Path: utzoo!censor!geac!torsqnt!news-server.csri.toronto.edu!rutgers!njin!princeton!udel!haven!adm!news
From: STANKULI%UWF.BITNET@cunyvm.cuny.edu ( stan kulikowski ii)
Newsgroups: comp.lang.pascal
Subject: string ghosts
Message-ID: <26159@adm.brl.mil>
Date: 27 Feb 91 22:58:10 GMT
Sender: news@adm.brl.mil
Lines: 58

(*
  i was having some strange behavior in one of my TP 5.5 programs...
  a string variable was behaving as if it still had the contents of previous
  assignments after it had been nulled.  even the turbo debugger saw
  that the string had null value, but it still operated as if the ghost
  of its previous assignment was still there...
*)


program STRING_CHECK;

var
   ANY_STRING : string;

begin (* Main Program *)

   ANY_STRING := 'OK';
   ANY_STRING := '';

   writeln;
   writeln ('ANY_STRING is "',ANY_STRING,'"');

   if (ANY_STRING 1! = 'O') and (ANY_STRING 2! = 'K')
      then
         writeln (' Uhoh.... string contents still there| ')
      else
         writeln (' Whew... string is gone. ');

   writeln (ANY_STRING 1!, ANY_STRING 2!);

end.


(*
  is this the way pascal is supposed to run?

  if so, this is very counterintuitive. when i null out a string,
  i obviously intend that all of its contents should be likewise null.
  surely any reference to a zero-length null string returns nil value.

    my understanding of fregean compositionality requires that

         if the value of any language structure is nil
            then any of its parts should also be nil
            else the value of the whole is not based on
                 the values of its parts.

    am i missing something important here?  this is elementary logic which
  was worked out in the 1920's.
                               stan


   .                      stankuli@UWF.bitnet
  ===
         close your eyes, my darling, or three of them at least
  ---                                           -- old venusian lullaby

*)