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,FREEMAIL_FROM autolearn=unavailable autolearn_force=no version=3.4.4 X-Received: by 10.140.131.146 with SMTP id 140mr57752826qhd.5.1452141695128; Wed, 06 Jan 2016 20:41:35 -0800 (PST) X-Received: by 10.182.176.40 with SMTP id cf8mr499466obc.11.1452141695086; Wed, 06 Jan 2016 20:41:35 -0800 (PST) Path: eternal-september.org!reader01.eternal-september.org!reader02.eternal-september.org!news.eternal-september.org!mx02.eternal-september.org!feeder.eternal-september.org!usenet.blueworldhosting.com!feeder01.blueworldhosting.com!peer02.iad.highwinds-media.com!news.highwinds-media.com!feed-me.highwinds-media.com!6no3281832qgy.0!news-out.google.com!l1ni6006igd.0!nntp.google.com!h5no941706igh.0!postnews.google.com!glegroupsg2000goo.googlegroups.com!not-for-mail Newsgroups: comp.lang.ada Date: Wed, 6 Jan 2016 20:41:34 -0800 (PST) In-Reply-To: <5a81226f-e719-4ca8-8cbc-d02cf4ab56e7@googlegroups.com> Complaints-To: groups-abuse@google.com Injection-Info: glegroupsg2000goo.googlegroups.com; posting-host=2601:18f:900:8350:ba86:87ff:fed6:5907; posting-account=3pYsyQoAAACcI-ym7XtMOI2PDU8gRZS5 NNTP-Posting-Host: 2601:18f:900:8350:ba86:87ff:fed6:5907 References: <7dcd49f3-b04f-4ea3-b431-5c27f73b9afe@googlegroups.com> <87poxixqmy.fsf@theworld.com> <112f5e6c-35c1-483a-b8dd-24f5f76dc6ce@googlegroups.com> <084197af-8e37-4250-a083-b45bd9ab4609@googlegroups.com> <5a81226f-e719-4ca8-8cbc-d02cf4ab56e7@googlegroups.com> User-Agent: G2/1.0 MIME-Version: 1.0 Message-ID: <768bb8bd-ed12-4235-a663-fa71fcb42795@googlegroups.com> Subject: Re: Instantiating package problems From: Andrew Shvets Injection-Date: Thu, 07 Jan 2016 04:41:35 +0000 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable X-Received-Bytes: 4131 X-Received-Body-CRC: 3077985578 Xref: news.eternal-september.org comp.lang.ada:29040 Date: 2016-01-06T20:41:34-08:00 List-Id: On Wednesday, January 6, 2016 at 12:07:15 AM UTC-5, Anh Vo wrote: > On Tuesday, January 5, 2016 at 9:00:50 PM UTC-8, Andrew Shvets wrote: > > On Tuesday, January 5, 2016 at 11:52:00 PM UTC-5, Anh Vo wrote: > > > On Tuesday, January 5, 2016 at 7:31:00 PM UTC-8, Andrew Shvets wrote: > > > > On Monday, January 4, 2016 at 3:49:32 PM UTC-5, Anh Vo wrote: > > > > > On Sunday, January 3, 2016 at 4:07:30 PM UTC-8, Andrew Shvets wro= te: > > > > > > Hi Bob, > > > > > >=20 > > > > > > Thanks for writing back. This is the entire example: > > > > > > http://pastebin.com/GEJT3WzL > > > > > =20 > > > > > Just recommend to add a precondition to function Division as show= n below. By the way, this feature is part of latest Ada (Ada 2012). In addi= tion, you should think about adding precondition to other operations such a= s Addition where Input1 + Input2 <=3D Integer'Last and Input1 + Input2 >=3D= Integer'Last.=20 > > > > >=20 > > > > > function Division( > > > > > Input1 : in Integer; > > > > > Input2 : in Integer) > > > > > return Integer > > > > > with pre =3D> Input2 /=3D 0; > > > > >=20 > > > > > Anh Vo > > > >=20 > > > > I'm not sure that that worked. I added it to my ads file and after= compilation and then re-running the application, this is what I got: > > > >=20 > > > > .... > > > >=20 > > > > Division: 4 > > > >=20 > > > >=20 > > > > raised CONSTRAINT_ERROR : calculator.adb:33 divide by zero > > > >=20 > > > > Shouldn't the division function been prevented from running the act= ual division operation beforehand? > > >=20 > > > The preconditions and postconditions are controlled by pragma Asserti= on_Policy. Thus, pragma Assertion_Policy(Check) must be added at the top of= the package specification. Absent of this pragma is equivalent to pragma A= ssertion_Policy (Ignore). That means these conditions are ignored. By the w= ay, ASSERTION_ERROR exception would be raised instead of CONSTRAINT_ERROR. > >=20 > > This is how the body looks like now: > > http://pastebin.com/Mt0E0HAD > >=20 > > I'm still getting a constraint error. >=20 > I only saw the pragma placed inside the package body. It should be placed= in the package specification. Alright, I put the pragma before each package keyword (in the body and the = declaration) and this is what I got: $ gnatmake -g main.adb gcc -c -g main.adb calculator.ads:5:01: pragma "assertion_policy" is not in declarative part o= r package spec gnatmake: "main.adb" compilation error