float smallcalc::Parser::level2()
{
float ans = level3();
TOKEN_TYPE operator_id = token_type;
while (operator_id == DIVISION_OP || operator_id == MULTIPLICATION_OP)
{
next_token();
ans = eval_operator(operator_id, ans, level3());
operator_id = token_type;
}
return ans;
}
float smallcalc::Parser::level1()
{
float ans = level2();
TOKEN_TYPE operator_id = token_type;
while (operator_id == ADDITION_OP || operator_id == SUBSTRACTION_OP)
{
next_token();
ans = eval_operator(operator_id, ans, level2());
operator_id = token_type;
}
return ans;
}
/*
* power
*/
double ExpParser::parse_level6()
{
int op_id;
double ans;
ans = parse_level7();
op_id = get_operator_id(token);
while (op_id == POW)
{
getToken();
ans = eval_operator(op_id, ans, parse_level7());
op_id = get_operator_id(token);
}
return ans;
}
/*
* multiply, divide, modulus, xor
*/
double ExpParser::parse_level5()
{
int op_id;
double ans;
ans = parse_level6();
op_id = get_operator_id(token);
while (op_id == MULTIPLY || op_id == DIVIDE || op_id == MODULUS || op_id == XOR)
{
getToken();
ans = eval_operator(op_id, ans, parse_level6());
op_id = get_operator_id(token);
}
return ans;
}
/*
* add or subtract
*/
double ExpParser::parse_level4()
{
int op_id;
double ans;
ans = parse_level5();
op_id = get_operator_id(token);
while (op_id == PLUS || op_id == MINUS)
{
getToken();
ans = eval_operator(op_id, ans, parse_level5());
op_id = get_operator_id(token);
}
return ans;
}
/*
* conditional operators
*/
double ExpParser::parse_level3()
{
int op_id;
double ans;
ans = parse_level4();
op_id = get_operator_id(token);
while (op_id == EQUAL || op_id == UNEQUAL || op_id == SMALLER || op_id == LARGER || op_id == SMALLEREQ || op_id == LARGEREQ)
{
getToken();
ans = eval_operator(op_id, ans, parse_level4());
op_id = get_operator_id(token);
}
return ans;
}
/*
* conditional operators and bitshift
*/
double ExpParser::parse_level2()
{
int op_id;
double ans;
ans = parse_level3();
op_id = get_operator_id(token);
while (op_id == AND || op_id == OR || op_id == BITSHIFTLEFT || op_id == BITSHIFTRIGHT)
{
getToken();
ans = eval_operator(op_id, ans, parse_level3());
op_id = get_operator_id(token);
}
return ans;
}
/*
* Factorial
*/
double ExpParser::parse_level7()
{
int op_id;
double ans;
ans = parse_level8();
op_id = get_operator_id(token);
while (op_id == FACTORIAL)
{
getToken();
// factorial does not need a value right from the
// operator, so zero is filled in.
ans = eval_operator(op_id, ans, 0.0);
op_id = get_operator_id(token);
}
return ans;
}
