Meador Inge wrote:

3. Using Decimal keeps the desired precision,

Well, sort of, but then you end up doing arithmetic in
decimal instead of binary, which could give different
results.

Even with the user-defined precision capabilities of the 'Decimal' class? In other words, can I create an instance of a 'Decimal' that behaves (in all operations: arithmetic, comparison, etc...) exactly as the extended double precision type offered by a given machine?

Maybe the solution is to give ctypes long double objects
the ability to do arithmetic?

Maybe, but then we would have to give all numeric 'ctypes' the ability to do arithmetic -- which may be more than we want.

-- Meador