Date: Thu, 09 Dec 1999 20:14:23 -0700 From: Brett Glass <brett@lariat.org> To: Roelof Osinga <roelof@nisser.com> Cc: David Scheidt <dscheidt@enteract.com>, Tani Hosokawa <unknown@riverstyx.net>, Jonathon McKitrick <jcm@dogma.freebsd-uk.eu.org>, Alfred Perlstein <bright@wintelcom.net>, Kris Kennaway <kris@hub.freebsd.org>, freebsd-chat <chat@FreeBSD.ORG> Subject: Re: Yahoo hacked last night Message-ID: <4.2.0.58.19991209200536.03b8b400@localhost> In-Reply-To: <38503FAC.8926658E@nisser.com> References: <38502053.28737F7B@nisser.com> <4.2.0.58.19991209162117.00cc0670@localhost>
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At 04:47 PM 12/9/1999 , Roelof Osinga wrote: >> Non-deterministic pattern matching and backward chaining languages are even > > more powerful (though dangerous in the wrong hands). SNOBOL and Prolog can > > both produce results that are surprising -- in a good way if you've > > programmed well; in a bad way otherwise. > >Well, have to disagree a bit. Prolog has depth-first search because >of efficiency, but it does mean it can miss solutions thus never >finish. If it's allowed to run to completion it will do a complete depth-first search and generate all possible solutions -- provided, of course, that the tree is finite. Much research has been done on rearranging Prolog rules so as to direct and speed up the search. >Barring Borland's Turbo Prolog most didn't have (past tense >since I didn't keep up) typechecking. Borland Turbo Prolog was based on Quintus Prolog. >Backward chaining doesn't ring a bell. Backward chaining is the mechanism of formal logic which Prolog implements. It tries to "chain" backward from a statement to the facts and rules which prove it to be true. >SNOBOL is truly ancient <g>. Long since superceded by Icon. However, it still has some niceties that Icon doesn't. Regular expressions as implemented in Perl are far less potent than SNOBOL patterns. (The original SNOBOL book contains a complete parser for the SNOBOL language in SNOBOL; the set of patterns is only about 20 lines long. --Brett To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-chat" in the body of the message
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