Re: Generic Package

[Georg Bauhaus <bauhaus@futureapps.de>]

On Sat, 2007-04-28 at 19:35 +0200, Dmitry A. Kazakov wrote:


> Yes, because that set is a representation [model] of some other [domain
> space] set which could be fundamentally unordered and/or uncountable.

Should we therefore tie the notion of iterating something to
procedures that a computer can't perform? ;-)

>  As an
> example consider merits of the loop:
> 
>    for X in 0.0..1.0 loop
> 
> Fortunately the above is illegal in Ada. Not because it were impossible:
> 
> declare
>    X : Float := 0.0;
> begin
>    while X <= 1.0 loop
>       ...
>       X := Float'Succ (X);
>    end loop;
> 
> but because it is a mess.
> 
> After interating reals we could proceed to complex numbers...

And on to more not fully representable things such as collections
of tuples made to correspond to the elements of a suitably defined
Cauchy sequence.
If only computers could produce the elements of more than zero
uncountable sets ...

Like Simon, I'm not sure I'm familiar with your iteration;
my containers would be providing iteration if they can do one of

- take a subprogram (e.g.) and call it for each of a collection
  of elements

- provide access to an element and then the next if any where the
  meaning of "next" is specified in the collection's contract 

The amount of determinism need not be 100%. E.g., the post-condition
if Iterate that each element is visited once, in no particular order,
seems reasonable to me.

http://www.icsi.berkeley.edu/~sather/Publications/toplas.html

Is there iteration in the following SETL expression?

  Result := { x : x in {1, 3, 24, 17, 11} | P(x) };