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=-0.3 required=5.0 tests=BAYES_00, REPLYTO_WITHOUT_TO_CC autolearn=no autolearn_force=no version=3.4.4 X-Google-Thread: 103376,40843b637af826a X-Google-NewGroupId: yes X-Google-Attributes: gida07f3367d7,domainid0,public,usenet X-Google-Language: ENGLISH,ASCII-7-bit Received: by 10.180.95.227 with SMTP id dn3mr6236459wib.1.1354125717015; Wed, 28 Nov 2012 10:01:57 -0800 (PST) X-FeedAbuse: http://nntpfeed.proxad.net/abuse.pl feeded by 88.191.116.97 Path: ha8ni67804wib.1!nntp.google.com!feeder1-2.proxad.net!proxad.net!feeder2-2.proxad.net!nntpfeed.proxad.net!dedibox.gegeweb.org!gegeweb.eu!gegeweb.org!aioe.org!.POSTED!not-for-mail From: "Dmitry A. Kazakov" Newsgroups: comp.lang.ada Subject: Re: IBM 437 encoded String to UTF-16 Wide_String Date: Wed, 28 Nov 2012 19:00:46 +0100 Organization: cbb software GmbH Message-ID: <1e9k8c3tgm89w$.v1ty0n5ucjqv.dlg@40tude.net> References: <11112110-03b1-4977-ba80-00204926ea23@googlegroups.com> <68663891-14ad-4780-a00d-1cc48ed75323@googlegroups.com> <027679a1-dc5e-4888-9dd1-2a4ccf32e66c@googlegroups.com> <50b5dcd0$0$6581$9b4e6d93@newsspool3.arcor-online.net> <1mefvxxar8vn3$.16pejjtgf8hhg.dlg@40tude.net> <50b5f60e$0$9524$9b4e6d93@newsspool1.arcor-online.net> <347rnekt4in1.12pbyz0phdelf$.dlg@40tude.net> <50b615d5$0$6584$9b4e6d93@newsspool3.arcor-online.net> <11j81z9v2gr02$.kxnnq6lqzoz$.dlg@40tude.net> <50b64b47$0$6571$9b4e6d93@newsspool3.arcor-online.net> Reply-To: mailbox@dmitry-kazakov.de NNTP-Posting-Host: kWJV5lTRAyCzy8lsfOrlcw.user.speranza.aioe.org Mime-Version: 1.0 X-Complaints-To: abuse@aioe.org User-Agent: 40tude_Dialog/2.0.15.1 X-Notice: Filtered by postfilter v. 0.8.2 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Date: 2012-11-28T19:00:46+01:00 List-Id: On Wed, 28 Nov 2012 18:35:06 +0100, Georg Bauhaus wrote: > On 28.11.12 15:23, Dmitry A. Kazakov wrote: >> On Wed, 28 Nov 2012 14:47:10 +0100, Georg Bauhaus wrote: >> >>> On 28.11.12 14:36, Dmitry A. Kazakov wrote: >>>> The problem is not construction of a container >>>> type. It is the relation of the obtained type to the string interface. The >>>> string interface is an array of code points. The container must implement >>>> this interface in order to be a string. All strings must implement this >>>> interface, this is why they are called "strings." >>> >>> This says that a string interface consists of operations >>> that allow us to use string objects like one uses arrays. >> >> It say that instance implementing the interface are substitutable where a >> string is expected. You should be able to pass IBM_437_String to Put_Line, >> Trim, To_Lower etc. >> >>> Is this set of array ops not included in a Vector's interface, >> >> By which means the language or the reader knows if it is? > > This is why I mentioned generics. It is not nice, Nice is a wrong word here. It just does not solve the problem, which is making string types strings. > but lets the > reader see the expected interface: He could see that from hexadecimal code as well, couldn't he? > But since Ada is not going to get this sort of type system... ... then it should be untyped and reader should deduce types from observed program behavior, right? >> Ada had manifesting type system, so far... >> >>> Which algorithms require a String_Interface that excludes >>> other array/vector operations? >> >> ? > > That is, is there a set difference between string operations > and "vector" operations such that, from a user's perspective, > nothing could turn vectors into objects of type String, or > Wide_String, or Wide_Wide_String? Irrelevant, so far Ada's type system was nominal. T1 /= T2 even if there is no difference between them in terms you described. You are thinking in terms of implementations while talking about contracts (interfaces). This is utterly wrong. A string can have any implementation. The set of operations is determined by the contract, not otherwise. -- Regards, Dmitry A. Kazakov http://www.dmitry-kazakov.de