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Newsgroups: comp.lang.ada
Subject: re: implicit array subtype conversion
Message-ID: <1990Jul27.135108.11518@planck.uucp>
Date: 27 Jul 90 13:51:08 GMT
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Organization: Calspan Corporation ATC  Buffalo, NY
List-Id: <comp.lang.ada>


In my zeal to limit my example and the size of the posting concerning
implict array subtype conversion, I inadvertently changed the nature of my
problem slightly.

I have defined a dynamic length string as follows:

   type STRING_RECORD (Len : NATURAL) is
      record
         S : Standard.STRING(1..Len);
      end record;

   type STRING is access STRING_RECORD;

Then, I declare some variables:

   A : Standard.STRING(7..7);
   B : Standard.STRING(1..1);
   C : STRING;

The following is accepted by the compiler (Verdix Sun 4 Self, version
6.0.2(g)) because of implicit array subtype conversion:

   A := "X";
   B := A;

However, the following is not.  Why?  I don't see the difference in the
assignment of the string because both B and C.S are constrained.

   C := new STRING_RECORD'(Len => A'length, S => A);

--
Terry J. Westley
Arvin/Calspan Advanced Technology Center
P.O. Box 400, Buffalo, NY 14225
acsu.buffalo.edu!planck!hercules!westley