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 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;
}
void TokenListToRPN(TokenList &a_list, RPNStack &a_rpn)
{
// Shunting yard algorithm
std::vector<Token*> opStack;
Token *c_token = a_list.head;
while (c_token)
{
switch (c_token->type)
{
case Token::Type::Name:
if (isalllower(c_token->name, true) && isvalidname(c_token->name))
{
if (G::functions.Exists(c_token->name))
{
opStack.push_back(c_token);
c_token->type = Token::Type::E_Function;
}
else if (G::variables.Exists(c_token->name))
{
a_rpn.push_back({ ExprNode::Type::Number, G::variables.Get(c_token->name) });
}
else throw ExpressionError("Undefined reference", c_token);
}
else if (isallupper(c_token->name, true) && isvalidname(c_token->name))
{
if (G::constants.Exists(c_token->name))
a_rpn.push_back({ ExprNode::Type::Number, G::constants.Get(c_token->name) });
else throw ExpressionError("Undefined constant", c_token);
}
else throw ExpressionError("Invalid value name", c_token);
break;
case Token::Type::Number:
a_rpn.push_back({ ExprNode::Type::Number, c_token->value });
break;
case Token::Type::Operator:
if (opStack.size() > 0)
{
if (c_token->optype == Token::OpType::RPar)
{
Token *tos = opStack.back();
if (opStack.size() == 0)
throw ExpressionError("#1 Mismatched parenthesis", c_token);
while (tos->optype != Token::OpType::LPar)
{
a_rpn.push_back({ ExprNode::Type::Operator, 0, tos->optype });
opStack.pop_back();
tos = opStack.back();
if (opStack.size() == 0)
throw ExpressionError("#2 Mismatched parenthesis", c_token);
}
opStack.pop_back(); // pop opening parantheses
if (opStack.size() > 0)
{
tos = opStack.back();
if (tos->type == Token::Type::E_Function)
{
a_rpn.push_back({ ExprNode::Type::Function, 0, Token::OpType::None,
HashFunc(tos->name) });
opStack.pop_back();
}
}
}
else if (c_token->optype == Token::OpType::Comma)
{
Token *tos = opStack.back();
if (opStack.size() == 0)
throw ExpressionError("Invalid separator", c_token);
while (tos->optype != Token::OpType::LPar)
{
a_rpn.push_back({ ExprNode::Type::Operator, 0, tos->optype });
opStack.pop_back();
tos = opStack.back();
if (opStack.size() == 0)
throw ExpressionError("Invalid separator", c_token);
}
}
else
{
if (c_token->optype != Token::OpType::LPar)
{
while (opStack.size() > 0 && opStack.back()->optype != Token::OpType::LPar)
{
Token *tos = opStack.back();
if ((is_la(c_token->optype) && precedence(c_token->optype) <= precedence(tos->optype)) ||
(is_ra(c_token->optype) && precedence(c_token->optype) < precedence(tos->optype)))
{
opStack.pop_back();
a_rpn.push_back({ ExprNode::Type::Operator, 0, tos->optype });
}
else break;
}
}
opStack.push_back(c_token);
}
}
else if (c_token->optype != Token::OpType::RPar ||
c_token->optype != Token::OpType::Comma)
opStack.push_back(c_token);
break;
case Token::Type::Special:
a_rpn.push_back({ ExprNode::Type::Special, 0, ExprNode::OpType::None, 0, c_token->sptype });
break;
}
c_token = c_token->next;
}
for (unsigned i = opStack.size(); i-- > 0; )
{
if (opStack[i]->optype == Token::OpType::LPar ||
opStack[i]->optype == Token::OpType::RPar)
throw ExpressionError("#3 Mismatched parenthesis", opStack[i]);
a_rpn.push_back({ ExprNode::Type::Operator, 0, opStack[i]->optype });
}
}
void RPNConst::evaluate(RPNScript & scr, RPNStack & st) const
{
st.push(clone());
scr.nextCmd();
}