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From: "Ehud Lamm" <mslamm@mscc.huji.ac.il>
Subject: Re: Escape Sequences in Strings
Date: 2000/11/15
Message-ID: <8uump3$s3o$1@news.huji.ac.il>#1/1
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References: <3A17B0E2@MailAndNews.com> <3A1275A2.F2A843E9@bton.ac.uk>
 <8uub09$9sr$1@nnrp1.deja.com>
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Date: 2000-11-15T00:00:00+00:00
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Robert Dewar <robert_dewar@my-deja.com> wrote in message
news:8uub09$9sr$1@nnrp1.deja.com...
> In article <3A1275A2.F2A843E9@bton.ac.uk>,
>   John English <je@bton.ac.uk> wrote:
>
> > Escape sequences are easy enough:
> >   Ada.Text_IO.Put(ASCII.ESC & "[2J");    -- clear the screen
>
>
> But we would never want to do that in a program, and indeed
> Ada here helps us avoid the nasty habit of embedding odd
> escape sequences in strings in C without any comments, often
> with a result of making the program non-portable. The proper
> coding in Ada would be:
>
>   Clear_Screen : constant String := ASCII.ESC & "[2J";
>   --  ANSI escape sequence for clearing screen. Modify to
>   --  meet requirements of your system.
>
>   Put (Clear_Screen);
>
> It is almost always wrong to have mysterious constants in code!
>

And while you are at it, put the constant in a seperate packge of env.
specific control codes.


--
Ehud Lamm   mslamm@mscc.huji.ac.il
http://purl.oclc.org/NET/ehudlamm <==  Me!