/// <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);
}
private static IEnumerable<CutState> RandomMemberImplementation(object[] args, PrologContext context)
{
if (args.Length != 2) throw new ArgumentCountException("random_member", args, "element", "list");
object objectArg = Term.Deref(args[0]);
object listArg = Term.Deref(args[1]);
if (listArg == null)
yield break;
var arg = listArg as LogicVariable;
if (arg != null)
throw new InstantiationException(arg, "List argument to random_member/2 must be instantiated to a proper list.");
var length = Prolog.PrologListLength(listArg);
var shuffler = new Shuffler((ushort)length);
while (!shuffler.Done)
#pragma warning disable 414, 168, 219
// ReSharper disable once UnusedVariable
foreach (var ignore in Term.Unify(objectArg, Prolog.PrologListElement(listArg, shuffler.Next())))
#pragma warning restore 414, 168, 219
yield return CutState.Continue;
}
/// <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);
}