From mboxrd@z Thu Jan  1 00:00:00 1970
X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me
X-Spam-Level: 
X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00 autolearn=ham
	autolearn_force=no version=3.4.4
X-Google-Language: ENGLISH,ASCII-7-bit
X-Google-Thread: 103376,38b27bed88e97415
X-Google-Attributes: gid103376,public
X-Google-ArrivalTime: 2003-02-20 01:30:01 PST
Path: 
 archiver1.google.com!news1.google.com!newsfeed.stanford.edu!news-spur1.maxwell.syr.edu!news.maxwell.syr.edu!fu-berlin.de!uni-berlin.de!tar-alcarin.cbb-automation.DE!not-for-mail
From: Dmitry A. Kazakov <mailbox@dmitry-kazakov.de>
Newsgroups: comp.lang.ada
Subject: Re: Question: Combination of Access and Constraining
Date: Thu, 20 Feb 2003 10:29:59 +0100
Message-ID: <9d795v0h3qa2922u8vodfhpfvprpre6ak2@4ax.com>
References: <1d13e1b4.0302200006.70207b86@posting.google.com>
NNTP-Posting-Host: tar-alcarin.cbb-automation.de (212.79.194.111)
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit
X-Trace: fu-berlin.de 1045733399 52461526 212.79.194.111 (16 [77047])
X-Newsreader: Forte Agent 1.8/32.548
Xref: archiver1.google.com comp.lang.ada:34261
Date: 2003-02-20T10:29:59+01:00
List-Id: <comp.lang.ada>

On 20 Feb 2003 00:06:15 -0800, papand0pul0@yahoo.com (Papandopulo)
wrote:

>Small Ada question:
>
>I need one function to accept
>an array of unknown size of Boolean,
>so I declare type and function:
>
>type Tp is array (Positive range <>) of Boolean;
>type Tp_Access is access all Tp;
>
>function Fn (Arg : in Tp_Access) return Natural;

Pointers are inherently bad. Why not:

function Fn (Arg : Tp) return Natural;

>Now I try to call it with the constrained array:
>
>declare
>  type TpCon is new Tp(1..1);
                       ^^^^^^
But this is another type! Probably you meant a subtype:

subtype TpCon is Tp(1..1);

>  Arr : aliased TpCon;
>begin
>  Arr(1) := True;
>  Res := Fn (Arr'Access);
>end;
>
>Compiler says on the invocation line:
>expected type: Tp_Access defined at ...
>found type TpCon defined at ...
>
>I think that access to constrained
>type should be convertible to access
>to unconstrained type.
>
>So where I am going wrong here ?

You are mixing types and subtypes. If you want just to put a
constraint on a type, declare a constrained subtype.

---
Regards,
Dmitry Kazakov
www.dmitry-kazakov.de