Re: Little people supporting Ada, possibly through AdaCore?

[Maciej Sobczak <see.my.homepage@gmail.com>]

W dniu czwartek, 19 lipca 2012 10:23:41 UTC+2 użytkownik Dmitry A. Kazakov napisał:

> >> True. However a set of truly unordered elements cannot be implemented
> >> otherwise than on top of an ordered set.
> > 
> > Why?
> 
> I guess it is related to computability.

Why? I see no relation. Or, to put it in more concrete terms - I don't care about implementation details; the purpose of abstraction is to be independent from them. You might need something ordered (array? or even addressable memory?) at the very bottom, but that does not make the *concepts* related, it just exposes limitations of your current implementation platform.

> > Membership test does not require any order.
> 
> You need to enumerate elements to be able to compute it.

No, you don't need to enumerate. If I remember correctly, the Pascal language provides sets as a language-level entity and membership test is commonly implemented as logical, bitwise operation. Now, you can argue that bitsets rely on some assumed ordering of implicitly assigned position numbers or whatever, but wait until I finish my hardware-based implementation of logical operations on bit-cubes. No ordering is required, it is just an artifact of our current, very limited hardware.

> In that case you would need to
> identify elements in the set in order to compare them with the testee. That
> again would require some order.

No. Just wait until I finish my organic neural network, where sets are just implemented as multiple neurons connected to the owner, all triggered with the same signal. The membership test is O(1) and has nothing to do with enumeration (and therefore nothing to do with ordering).

Don't define general concepts in terms of current limited implementations on some crappy hardware.

-- 
Maciej Sobczak * http://www.msobczak.com * http://www.inspirel.com