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,bc3e3a6e4f85e03f
X-Google-Attributes: gid103376,public
X-Google-ArrivalTime: 2002-06-10 06:00:55 PST
Path: 
 archiver1.google.com!news1.google.com!newsfeed.stanford.edu!news-spur1.maxwell.syr.edu!news.maxwell.syr.edu!wn1feed!wn4feed!worldnet.att.net!216.166.61.6!nntp2.aus1.giganews.com!nntp.giganews.com!nntp3.aus1.giganews.com!bin7.nnrp.aus1.giganews.com.POSTED!not-for-mail
Sender: Stephe@TAKVER
Newsgroups: comp.lang.ada
Subject: Re: class wide object in generic package
References: <3D045767.8020102@rcs.ei.tum.de>
From: Stephen Leake <stephen_leake@acm.org>
Message-ID: <wkelffffuy.fsf@acm.org>
User-Agent: Gnus/5.09 (Gnus v5.9.0) Emacs/21.1
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
X-GC-Trace: gv1-YxWUOXx+XJI8vH9J9rX8S3EU8WkV5gZPA9CyNE=
NNTP-Posting-Date: Mon, 10 Jun 2002 08:00:37 CDT
Organization: Giganews.Com - Premium News Outsourcing
X-Trace: 
 sv3-3yBwz/mhKnbvFv+jQTy4P8T4U1Jg+efsx3gwqAYy1VH1P1ByKfjR6kcQa5D9KUt3JmNNXO/H4hVzGRK!5GzC9z1jMI9vtDZYRNczd6uK9QT0FcNidd6xbWxbidV+BzMrvjcStA==
X-Complaints-To: abuse@comcast.com
X-DMCA-Complaints-To: dmca@comcast.net
X-Abuse-Info: Please be sure to forward a copy of ALL headers
X-Abuse-Info: Otherwise we will be unable to process your complaint properly
Date: Mon, 10 Jun 2002 13:00:37 GMT
Xref: archiver1.google.com comp.lang.ada:25668
Date: 2002-06-10T13:00:37+00:00
List-Id: <comp.lang.ada>

Thomas Maier-Komor <maierkom@rcs.ei.tum.de> writes:

> Hi everybody,
> 
> I am getting this error message when compiling the
> code at the end of the message:
> 
> generic_pac.adb:7:26: class-wide argument not allowed here
> generic_pac.adb:7:26: "eval" is not a primitive operation of "Object"
> 
> 
> my question is:
> first: is it possible to declare a procedure in the
> generic part so that it will be a primitive operation of
> Object?

No. All primitive operations are declared in the same declarative
region as the type.

> second: why isn't a class-wide argument not allowed in this place?

Because "eval" isn't a primitive operation of Object :). Using a
class-wide argument means you _want_ dispatching. Only primitive
operations can be dispatching.

You have a couple choices to make this work. If you don't actually
need dispatching, you can make eval take a class-wide argument:

with procedure eval(o : in out Object'class);

If you want dispatching, you'll have to use a generic formal package
parameter:

generic
   package Object_Package is new Generic_Obj_Package (...);
package generic_pac ...

Then in Generic_Obj_Package, declare Object and Eval. Note that it has
to be generic!

Good luck,

-- 
-- Stephe