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
Path: 
 eternal-september.org!reader01.eternal-september.org!reader02.eternal-september.org!news.eternal-september.org!news.eternal-september.org!news.eternal-september.org!feeder.eternal-september.org!aioe.org!.POSTED!not-for-mail
From: Pascal Obry <pascal@obry.net>
Newsgroups: comp.lang.ada
Subject: Re: Your wish list for Ada 202X
Date: Sun, 30 Mar 2014 21:59:26 +0200
Organization: Home - http://www.obry.net
Message-ID: <1396209566.14855.1.camel@pascal.home.net>
References: <7f1c01c5-3563-4b94-9831-152dbbf2ecdc@googlegroups.com>
	 <f188948a-6d8a-4888-80f1-d337a9b6558e@googlegroups.com>
	 <1396206120.12713.8.camel@pascal.home.net>
	 <1rmd466o46wkh$.xv2pypcsl4nb.dlg@40tude.net>
Reply-To: pascal@obry.net
NNTP-Posting-Host: L9vAWPXftET0fEf5/kGUFw.user.speranza.aioe.org
Mime-Version: 1.0
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
X-Complaints-To: abuse@aioe.org
X-Mailer: Evolution 3.8.5-2+b3 
X-Notice: Filtered by postfilter v. 0.8.2
Xref: news.eternal-september.org comp.lang.ada:19057
Date: 2014-03-30T21:59:26+02:00
List-Id: <comp.lang.ada>

Le dimanche 30 mars 2014 =C3=A0 21:33 +0200, Dmitry A. Kazakov a =C3=A9crit=
 :=20
I did such things, it is not so simple.
>=20
Sure!

You need a set of "seed" functions to produce initial Formatted_String,
> e.g.
>=20
>    function "&" (L, R : Character) return Formatted_String;
>    function "&" (L : Character; R : Integer) return Formatted_String;
>    ...
>=20
No since you always start with the Formatted_String (not derived from
string). We need at least a function to create the formatted_string from
a string:

   function "+" (Format : in String) return Formatted_String;

Then:

   +"%c" & var

Or you have to use Empty_Formatted_String constant in each expression.
>=20
> Another consideration is efficiency, as it would keep on copying the
string
> upon each concatenation.
>=20
Copies should be avoided by using a reference semantic. Note that I have
declared Formatted_String as:

   type Formatted_String is private;

Maybe it should be a tagged type.

This type is a record with the format. The result (Unbounded_String?)
and an index to the current format. That's what I'm thinking.

Let's say we have:

   type Formatted_String is record
      Format : Unbounded_String;
      Index  : Positive;
      Result : Unbounded_String;
   end record;

Then

   +"%c %c"

Set such record to ("%c %c", 1, "")

Then with : & Var

If Var is not a character =3D> raise exception

Let's say Var :=3D 'x'

If a char then the record becomes : ("%c %c", 3, "x")

That's how I would do such implementation.


--=20
  Pascal Obry /  Magny Les Hameaux (78)

  The best way to travel is by means of imagination

  http://v2p.fr.eu.org
  http://www.obry.net

  gpg --keyserver keys.gnupg.net --recv-key F949BD3B