/// <summary>
        /// Fills in fields given head and body terms.
        /// </summary>
        protected KnowledgeBaseRule(Structure ruleHead, Structure[] ruleBody, bool checkSingletons, string source, int line)
        {
            SourceFile       = source;
            SourceLineNumber = line;
            head             = ruleHead;
            if (ruleHead == null)
            {
                throw new ArgumentNullException("ruleHead");
            }
            HeadArgs      = ruleHead.Arguments;
            headIndexers  = PredicateArgumentIndexer.ArglistIndexers(HeadArgs);
            BodyGoals     = ruleBody;
            FreeVariables = new List <LogicVariable>();
            var singletons = new List <LogicVariable>();

            foreach (var a in HeadArgs)
            {
                FindVariables(a, singletons);
            }
            foreach (var g in BodyGoals)
            {
                FindVariables(g, singletons);
            }
            if (checkSingletons && singletons.Count > 0)
            {
                foreach (var v in singletons)
                {
                    PrintWarning("singleton variable: {0}", v.Name);
                }
            }
            Functor = ruleHead.Functor;
        }
Exemplo n.º 2
0
        /// <summary>
        /// Tests clauses in a randomized order (but still exhaustively).
        /// Uses Shuffler to generate a random permutation.
        /// </summary>
        IEnumerable <CutState> TestShuffledClauses(object[] args, PrologContext context, ushort myFrame)
        {
            entriesListUsed = true;
            var mark        = context.MarkTrace();
            var shuffler    = new Shuffler((ushort)Entries.Count);
            var argIndexers = PredicateArgumentIndexer.ArglistIndexers(args);

            while (!shuffler.Done)
            {
                var entry = Entries[shuffler.Next()];
                if (entry.Prematch(argIndexers))
                {
                    // This shouldn't be here...
                    //context.PushGoalStack(Name, args, myFrame);
                    context.SetCurrentRule(entry);
                    foreach (var cutState in entry.Prove(args, context, myFrame))
                    {
                        if (cutState == CutState.ForceFail)
                        {
                            if (KnowledgeBase.Trace || Trace)
                            {
                                context.TraceOutput("Cut: {0}", new Structure(Name, args));
                            }
                            goto fail;
                        }
                        if (KnowledgeBase.Trace || Trace)
                        {
                            context.TraceOutput("Succeed: {0}", new Structure(Name, args));
                        }
                        yield return(CutState.Continue);

                        if (KnowledgeBase.Trace || Trace)
                        {
                            context.TraceOutput("Retry: {0}", new Structure(Name, args));
                        }
                    }
                }
            }
fail:
            context.RestoreVariables(mark);
            if (KnowledgeBase.Trace || Trace)
            {
                context.TraceOutput("Fail: {0}", new Structure(Name, args));
            }
            //context.UnwindStack(Name, args);
            context.UnwindStack(myFrame);
        }
Exemplo n.º 3
0
        /// <summary>
        /// Tests clauses in the order they appear in the database.
        /// </summary>
        IEnumerable <CutState> TestClausesInOrder(object[] args, PrologContext context, ushort myFrame)
        {
            var mark        = context.MarkTrace();
            var argIndexers = PredicateArgumentIndexer.ArglistIndexers(args);

            entriesListUsed = true;
            foreach (var entry in Entries)
            {
                if (entry.Prematch(argIndexers))
                {
                    context.SetCurrentRule(entry);
                    foreach (var cutState in entry.Prove(args, context, myFrame))
                    {
                        if (cutState == CutState.ForceFail)
                        {
                            if (KnowledgeBase.Trace || Trace)
                            {
                                context.TraceOutput("Cut: {0}", new Structure(Name, args));
                            }
                            goto fail;
                        }
                        if (KnowledgeBase.Trace || Trace)
                        {
                            context.TraceOutput("Succeed: {0}", new Structure(Name, args));
                        }
                        yield return(CutState.Continue);

                        if (KnowledgeBase.Trace || Trace)
                        {
                            context.TraceOutput("Retry: {0}", new Structure(Name, args));
                        }
                    }
                }
            }
fail:
            context.RestoreVariables(mark);
            if (KnowledgeBase.Trace || Trace)
            {
                context.TraceOutput("Fail: {0}", new Structure(Name, args));
            }
            //context.UnwindStack(Name, args);
            context.UnwindStack(myFrame);
        }