comp.lang.prolog Google Group

PROLOG TESTING SEQUENCE - Getting Your ROBOT Off The Ground!

grahamcoop...@gmail.com (Graham Cooper) — Mon, 20 May 2013 05:37:54 UT

STEP 1: START UP YOUR FAVORITE PROLOG EDITOR!

ENTER: [link]
[LIST]

STEP 2: ENTER THE FOLLOWING TEST CODE!

[NEW]
test1 a.
test1 b.
test2 X.
test3 [sub a b c].

STEP 3: CHECK THE FOLLOWING COMMAND RESULTS!

test1 a ? CONFIRM!
test1 b ? CONFIRM!

comp.lang.prolog Frequently Asked Questions

tri...@logic.at — Thu, 16 May 2013 19:02:00 UT

Frequently Asked Questions - comp.lang.prolog

Last-modified: 2012-08-16
Last-changes: Update many links. Jan Burse.

Markus Triska (Mar. 2 2007 - ... )

Remko Troncon (Jan. 6 2002 - Mar. 2 2007)

Dirk-Jan Faber (Feb. 1 1999 - Jan. 6 2002)

Jamie Andrews (Aug 26 1992 - Oct. 16 1997)

Re: Prolog Web Services 0.1 (alpha) released

pico...@alice.it — Thu, 16 May 2013 16:33:48 UT

I'm currently using a modified version of your http_cgi.pl module (you can find it inside my prologws pack, file http_prologws.pl). However, I will be happy to use your own when it will be included in the core.

A first comment on this is that your code don't work for me unless I tell explicitly how many bytes (i.e. content length) to copy from the current request input stream to the input stream of the cgi process.

Re: Prolog Web Services 0.1 (alpha) released

j...@invalid.invalid (Jan Wielemaker) — Thu, 16 May 2013 11:52:48 UT

Comments make things better :-)

Hmmm. The HTTP server libs have a long history, starting as a small
hack before there were even threads in SWI-Prolog and incrementally
extended to handle more and more demands. I think there are two reaons.

First of all, one needs the infrastructure to handle exceptions from

Re: Swi-Prolog - PROLOG SYSTEM ERROR - While in 13x-th garbage collection

j...@invalid.invalid (Jan Wielemaker) — Thu, 16 May 2013 10:05:08 UT

First upgrade?

Call checkStacks(NULL) before the PL_call_predicate() to verify the state (requires -DSECURE_GC)

Cheers --- Jan

Re: Displaying HTTP 500 reply error messages (SWI HTTP)

j...@invalid.invalid (Jan Wielemaker) — Thu, 16 May 2013 09:59:46 UT

Ah, now we are getting somewhere. load_files/2 catches all exceptions
itself and calls print_message/2 on them, continuing the compilation.
The only exception to this rule are errors trying to open the file
(existence, permission). These messages are by default printed to
the user_error stream, and hence you do not see them in the browser

Re: Swi-Prolog - PROLOG SYSTEM ERROR - While in 13x-th garbage collection

oleh.lozyns...@gmail.com (Oleh) — Thu, 16 May 2013 07:46:21 UT

on the older 6.0.2 version

yes :) it is the sequence :) and inconsistency appearing int the "PL_call_predicate" iff "garbageCollect" take place.

Thanks & Cheers
Oleh

Re: Displaying HTTP 500 reply error messages (SWI HTTP)

pico...@alice.it — Wed, 15 May 2013 19:41:29 UT

Sorry for the lack of details.

I have a handler that basically call load_files/2 on some Prolog sources. What I need is to have informative error messages relative to the source files. This is why I'm not interested in stack trace upstream load_files/2 (where I know there is no problem).

As a first option, I solved by asserting user:message_hook/3 prior to load_files/2 and storing everything to be examined later on. This caused some issues with throw(http_reply(...)), which I posted elsewhere in this newsgroup.

Re: Prolog Web Services 0.1 (alpha) released

pico...@alice.it — Wed, 15 May 2013 19:23:06 UT

Thank you so much.

Probably it is something that I did because I realized that it only happens with ".psp" files. The good is that now you have a running example ;)

I will try to figure out where is the problem.

A note on the implementation of the server. Why did you choose to send http reply via throw/1? I ask this because I had troubles with normal exception handling and I had to add a rule to intercept http_reply exception. This is by no means criticism, but what was the rationale?

Re: Prolog Web Services 0.2.1 released

pico...@alice.it — Wed, 15 May 2013 19:08:53 UT

Updated to 0.2.2 (some bugfixes).

Re: Prolog Web Services 0.1 (alpha) released

janwielema...@gmail.com — Wed, 15 May 2013 13:33:18 UT

So, added handling of Location (and Status) to the core HTTP server libs.
I tried to reproduce the above, but I failed. Seems this depends on the
specific handler code, the OS, version, ... You'll have to give details
(preferably a fully running example). Preferably make a report on the
SWI-Prolog Bugzilla at [link]

Re: Displaying HTTP 500 reply error messages (SWI HTTP)

janwielema...@gmail.com — Wed, 15 May 2013 13:26:30 UT

?? In both cases, the server calls print_message(error, Exception) to
get a printable representation of the exception. Errors are of the from
error(ISOTerm, SWITerm), where SWITerm is typically unbound, but may be
bound to a term context(Location, Comment). Location may be set by the
initiator, but normally it is left to the system, which sticks the predicate indicator of the caller there. Library(http/http_error) uses library(prolog_stack) to replace this with a stack trace, which includes

Displaying HTTP 500 reply error messages (SWI HTTP)

pico...@alice.it — Wed, 15 May 2013 10:59:49 UT

I have an issue for reply 500 (internal server error).

In particular, I do not like library('http/http_error.pl') because it removes the error context to add stack trace. However, if I do not use it errors are not displayed at all (only browser's 500) and I have to look at the log file to figure out what's happening.

Re: Prolog Web Services 0.2.1 released

janbu...@fastmail.fm (Jan Burse) — Tue, 14 May 2013 20:06:40 UT

Jan Burse schrieb:

The bottomline is currently that interpreter objects are not
pooled, in contrast to the thread objects. I think thread objects
are pooled in many servlet containers since they are again a
little more expensive to create, also their size is a little
bigger. And maybe there are additional reasons to pool them, such

Re: Prolog Web Services 0.2.1 released

janbu...@fastmail.fm (Jan Burse) — Tue, 14 May 2013 19:58:50 UT

ses schrieb:
> Server Pages examples.

You might also look at the deployment examples for Jekejeke
Prolog Runtime. A poor mans solution to web services is to use
the GET method and extract the parameters, and then generate
a response. This is for example done here:

[link]

Re: Prolog Web Services 0.2.1 released

pico...@alice.it — Tue, 14 May 2013 15:31:19 UT

Thank you for your message. I am (slowly) working on it.

If you wish to contribute something you are welcome.

I have a couple of questions. Do you think WSDL+SOAP-based web services can be useful to Prolog? If yes, do you agree that Prolog would need the definition of Prolog-to-XML translation? Do you think it should be possible to avoid "typing Prolog" during this process?

Re: wouldnt prolog make a great singles matching app?

stew...@ssims.co.uk (ses) — Tue, 14 May 2013 12:57:17 UT

In short, yes. I think it has been used several times for matching rules engines in dating websites.

Re: Prolog Web Services 0.2.1 released

stew...@ssims.co.uk (ses) — Tue, 14 May 2013 12:53:25 UT

Hi,

This looks like a really interesting project. There hasn't been much further development of Prolog web capabilities since SWAPP ([link]) and some work I did for an XML based web service wrapper based on this ([link]).

Re: Prolog Web Services 0.1 (alpha) released

pico...@alice.it — Tue, 14 May 2013 01:50:25 UT

Yes, I am aware of that. I understand your point and completely agree.

I am just experimenting and the inclusion of PHP was a two-hours diversion.

My primary aim was to develop a web-based front-end for prolog source files (sort of programming over the internet). I am working on it in my free time.

Re: Prolog Web Services 0.1 (alpha) released

j...@invalid.invalid (Jan Wielemaker) — Mon, 13 May 2013 19:33:48 UT

Do you have a complete example of this behaviour?

The server is definitely not designed to be a replacement for Apache.
The basic design is to allow Prolog code to respond to HTTP queries
while maintaining state (i.e., not running Prolog as a CGI script). But
yes, it has facilities to serve static files as these are needed by many

Re: Prolog Web Services 0.1 (alpha) released

j...@invalid.invalid (Jan Wielemaker) — Mon, 13 May 2013 19:22:41 UT

Yes. Considering the situation I think it is better if this was moved
into the standard HTTP handling code. However, even if it is, the above
should work fine.

Cheers --- Jan

Prolog Web Services 0.2.1 released

pico...@alice.it — Mon, 13 May 2013 16:37:10 UT

Sorry for opening another thread but this is to spur on those potentially interested.

New version complies with SWI Prolog HTTP library (http_dispatch).

It also includes PHP support (CGI). MySQL is not yet supported, but I tested several text-based-database CMS. It is not 100% fluent but basic things are there.

Re: library(lambda) benchmarks around?

janbu...@fastmail.fm (Jan Burse) — Mon, 13 May 2013 15:37:59 UT

Hi,

I guess we can distinguish two approaches to library(lambda).
Namely we might find:

- global-by-default: The variables in the body of the lambda
expression are local by default, if they are not mentioned
by an extra binder.

- local-by-default: The variables in the body of the lambda

Re: FAQ: Insults

alewa...@aol.com (A. L.) — Mon, 13 May 2013 14:30:50 UT

For technical reasons I was absent for a while. It is nice to see that
in the meantime discussion on this group has elevated to new, more
advanced professional level

A.L.

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Re: Prolog Web Services 0.1 (alpha) released

pico...@alice.it — Sat, 11 May 2013 15:34:47 UT

I am playing with my new PHP installation under SWI Prolog webserver. It is working quite well. Unfortunately, so far I could not let PhpMyAdmin working.

Anyway, while using Fiddler to monitor HTTP traffic, I noticed that the SWI Prolog server (almost) systematically send "too much" data. I get a violation of the HTTP protocol with respect to Content-Length. Specifically, the server response is 16 bytes longer than indicated in the header. This is not causing any problem, but it would be nice not to see that warning.

Re: Prolog Web Services 0.1 (alpha) released

pico...@alice.it — Fri, 10 May 2013 14:44:55 UT

I solved by adding these lines in my http handler:

...,
current_output(CGI),
cgi_property(CGI, header(Header)),
( memberchk(location(Location), Header)
-> throw(http_reply(moved(Locatio n)))
; true
).

Do you think it can be considered safe?

I hope this could be of help.

library(lambda) benchmarks around?

janbu...@fastmail.fm (Jan Burse) — Fri, 10 May 2013 13:17:34 UT

Dear All,

These benchmarks would to some extend test the
speed of call/n but foremost they would test the
speed of lambda expressions such as (*) in Prolog.

I would be interested in benchmarks that are not
synthetic, but rather little toy examples that
test some aspect of lambda expressions.

Re: Prolog Web Services 0.1 (alpha) released

pico...@alice.it — Thu, 09 May 2013 21:50:40 UT

By the way, I would like to use the "Location" header as in the following:

go_to_google(_) :- write('Location: [link]n\n').

I am happy with throw(http_reply(moved, url)) or with the more elegant http_redirect(moved, url, Request) but I would like to use the "Location" header with the same nonchalance of most PHP programmers...

Re: Prolog Web Services 0.1 (alpha) released

pico...@alice.it — Thu, 09 May 2013 21:41:25 UT

I got http_cgi.pl and I used something in there.

PHP is working fine with SWI Webserver. However, I was unable to solve the HTTP header issue. I do not want any workaround, as in most of the PHP-based software (notably CMS) one finds a lot of "header('Location: url');" which at the moment makes the interface useless.

Re: Prolog Web Services 0.1 (alpha) released

pico...@alice.it — Thu, 09 May 2013 08:55:12 UT

Sorry for my naive question, but do you mean that "Location: url" will not work if the HTTP reply code is, e.g., 200?

I read somewhere that issuing a "Location: url" header SHOULD automatically set the reply to 302 (if I remember correctly). Isn't it?

PS: I could not download http_cgi.pl. Can you help me?

Re: Prolog Web Services 0.1 (alpha) released

j...@invalid.invalid (Jan Wielemaker) — Thu, 09 May 2013 07:49:38 UT

There is a file http_cgi.pl that is part of the SWI-Prolog website
sources ([link]), which uses CGI to
run the GIT web frontend. It would be a bit of hacking, but I guess it
should be doable to change the HTTP reply code (that is the problem;
otherwise it just passes the header fields you give it).

Re: Prolog Web Services 0.1 (alpha) released

pico...@alice.it — Wed, 08 May 2013 21:35:08 UT

While trying to add support for PHP (as CGI process, of course) I realized that in my case the SWI Prolog HTTP server does not recognize "Location: xxx" header.

Conversely, throw(http_reply(moved, xxx)) works as expected.

Any suggestion?

Thank you very much.
Mauro

PPDP 2013: 2nd Call for Papers

tomenanne...@gmail.com — Tue, 07 May 2013 13:40:54 UT

============================== ============================== =========

2nd Call for papers
15th International Symposium on
Principles and Practice of Declarative Programming
PPDP 2013

Special Issue of Science of Computer Programming (SCP)

Re: can prolog do shell scripting kinda tasks?

neng.z...@gmail.com — Mon, 06 May 2013 22:20:10 UT

Scripting is one of the main reasons why we designed the Picat language. You will find the functional notations and loops pleasant for scripting. Please wait for one month or so to see the first working version of Picat. Meanwhile you can learn Picat by reading the proposal at [link].

Re: can prolog do shell scripting kinda tasks?

visphatesj...@gmail.com (johannes falcone) — Mon, 06 May 2013 20:07:25 UT

How does prolog replace endless if then else?

SOME SCREEN SHOTS OF THE NEW BLoCKPROLOG

grahamcoop...@gmail.com (Graham Cooper) — Mon, 06 May 2013 02:45:26 UT

HOME SCREEN

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Re: speed of Marseille Prolog

ulr...@mips.complang.tuwien.ac.at (Ulrich Neumerkel) — Sat, 04 May 2013 14:40:25 UT

According to [MvC86], [War74] reads:

The present systems (Prolog I) is implemented partly in For-
tran, partly in Prolog itself, and running on an IBM 360-67
achieves roughly 200 unifications per second.

[MvC86] Michel van Changehem, L'anatomie de Prolog, InterEditions, 1986.

[War74] D.H.D. Warren, Warplan: A system for generating plans, memo 76,

Re: Feasible? (Was: ANN: VivoMind Unicode)

janbu...@fastmail.fm (Jan Burse) — Sun, 05 May 2013 12:21:41 UT

Paulo Moura schrieb:

Actually the applications of Unicode are numerous. So it
should be plural applications and not singular application.
Here is a little excerpt:

- Parsing Prolog Texts: Enlarged classes based on Unicode
for the character classes already found in the ISO core
standard syntax definition. Including numerals in foreign

Re: can prolog do shell scripting kinda tasks?

j...@invalid.invalid (Jan Wielemaker) — Sat, 04 May 2013 11:56:58 UT

Many Prolog systems can do this. The downside is that people trying
to write portable code often complain about the many differences and
capabilities to access system resources.

Of course, whether it is useful ... I sometimes do siginificant amounts
of tasks one should normally write as a shell script. I recognise some

speed of Marseille Prolog

dr.mtar...@ukonline.co.uk (Mark Tarver) — Sat, 04 May 2013 11:00:12 UT

Does anybody have any figures on the LIPS performance of Marseille
Prolog?

Mark

comp.lang.prolog Frequently Asked Questions

tri...@logic.at — Thu, 02 May 2013 22:59:54 UT

Frequently Asked Questions - comp.lang.prolog

Last-modified: 2012-08-16
Last-changes: Update many links. Jan Burse.

Markus Triska (Mar. 2 2007 - ... )

Remko Troncon (Jan. 6 2002 - Mar. 2 2007)

Dirk-Jan Faber (Feb. 1 1999 - Jan. 6 2002)

Jamie Andrews (Aug 26 1992 - Oct. 16 1997)

Re: Swi-Prolog - PROLOG SYSTEM ERROR - While in 13x-th garbage collection

j...@invalid.invalid (Jan Wielemaker) — Thu, 02 May 2013 18:32:04 UT

At least as something that may well explain GC errors. Is this with the old
version or the 6.3.x version?

Otherwise, I have little clue. Not sure you can mess this up easily through
the external interface.

That is more a sequence than a stack :-) Looks ok to me. Where in this
sequence does the inconsistency appear?

Re: Swi-Prolog - PROLOG SYSTEM ERROR - While in 13x-th garbage collection

oleh.lozyns...@gmail.com (Oleh) — Thu, 02 May 2013 12:50:48 UT

Hello Jan

thank you for your reply, actually weird things happend with my posting in this group (went in timeout and thus didnot posted one more msg... sorry about the mess) here it is---

I have followed your suggestion.

after compiling and running in DEBUG/SECURE_GC I have following assertion warnings: assert(s == fr->size);

Re: Swi-Prolog - PROLOG SYSTEM ERROR - While in 13x-th garbage collection

j...@invalid.invalid (Jan Wielemaker) — Thu, 02 May 2013 08:04:32 UT

Good to be able to generate a call stack. The bad news is that call
stacks rarely help in debugging GC issues. This is because the
damage generally happened long before the actual crash :-(

That only catches nice Prolog exceptions. Here, you are in unforeseen land.

The first step would be to try the current development releases. Quite a

Re: Feasible? (Was: ANN: VivoMind Unicode)

burse...@gmail.com — Tue, 30 Apr 2013 18:18:51 UT

I guess i had a look at OpenJDK:
[link]

Can provide a more exact ref if desired.

Re: Feasible? (Was: ANN: VivoMind Unicode)

burse...@gmail.com — Tue, 30 Apr 2013 17:35:53 UT

There is nothing on my side that i could contribute
Right now. There is no necessety to implement
A prolog token scanner that is capable of unicode
To implement in Prolog itself.

You can use any programming language for that
Purpose, i.e C, Ada, Java, etc..

I already posted a link to the IBM UCharacter class

Re: Feasible? (Was: ANN: VivoMind Unicode)

burse...@gmail.com — Tue, 30 Apr 2013 13:35:09 UT

I guess with some state machine technique and some
Cuts the problem can be slightly mitigated, at least
For ascii and latin. But for the cut to work the properties
Have to be ordered according to the scanner. Ugly.

Re: Feasible? (Was: ANN: VivoMind Unicode)

burse...@gmail.com — Tue, 30 Apr 2013 13:16:01 UT

The positive case is when the predicate succeeds. For ascii and latin
You might have practically O(1), since the intervals are at the beginning.

The negative case us wben the predicate fails. For any encoding
You have O(n). With or without multi-argument indexing.

The negative case is quite common in parsing. For example

Re: Feasible? (Was: ANN: VivoMind Unicode)

pjlmo...@gmail.com (Paulo Moura) — Tue, 30 Apr 2013 11:08:40 UT

Again, these are data files. From the documentation: "The VivoMind
Prolog Unicode Resources are a set of files resulting from the
conversion of most (but not all) official UCD 6.1 files and updated
for the few changes in the 6.2 standard."

"You should also" really sums it all. Note that those "derived files",

comp.lang.prolog Google Group

PROLOG TESTING SEQUENCE - Getting Your ROBOT Off The Ground!

comp.lang.prolog Frequently Asked Questions

Re: Prolog Web Services 0.1 (alpha) released

Re: Prolog Web Services 0.1 (alpha) released

Re: Swi-Prolog - PROLOG SYSTEM ERROR - While in 13x-th garbage collection

Re: Displaying HTTP 500 reply error messages (SWI HTTP)

Re: Swi-Prolog - PROLOG SYSTEM ERROR - While in 13x-th garbage collection

Re: Displaying HTTP 500 reply error messages (SWI HTTP)

Re: Prolog Web Services 0.1 (alpha) released

Re: Prolog Web Services 0.2.1 released

Re: Prolog Web Services 0.1 (alpha) released

Re: Displaying HTTP 500 reply error messages (SWI HTTP)

Displaying HTTP 500 reply error messages (SWI HTTP)

Re: Prolog Web Services 0.2.1 released

Re: Prolog Web Services 0.2.1 released

Re: Prolog Web Services 0.2.1 released

Re: wouldnt prolog make a great singles matching app?

Re: Prolog Web Services 0.2.1 released

Re: Prolog Web Services 0.1 (alpha) released

Re: Prolog Web Services 0.1 (alpha) released

Re: Prolog Web Services 0.1 (alpha) released

Prolog Web Services 0.2.1 released

Re: library(lambda) benchmarks around?

Re: FAQ: Insults

Cheap Nike Air Max 2013 Shoes men's women's wholesale www.Buy-Good-Goods.com

Re: Prolog Web Services 0.1 (alpha) released

Re: Prolog Web Services 0.1 (alpha) released

library(lambda) benchmarks around?

Re: Prolog Web Services 0.1 (alpha) released

Re: Prolog Web Services 0.1 (alpha) released

Re: Prolog Web Services 0.1 (alpha) released

Re: Prolog Web Services 0.1 (alpha) released

Re: Prolog Web Services 0.1 (alpha) released

PPDP 2013: 2nd Call for Papers

Re: can prolog do shell scripting kinda tasks?

Re: can prolog do shell scripting kinda tasks?

** SOME SCREEN SHOTS OF THE NEW BLoCKPROLOG **

Re: speed of Marseille Prolog

Re: Feasible? (Was: ANN: VivoMind Unicode)

Re: can prolog do shell scripting kinda tasks?

speed of Marseille Prolog

comp.lang.prolog Frequently Asked Questions

Re: Swi-Prolog - PROLOG SYSTEM ERROR - While in 13x-th garbage collection

Re: Swi-Prolog - PROLOG SYSTEM ERROR - While in 13x-th garbage collection

Re: Swi-Prolog - PROLOG SYSTEM ERROR - While in 13x-th garbage collection

Re: Feasible? (Was: ANN: VivoMind Unicode)

Re: Feasible? (Was: ANN: VivoMind Unicode)

Re: Feasible? (Was: ANN: VivoMind Unicode)

Re: Feasible? (Was: ANN: VivoMind Unicode)

Re: Feasible? (Was: ANN: VivoMind Unicode)

SOME SCREEN SHOTS OF THE NEW BLoCKPROLOG