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=-1.8 required=5.0 tests=BAYES_00,URI_HEX autolearn=no autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 103376,6eac62e4f2badf3a X-Google-Attributes: gid103376,public X-Google-ArrivalTime: 2003-04-08 06:41:24 PST Path: archiver1.google.com!news1.google.com!newsfeed.stanford.edu!bloom-beacon.mit.edu!news.telebyte.nl!fu-berlin.de!uni-berlin.de!212.97.175.23!not-for-mail From: Jano Newsgroups: comp.lang.ada Subject: Re: Persistence of limited tagged types Date: Tue, 8 Apr 2003 15:41:48 +0200 Message-ID: References: <3E91DCEA.5030006@psu.edu> <3E92C6F9.70303@psu.edu> NNTP-Posting-Host: 212.97.175.23 X-Trace: fu-berlin.de 1049809282 9644171 212.97.175.23 (16 [49872]) X-Newsreader: MicroPlanet Gravity v2.50 Xref: archiver1.google.com comp.lang.ada:35989 Date: 2003-04-08T15:41:48+02:00 List-Id: Robert Spooner dice... > > Stephen Leake wrote: > > Robert Spooner writes: > > > > > >>I think that if you use 'output to put the object onto the disk, it > >>will put the external representation of the tag out with it. Then if > >>you use 'imput to read it back in as an object of type Object'class > >>you will get what you're looking for. > > > > > > That is certainly true. The trick is to get an object of type > > Object'class; it's an unconstrained type, so you can't just do: > > > > An_Object : Object'class; > > > > In practice, you need to know the concrete object type _before_ you > > call 'input, so you can allocate (or declare) an object of that type. > > That means some representation of the tag must be stored in the > > external file separately from the object, so you can read it first. > > > > The input attribute is a function, so you can initialize an object of > the class using it without a priori knowledge of the type. Yes, the whole matter arises because we are discussing limited types that can't be created that way. -- ------------------------- Jano 402450.at.cepsz.unizar.es -------------------------