Re: [Flora-development] [Xsb-development] XSB and Flora-2 wrappers for .NET and Python

[Markus S. <msc...@fo...>]

Dear Gon=E7alo,

I had a similar problem (Memory Access Violation error) when I tried to=20
run xsb_init from a windows application (VB.NET) without a console=20
window. After hours and hours of searching without any success I started a=
=20
long try-fail approach. After playing with the code I figured out that=20
xsb_init tries to write some messages to standard output (console) and=20
=2ENET didn't allow that if there was no console present. After starting th=
e=20
app from console all errors where gone. I don't know if this fixes your=20
problem but I hope it helps.

I wanted to ask you if you were maybe interested in coordinating our two=20
projects to create a wrapper for XSB and Flora-2? I took a look at your=20
code, and since you took a different approach (I created a C# Class=20
Library which imports functions exported in xsb.dll) and I think your one=
=20
is more intuitive for .NET programmers I propose I change my examples in=20
VB.NET and C# to use your interface and add them to the wrapper. Maybe it=
=20
would be a good idea to create a more intuitive way of using Flora-2 from=
=20
=2ENET (not through flora_query/4 etc. but through an interface like the on=
e=20
you created for XSB). So what do you say?

Best regards

--
Markus Schatten, dipl. inf.
e-mail: mar...@fo...
http://www.tiaktiv.hr


On Wed, 17 Jan 2007, Gon=E7alo Lopes wrote:

> Dear all,
>
> Now for the single issue with XSBDotNet so far. Apparently, when
> running a debug session of a XSBDotNet application in Visual Studio C#
> Express, there is a memory access violation when calling xsb_init. I
> don't know why this happens, but it is very specific, in that if you
> run the executable there is no problem, if running the Visual C++
> Express debugger things also work fine.
>
> I don't understand why it would crash specifically with this debugger
> environment, but maybe it has something to do with the C# debugger
> changing specific parameters that influence some behaviour on the XSB
> side, causing it to crash (i.e. changing some stack sizes).
>
> I'm sorry for the technical blowout, but I can't seem to workaround
> this very specific issue. Otherwise, all XSBDotNet applications work
> fine on every environment.
>
> Best regards,
>
> Gon=E7alo
>
>
> On 1/17/07, Gon=E7alo Lopes <gon...@gm...> wrote:
>> Dear Markus, David et al,
>>
>> It's great to find growing support and interest on a .NET interface.
>> I've set up a management page for my current source code at
>> http://articaserv.ath.cx/XSBDotNet. The SVN code can be offloaded from
>> the repository using any SVN client at
>> svn://articaserv.ath.cx/XSBDotNet. I can also make a binary release
>> available to those who just want to try it out "out-of-the-box". I'll
>> definitely work on proper documentation and usually I try to use a
>> unit testing methodology.
>>
>> So far, all the tests I've made have been successful, but there are
>> bound to be issues, especially where the multithreaded engine is
>> concerned. I'll post one of these issues in the following e-mail.
>> Right now, I'll just post two small code snippets of what XSBDotNet
>> offers so far for the .NET programmer (in C#):
>>
>>         static void Main(string[] args)
>>         {
>>             XSBPrologEngine engine =3D XSBPrologEngine.Instance;
>>             engine.Command("consult(basics).");
>>             QueryHandle handle =3D engine.Query("member(X,[1,2,3]).");
>>             foreach (PrologAnswer answer in handle)
>>             {
>>                 PrologTerm groundedTerm =3D answer.QueryTerm;
>>                 System.Console.Out.WriteLine(
>>                     "Answer: {0}",
>>                     groundedTerm.GetFunctorArgument(1).GetIntValue()
>>                 );
>>             }
>>         }
>>
>> As you can see, the PrologEngine instance is a singleton, since for
>> now you can only call xsb_init once. There is support for commands and
>> queries, supporting both strings and PrologTerms built from C#. The
>> result from a query is in fact an enumeration of all the possible
>> answers, containing both the terms from reg1 and reg2. At each step of
>> the foreach cycle, a backtrack is issued and a new answer, if any, is
>> produced. It is also possible to terminate the enumeration at any
>> given time by just closing the handle.
>>
>> Now a small example of defining a C# method to run as a XSB predicate:
>>
>>         static bool HelloFromDotNet(PrologTerm[] arguments)
>>         {
>>             if (arguments.Length !=3D 0)
>>             {
>>                 arguments[0].BindAtom("hello");
>>                 return true;
>>             }
>>             else return false;
>>         }
>>
>>         static void Main(string[] args)
>>         {
>>             XSBPrologEngine engine =3D XSBPrologEngine.Instance;
>>             engine.RegisterManagedPredicate("hellodotnet", HelloFromDotN=
et);
>>             QueryHandle hello =3D engine.Query("managed(hellodotnet(X)).=
");
>>             foreach (PrologAnswer answer in hello)
>>             {
>>                 System.Console.Out.WriteLine(
>>                     "Echo: {0}",
>>                     answer.QueryTerm.GetFunctorArgument(1).GetAtomName()
>>                 );
>>             }
>>         }
>>
>> As you see, the only requirement for the C# method is that it returns
>> bool and receives an array of PrologTerm representing the arguments of
>> the goal. Then, it's only necessary to register the function with the
>> XSBPrologEngine, passing it the name of the Prolog predicate being
>> implemented by the function.
>>
>> engine.RegisterManagedPredicate("hellodotnet", HelloFromDotNet);
>>
>> After that, the method can be called from XSB by use of the managed/1
>> predicate, which receives a goal to execute inside .NET framework:
>>
>> QueryHandle hello =3D engine.Query("managed(hellodotnet(X)).");
>>
>> It is of course admissible to "inline" the predicate with something like=
:
>>
>> hellodotnet(X) :- managed(hellodotnet(X)).
>>
>> for greater declarativity (there are some other solutions to go around
>> this, but I aimed for implementation simplicity first).
>>
>> That's it for now.
>>
>> Best regards,
>>
>> Gon=E7alo
>>
>>
>> On 1/17/07, David Warren <wa...@cs...> wrote:
>>> Markus and Gon=E7alo (et al.),
>>>
>>> I really appreciate your willingness to contribute to the XSB effort.
>>> I have essentially no knowledge of .NET, so we'll have to depend on
>>> you two.  And it's good that there are two of you with knowledge and
>>> interest to determine the best interface.
>>>
>>> One important thing to keep in mind is that XSB, and the environments
>>> in which it runs, are both evolving.  So code that works today may not
>>> work tomorrow.  The best solution is to make the code transparent and
>>> to incorporate tests of it somehow into the XSB testsuite.  Then
>>> changes that affect your code can be caught early and they (or your
>>> code) can be fixed before problems accumulate.  We will have to think
>>> about how to include your subsystem in the XSB system.  We don't like
>>> to distribute broken code, which means we will need to find a way to
>>> ensure that it stays up-to-date.
>>>
>>> Of course, good documentation is also a requirement :-).
>>>
>>> Good luck and keep us posted on your progress,
>>> -David
>>>
>>> -----------------------------------------------------------------------=
--
>>> Take Surveys. Earn Cash. Influence the Future of IT
>>> Join SourceForge.net's Techsay panel and you'll get the chance to share=
 your
>>> opinions on IT & business topics through brief surveys - and earn cash
>>> http://www.techsay.com/default.php?page=3Djoin.php&p=3Dsourceforge&CID=
=3DDEVDEV
>>> _______________________________________________
>>> Xsb-development mailing list
>>> Xsb...@li...
>>> https://lists.sourceforge.net/lists/listinfo/xsb-development
>>>
>>
>
> -------------------------------------------------------------------------
> Take Surveys. Earn Cash. Influence the Future of IT
> Join SourceForge.net's Techsay panel and you'll get the chance to share y=
our
> opinions on IT & business topics through brief surveys - and earn cash
> http://www.techsay.com/default.php?page=3Djoin.php&p=3Dsourceforge&CID=3D=
DEVDEV
> _______________________________________________
> Flora-development mailing list
> Flo...@li...
> https://lists.sourceforge.net/lists/listinfo/flora-development
>