Re: Copying rows in a two dimensional array.

[Robert A Duff <bobduff@shell01.TheWorld.com>]

tmoran@acm.org writes:

>> Discriminated arrays would be more efficient than Ada's arrays.
>> We would have:
>>
>>     type String (Length : Natural) is
>>         array (Positive range 1..Length) of Character;
>
>   How would you handle slices, either in assignments or as parameters?

Sliding.  All strings should start at 1, including slices.

In Ada, if you do "P(X(5..10));" procedure P can see that the
lower bound is 5.  That's a break in the abstraction -- P shouldn't
know or care where the string came from.

If both bounds are constrained, then slices should be illegal.
That is, "is array(1..10) of ..." should mean that ALL objects
of that type have bounds exactly 1..10.

Actually, slices are one of the least useful features of Ada.
I wouldn't mind (much) if they didn't exist in the first place.

- Bob