/// <summary>
/// Append the Some(x) of one option to the Some(y) of another.
/// For numeric values the behaviour is to sum the Somes (lhs + rhs)
/// For string values the behaviour is to concatenate the strings
/// For Lst/Stck/Que values the behaviour is to concatenate the lists
/// For Map or Set values the behaviour is to merge the sets
/// Otherwise if the T type derives from IAppendable then the behaviour
/// is to call lhs.Append(rhs);
/// </summary>
/// <param name="lhs">Left-hand side of the operation</param>
/// <param name="rhs">Right-hand side of the operation</param>
/// <returns>lhs + rhs</returns>
public static T?append <T>(T?lhs, T?rhs) where T : struct
{
if (!lhs.HasValue && !rhs.HasValue)
{
return(lhs); // None + None = None
}
if (!rhs.HasValue)
{
return(lhs); // Value + None = Value
}
if (!lhs.HasValue)
{
return(rhs); // None + Value = Value
}
return(TypeDesc.Append(lhs.Value, rhs.Value, TypeDesc <T> .Default));
}
/// <summary>
/// Append the Some(x) of one option to the Some(y) of another.
/// For numeric values the behaviour is to sum the Somes (lhs + rhs)
/// For string values the behaviour is to concatenate the strings
/// For Lst/Stck/Que values the behaviour is to concatenate the lists
/// For Map or Set values the behaviour is to merge the sets
/// Otherwise if the T type derives from IAppendable then the behaviour
/// is to call lhs.Append(rhs);
/// </summary>
/// <param name="lhs">Left-hand side of the operation</param>
/// <param name="rhs">Right-hand side of the operation</param>
/// <returns>lhs + rhs</returns>
public OptionUnsafe <T> Append(OptionUnsafe <T> rhs)
{
if (IsNone && rhs.IsNone)
{
return(this); // None + None = None
}
if (rhs.IsNone)
{
return(this); // Value + None = Value
}
if (this.IsNone)
{
return(rhs); // None + Value = Value
}
return(TypeDesc.Append(Value, rhs.Value, TypeDesc <T> .Default));
}
public NewType <T> Append(NewType <T> rhs) =>
GetType() == rhs.GetType()
? (NewType <T>) NewType.Construct(GetType(), TypeDesc.Append(Value, rhs.Value, TypeDesc <T> .Default))
: failwith <NewType <T> >("Mismatched NewTypes in append/add");