CODEWITHSUNDEEP
c#prologffiswi-prologaleph-ilp
Ros
Ros

Reputation: 37

Using Aleph in C# with SWI Prolog?

In a C# application, I want to use Aleph for constructing a theory.

The following works in SWI-Prolog:

?- [aleph.pl].

?- working_directory(CDW,'C:/Users/admin/Desktop/inputFiles').

?- read_all(datainput).

?- induce.

But in C# these commands don't:

if (!PlEngine.IsInitialized)
{
    String[] param = { "-q" };    
    PlEngine.Initialize(param);

    PlQuery.PlCall("consult('C:/Users/admin/Desktop/Aleph_pack/Aleph.pl')");

    PlQuery.PlCall("working_directory(CDW,'C:/Users/admin/Desktop/inputFiles'));

    PlQuery.PlCall("assert(read_all(datainput))");   // ERROR!

    PlQuery.PlCall("assert(induce)");
}

I get the following error for PlQuery.PlCall("assert(read_all(datainput))"):

An unhandled exception of type 'SbsSW.SwiPlCs.Exceptions.PlException' occurred in SwiPlCs.dll
Details:
SbsSW.SwiPlCs.Exceptions.PlException was unhandled
 HResult=-2146233088
 Message=assert/1: No permission to modify static procedure `read_all/1'
 Defined at c:/users/admin/desktop/aleph_pack/aleph.pl:8857

How can I fix this error?

Upvotes: 0

Views: 343

Answers (1)

repeat
repeat

Reputation: 18726

The reason why you get the error with C#, but not when using Prolog directly, is this:

You are doing two different things!

Let's interleave the above two snippets:

?-                        read_all(datainput)   .
%% PlQuery.PlCall("assert(read_all(datainput))");

?-                        induce   .
%% PlQuery.PlCall("assert(induce)");

So you are using in the C# code, but not in the interactive SWI-Prolog session.

A part of the multi-line error you got, points in that direction, too:

assert/1: No permission to modify static procedure `read_all/1'

Resume your investigation by pondering on that difference. If you have older versions of your code that exhibited different behaviour, examine them (and the delta to the current code), too!

Upvotes: 1

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