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=-0.3 required=5.0 tests=BAYES_00,
	REPLYTO_WITHOUT_TO_CC autolearn=no autolearn_force=no version=3.4.4
X-Google-Thread: 103376,6c383a046f41e91
X-Google-Attributes: gid103376,domainid0,public,usenet
X-Google-Language: ENGLISH,ASCII-7-bit
Path: 
 g2news1.google.com!news2.google.com!news1.google.com!news.glorb.com!newsfeed-0.progon.net!progon.net!newsfeed.ision.net!newsfeed2.easynews.net!ision!newsfeed.arcor.de!newsspool3.arcor-online.net!news.arcor.de.POSTED!not-for-mail
From: "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>
Subject: Re: Text_IO from a stream
Newsgroups: comp.lang.ada
User-Agent: 40tude_Dialog/2.0.15.1
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7bit
Reply-To: mailbox@dmitry-kazakov.de
Organization: cbb software GmbH
References: 
 <0465edf8-7272-43c8-82fd-fcae7cf0ef11@y21g2000hsf.googlegroups.com>
  <1y2oi69ev939v.1xugoel9fadnb$.dlg@40tude.net>
 <0c9ab8b7-a666-4fd2-a876-dca818ad5461@c65g2000hsa.googlegroups.com>
Date: Mon, 31 Mar 2008 18:33:23 +0200
Message-ID: <17unr8ffxzcm.1ee1ucd0fwd1q$.dlg@40tude.net>
NNTP-Posting-Date: 31 Mar 2008 18:33:27 CEST
NNTP-Posting-Host: aba0ef84.newsspool2.arcor-online.net
X-Trace: 
 DXC=NRidTRHmJ<c]l@YUW5NBknA9EHlD;3Ycb4Fo<]lROoRaFl8W>\BH3YbbVCFON;JZ4cDNcfSJ;bb[eIRnRBaCd<MniXIM:4b29:c0`nV<g^8@2m
X-Complaints-To: usenet-abuse@arcor.de
Xref: g2news1.google.com comp.lang.ada:20681
Date: 2008-03-31T18:33:27+02:00
List-Id: <comp.lang.ada>

On Mon, 31 Mar 2008 09:05:35 -0700 (PDT), gautier_niouzes@hotmail.com
wrote:

> Dmitry A. Kazakov:
> 
>> You can always wrap a File_Type in your own stream object.
> 
> Do you mean something like:
> 
>  type Text_Stream_Type is new Ada.Streams.Root_Stream_Type with record
>    virtual_file : Ada.Text_IO.File_Type;
>  end record;

Yes

> At the end of the day, what I'd really like is
>   function File(stream: access Ada.Streams.Root_Stream_Type 'Class)
> return Ada.Text_IO.File_Type;
> so that I can do read ASCII data from any stream:
>   f:= File(my_stream);
>   -- f is as if open in In_File mode
>   Get_Line(f, a_string, length);
>   Get(f, an_integer); -- not binary, but 123_456
>   Get(f, a_float);    -- not binary, but -123.456e78
> 
> I guess it would be difficult... But maybe I'm wrong ?
> Gautier

But a stream has no defined formatting and is unrelated to ASCII. Then the
idea of parsing stream looks problematic. If you have in the stream a
sequence "  +  -", what Get should do after discovering '-'?

Anyway, it is quite simple to do. You can do

   type Formatted_Stream (Source : access Root_Stream_Type'Class) is
      tagged limited private;
   function Get (Stream : access Formatted_Stream) return Integer;
   ...

The implementation of Formatted_Stream will use Source for all its I/O. So
you could hang it on any existing stream.

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de