/// <summary>
/// Determines whether this instance is ever true during a specified time period.
/// </summary>
public Tbool IsEverTrue(Tdate start, Tdate end)
{
Tbool equalsVal = this == true;
Tbool isDuringInterval = Time.IsBetween(start, end);
Tbool isOverlap = equalsVal & isDuringInterval;
return(isOverlap.IsEverTrue());
}
/// <summary>
/// Returns a Tvar when its associated Tbool is true.
/// </summary>
/// <remarks>
/// Similar in principle to a C# switch statement, just temporal.
/// Sample usage: Switch(Tbool1, Tvar1, Tbool2, Tvar2, ..., defaultTvar).
/// Returns Tvar1 if Tbool2 is true, else Tvar2 if Tbool2 is true, etc., else defaultTvar.
/// </remarks>
public static T Switch <T>(params Func <Tvar>[] arguments) where T : Tvar
{
// Default result
Hval h = new Hval(null, Hstate.Null);
T result = (T)Util.ReturnProperTvar <T>(h);
// Analyze each condition-value pair...and keep going
// until all intervals of the result Tvar are defined...
int len = (int)arguments.Length;
for (int arg = 0; arg < len - 1; arg += 2)
{
// Get value of the condition
Tbool newCondition = Util.ConvertToTvar <Tbool>(arguments[arg].Invoke());
// Identify the intervals when the new condition is neither false nor true
// Falsehood causes it to fall through to next condition. Truth causes the
// result to assume the value during that interval.
Tbool newConditionIsUnknown = Util.HasUnknownState(newCondition);
// Merge these 'unknown' intervals in new condition into the result.
result = Util.MergeTvars <T>(result,
Util.ConditionalAssignment <T>(newConditionIsUnknown, newCondition));
// Identify the intervals when the new condition is true.
// Ignore irrelevant periods when result is already determined.
// During these intervals, "result" takes on the value of its conclusion.
Tbool newConditionIsTrueAndResultIsNull = newCondition && Util.IsNull(result);
// If new true segments are found, accumulate the values during those intervals
if (newConditionIsTrueAndResultIsNull.IsEverTrue())
{
T val = (T)Util.ConvertToTvar <T>(arguments[arg + 1].Invoke());
result = Util.MergeTvars <T>(result,
Util.ConditionalAssignment <T>(newConditionIsTrueAndResultIsNull, val));
}
if (!Util.HasUndefinedIntervals(result))
{
return(result.LeanTvar <T>());
}
}
T defaultVal = (T)Util.ConvertToTvar <T>(arguments[len - 1].Invoke());
result = Util.MergeTvars <T>(result, defaultVal);
return(result.LeanTvar <T>());
}
