Re: OO Style with Ada Containers

[Pascal Obry <pascal@obry.net>]

braver a �crit :
> Very ineteresting -- Matt, can you pls elucidate these idioms below?
> 
> On Nov 19, 5:24 am, Matthew Heaney <matthewjhea...@earthlink.net>
> wrote:
> 
>>    type Scanner (<>) is tagged limited private;
> 
> What does (<>) say here -- that the type is unconstrained?

Yes. Scanner has a privately defined discriminant. So the public view of
Scanner must be declared unconstrained.

>> private
>>
>>    type Handle (S : not null access Scanner) is limited null record;
>>
>>    type Scanner (Last : Natural) is tagged limited record
>>       H          : Handle (Scanner'Access);
>>       Line       : String (1 .. Last);
>>       Word_First : Positive;
>>       Word_Last  : Natural;
>>    end record;
>>
> 
> What's the logic behind the definition and usage of the Handle H
> throughout?

It is for gaining write access to function in parameter. A simpler
solution is:

    type Scanner (Last : Natural) is tagged limited record
       Self       : access Scanner := Scanner'Unchecked_Access;
       Line       : String (1 .. Last);
       Word_First : Positive;
       Word_Last  : Natural;
    end record;

Pascal.

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