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: 103376,449670964aa111f5,start
X-Google-Attributes: gid103376,public
From: m88asjn@mtek.chalmers.se (Anders H Johansson)
Subject: GNAT error messages, strange generic construction
Date: 1995/04/06
Message-ID: <3m10hi$eu0@nyheter.chalmers.se>#1/1
X-Deja-AN: 100939396
organization: Chalmers University of Technology
newsgroups: comp.lang.ada
Date: 1995-04-06T00:00:00+00:00
List-Id: <comp.lang.ada>

Hi!

I'm compiling my Ada code with the GNAT 2.04 compiler. I've got
two questions:

1. I have got a compiler one-liner error message that I don't
   understand. If I want further information about this error,
   where can I get it? The message, if anyone's interested:
   "controlling argument is not dynamically tagged".

2. What's the point of this generic package construction (mentioned 
   e.g. in J.G.P Barnes "Programming in Ada", p. 447-448):

   with Generic_Elementary_Functions;
   with Generic_Complex_Numbers;
   generic
     with package Elementary_Functions is
       new Generic_Elementary_Functions(<>);
     with package Complex_Numbers is
       new Generic_Complex_Numbers(Elementary_Functions.Float_Type);
   package xxx is
   .
   .
I think it would be more reasonable to transform the generic package parameter
Complex_Numbers into an ordinary instantiation, placed inside the package
xxx. Since it is already decided how it will be instantiated, the genericity
fills no function?!

package xxx is
   package Complex_Numbers is
      new Generic_Complex_Numbers(Elementary_Functions.Float_Type);

---------
Tomas Lindh
erelih@ereyc.ext.ericsson.se