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 RPNFunction::evaluate(RPNScript & scr, RPNStack & st) const
{
RPNConst * res = evaluateFun(st);
if (res != 0)
st.push(res);
scr.nextCmd();
}
void RPNConst::evaluate(RPNScript & scr, RPNStack & st) const
{
st.push(clone());
scr.nextCmd();
}