gmane.comp.ai.prolog.swi

Re: odbc problem

Gaya Nadarajan — 2012-05-16T16:04:45

I have decided to use PrologScript instead and it works ok now.
Gaya

On 08/05/12 11:09, Jan Wielemaker wrote:

Re: blob atoms

Alan Baljeu — 2012-05-15T13:56:52

It's working.  


Example reads D from a stream, but establishes the amount of input accepted after.


15 ?- test_data(D), (length(D, 5) ; length(D, 3) ; length(D, 6) ; length(D, 10)).
D = [115, 109, 97, 108, 108] ;
D = [115, 109, 97] ;
D = [115, 109, 97, 108, 108, 13] ;
false.

 
Alan Baljeu


From: Alan Baljeu <alanbaljeu< at >yahoo.com>

To: Jan Wielemaker <J.Wielemaker< at >vu.nl> 
Cc: Prolog <swi-prolog< at >lists.iai.uni-bonn.de> 
Sent: Monday, May 14, 2012 4:35:26 PM
Subject: Re: [SWIPL] blob atoms
 
From: Jan Wielemaker <J.Wielemaker< at >vu.nl>


As I see things, I call a C function make_my_blob(term_t), which creates
 data and does a put_blob or something into the term.  I don't know  
when "the blob is new" happens, or what should be done then.  



Yes.  For my part, the problem was I couldn't figure out a good system 
within prolog that was both proof against backtracking and would grow 
on demand.  That is, it was clearly possible, but rather headache inducing 
to manage the behavior.


Exactly.



As long

Re: blob atoms

Alan Baljeu — 2012-05-14T21:38:26

New thought: Using 2 threads is a viable way to have non-backtracking behavior?  I don't know the means of communicating between threads but it's a thought.

Alan Baljeu

From: Alan Baljeu <alanbaljeu< at >yahoo.com>

To: Jan Wielemaker <J.Wielemaker< at >vu.nl> 
Cc: Prolog <swi-prolog< at >lists.iai.uni-bonn.de> 
Sent: Monday, May 14, 2012 4:35:26 PM
Subject: Re: [SWIPL] blob atoms

From: Jan Wielemaker <J.Wielemaker< at >vu.nl>

As I see things, I call a C function make_my_blob(term_t), which creates
 data and does a put_blob or something into the term.  I don't know  
when "the blob is new" happens, or what should be done then.  

Yes.  For my part, the problem was I couldn't figure out a good system 
within prolog that was both proof against backtracking and would grow 
on demand.  That is, it was clearly possible, but rather headache inducing 
to manage the behavior.

Exactly.

As long as you can go back on your read, you need infinite caching.  
Once you commit, you can cut off the backtracking and star

Re: blob atoms

Alan Baljeu — 2012-05-14T20:35:26

From: Jan Wielemaker <J.Wielemaker< at >vu.nl>


As I see things, I call a C function make_my_blob(term_t), which creates
 data and does a put_blob or something into the term.  I don't know  
when "the blob is new" happens, or what should be done then.  



Yes.  For my part, the problem was I couldn't figure out a good system 
within prolog that was both proof against backtracking and would grow 
on demand.  That is, it was clearly possible, but rather headache inducing 
to manage the behavior.


Exactly.



As long as you can go back on your read, you need infinite caching.  
Once you commit, you can cut off the backtracking and start a new cache 
on your same infinite stream.  I haven't implemented such, but I could add a 
commit call to clip the existing cache.

    Cheers --- Jan
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Position available for a Prolog programmer.

Jan Wielemaker — 2012-05-14T19:58:21

Hi,

There is a position available for a (SWI-)Prolog programmer. I have
spent some time on the pilot phase, so I can explain the problem.

There is a legacy expert system in chemical process design that has been
designed since the late 80s. The system is huge (about 1,000,000 lines
of Prolog). It was initially written for IF/Prolog 4 on Unix/X11. It has
been ported to IF/Prolog 5 on Windows/MFC. During the pilot, we ported
most of it to SWI-Prolog using a web-based interface.

25 years of development where we now emulate IF/Prolog 5 in SWI-Prolog,
while the code emulates IF/Prolog 4 means that it is time for big-time
refactoring. This requires a quite experienced Prolog programmer who can
deal with Prolog meta-programming, which is used a lot in the emulation
layers as well as the expert system itself. Meta-programming and program
analysis skills are also needed to automate the upcomming refactoring
process.  In other words, this is a nice engineering challenge :-)

Oh, about 80% of the code is in German an

Re: blob atoms

Jan Wielemaker — 2012-05-14T19:32:16

Roughly, the acquire() is called if the blob is new.   That depends
on the UNIQUE flag of the blob type.  release() is called if atom-gc
decides to remove the object.  write() and compare() should be fairly
easy, but are in general not needed.

Another source of examples is src/pl-dbref.c, dealing with clause
and recorded database references.


Interesting.  Does this mean that the C-part provides a backup of what
is read from the stream?  The problem there is of course that it may
be a little more efficient than Prolog, but not by that much.

I've considered using the current pure_input code, but using nb_setarg
to bind the next part rather than simple unification.  I still think that
should work, but I never managed to get it working :-(


That is a bit unclear.  Getting pure input to work on streams would be
really nice, but one of the nice aspects of pure input is that it can
work with limited resources on infinite streams.  I guess that is not
the case for your approach.  This still would make your app

Re: blob atoms

Alan Baljeu — 2012-05-14T19:19:59

Having got that archive4pl.c, I'm afraid I don't understand it :-(

Anyhow, I have got something that appears to work which only uses the release part of the blob definition (and I haven't tested the release).  I can't figure out a need or use for the other 3 parts.




For what it's worth, I'm making a stream interface that if you backtrack and re-read it remembers what was read before instead of pulling from the stream again.  The C++ side is just a vector-based history, and Prolog manages the rest.  


This can be used in conjunction with freeze/2 to make a DCG drive the reading of an input stream.  I could make this available if there's interest.



Alan Baljeu


From: Jan Wielemaker <J.Wielemaker< at >vu.nl>

To: Alan Baljeu <alanbaljeu< at >yahoo.com> 
Sent: Monday, May 14, 2012 2:17:43 PM
Subject: Re: [SWIPL] blob atoms
 
On 05/14/2012 05:55 PM, Alan Baljeu wrote:

Maybe the new archive package gives a reasonable example?

    Cheers --- Jan
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blob atoms

Alan Baljeu — 2012-05-14T15:55:24

I'm slightly overwhelmed by the PL_blob_t stuff, and underwhelmed by the clarity of the documentation.

I'm looking at a case I think would be the most common, and wish there was an example: Allocate a pointer (it's shared, never copied), store it in an atom, and have the pointer freed when all references go away.

One point of confusion is the allocator predicate.  It seems the only way to create a blob is to register my own foreign_t which will then create the blob object.  But then why is the acquire(atom_t) function pointer needed?

Anyway, it seems so basic, I wonder if there's a standing example that just defines the three methods to 

1) malloc/new a pointer and put it in a blob atom

2) extract the pointer from an atom
3) delete the pointer

and hooks this to SWI.

 
Alan Baljeu
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Re: Can anyone suggest a good book on User Interface Design?

Alan Baljeu — 2012-05-14T14:15:39

That topic is huge, Jeff!  It's like asking for a good book on programming.  You could do worse than reading "The Inmates Are Running the Asylum" by Alan Cooper.

Thesis: Programmers are crazy, at least from everyone else's perspective, and that's why they create such hard to use software.
Approach: Don't design for the "user", but for specific people or kinds of people.  If they aren't programmers, they don't understand or want to understand how computers think.  Figure out how they think, what they want to do, and how they might hope to go about doing their job.  

Or maybe you are looking for a completely different book.

 
Alan Baljeu


________________________________
 From: Jeff Rosenwald <jeffrose< at >aol.com>
To: swi-prolog< at >lists.iai.uni-bonn.de 
Sent: Sunday, May 13, 2012 11:23:00 AM
Subject: [SWIPL] Can anyone suggest a good book on User Interface Design?
 
All:

Sorry for the off-topic post, but can anyone suggest a good book or other resource on User Interface Design (that's in print here in th

Re: Ann: SWI-Prolog 6.1.4

Jan Wielemaker — 2012-05-13T19:09:56

Abort is mapped to the exception '$aborted'.  You can catch these, but the
logic will change the recovery handler to (Handler, abort), trying to make
the abort really abort the program.

Some of the code dealing with printing unhandled has changed, causing double
messages.  Not really a show stopper, but it needs some cleanup.

Cheers --- Jan


_______________________________________________
SWI-Prolog mailing list
SWI-Prolog< at >lists.iai.uni-bonn.de
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Can anyone suggest a good book on User Interface Design?

Jeff Rosenwald — 2012-05-13T15:23:00

All:

Sorry for the off-topic post, but can anyone suggest a good book or other resource on User Interface Design (that's in print here in the U.S.).

Regards,
Jeff R.
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Re: Ann: SWI-Prolog 6.1.4

Jeff Rosenwald — 2012-05-13T11:48:44

All:

One thing: I am now seeing this "unhandled exception" message at the top level:

^CAction (h for help) ? abort
ERROR: Unhandled exception: Execution Aborted
% Execution Aborted

I thought that aborts weren't (supposed to be) catchable as a rule.

Regards,
Jeff R.

 

 

 

-----Original Message-----
From: Jeff Rosenwald <jeffrose< at >aol.com>
To: pmoura <pmoura< at >di.ubi.pt>; swi-prolog <swi-prolog< at >lists.iai.uni-bonn.de>
Sent: Sun, May 13, 2012 7:22 am
Subject: Re: [SWIPL] Ann: SWI-Prolog 6.1.4


SWIPL 6.1.4 Upgrade proceeds quietly on Ubuntu 10.10, except for new packages 
dependency satisfied by: 

sudo apt-get install libarchive-dev

Jeff R.


 

 

-----Original Message-----
From: Paulo Moura <pmoura< at >di.ubi.pt>
To: Prolog Forum <swi-prolog< at >lists.iai.uni-bonn.de>
Sent: Sun, May 13, 2012 6:00 am
Subject: Re: [SWIPL] Ann: SWI-Prolog 6.1.4



On 13/05/2012, at 09:08, Jan Wielemaker wrote:


cannot open `../ac_swi_c.m4': No such file or directory
file or directory

cannot open `../ac_swi_noc.m4': No such file

Re: Ann: SWI-Prolog 6.1.4

Jeff Rosenwald — 2012-05-13T11:21:07

SWIPL 6.1.4 Upgrade proceeds quietly on Ubuntu 10.10, except for new packages dependency satisfied by: 

sudo apt-get install libarchive-dev

Jeff R.


 

 

-----Original Message-----
From: Paulo Moura <pmoura< at >di.ubi.pt>
To: Prolog Forum <swi-prolog< at >lists.iai.uni-bonn.de>
Sent: Sun, May 13, 2012 6:00 am
Subject: Re: [SWIPL] Ann: SWI-Prolog 6.1.4



On 13/05/2012, at 09:08, Jan Wielemaker wrote:

cannot open `../ac_swi_c.m4': No such file or directory
file or directory
cannot open `../ac_swi_noc.m4': No such file or directory
file or directory

The above magic incantation failed with the same error messages.

origin/master".


This second magic incantation succeeded :-) Thanks.

Cheers,

Paulo


-----------------------------------------------------------------
Paulo Jorge Lopes de Moura, PhD
Assistant Professor
Dep. of Computer Science, University of Beira Interior
6201-001 Covilhã, Portugal

Office 3.18  Ext. 3276
Phone: +351 275 242081 Fax: +351 275 319899
Email: <mailto:pmoura< at >di.ubi.pt>

Home page: <htt

Re: Ann: SWI-Prolog 6.1.4

Paulo Moura — 2012-05-13T09:58:36

On 13/05/2012, at 09:08, Jan Wielemaker wrote:


The above magic incantation failed with the same error messages.



This second magic incantation succeeded :-) Thanks.

Cheers,

Paulo


-----------------------------------------------------------------
Paulo Jorge Lopes de Moura, PhD
Assistant Professor
Dep. of Computer Science, University of Beira Interior
6201-001 Covilhã, Portugal

Office 3.18  Ext. 3276
Phone: +351 275 242081 Fax: +351 275 319899
Email: <mailto:pmoura< at >di.ubi.pt>

Home page: <http://www.di.ubi.pt/~pmoura>
Research:  <http://logtalk.org/> Blog: <http://blog.logtalk.org/>
-----------------------------------------------------------------

Re: Ann: SWI-Prolog 6.1.4

Jan Wielemaker — 2012-05-13T08:08:44

% port install libarchive

should fix that.  The idea was that it would simply discard installing
tha archive access library, but this apparently doesn't work ...



Doesn't ring a bell.  I have done the installation from git
on two MacOS Lion systems and four Linux systems.  I suspect some 
update/merge
conflict that creates in incomplete system.  Except for starting over 
again,
there is this emergency, to run from the toplevel dir:

% mv build .. (or some other safe place outside the tree)
% git clean -xfd
% git submodule foreach git clean -xfd
% git pull
% mv ../build .
% ./prepare
% ./build

If the git pull fails, try "git fetch" and then "git reset --hard 
origin/master".
Note that the latter looses all local changes (if any).

Cheers --- Jan

Re: Ann: SWI-Prolog 6.1.4

Jochem Liem — 2012-05-13T06:34:52

I have no trouble fetching/merging and using prepare. However, when
building the file archive.h seems to be missing from the new archive
package:

archive4pl.o archive4pl.c
archive4pl.c:29:21: error: archive.h: No such file or directory
(...)
make[2]: *** [archive4pl.o] Error 1

Cheers,
Jochem

On Sat, May 12, 2012 at 11:11 PM, Paulo Moura <pmoura< at >di.ubi.pt> wrote:

Re: Ann: SWI-Prolog 6.1.4

Paulo Moura — 2012-05-12T20:11:45

On 12/05/2012, at 15:43, Jan Wielemaker wrote:


Trying to build from the git repository gives:

$ git pull
Already up-to-date.
$ git submodule update
$ ./prepare
All submodules are up-to-date
Generating configure in ./packages/archive ... /opt/local/bin/gm4:configure.in:10: cannot open `../ac_swi_c.m4': No such file or directory
autom4te: /opt/local/bin/gm4 failed with exit status: 1
autoheader: '/opt/local/bin/autom4te' failed with exit status: 1
/opt/local/bin/gm4:configure.in:10: cannot open `../ac_swi_c.m4': No such file or directory
autom4te: /opt/local/bin/gm4 failed with exit status: 1
done
Generating configure in ./packages/chr ... /opt/local/bin/gm4:configure.in:7: cannot open `../ac_swi_noc.m4': No such file or directory
autom4te: /opt/local/bin/gm4 failed with exit status: 1
autoheader: '/opt/local/bin/autom4te' failed with exit status: 1
/opt/local/bin/gm4:configure.in:7: cannot open `../ac_swi_noc.m4': No such file or directory
autom4te: /opt/local/bin/gm4 failed with exit status: 1
done
...

Extensions packs 0.1

Jan Wielemaker — 2012-05-12T15:10:42

Hi,

The current SWI-Prolog package management was clearly a too big hurdle
to take for many users. Before something can be accepted as standard
package, it must

  - be maintained in a git repository
  - be portable to the main target systems:
    Linux, MacOS and Windows, 32 and 64-bits and at least in
    principle to other POSIX systems.
  - Be documented using the LaTeX and/or PlDoc standards
  - Have appropriate configure and make support.
  - Have a fair tradeof between value for users and size because it
    comes with all tarballs and binaries.

After some peer pressure (especially by Tom Schrijvers; thanks), I
finally came up with the first steps to make something really simple and
without any central authority.  It is far from complete, but in a nutshell

  - A pack is a directory with a small info file called pack.pl and a
    subdirectory 'prolog' that is added to the Prolog library.
  - Create an archive from this using tar or zip and put in on an HTTP
    server.
  - Download it yourself and i

Ann: SWI-Prolog 6.1.4

Jan Wielemaker — 2012-05-12T14:43:40

Hi,

I'm happy to announce SWI-Prolog 6.1.4.  The list of changes is long.  Here
are the highlights:

   * Randy Sharp has fixed zillions of typos in the reference manual. 
Thanks!
   * There is a basic package management system that allows users to share
     packages really easily (I hope).  Will be announced in a seperate mail.
   * Many enhancements to code reachability checking for list_undefined
     (make), autoload and development tools.
   * Various enhancements to PceEmacs.  Ctrl+/- to zoom in/out, colouring,
     etc.
   * Distinguish imports using use_module/1 from use_module/2.  The first
     may be locally overruled.
   * Various stability issues.

Enjoy --- Jan


=================================
SWI-Prolog Changelog since V6.1.3
=================================

  * ADDED: library(prolog_pack) for installation of Prolog package.

  * FIXED: Recent changes to autoload update didn't work with patterns
    like dir/*.pl.

  * FIXED: numbervars/3 to number inside '$VAR'(X).  Tobias Rho.

  * E

Re: pure input on a socket

Alan Baljeu — 2012-05-11T13:27:56

That's awesome Jeff.  It hardly even seems like a workaround.

Alan Baljeu

From: Jeff Rosenwald <jeffrose< at >aol.com>

To: nicolas.pelletier3< at >gmail.com; swi-prolog< at >lists.iai.uni-bonn.de 
Sent: Friday, May 11, 2012 7:36:05 AM
Subject: Re: [SWIPL] pure input on a socket

Alan:

Here's one simple way to solve your immediate problem that side-steps the issue of pure_input on non-positionable streams:

read_more_data(In, Data) :-
    \+at_end_of_stream(In),
    read_pending_input(In, Data, More),
    (   More = []; read_more_data(In, More)).

test_data(Data) :-
    open('slgln10_21.txt', read, In)
      ~> close(In),

    read_more_data(In, Data).

Tested:

?- test_data(Data), length(Data, N).
Data = [13, 10, 67, 72, 65, 80, 84, 69, 82|...],
N = 4096 ;
Data = [13, 10, 67, 72, 65, 80, 84, 69, 82|...],
N = 8192 ;
Data = [13, 10, 67, 72, 65, 80, 84, 69, 82|...],
N = 11928 ;
false.

The above builds up a real list of input data by tacking new input of the tail of old input nondeterministically.

Re: pure input on a socket

Jeff Rosenwald — 2012-05-11T11:36:05

 Alan:

Here's one simple way to solve your immediate problem that side-steps the issue of pure_input on non-positionable streams:

read_more_data(In, Data) :-
    \+at_end_of_stream(In),
    read_pending_input(In, Data, More),
    (   More = []; read_more_data(In, More)).


test_data(Data) :-
    open('slgln10_21.txt', read, In)
      ~> close(In),

    read_more_data(In, Data).

 

 Tested:

?- test_data(Data), length(Data, N).
Data = [13, 10, 67, 72, 65, 80, 84, 69, 82|...],
N = 4096 ;
Data = [13, 10, 67, 72, 65, 80, 84, 69, 82|...],
N = 8192 ;
Data = [13, 10, 67, 72, 65, 80, 84, 69, 82|...],
N = 11928 ;
false.

The above builds up a real list of input data by tacking new input of the tail of old input nondeterministically. If your DCG parse fails due to insufficient data, it will backtrack into read_more_data/2. It will supply additional data as needed (and blocking as necessary) until and end_of_file occurs.

Regards,
Jeff R.



-----Original Message-----
From: Nicolas Pelletier <nicolas.pelletier3< at >gma