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 10.50.73.231 with SMTP id o7mr12202471igv.10.1452145292085; Wed, 06 Jan 2016 21:41:32 -0800 (PST) X-Received: by 10.182.227.200 with SMTP id sc8mr283547obc.0.1452145292066; Wed, 06 Jan 2016 21:41:32 -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!news.glorb.com!h5no953749igh.0!news-out.google.com!f6ni45888igq.0!nntp.google.com!h5no953744igh.0!postnews.google.com!glegroupsg2000goo.googlegroups.com!not-for-mail Newsgroups: comp.lang.ada Date: Wed, 6 Jan 2016 21:41:31 -0800 (PST) In-Reply-To: <768bb8bd-ed12-4235-a663-fa71fcb42795@googlegroups.com> Complaints-To: groups-abuse@google.com Injection-Info: glegroupsg2000goo.googlegroups.com; posting-host=24.6.21.101; posting-account=Qh2kiQoAAADpCLlhT_KTYoGO8dU3n4I6 NNTP-Posting-Host: 24.6.21.101 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> <768bb8bd-ed12-4235-a663-fa71fcb42795@googlegroups.com> User-Agent: G2/1.0 MIME-Version: 1.0 Message-ID: <2ae043b6-e745-4f27-a9ab-cc183a25ca56@googlegroups.com> Subject: Re: Instantiating package problems From: Anh Vo Injection-Date: Thu, 07 Jan 2016 05:41:32 +0000 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Xref: news.eternal-september.org comp.lang.ada:29042 Date: 2016-01-06T21:41:31-08:00 List-Id: On Wednesday, January 6, 2016 at 8:41:38 PM UTC-8, Andrew Shvets wrote: > 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 wrot= e: > > > > > 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 w= rote: > > > > > > > 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 sh= own below. By the way, this feature is part of latest Ada (Ada 2012). In ad= dition, you should think about adding precondition to other operations such= as 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 aft= er 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 a= ctual division operation beforehand? > > > >=20 > > > > The preconditions and postconditions are controlled by pragma Asser= tion_Policy. Thus, pragma Assertion_Policy(Check) must be added at the top = of the package specification. Absent of this pragma is equivalent to pragma= Assertion_Policy (Ignore). That means these conditions are ignored. By the= way, 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 plac= ed in the package specification. >=20 > Alright, I put the pragma before each package keyword (in the body and th= e declaration) and this is what I got: >=20 > $ gnatmake -g main.adb > gcc -c -g main.adb > calculator.ads:5:01: pragma "assertion_policy" is not in declarative part= or package spec > gnatmake: "main.adb" compilation error what I meant was on top of the package specification as shown below. pragma Assertion_Policy (Check); with Ada.Text_IO; package Calculator is --... end Calculator;