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=-1.3 required=5.0 tests=BAYES_00,INVALID_MSGID
	autolearn=no autolearn_force=no version=3.4.4
X-Google-Language: ENGLISH,ASCII-7-bit
X-Google-Thread: 103376,54c513170bafd693
X-Google-Attributes: gid103376,public
From: Gautier <gautier.demontmollin@maths.unine.ch>
Subject: Re: Strings TP/Ada (was Desirability of C++)
Date: 2000/05/02
Message-ID: <390EF94D.AE560CBD@maths.unine.ch>#1/1
X-Deja-AN: 618303874
Content-Transfer-Encoding: 7bit
References: <390DEC7F.9429C82C@online.no>
 <LnoP4.768$Q_.926416@news.pacbell.net> <8emhtk$pka4@ftp.kvaerner.com>
 <slrn8gtqcd.iq.randhol+nospam@kiuk0156.chembio.ntnu.no>
X-Accept-Language: en
Content-Type: text/plain; charset=us-ascii
X-Trace: 2 May 2000 17:50:38 +0100, mac13-32.unine.ch
Organization: Maths - Uni =?iso-8859-1?Q?Neuch=E2tel?=
MIME-Version: 1.0
Newsgroups: comp.lang.ada
Date: 2000-05-02T00:00:00+00:00
List-Id: <comp.lang.ada>

Preben Randhol:

> As I cannot remember much of turbopascal I curious:

> If you write in turbopascal.

> line : string[12];
> short_line : string[5];
> line := "Hello World!";
> short_line := line;

> would short_line be "Hello" or will it be altered to a string[12] and
> thus contain all of line?

No - the variable is not extensible (string[5] reserves 6 bytes on stack).
Will "Hello World!" be truncated or issue a range check error ? It may depend
on the state of the range check switch ({$R+/-}), the version of TP, the fast
library patches, and so on...

In fact string[N] is a predefined unconstrained type in TP (and the
only!), and corresponds to an array[0..N]. The 0th character contains the length.

Some nice things:
  - String (without [N]) means String[255]
  - A very Borlandesque one: the {$V+/-} switch (strict var checking)
    alters the language semantic where it appears and until the next one!
    Also as command-line, or in tpc.cfg, or as a check in option panel...
    When it is "on", you can pass as "var" (by reference) only variables
    of the same subtype as specified; when "off", all variables of type String !

So, don't applause too early the whole "Borland string model"... In addition, you can
program all that in Ada with unconstrained types, so it's not a so awful situation...

_____________________________________________
Gautier  --  http://members.xoom.com/gdemont/