public override IValue Evaluate()
{
string literal = _tokenText.Evaluate().AsString;
var stream = new AntlrInputStream(literal);
var lexer = new VBADateLexer(stream);
var tokens = new CommonTokenStream(lexer);
var parser = new VBADateParser(tokens);
var dateLiteral = parser.dateLiteral();
var dateOrTime = dateLiteral.dateOrTime();
int year;
int month;
int day;
int hours;
int mins;
int seconds;
Predicate<int> legalMonth = (x) => x >= 0 && x <= 12;
Func<int, int, int, bool> legalDay = (m, d, y) =>
{
bool legalYear = y >= 0 && y <= 32767;
bool legalM = legalMonth(m);
bool legalD = false;
if (legalYear && legalM)
{
int daysInMonth = DateTime.DaysInMonth(y, m);
legalD = d >= 1 && d <= daysInMonth;
}
return legalYear && legalM && legalD;
};
Func<int, int> yearFunc = (x) =>
{
if (x >= 0 && x <= 29)
{
return x + 2000;
}
else if (x >= 30 && x <= 99)
{
return x + 1900;
}
else
{
return x;
}
};
int CY = DateTime.Now.Year;
if (dateOrTime.dateValue() == null)
{
year = 1899;
month = 12;
day = 30;
}
else
{
var dateValue = dateOrTime.dateValue();
var txt = dateOrTime.GetText();
var L = dateValue.dateValuePart()[0];
var M = dateValue.dateValuePart()[1];
VBADateParser.DateValuePartContext R = null;
if (dateValue.dateValuePart().Count == 3)
{
R = dateValue.dateValuePart()[2];
}
// "If L and M are numbers and R is not present:"
if (L.dateValueNumber() != null && M.dateValueNumber() != null && R == null)
{
var LNumber = int.Parse(L.GetText(), CultureInfo.InvariantCulture);
var MNumber = int.Parse(M.GetText(), CultureInfo.InvariantCulture);
if (legalMonth(LNumber) && legalDay(LNumber, MNumber, CY))
{
month = LNumber;
day = MNumber;
year = CY;
}
else if ((legalMonth(MNumber) && legalDay(MNumber, LNumber, CY)))
{
month = MNumber;
day = LNumber;
year = CY;
}
else if (legalMonth(LNumber))
{
month = LNumber;
day = 1;
year = MNumber;
}
else if (legalMonth(MNumber))
{
month = MNumber;
day = 1;
year = LNumber;
}
else
{
throw new Exception("Invalid date: " + dateLiteral.GetText());
}
}
// "If L, M, and R are numbers:"
else if (L.dateValueNumber() != null && M.dateValueNumber() != null && R != null && R.dateValueNumber() != null)
{
var LNumber = int.Parse(L.GetText(), CultureInfo.InvariantCulture);
var MNumber = int.Parse(M.GetText(), CultureInfo.InvariantCulture);
var RNumber = int.Parse(R.GetText(), CultureInfo.InvariantCulture);
if (legalMonth(LNumber) && legalDay(LNumber, MNumber, yearFunc(RNumber)))
{
month = LNumber;
day = MNumber;
year = yearFunc(RNumber);
}
else if (legalMonth(MNumber) && legalDay(MNumber, RNumber, yearFunc(LNumber)))
{
month = MNumber;
day = RNumber;
year = yearFunc(LNumber);
}
else if (legalMonth(MNumber) && legalDay(MNumber, LNumber, yearFunc(RNumber)))
{
month = MNumber;
day = LNumber;
year = yearFunc(RNumber);
}
else
{
throw new Exception("Invalid date: " + dateLiteral.GetText());
}
}
// "If either L or M is not a number and R is not present:"
else if ((L.dateValueNumber() == null || M.dateValueNumber() == null) && R == null)
{
int N;
string monthName;
if (L.dateValueNumber() != null)
{
N = int.Parse(L.GetText(), CultureInfo.InvariantCulture);
monthName = M.GetText();
}
else
{
N = int.Parse(M.GetText(), CultureInfo.InvariantCulture);
monthName = L.GetText();
}
int monthNameNumber;
if (monthName.Length == 3)
{
monthNameNumber = DateTime.ParseExact(monthName, "MMM", CultureInfo.InvariantCulture).Month;
}
else
{
monthNameNumber = DateTime.ParseExact(monthName, "MMMM", CultureInfo.InvariantCulture).Month;
}
if (legalDay(monthNameNumber, N, CY))
{
month = monthNameNumber;
day = N;
year = CY;
}
else
{
month = monthNameNumber;
day = 1;
year = N;
}
}
// "Otherwise, R is present and one of L, M, and R is not a number:"
else
{
int N1;
int N2;
string monthName;
if (L.dateValueNumber() == null)
{
monthName = L.GetText();
N1 = int.Parse(M.GetText(), CultureInfo.InvariantCulture);
N2 = int.Parse(R.GetText(), CultureInfo.InvariantCulture);
}
else if (M.dateValueNumber() == null)
{
monthName = M.GetText();
N1 = int.Parse(L.GetText(), CultureInfo.InvariantCulture);
N2 = int.Parse(R.GetText(), CultureInfo.InvariantCulture);
}
else
{
monthName = R.GetText();
N1 = int.Parse(L.GetText(), CultureInfo.InvariantCulture);
N2 = int.Parse(M.GetText(), CultureInfo.InvariantCulture);
}
int monthNameNumber;
if (monthName.Length == 3)
{
monthNameNumber = DateTime.ParseExact(monthName, "MMM", CultureInfo.InvariantCulture).Month;
}
else
{
monthNameNumber = DateTime.ParseExact(monthName, "MMMM", CultureInfo.InvariantCulture).Month;
}
if (legalDay(monthNameNumber, N1, yearFunc(N2)))
{
month = monthNameNumber;
day = N1;
year = yearFunc(N2);
}
else if (legalDay(monthNameNumber, N2, yearFunc(N1)))
{
month = monthNameNumber;
day = N2;
year = yearFunc(N1);
}
else
{
throw new Exception("Invalid date: " + dateLiteral.GetText());
}
}
}
if (dateOrTime.timeValue() == null)
{
hours = 0;
mins = 0;
seconds = 0;
}
else
{
var timeValue = dateOrTime.timeValue();
hours = int.Parse(timeValue.timeValuePart()[0].GetText(), CultureInfo.InvariantCulture);
if (timeValue.timeValuePart().Count == 1)
{
mins = 0;
}
else
{
mins = int.Parse(timeValue.timeValuePart()[1].GetText(), CultureInfo.InvariantCulture);
}
if (timeValue.timeValuePart().Count < 3)
{
seconds = 0;
}
else
{
seconds = int.Parse(timeValue.timeValuePart()[2].GetText(), CultureInfo.InvariantCulture);
}
var amPm = timeValue.AMPM();
if (amPm != null && (amPm.GetText().ToUpper() == "P" || amPm.GetText().ToUpper() == "PM") && hours >= 0 && hours <= 11)
{
hours += 12;
}
else if (amPm != null && (amPm.GetText().ToUpper() == "A" || amPm.GetText().ToUpper() == "AM") && hours == 12)
{
hours = 0;
}
}
return new DateValue(new DateTime(year, month, day, hours, mins, seconds));
}
}
