private static IExpression CreateContainsExpression(IExpression lhs, IExpression rhs)
{
// The "contains" operator is a bit fuzzy in that it sometimes performs an equal operation, and at other times it performs a range check.
// It exists to allow users to construct complex filters using a simple language.
// Example: "today contains $timestamp" is understandable to most people even though it actually evaluates to
// "$timestamp.year == now.year and $timestamp.month == now.month and $timestamp.day == now.day"
if (lhs is IExpression <IInterval <DateTime?> > lhsDateTimeInterval &&
rhs is IExpression <DateTime?> rhsDateTime)
{
return(ContainsTimestampExpression.Create(lhsDateTimeInterval, rhsDateTime));
}
if (lhs is IExpression <string> lhsString &&
rhs is IExpression <string> rhsString)
{
return(ContainsStringExpression.Create(lhsString, rhsString));
}
throw new NotImplementedException();
}
private bool Equals(ContainsTimestampExpression other)
{
return(_lhs.Equals(other._lhs) && _rhs.Equals(other._rhs));
}