Re: Ada.Containers.Vectors - querying multiple elements

["Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>]

On 03 May 2005 19:30:29 -0400, Robert A Duff wrote:

> "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de> writes:
> 
>> I don't think that statistical approach is appropriate here. Anyway it
>> makes an implementation of many generic algorithms and container libraries
>> very difficult if possible.
> 
> I don't see a big problem here.  If you're counting things, use signed
> integers, and start counting at zero or one.  If you're using enums or
> modulars, you're not "counting", and zero-length arrays/vectors/whatever
> make no sense.

Come on, empty set appear *before* number and arithmetic. Further, to be
countable is much weaker than to be ordered. In an imaginary, better Ada
there should be unordered, uncountable types which would still allow
containers. There would be no way to enumerate elements in such container,
but for any given X it would be possible to Is_In (X, C). Even for such
weak types there should be empty containers such that Is_In returns false
for any X. 

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de