/// <summary>Converts the parameters to a constant day expression </summary>
/// <param name="expr">The function call expressions</param>
public object ToRelativeDay(BindingCallExpr expr)
{
var day = Convert.ToInt32(expr.ParamList[0]);
var time = (string)expr.ParamList[1];
var token = expr.ParamList[2] as TokenData;
var dayName = _data.LookupDayName(day);
return(Exprs.Day(dayName, time, token));
}