.top();
}
void RPNGo::evaluate(RPNScript & scr, RPNStack & st) const
{
RPNElem * op = st.pop();
RPNLabel * label = dynamic_cast<RPNLabel *>(op);
if (label == 0)
throw RPNError("Operand is not label");
scr.goToCmd(label->get());
delete op;
}
void RPNGoFalse::evaluate(RPNScript & scr, RPNStack & st) const
{
RPNConst * opl = st.pop();
RPNConst * ope = st.pop();
RPNLabel * label = dynamic_cast<RPNLabel *>(opl);
RPNInt * exp = dynamic_cast<RPNInt *>(ope);
if (exp == 0)
throw RPNError("Operand 1 is not integer");
if (label == 0)
throw RPNError("Operand 2 is not label");
if (exp->get() == 0)
scr.goToCmd(label->get());
else
scr.nextCmd();
delete opl;
delete ope;
}
