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 autolearn=ham autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: f4fd2,23202754c9ce78dd X-Google-Attributes: gidf4fd2,public X-Google-Thread: fac41,15edb893ef79e231 X-Google-Attributes: gidfac41,public X-Google-Thread: 103376,15edb893ef79e231 X-Google-Attributes: gid103376,public X-Google-Thread: 114809,15edb893ef79e231 X-Google-Attributes: gid114809,public X-Google-ArrivalTime: 2002-01-23 16:16:45 PST Path: archiver1.google.com!news1.google.com!newsfeed.stanford.edu!news-spur1.maxwell.syr.edu!news.maxwell.syr.edu!jfk3-feed1.news.digex.net!dca6-feed2.news.digex.net!intermedia!newsfeed1.cidera.com!Cidera!nyccyc01!news-out.nyc.rr.com!typhoon.nyc.rr.com.POSTED!not-for-mail Message-ID: <3C4EA9BB.B9AB65AE@nyc.rr.com> From: Kenny Tilton X-Mailer: Mozilla 4.78 [en] (WinNT; U) X-Accept-Language: en MIME-Version: 1.0 Newsgroups: comp.lang.lisp,comp.lang.ada,comp.lang.eiffel,comp.lang.smalltalk Subject: Re: True faiths ( was Re: The true faith ) References: <%njZ7.279$iR.150960@news3.calgary.shaw.ca> <3c36fbc5_10@news.newsgroups.com> <4idg3u40ermnp682n6igc5gudp7hajkea9@4ax.com> <76be8851.0201101909.9db0718@posting.google.com> <9jtu3u8cq92b05j47uat3412tok6hqu1ki@4ax.com> <3C3F8689.377A9F0F@brising.com> <3219936759616091@naggum.net> <3C483CE7.D61D1BF@removeme.gst.com> <7302e4fa4a.simonwillcocks@RiscPC.enterprise.net> <3C4D9B03.60803@mail.com> <3C4DE2F3.9020904@mail.com> <3C4DF550.24D3333A@nyc.rr.com> <3C4F272B.6020209@mail.com> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Date: Thu, 24 Jan 2002 00:15:23 GMT NNTP-Posting-Host: 66.108.26.20 X-Complaints-To: abuse@rr.com X-Trace: typhoon.nyc.rr.com 1011831323 66.108.26.20 (Wed, 23 Jan 2002 19:15:23 EST) NNTP-Posting-Date: Wed, 23 Jan 2002 19:15:23 EST Organization: Road Runner - NYC Xref: archiver1.google.com comp.lang.lisp:25114 comp.lang.ada:19266 comp.lang.eiffel:5515 comp.lang.smalltalk:18557 Date: 2002-01-24T00:15:23+00:00 List-Id: Hyman Rosen wrote: > > Kenny Tilton wrote: > > Hyman Rosen wrote: > >>You don't get to redefine the problem so that your favorite technique > >>becomes the solution. > > > > GC does not redefine the problem, it eliminates it. Which was the point. > > It does no such thing. The original problem specified an object with > two subobjects which were owned by the parent and with a non-empty > base object. You must write assignment for this type so that the > destination acquires its own private copies of the subobjects of the > source, and such that if copying any subcomponent fails (with an > exception) you leave the destination object undamaged. > > You do *not* get to hand-wave away the requirement of copying the > subobjects. Say, for example, they represent a pair of buffers. After > the copy is made, the source object and the destination object are > independent - when one writes into its buffers, the other must not > see any change to its own. Perhaps I misunderstood. The problem of /copying/ a structure is clear--how deep is something only the application can decide. Fine. Now what is all this about assignment having to worry about copying? The story I saw seemed to think you needed both a copy and assignment method in C++, and that the assignment method also had to worry about what to copy (and blowing up during a copy). Why confuse the two? I just pass pointers (if you will) around. assignment is always by reference. Automatic GC gets to clean up after me. Life is good. When I /copy/ a structure...well, I'll have to get back to you if it ever comes up. :) kenny clinisys