gmane.comp.ai.prolog.swi

Re: Need help

2008-12-03T14:32:44

Re: Operator definitions

Richard O'Keefe — 2008-12-03T00:04:43

On 2 Dec 2008, at 11:47 pm, Günter Kniesel wrote: That's mixing two languages of the same *kind*, and even then, if you have something for which performance is an issue, you shouldn't do it. Amongst Prolog's successor languages, both Goedel and Mercury refuse to have anything to do with language/metalanguage amalgamation and there are long-published reasons for this rejection. As it happens, I have my own Smalltalk system (not quite finished, but at long last it's far enough along to run benchmarks and test cases). Because it compiles via C, it lets you embed C code inside Smalltalk. So you can do things like integer_between: lower and: upper ^C: 'ASBOOL((Int)lower <= (Int)self && (Int)self <= (Int)upper && ISINT((lower|upper|self)))' The nasty thing is that the C code has to be able to include bits of Smalltalk as well (lower, upper, self). There are bits it can (variable names beginning with a lower case letter) and bits it can't (anything else), but e

Ann: SWI-Prolog 5.6.63 and 5.7.3

Jan Wielemaker — 2008-12-02T21:53:35

Hi, Bit busy, but there where enough fixes to release a new version as a present to ICLP08. Markus has been doing performance work on clp(fd). My contribution is bug-fixes only. Most applied to both versions; some were specific issues of 5.7.3: wakeup problems with attributed variables and some debugging issues. Notably users of threading on Unix systems are urged to upgrade: fixes to thread-specific CPU time measurement on some versions (wrong results and crashes) and fixed a possible deadlock related to shell/1 and the library(process). Please try out 5.7.3 as a release candidate for 5.8.0. 5.7.x contains some very obvious optimizations, notably to unification, arithmetic and reduction of the overhead of calling predicates in general that has proved to improve performance somewhere between 0 and 40% on large applications (0 and 400% on small benchmarks). Your mileage depends mainly on the programming style. Generally, good style pays better :-) Oops, I should close my mailbox now ... If it holds, I wil

Re: Operator definitions

Günter Kniesel — 2008-12-02T10:47:34

Richard O'Keefe schrieb: The mix of two languages is obviously accepted in Prolog and the basis of much of its power. You might remember Robert Kowalski's famous article about "Mixing language and Metalanguage". ;) Günter

Re: Need help

Carlo Capelli — 2008-12-02T10:33:44

Beware that building an expert system the emphasis should stay on 'expert'. For the 'system' part, you have a number of choices (primarly forward/backward chaining), and implementing them can be tricky in any language. Of course, googling for 'expert system in Prolog' gives so many hints... The first link (www.amzi.com/ExpertSystemsInProlog/xsipfrtop.htm) it's so interesting and (at first glance) so well done! Anyway, i think almost any text book on Prolog exposes the basic. So you should concentrate on some simpler task (Hello World!) to interface from Delphi, then attach any code you find and (possibly) understand. Bye Carlo "menguele francois" yahoo.fr> ha scritto nel messaggio news:360550.28846.qm__14068.5621453033$1228143398$gmane$org< at >web25907.mail.ukl.yahoo.com... Good morning. I'm a new delphi programmer and i want to be initiate to expert system. I downloadded the delphiswi.zip which must help me to embbed prolog in delphi. The problem is that i don't know how to

Re: Operator definitions

Richard O'Keefe — 2008-12-02T05:19:26

On 1 Dec 2008, at 9:50 pm, Lukas Degener wrote: There is a non-sequitur there. Assuming that "arbitrary Prolog expressions" means "arbitrary Prolog terms with no annotations on variables", then ANY such term can be written without any operators whatsoever and can therefore be read by a parser that knows nothing at all about operators. Indeed, if you want to be *sure* you can read Prolog data in, that's how you should write them. There's also some highly questionable design going on there: mixing two languages in a single construct is, um, well, let me put it this way: that way lies XSLT. You really don't want to go there. Does SWI Prolog allow ¡ as an operator symbol? If not, I'm sure it could without breaking anything. Instead of using !!!, use ¡¡¡ and the problem goes away.

Re: Need help

Alan Baljeu — 2008-12-01T15:29:17

Prolog is not an expert system shell. It is a general purpose programming language that happens to be very adept for doing complex search algorithms, and symbolic manipulation. Both of those features make it suitable for designing an expert system. But Prolog doesn't prescribe any method of building an expert system. Tutorials commonly advise one of two methods to build Prolog programs. One way is to make lots of facts in the Prolog database, and then build programs that query the facts and make connections. This is easy and works well for smaller prorgrams. The other is to use lists and other datastructures to manage and manipulate knowledge. This is more complicated, but is also more scalable. To learn the language, search "prolog tutorial", and choose one of the many. After, lookup the book "The Craft of Prolog" by Richard O'Keefe. Then we can talk about expert system building. Alan Baljeu ________________________________ From: menguele francois yahoo.fr> To: swi-prolog< at >iai.

Need help

menguele francois — 2008-12-01T11:21:43

Good morning. I'm a new delphi programmer and i want to be initiate to expert system. I downloadded the delphiswi.zip which must help me to embbed prolog in delphi. The problem is that i don't know how to use it. So please can u help me. I really want to implement my first expert system. Thanks.

Re: Operator definitions

Günter Kniesel — 2008-12-01T09:30:00

Richard O'Keefe schrieb: That's indeed a very nasty consequence of which I didn't think before. Thanks for the explanation. Also to Ulrich and Jan. Günter

Re: Operator definitions

Lukas Degener — 2008-12-01T08:50:35

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Richard O'Keefe schrieb: I think this is a good idea in most situations. However if you want to parse data that contains arbitrary Prolog expressions (I think this is what Günter needs), then your parser probably won't be trivial: You would have to reimplement the parsing used by SWI-Prolog, which is difficult *because* of user defined operators, etc. Here is what I would try. Not as elegant and probably not as robust as having a single parser, but -- I think -- easier to implement: 1) Use a very simple parser that only does a rough partitioning of the input (filter out comments, make string/atom-literals opaque). 2) In a second pass, put quotes around all occurrences of !!! (or whatever you are using) in the remaining regions of the input. 3) Then feed the result to SWI-Prolog. Regards, - --lu -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.9 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iEYEARECAAYFAkkzpVQACgkQ6CpjlIRm

Re: Operator definitions

Ulrich Neumerkel — 2008-12-01T06:54:29

Even determining the end of a read-term would depend on the current operator definitions. If more elaborate operators are desired, UTF-8 provides plenty of characters. What about ?- op(1175, xfx, '\u2225'). in place of ||| or '\u203c' in place of !!! ?

Re: Operator definitions

Richard O'Keefe — 2008-12-01T06:23:22

On 1 Dec 2008, at 10:13 am, Günter Kniesel wrote: YIKE! There was a Prolog system that worked that way. More than one, in fact. Trying to figure out how to parse it was a nightmare, because the operator declaration that licensed a particular token might not be in the same file as the token in question. Some things just don't work well in practice. It's an even worse idea than APL's "you can't even parse me until run time" "cleverness". The problem is that some people wanted to write "a:-!." or "a:-!, b.", which means that "!" has to be in a different character class from "-". If you are happy to break that, then there would be no problem in putting "!" in the same character class as "-" and ":". Nothing stops you designing your own new syntax and plugging it in. Certainly nothing stops you writing your own parser for "data" and mapping that into some other Prolog; using operator-heavy stuff *at run time* has a nasty habit of leading to inefficiency, because what is optimised for human reading is n

Re: Operator definitions

Günter Kniesel — 2008-11-30T21:13:12

Ulrich Neumerkel schrieb: Hi Ulrich, I understand the historic reasons for the current state but not why it wouldn't be possible to treat !!! as a token as soon as there is a corresponding operator definition. That wouldn't require extra space in other cases (such as those you mentioned above). It might require replacing the special treatment of ! and friends in the parser to check for special tokens defined by operator declarations. I don't know how much work that is but I know it would definitely help me a lot ;) The current state prevents some very useful operator definitions. The exclamation and pipe are very intuitive in many contexts, so it is a pity that one cannot use them in operators. Günter

Re: Operator definitions

Ulrich Neumerkel — 2008-11-30T14:03:43

They are solo- and punctuation characters respectively. They do not glue together with other characters and thus will always represent one token unless quoted like '!!!'. Other characters with similar properties are ; , [ ] ( ) { } but not . which is not a punctuation character but only a symbol character to make =.. work, a remainder from the ancient ,.. notation for lists. Without solos and punctuations we would have to add extra space to a :- !. L0 = [+,a,-|L1]. resulting in less compact text a :- ! . L0 = [ + ,a, - |L1] .

Operator definitions

Günter Kniesel — 2008-11-30T12:27:48

Hi SWI team, in general, it is possible to write an operator that has another one as prefix. For instance, :- op(1175, xfx, +++). :- op(1175, xfx, ---). is OK, although + and - are operators too. This is what I would like also for ! and | but: ?- op(1175, xfx, |||). ERROR: [Thread pdt_console_client_0< at >localhost] op/3: Type error: `list' expected, found `(|)||' ?- op(1175, xfx, !!!). op(1175, xfx, !!!). ERROR: [Thread pdt_console_client_0< at >localhost] Syntax error: Operator expected ERROR: [Thread pdt_console_client_0< at >localhost] op(1175, xfx, set_stream(current_output,tty(true)),set_stream(current_input,tty(true)) ERROR: [Thread pdt_console_client_0< at >localhost] ** here ** ERROR: [Thread pdt_console_client_0< at >localhost] !) . It seems that the symbols ! and | are treated by the parser in a special way that makes it impossible to define operators that contain these symbols without being forced to add ugly quotes around the operator. Could this be fixed? Regards, Günter

RE: help about programing with prolog

Faiz ul haque Zeya — 2008-11-30T10:23:41

The program is parent(tom,socrates). parent(john,tom). succ(A,B):-parent(A,B). succ(A,B):-parent(A,C),succ(C,B). Try it with queries such as succ(john,socrates). regards Faiz ul haque Zeya From: swi-prolog-admin< at >iai.uni-bonn.de [mailto:swi-prolog-admin< at >iai.uni-bonn.de] On Behalf Of Setareh Rastad Sent: Sunday, November 30, 2008 12:33 AM To: swi-prolog< at >iai.uni-bonn.de Subject: [SWIPL] help about programing with prolog excuseme I want a simple program prolog that contains rules and fact. Thank you very much.

help about programing with prolog

Setareh Rastad — 2008-11-29T19:32:32

excuseme I want a simple program prolog that contains rules and fact. Thank you very much.

Re: delphiswi.zip

leledumbo — 2008-11-26T08:44:46

menguele francois wrote: http://gollem.science.uva.nl/twiki/pl/bin/view/Foreign/DelphiInterface This link works fine.

Re: open/4 and invalid options

Markus Triska — 2008-11-25T11:37:40

Hi Matt, To me, ignoring unknown options seems least user-friendly; silent failure is already better, and a domain error seems best. All the best, Markus

Re: depth & breadth first search

Richard O'Keefe — 2008-11-24T23:05:40

On 22 Nov 2008, at 8:46 am, Ralf Meermeier wrote: So this is a homework problem. This can *only* be a homework problem, because for serious work, iterative deepening is preferred to breadth first. Recommendation 1: GO TO YOUR LECTURER AND ASK FOR HELP. I'm a lecturer myself. One of the things that *REALLY* upsets me is students who flounder around wasting their and other people's time when they could just come and ASK me. I don't bite. Neither does your lecturer. We are PAID to explain stuff to our own students. Amongst other things, your lecturer needs to know when students are having difficulty so that s/he can revise the material appropriately. Going behind the lecturer's back is a species of deception which does nobody any good. Recommendation 2: Buy my book if you can find a copy. (The Craft of Prolog.) If you can't, buy, or at least borrow, practically ANY book about Prolog. Recommendation 3: Google for (Prolog breadth first search).

[XPCE] how tu execute item actions in a popup ?

Joel Foutelet — 2008-11-24T18:18:48

Hello I'd like to use a context-menu, so I create a popup but it doesn't work : the popup is showed, but when I clik on an item, nothing happens ! Thank you for any remark . Joel Here is my code, with different tests. :- pce_begin_class(my_popup, popup, "Gestion du menu des popup "). initialise(P) :-> send(P, send_super, initialise, message := message(< at >prolog, init)), send_list(P, append, [new(_, menu_item('item 1', message := message(< at >prolog, test_item1))), new(_, menu_item('item 2', message := message(< at >prolog, test_item2)))]). /* % essai 4 creation toute simple send_list(P, append, ['item 1','item 2']). */ /* % essai 3 sans création avec new send_list(P, append, [menu_item('item 1',< at >default), menu_item('item 2',< at >default)]). */ /* % essai numero 2 avec messages par défaut send_list(P, append, [new(_, menu_item('item 1',< at >default)), new(_, menu_item('item 2',< at >default))]). */ /* % essai numero 1 avec des messages associés send_