PlQuery Constructor (goal)

SbsSW.SwiPlCs

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Swi-cs-pl - A CSharp class library to connect .NET languages with SWI-Prolog PlQuery Constructor (goal)
SwiPlCs interface ► SbsSW.SwiPlCs ► PlQuery ► PlQuery(String)

With this constructor a query is created from a string.

Uppercase parameters are interpreted a variables but can't be nested in sub terms. If you need a variable in a nested term use PlQuery(String, PlTermV). See the examples for details.

Declaration Syntax
C# Visual Basic Visual C++ F# 
public PlQuery(
	string goal
)
Public Sub New ( 
	goal As String
)
public:
PlQuery(
	String^ goal
)
new : 
        goal : string -> PlQuery
Parameters
goal (String)
A string for a prolog query
Remarks
Muddy Waters sang:"I'am build for comfort, I ain't build for speed"
Examples
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public void QueryStringForeach()
{
    string[] mm = { "aa", "bb", "cc" };
    var q = new PlQuery("member(A, [aa, bb, cc])");
    int i = 0;
    foreach (PlTermV s in q.Solutions)
    {
        Assert.AreEqual(mm[i++], s[0].ToString());
    }
    // or with named variables
    i = 0;
    foreach (PlQueryVariables s in q.SolutionVariables)
    {
        Assert.AreEqual(mm[i++], s["A"].ToString());
    }
}

This sample shows a query with two variables.

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public void QueryString2()
{
    var q = new PlQuery("append(A, B, [a,b,c])");
    Assert.IsTrue(q.NextSolution());
    Assert.AreEqual("[]", q.Args[0].ToString());
    Assert.AreEqual("[a,b,c]", q.Args[1].ToString());
    Assert.IsTrue(q.NextSolution());
    Assert.AreEqual("[a]", q.Args[0].ToString());
    Assert.AreEqual("[b,c]", q.Args[1].ToString());
}

And the same with named variables.

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public void QueryStringNamed()
{
    var q = new PlQuery("append(A, B, [a,b,c])");
    Assert.IsTrue(q.NextSolution());
    Assert.AreEqual("[]", q.Variables["A"].ToString());
    Assert.AreEqual("[a,b,c]", q.Variables["B"].ToString());
    Assert.IsTrue(q.NextSolution());
    Assert.AreEqual("[a]", q.Variables["A"].ToString());
    Assert.AreEqual("[b,c]", q.Variables["B"].ToString());
}

This sample shows what happens if the argument vector is used with compound terms.

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public void PlCallQueryCompound_string()
{
    string[] mm = { "comp(aa,aa1)", "comp(aa,aa2)", "comp(aa,aa3)" };
    build_pred();   // create: test(comp(X,Y)) :- member(Z,[1,2,3]), atomic_list_concat([X,Z],Y).
    var q = new PlQuery("test(comp(aa,X))");
    int i = 0;
    foreach (PlTermV s in q.Solutions)
    {
        Assert.AreEqual(mm[i++], s[0].ToString());
    }
}

And here how to get the results with named variables with compound terms.

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public void PlCallQueryCompoundNamed_string()
{
    string[] mm = { "aa1", "aa2", "aa3" };
    build_pred();   // create: test(comp(X,Y)) :- member(Z,[1,2,3]), atomic_list_concat([X,Z],Y).
    var q = new PlQuery("test(comp(aa,X))");
    int i = 0;
    foreach (PlQueryVariables v in q.SolutionVariables)
    {
        Assert.AreEqual(mm[i++], v["X"].ToString());
    }
}

Assembly: SwiPlCs (Module: SwiPlCs.dll) Version: 1.1.60605.0 (1.1.60605.0)

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