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=0.5 required=5.0 tests=BAYES_00,FREEMAIL_FROM, LOTS_OF_MONEY,PP_MIME_FAKE_ASCII_TEXT,REPLYTO_WITHOUT_TO_CC autolearn=no autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,ASCII X-Google-Thread: 103376,e382b50ddc696050 X-Google-Attributes: gid103376,public X-Google-ArrivalTime: 2001-12-09 10:22:57 PST Path: archiver1.google.com!news1.google.com!newsfeed.stanford.edu!info1.fnal.gov!nntp.upenn.edu!msunews!not-for-mail From: "Chad R. Meiners" Newsgroups: comp.lang.ada Subject: Re: Basic Properties of Lists Date: Sun, 9 Dec 2001 13:16:48 -0500 Organization: Michigan State University Message-ID: <9v0962$63f$1@msunews.cl.msu.edu> References: <3C0DB9D0.7184868A@acm.org> <3C0EB851.77E7172A@boeing.com> <3C0FAF78.6F006DF7@boeing.com> <3C110606.A37E9D10@boeing.com> <8%8Q7.53294$xS6.88020@www.newsranger.com> <3C114702.98662A90@boeing.com> Reply-To: "Chad R. Meiners" NNTP-Posting-Host: arctic.cse.msu.edu X-Priority: 3 X-MSMail-Priority: Normal X-Newsreader: Microsoft Outlook Express 6.00.2600.0000 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2600.0000 Xref: archiver1.google.com comp.lang.ada:17647 Date: 2001-12-09T13:16:48-05:00 List-Id: Why not create two different Iterator types: Standard_Iterator and Reversed_Iterator (Or Cat_Iterator and Dog_Iterator)? Each would have its own First, Last, Next, and Previous subroutines. Perhaps a Flip function would be useful too. -CRM "Mark Lundquist" wrote in message news:dcKQ7.23845$Yy.297532@rwcrnsc53... > > "Jeffrey Carter" wrote in message > news:3C114702.98662A90@boeing.com... > > > > If we can't agree on the basic properties of lists we'll never get > > anywhere. Perhaps we need an appeal to authority here. > > Look, you guys both know what a doubly-linked list is; you don't need some > double-dome to weigh in with a ruling on it! > > You are having an argument about nomenclature, not about the basic > properties of anything. You just think you are because you have befuddled > each other with bad arguments. > > Jeffrey -- of course "sequence" (extrinsic ordering) is a fundamental > property of any kind of a linked list. I don't think anyone is confusing > the data structure in question with a set, bag, heap, or any other kind of > intrinsically ordered thing. Your point is irrelevant to the nomenclature > question. Ted doesn't deny that a list has direction, he's saying that a > doubly-linked list has two directions, and for some reason he feels strongly > about any kind of preferential scheme that would seem to establish one end > or direction as secondary or relative (like "Normal" vs. "Bass_Ackwards" > :-). > > But Ted, what's the big whoopie deal about this, anyway? Who cares if the > names have a "directional bias", as long as the semantics are clear? The > important thing is the relationship between the names you choose for the > extremities and the names you choose for "direction", right? So if the > extremities are "Bow" and "Stern", then the directions had better be > "Forward" and "Aft". That's why "Head/Tail" is kinda bad -- with a na�ve > choice for the direction names, like "Forward/Reverse", even the originator > of the naming scheme probably wouldn't be able to keep them straight :-). > But you have to start somewhere, and everybody knows it's arbitrary which > ends you call "First" and "Last". I don't buy the argument that a > preferential naming scheme entails a loss of flexibility or that it obscures > the property of bidirectionality. > > Cheers, > -- mark > > > >