Andrew Dunstan wrote: > > > Bruce Momjian wrote: > > >Gaetano Mendola wrote: > > > > > >>I don't think the article is available online, alas, but you can find some > >>related source code demonstrating the technique at: > >> > >> http://www.semantics.org/tyr/tyr0_5/list.h > >> > >> > > > >That certainly is an amazing idea. You know the pointer you are coming > >from so you can XOR to find the next pointer. > > > >I agree with a Tom that we don't have much use for double-link lists, > >but is a nice idea. > > > > > > > I must confess that it strikes me as a really really horrid and ugly > hack - very likely to be error-prone and non-portable and undebuggable, > and for almost no saving worth having. But maybe that's just me. > > In general I've been impressed with the quality of Pg code over the last > 6 months or so - I'd hate to see it polluted by something like this.
Agreed, I just thought it was neat and I hadn't realized it was possible. Also, I don't think the problems for doing this for swaping values without a temp table is relevant. In those cases, you are doing the swap without a temp variable, and this is the problem, more than the XOR itself, which is what we would use and use real temp table. -- Bruce Momjian | http://candle.pha.pa.us [EMAIL PROTECTED] | (610) 359-1001 + If your life is a hard drive, | 13 Roberts Road + Christ can be your backup. | Newtown Square, Pennsylvania 19073 ---------------------------(end of broadcast)--------------------------- TIP 2: you can get off all lists at once with the unregister command (send "unregister YourEmailAddressHere" to [EMAIL PROTECTED])
