/// <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;
}
/// <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);
}
/// <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);
}