Re: Processing array subsections, a newbie question.

[Stephen Leake <stephen_leake@stephe-leake.org>]

Simon Wright <simon@pushface.org> writes:

> Stephen Leake <stephen_leake@stephe-leake.org> writes:
>
>> "Peter C. Chapin" <pcc482719@gmail.com> writes:
>>
>>> procedure Do_Something
>>>    (Buffer : in  Buffer_Type;
>>>     Fst    : in  Natural;
>>>     Lst    : out Natural;
>>>     Ok     : out Boolean);
>>
>> Change this to:
>>
>> procedure Do_Something
>>    (Buffer : in     Buffer_Type;
>>     Last   : in out Natural;
>>     Ok     :    out Boolean);
>>
>> --  Operate on Buffer (Last + 1 ..), update Last to last item operated
>> --  on.
>
> What would happen if Buffer'First was Natural'First?

Good point. Last should be Integer, not Natural, so Last can be
initialized to Buffer'first - 1.

Which involves defining the type with an "extra" value, which Peter said
he didn't like. I find it quite useful in situations like this.

-- 
-- Stephe