Way off. You need to learn the difference between vars, var, and int.
Also, read the manual and verify what each function returns, and why.
For example, asset() does **not** return a vars.
function run()
{
asset("EUR/USD");
vars c_euro= series(price());
int shortma = 20;
vars euro_ema= series(EMA(c_euro,shortma));
vars euro = series(c_euro[0]/ euro_ema[0]);
}