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 10.107.10.203 with SMTP id 72mr4190375iok.8.1512040264397; Thu, 30 Nov 2017 03:11:04 -0800 (PST) X-Received: by 10.157.87.203 with SMTP id q11mr155836oti.8.1512040264310; Thu, 30 Nov 2017 03:11:04 -0800 (PST) Path: eternal-september.org!reader01.eternal-september.org!reader02.eternal-september.org!feeder.eternal-september.org!news.kjsl.com!usenet.stanford.edu!i6no434167itb.0!news-out.google.com!193ni622iti.0!nntp.google.com!193no426995itr.0!postnews.google.com!glegroupsg2000goo.googlegroups.com!not-for-mail Newsgroups: comp.lang.ada Date: Thu, 30 Nov 2017 03:11:04 -0800 (PST) In-Reply-To: <16c980c2-1fa6-4084-97ea-b576c75b99c3@googlegroups.com> Complaints-To: groups-abuse@google.com Injection-Info: glegroupsg2000goo.googlegroups.com; posting-host=2003:c7:83c9:d64b:a966:8f28:bb6b:91d0; posting-account=rmHyLAoAAADSQmMWJF0a_815Fdd96RDf NNTP-Posting-Host: 2003:c7:83c9:d64b:a966:8f28:bb6b:91d0 References: <0b6bd27e-e9ec-4854-bbb1-85e1d9ac92e1@googlegroups.com> <227d5a7f-6d5b-4b76-ac31-7d15bb6dc284@googlegroups.com> <16c980c2-1fa6-4084-97ea-b576c75b99c3@googlegroups.com> User-Agent: G2/1.0 MIME-Version: 1.0 Message-ID: <3ca6a682-9af1-40e3-a4ac-db739b38e4d7@googlegroups.com> Subject: Re: How to access an array using two different indexing schemes From: AdaMagica Injection-Date: Thu, 30 Nov 2017 11:11:04 +0000 Content-Type: text/plain; charset="UTF-8" Xref: reader02.eternal-september.org comp.lang.ada:49272 Date: 2017-11-30T03:11:04-08:00 List-Id: Am Donnerstag, 30. November 2017 06:56:26 UTC+1 schrieb Jerry: > On Wednesday, November 29, 2017 at 1:56:59 PM UTC-7, Randy Brukardt wrote: > > "AdaMagica" wrote in message > > > Am Mittwoch, 29. November 2017 17:03:04 UTC+1 schrieb Shark8: > > > > > >> Procedure Do_Stuffs( Data : in out General_Real_Array ) is > > >> Subtype Indexing is General_Real_Array(1..Data'Length); > > >> Subtype Offset is General_Real_Array(0..Integer'Pred(Data'Length)); > > >> > > >> Indexed : Indexing renames Data; > > >> Offseted : Offset renames Data; > > > > > > No, that doesn't work! See previous posts. > > > > Should have showed what does work: > > > > Indexed : Indexing renames Indexing(Data); > > Offseted : Offset renames Offset(Data); > > > > The type conversions change the bounds as needed. Renames does not allocate > > new memory. > > > > Randy. > > Combining Shark8's plan with Randy's change and wrapping into a main program like this: > > Procedure Shark8_And_Randy is > Subtype Real is Float range Float'Range; -- Get rid of non-numeric. > Type General_Real_Array is Array(Integer range <>) of Real; > > Procedure Do_Stuffs( Data : in out General_Real_Array ) is > Subtype Indexing is General_Real_Array(1..Data'Length); > Subtype Offset is General_Real_Array(0..Integer'Pred(Data'Length)); > > Indexed : Indexing renames Indexing(Data); > Offseted : Offset renames Offset(Data); > Begin > -- Stuffs! > null; > End Do_Stuffs; > Begin > null; > End Shark8_And_Randy; > > Results in GNAT complaining as such: > > shark8_and_randy.adb:9:37: renaming of conversion only allowed for tagged types > shark8_and_randy.adb:10:35: renaming of conversion only allowed for tagged types Then try: procedure Do_Stuffs (Data: in out General_Real_Array) is subtype Indexing is General_Real_Array (1..Data'Length); subtype Offset is General_Real_Array (0..Integer'Pred (Data'Length)); procedure Use_1_Based (X: in out Indexing) is separate; procedure Use_0_Based (X: in out Offset ) is separate; begin Use_1_Based (Indexing (Data)); Use_0_Based (Offset (Data)); end Do_Stuffs;