Path: dp-news.maxwell.syr.edu!spool.maxwell.syr.edu!news-spur1.maxwell.syr.edu!news.maxwell.syr.edu!postnews.google.com!s13g2000cwa.googlegroups.com!not-for-mail From: "Marshall" Newsgroups: comp.databases.theory Subject: Re: views of binary operations Date: 17 Jul 2006 22:10:46 -0700 Organization: http://groups.google.com Lines: 18 Message-ID: <1153199446.798895.200580@s13g2000cwa.googlegroups.com> References: <1153017368.456165.270950@m73g2000cwd.googlegroups.com> <1153136855.570462.180130@75g2000cwc.googlegroups.com> NNTP-Posting-Host: 24.4.95.46 Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" X-Trace: posting.google.com 1153199452 4065 127.0.0.1 (18 Jul 2006 05:10:52 GMT) X-Complaints-To: groups-abuse@google.com NNTP-Posting-Date: Tue, 18 Jul 2006 05:10:52 +0000 (UTC) In-Reply-To: <1153136855.570462.180130@75g2000cwc.googlegroups.com> User-Agent: G2/0.2 X-HTTP-UserAgent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.0.4) Gecko/20060508 Firefox/1.5.0.4,gzip(gfe),gzip(gfe) Complaints-To: groups-abuse@google.com Injection-Info: s13g2000cwa.googlegroups.com; posting-host=24.4.95.46; posting-account=s2xCFw0AAAD2mIwYYHAqjdsecwG0axmW Xref: dp-news.maxwell.syr.edu comp.databases.theory:43433 erk wrote: > > At the risk of repeating what you already know, I think Marshall > intends the unadorned assignment (r = A op B) to assign a value > (snapshot) to r. But the view doesn't assign a value to r - it's a lazy > evaluation (but without the closure that usually goes along with it). > The hybrids are partial lazy evaluations - as such, I guess they're > closures. For example, "r = view(A) op B" closes over B, capturing its > value at the time this statement is evaluated, but only "capturing" A's > value when the value of r is used. So a temporary, local snapshot is > created. Yes, that was my idea. The question is, is it useful to be able to slice things up that finely? I kind of think not, but I'm not sure. Marshall