PlEngine Class

SbsSW.SwiPlCs

previous page next page

Swi-cs-pl - A CSharp class library to connect .NET languages with SWI-Prolog PlEngine Class

This static class represents the prolog engine.

Declaration Syntax

Visual Basic

Visual C++

public static class PlEngine

Public NotInheritable Class PlEngine

public ref class PlEngine abstract sealed

[<AbstractClassAttribute>]
[<SealedAttribute>]
type PlEngine =  class end

Members

All Members	Methods	Properties
Public Protected		Instance Static		Declared Inherited

Icon	Member	Description
	Initialize(array<String>[]()[][])	Initialise SWI-Prolog The write method of the output stream is redirected to SbsSW.SwiPlCs.Streams before Initialize. The read method of the input stream just after Initialize.
	IsInitialized	To test if the prolog engine is up.
	PlCleanup()()()()	Try a clean up but it is buggy search the web for "possible regression from pl-5.4.7 to pl-5.6.27" to see reasons
	PlHalt()()()()	Stops the PlEngine and the program
	PlThreadAttachEngine()()()()	return : reference count of the engine If an error occurs, -1 is returned. If this Prolog is not compiled for multi-threading, -2 is returned.
	PlThreadDestroyEngine()()()()	Destroy the Prolog engine in the calling thread. Only takes effect if PL_thread_destroy_engine() is called as many times as PL_thread_attach_engine() in this thread. Please note that construction and destruction of engines are relatively expensive operations. Only destroy an engine if performance is not critical and memory is a critical resource.
	PlThreadSelf()()()()	This method is also provided in the single-threaded version of SWI-Prolog, where it returns -2.
	RegisterForeign(Delegate)	Register a C# callback method
	RegisterForeign(String, Delegate)	Register a C# callback method
	RegisterForeign(String, Int32, Delegate)	Register a C# callback method
	RegisterForeign(String, String, Int32, Delegate)	Register a C# callback method
	SetStreamFunctionRead(PlStreamType, DelegateStreamReadFunction)	TODO
	SetStreamFunctionWrite(PlStreamType, DelegateStreamWriteFunction)	This is a primitive approach to enter the output from a stream.

Examples

A sample

	Copy
if (!PlEngine.IsInitialized) { String[] empty_param = { "" }; PlEngine.Initialize(empty_param); // do some funny things ... PlEngine.PlCleanup(); } // program ends here

The following sample show how a file is consult via comand-line options.

	Copy
public void Demo_consult_pl_file_by_param() { string[] ref_values = { "gloria", "melanie", "ayala" }; Console.WriteLine("Demo_consult_pl_file_by_param"); // Build a prolog source file (skip this step if you already have one :-) string filename = Path.GetTempFileName(); StreamWriter sw = File.CreateText(filename); sw.WriteLine("father(martin, inka)."); sw.WriteLine("father(uwe, gloria)."); sw.WriteLine("father(uwe, melanie)."); sw.WriteLine("father(uwe, ayala)."); sw.Close(); // build the parameterstring to Initialize PlEngine with the generated file String[] param = { "-q", "-f", filename }; try { PlEngine.Initialize(param); Console.WriteLine("all child's from uwe:"); using (PlQuery q = new PlQuery("father(uwe, Child)")) { int idx = 0; foreach (PlQueryVariables v in q.SolutionVariables) { Console.WriteLine(v["Child"].ToString()); Assert.AreEqual(ref_values[idx++], v["Child"].ToString()); } } } catch (PlException e) { Console.WriteLine(e.MessagePl); Console.WriteLine(e.Message); } finally { PlEngine.PlCleanup(); } } // Demo_consult_pl_file_by_param

Copy

public void Demo_consult_pl_file_by_param()
{
    string[] ref_values = { "gloria", "melanie", "ayala" };
    Console.WriteLine("Demo_consult_pl_file_by_param");

    // Build a prolog source file (skip this step if you already have one :-)
    string filename = Path.GetTempFileName();
    StreamWriter sw = File.CreateText(filename);
    sw.WriteLine("father(martin, inka).");
    sw.WriteLine("father(uwe, gloria).");
    sw.WriteLine("father(uwe, melanie).");
    sw.WriteLine("father(uwe, ayala).");
    sw.Close();

    // build the parameterstring to Initialize PlEngine with the generated file
    String[] param = { "-q", "-f", filename };
    try
    {
        PlEngine.Initialize(param);
        Console.WriteLine("all child's from uwe:");
        using (PlQuery q = new PlQuery("father(uwe, Child)"))
        {
            int idx = 0;
            foreach (PlQueryVariables v in q.SolutionVariables)
            {
                Console.WriteLine(v["Child"].ToString());
                Assert.AreEqual(ref_values[idx++], v["Child"].ToString());
            }
        }
    }
    catch (PlException e)
    {
        Console.WriteLine(e.MessagePl);
        Console.WriteLine(e.Message);
    }
    finally
    {
        PlEngine.PlCleanup();
    }
} // Demo_consult_pl_file_by_param

Inheritance Hierarchy

Object
	PlEngine