public static BigInteger ParseBigInteger(this NumeralSystem system, string s)
{
s = system.PrepareForParse(s);
var result = new BigInteger();
foreach (var c in s)
{
var value = system.GetValueForSymbol(c);
if (value == -1)
{
continue;
}
result = (result * system.Base) + value;
}
return(result);
}
