sampleeval.cpp

const RCP<const Basic> handle_minus(const RCP<const Basic> &arg, bool odd)
{
    if(could_extract_minus(r)) {
        if(odd) 
            return mul(minus_one, r);
        else
            return r;
    }
}

// \return true of conjugate has to be returned finally else false
bool eval(const RCP<const Basic> &arg, int period, bool odd, //input 
                      const Ptr<RCP<const Basic>> arg&,int& index, int& sign) //output
{
    if (eq(arg, zero)) return zero;
    bool check;
    RCP<const Integer> n;
    RCP<const Basic> r;
    check = get_pi_shift(arg, outArg(n), outArg(r));
    if (check) {
        int m = n->as_int();
        m = m % (12*period);
        sign = 1;
        if (eq(r, zero)) {
            index = m;
            *arg = zero;
            return false; 
        }
        else if ((m % (12*period)) == 0) {
            index = 0;
            *arg = handle_minus(r, odd);
            if (!odd) 
                sign = -1;
            return false;
        }
        else if ((m % 6) == 0)) {
            if (m == 6)
                sign = 1;
            else
                sign = -1;
            *arg = r;
            return true;
        }
    }
    else {
        *arg = r;
        index = -1;
        return false;
    }
        
}

RCP<const Basic> sin(const RCP<const Basic> &arg) 
{
    RCP<const Basic>>& ret_arg;
    int index;
    int sign;
    bool conjugate =  eval(arg, 2, 1, //input 
                      outArg(ret_arg), index, sign); //output
    
    if (conjugate) {
        // cos has to be returned
        if (sign == 1)
            return rcp(new Cos(ret_arg));
        else
            return mul(minus_one, rcp(new Cos(ret_arg)));
    }
    else {
        if (eq(ret_arg, zero)) {
            return sign*sin_table[index];
        }
        else {
            if (sign == 1) 
                return rcp(new Sin(ret_arg));
            else
                return mul(minus_one, rcp(new Sin(ret_arg)));
        }
    }
}