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: 103376,715875e575230543
X-Google-Attributes: gid103376,public
X-Google-ArrivalTime: 2003-10-21 16:13:13 PST
Path: 
 archiver1.google.com!news2.google.com!news.maxwell.syr.edu!eusc.inter.net!cs.tu-berlin.de!uni-duisburg.de!not-for-mail
From: Georg Bauhaus <sb463ba@l1-hrz.uni-duisburg.de>
Newsgroups: comp.lang.ada
Subject: Re: Thought this was funny
Date: Tue, 21 Oct 2003 23:13:12 +0000 (UTC)
Organization: GMUGHDU
Message-ID: <bn4ei8$58b$1@a1-hrz.uni-duisburg.de>
References: <bn42kf$ca3@cui1.lmms.lmco.com>
 <afhlb.9619$PZ1.935@nwrdny03.gnilink.net> <3F95AFE3.7030308@comcast.net>
NNTP-Posting-Host: l1-hrz.uni-duisburg.de
X-Trace: a1-hrz.uni-duisburg.de 1066777992 5387 134.91.1.34 (21 Oct 2003
 23:13:12 GMT)
X-Complaints-To: usenet@news.uni-duisburg.de
NNTP-Posting-Date: Tue, 21 Oct 2003 23:13:12 +0000 (UTC)
User-Agent: tin/1.5.8-20010221 ("Blue Water") (UNIX) (HP-UX/B.11.00
 (9000/800))
Xref: archiver1.google.com comp.lang.ada:1342
Date: 2003-10-21T23:13:12+00:00
List-Id: <comp.lang.ada>

Robert I. Eachus <rieachus@comcast.net> wrote:
: Stephane Richard wrote:
: 
:> I'm canadian and that code made me chuckle too ;-). The programmer much have
:> read how to handle the enumeration type first, then read about the Boolean
:> type being an enumeration of True and False maybe? ;-).
: 
: No, he must have been taught that your program design should allow for 
: changes in requirements.  He was prepared for another value being added 
: to Boolean. ;-)

Or he is just a careful programmer, who knows GNAT, case statements,
and Unchecked_Conversion :-)

with Unchecked_Conversion;
with Ada.Text_IO; use Ada;

procedure test is

   type This_Or_That is (This, That);
   for This_Or_That use (That => 17, This => 4);
   for This_Or_That'Size use 8;

   type My_Truth is new Boolean;
   for My_Truth'Size use 8;



   function from_This_Or_That is
      new Unchecked_Conversion(This_Or_That, My_Truth);

begin

   if from_This_Or_That(This) then
      Text_IO.put_line("Y");
   else
      Text_IO.put_line("N");
   end if;


   case from_This_Or_That(This) is
      when True =>
         Text_IO.put_line("Y");

      when False =>
         Text_IO.put_line("N");
   end case;

end test;


$ ./test
Y

raised CONSTRAINT_ERROR : test.adb:27 invalid data


Georg