/// <summary>
/// Evaluates a math expression of 2 time spans.
/// </summary>
/// <param name="node">The AST node the evaluation is a part of.</param>
/// <param name="lhs">The time on the left hand side</param>
/// <param name="rhs">The time on the right hand side</param>
/// <param name="op">The math operator.</param>
/// <returns></returns>
public static LBool CompareDates(AstNode node, LDate lhs, LDate rhs, Operator op)
{
var left = lhs.Value;
var right = rhs.Value;
var result = false;
if (op == Operator.LessThan) result = left < right;
else if (op == Operator.LessThanEqual) result = left <= right;
else if (op == Operator.MoreThan) result = left > right;
else if (op == Operator.MoreThanEqual) result = left >= right;
else if (op == Operator.EqualEqual) result = left == right;
else if (op == Operator.NotEqual) result = left != right;
return new LBool(result);
}
/// <summary>
/// Execute the continue.
/// </summary>
public object VisitDay(DayExpr expr)
{
var date = DateTime.Today;
var dayOfweek = DayOfWeek.Monday;
var isDayOfWeek = false;
var isTimeSpecified = expr.Time != "0";
var dayName = expr.Name.ToLower();
// 1. Determine date/day
if (dayName == "today") date = DateTime.Today;
else if (dayName == "yesterday") date = DateTime.Today.AddDays(-1);
else if (dayName == "tomorrow") date = DateTime.Today.AddDays(1);
else if (dayName == "monday") { isDayOfWeek = true; dayOfweek = DayOfWeek.Monday; }
else if (dayName == "tuesday") { isDayOfWeek = true; dayOfweek = DayOfWeek.Tuesday; }
else if (dayName == "wednesday") { isDayOfWeek = true; dayOfweek = DayOfWeek.Wednesday; }
else if (dayName == "thursday") { isDayOfWeek = true; dayOfweek = DayOfWeek.Thursday; }
else if (dayName == "friday") { isDayOfWeek = true; dayOfweek = DayOfWeek.Friday; }
else if (dayName == "saturday") { isDayOfWeek = true; dayOfweek = DayOfWeek.Saturday; }
else if (dayName == "sunday") { isDayOfWeek = true; dayOfweek = DayOfWeek.Sunday; }
// Case 1 -
if (isDayOfWeek)
{
// Case 1a: day of week only
if(!isTimeSpecified)
return new LDayOfWeek(dayOfweek);
// Case 1b: day of week ( with time )
var today = DateTime.Today;
var count = 0;
while (today.DayOfWeek != dayOfweek && count < 8)
{
today = today.AddDays(1);
}
}
// 3. Finally - add the time to the day.
if(expr.Time != "0")
{
var t = TimeSpan.Parse(expr.Time);
date = date.AddMilliseconds(t.TotalMilliseconds);
}
var result = new LDate(date);
return result;
}
/// <summary>
/// Evaluates a math expression of 2 time spans.
/// </summary>
/// <param name="node">The AST node the evaluation is a part of.</param>
/// <param name="lhs">The time on the left hand side</param>
/// <param name="rhs">The time on the right hand side</param>
/// <param name="op">The math operator.</param>
/// <returns></returns>
public static LTime CalcDates(AstNode node, LDate lhs, LDate rhs, Operator op)
{
if (op != Operator.Subtract)
throw ExceptionHelper.BuildRunTimeException(node, "Can only subtract dates");
var left = lhs.Value;
var right = rhs.Value;
var result = left - right;
return new LTime(result);
}
