public static IEnumerable <bool> For(WamMachine machine, WamReferenceTarget[] arguments)
{
Debug.Assert(arguments.Length == 3);
WamReferenceTarget wamReferenceTargetFrom = arguments[1].Dereference();
WamValueInteger wamValueIntegerFrom = wamReferenceTargetFrom as WamValueInteger;
if (wamValueIntegerFrom == null)
{
yield break;
}
WamReferenceTarget wamReferenceTargetTo = arguments[2].Dereference();
WamValueInteger wamValueIntegerTo = wamReferenceTargetTo as WamValueInteger;
if (wamValueIntegerTo == null)
{
yield break;
}
for (int index = wamValueIntegerFrom.Value; index <= wamValueIntegerTo.Value; ++index)
{
WamValueInteger wamValueIntegerResult = WamValueInteger.Create(index);
if (machine.Unify(arguments[0], wamValueIntegerResult))
{
yield return(true);
}
else
{
yield break;
}
}
}
private WamReferenceTarget m_referenceTarget; // 4 bytes
#endregion
#region Constructors
public WamInstruction(WamInstructionOpCodes opCode, WamInstructionRegister sourceRegister, Functor functor, int index, WamInstructionRegister targetRegister)
{
if (sourceRegister.IsUnused)
{
throw new ArgumentException("Invalid value.", "sourceRegister");
}
if (functor == null)
{
throw new ArgumentNullException("functor");
}
if (index < 0)
{
throw new ArgumentException("Invalid index.", "index");
}
if (targetRegister.IsUnused)
{
throw new ArgumentException("Invalid value.", "targetRegister");
}
m_opCode = opCode;
m_sourceRegister = sourceRegister;
m_functor = functor;
m_index = index;
m_targetRegister = targetRegister;
m_referenceTarget = null;
}
public static void Eval(WamMachine machine, WamReferenceTarget[] arguments)
{
Debug.Assert(arguments.Length == 1);
WamReferenceTarget expression = arguments[0].Dereference();
WamCompoundTerm compoundTerm = expression as WamCompoundTerm;
if (compoundTerm == null)
{
return;
}
WamInstructionStreamBuilder builder = new WamInstructionStreamBuilder();
builder.Write(new WamInstruction(WamInstructionOpCodes.Allocate));
for (int idx = 0; idx < compoundTerm.Functor.Arity; ++idx)
{
builder.Write(new WamInstruction(
WamInstructionOpCodes.PutValue,
compoundTerm.Children[idx],
new WamInstructionRegister(WamInstructionRegisterTypes.Argument, (byte)idx)));
}
builder.Write(new WamInstruction(WamInstructionOpCodes.Call, compoundTerm.Functor));
builder.Write(new WamInstruction(WamInstructionOpCodes.Deallocate));
builder.Write(new WamInstruction(WamInstructionOpCodes.Proceed));
machine.SetInstructionStream(builder.ToInstructionStream());
}
public static void Eval(WamMachine machine, WamReferenceTarget[] arguments)
{
Debug.Assert(arguments.Length == 1);
WamReferenceTarget expression = arguments[0].Dereference();
WamCompoundTerm compoundTerm = expression as WamCompoundTerm;
if (compoundTerm == null)
{
return;
}
WamInstructionStreamBuilder builder = new WamInstructionStreamBuilder();
builder.Write(new WamInstruction(WamInstructionOpCodes.Allocate));
for (int idx = 0; idx < compoundTerm.Functor.Arity; ++idx)
{
builder.Write(new WamInstruction(
WamInstructionOpCodes.PutValue,
compoundTerm.Children[idx],
new WamInstructionRegister(WamInstructionRegisterTypes.Argument, (byte)idx)));
}
builder.Write(new WamInstruction(WamInstructionOpCodes.Call, compoundTerm.Functor));
builder.Write(new WamInstruction(WamInstructionOpCodes.Deallocate));
builder.Write(new WamInstruction(WamInstructionOpCodes.Proceed));
machine.SetInstructionStream(builder.ToInstructionStream());
}
ExecutionResults OnLibraryCallPredicate(WamInstruction instruction, Predicate predicate)
{
var arguments = new WamReferenceTarget[instruction.Functor.Arity];
for (var index = 0; index < instruction.Functor.Arity; ++index)
{
arguments[index] = ArgumentRegisters[index];
}
bool result;
try
{
result = predicate.PredicateDelegate(this, arguments);
}
catch
{
// Backtrack on exception.
//
return(ExecutionResults.Backtrack);
}
if (result == false)
{
return(ExecutionResults.Backtrack);
}
InstructionPointer = InstructionPointer.GetNext();
return(ExecutionResults.None);
}
public static bool Callable(WamMachine machine, WamReferenceTarget[] arguments)
{
Debug.Assert(arguments.Length == 1);
var wamReferenceTarget = arguments[0].Dereference();
var wamCompoundTerm = wamReferenceTarget as WamCompoundTerm;
return wamCompoundTerm != null;
}
ExecutionResults OnLibraryCallBacktrackingPredicate(WamInstruction instruction, BacktrackingPredicate predicate)
{
var arguments = new WamReferenceTarget[instruction.Functor.Arity];
for (var index = 0; index < instruction.Functor.Arity; ++index)
{
arguments[index] = ArgumentRegisters[index];
}
IEnumerable <bool> enumerable;
try
{
enumerable = predicate.BacktrackingPredicateDelegate(this, arguments);
}
catch
{
// Backtrack on exception.
//
return(ExecutionResults.Backtrack);
}
var enumerator = enumerable.GetEnumerator();
ChoicePoint = new WamChoicePoint(ChoicePoint, Environment, StackIndex, ReturnInstructionPointer, ArgumentRegisters, CutChoicePoint)
{
BacktrackInstructionPointer = InstructionPointer.GetNext(),
PredicateEnumerator = enumerator
};
InstructionPointer = ChoicePoint.BacktrackInstructionPointer;
PredicateEnumerator = ChoicePoint.PredicateEnumerator;
return(ExecutionResults.None);
}
readonly WamReferenceTarget _referenceTarget; // 4 bytes
public WamInstruction(WamInstructionOpCodes opCode, WamInstructionRegister sourceRegister, Functor functor, int index, WamInstructionRegister targetRegister)
{
if (sourceRegister.IsUnused)
{
throw new ArgumentException("Invalid value.", "sourceRegister");
}
if (functor == null)
{
throw new ArgumentNullException("functor");
}
if (index < 0)
{
throw new ArgumentException("Invalid index.", "index");
}
if (targetRegister.IsUnused)
{
throw new ArgumentException("Invalid value.", "targetRegister");
}
_opCode = opCode;
_sourceRegister = sourceRegister;
_functor = functor;
_index = index;
_targetRegister = targetRegister;
_referenceTarget = null;
}
public static IEnumerable<bool> For(WamMachine machine, WamReferenceTarget[] arguments)
{
Debug.Assert(arguments.Length == 3);
var wamReferenceTargetFrom = arguments[1].Dereference();
var wamValueIntegerFrom = wamReferenceTargetFrom as WamValueInteger;
if (wamValueIntegerFrom == null)
{
yield break;
}
var wamReferenceTargetTo = arguments[2].Dereference();
var wamValueIntegerTo = wamReferenceTargetTo as WamValueInteger;
if (wamValueIntegerTo == null)
{
yield break;
}
for (var index = wamValueIntegerFrom.Value; index <= wamValueIntegerTo.Value; ++index)
{
var wamValueIntegerResult = WamValueInteger.Create(index);
if (machine.Unify(arguments[0], wamValueIntegerResult))
{
yield return true;
}
else
{
yield break;
}
}
}
public static bool Is(WamMachine machine, WamReferenceTarget[] arguments)
{
Debug.Assert(arguments.Length == 2);
var lhs = arguments[0];
var rhs = machine.Evaluate(arguments[1]);
return machine.Unify(lhs, rhs);
}
public static bool Float(WamMachine machine, WamReferenceTarget[] arguments)
{
Debug.Assert(arguments.Length == 1);
WamReferenceTarget wamReferenceTarget = arguments[0].Dereference();
return wamReferenceTarget is WamValueDouble;
}
public static bool Nonvar(WamMachine machine, WamReferenceTarget[] arguments)
{
Debug.Assert(arguments.Length == 1);
WamReferenceTarget wamReferenceTarget = arguments[0].Dereference();
return !(wamReferenceTarget is WamVariable);
}
public static bool Nonvar(WamMachine machine, WamReferenceTarget[] arguments)
{
Debug.Assert(arguments.Length == 1);
WamReferenceTarget wamReferenceTarget = arguments[0].Dereference();
return(!(wamReferenceTarget is WamVariable));
}
public static bool Float(WamMachine machine, WamReferenceTarget[] arguments)
{
Debug.Assert(arguments.Length == 1);
WamReferenceTarget wamReferenceTarget = arguments[0].Dereference();
return(wamReferenceTarget is WamValueDouble);
}
public void Unbind()
{
if (Target == null)
{
throw new InvalidOperationException("Attempt to unbind an unbound variable.");
}
Target = null;
}
public void Unbind()
{
if (Target == null)
{
throw new InvalidOperationException("Attempt to unbind an unbound variable.");
}
Target = null;
}
public static bool ListOrPartialList(WamMachine machine, WamReferenceTarget[] arguments)
{
Debug.Assert(arguments.Length == 1);
WamReferenceTarget wamReferenceTarget = arguments[0].Dereference();
return(IsListOrPartialList(wamReferenceTarget));
}
public static bool GetSeed(WamMachine machine, WamReferenceTarget[] arguments)
{
Debug.Assert(arguments.Length == 1);
var operand = arguments[0];
var seed = WamValueInteger.Create(s_seed);
return machine.Unify(operand, seed);
}
public static bool NextDouble(WamMachine machine, WamReferenceTarget[] arguments)
{
Debug.Assert(arguments.Length == 1);
var operand = arguments[0];
var value = WamValueDouble.Create(s_random.NextDouble());
return machine.Unify(operand, value);
}
public WamInstruction(WamInstructionOpCodes opCode)
{
_opCode = opCode;
_sourceRegister = WamInstructionRegister.Unused;
_functor = null;
_index = -1;
_targetRegister = WamInstructionRegister.Unused;
_referenceTarget = null;
}
public static bool Randomize(WamMachine machine, WamReferenceTarget[] arguments)
{
Debug.Assert(arguments.Length == 0);
s_seed = -1;
s_random = new Random();
return true;
}
public WamInstruction(WamInstructionOpCodes opCode)
{
m_opCode = opCode;
m_sourceRegister = WamInstructionRegister.Unused;
m_functor = null;
m_index = -1;
m_targetRegister = WamInstructionRegister.Unused;
m_referenceTarget = null;
}
public static bool GetSeed(WamMachine machine, WamReferenceTarget[] arguments)
{
Debug.Assert(arguments.Length == 1);
WamReferenceTarget operand = arguments[0];
WamValueInteger seed = WamValueInteger.Create(s_seed);
return(machine.Unify(operand, seed));
}
public static bool NextDouble(WamMachine machine, WamReferenceTarget[] arguments)
{
Debug.Assert(arguments.Length == 1);
WamReferenceTarget operand = arguments[0];
WamValueDouble value = WamValueDouble.Create(s_random.NextDouble());
return(machine.Unify(operand, value));
}
public static bool Is(WamMachine machine, WamReferenceTarget[] arguments)
{
Debug.Assert(arguments.Length == 2);
WamReferenceTarget lhs = arguments[0];
WamReferenceTarget rhs = machine.Evaluate(arguments[1]);
return(machine.Unify(lhs, rhs));
}
public static WamCompoundTerm Create(CodeCompoundTerm codeCompoundTerm)
{
var functor = Functor.Create(codeCompoundTerm.Functor);
var result = WamCompoundTerm.Create(functor);
for (var index = 0; index < functor.Arity; ++index)
{
result.Children[index] = WamReferenceTarget.Create(codeCompoundTerm.Children[index]);
}
return(result);
}
public static bool Compound(WamMachine machine, WamReferenceTarget[] arguments)
{
Debug.Assert(arguments.Length == 1);
var wamReferenceTarget = arguments[0].Dereference();
var wamCompoundTerm = wamReferenceTarget as WamCompoundTerm;
if (wamCompoundTerm != null)
{
return wamCompoundTerm.Functor.Arity > 0;
}
return false;
}
public static bool Atomic(WamMachine machine, WamReferenceTarget[] arguments)
{
Debug.Assert(arguments.Length == 1);
var wamReferenceTarget = arguments[0].Dereference();
var wamCompoundTerm = wamReferenceTarget as WamCompoundTerm;
if (wamCompoundTerm != null)
{
return wamCompoundTerm.Functor.Arity == 0;
}
return wamReferenceTarget is WamValueInteger || wamReferenceTarget is WamValueDouble;
}
public void Bind(WamReferenceTarget target)
{
if (target == null)
{
throw new ArgumentNullException("target");
}
if (Target != null)
{
throw new InvalidOperationException("Attempt to bind to bound variable.");
}
Target = target;
}
public void Bind(WamReferenceTarget target)
{
if (target == null)
{
throw new ArgumentNullException("target");
}
if (Target != null)
{
throw new InvalidOperationException("Attempt to bind to bound variable.");
}
Target = target;
}
public WamInstruction(WamInstructionOpCodes opCode, WamInstructionRegister targetRegister)
{
if (targetRegister.IsUnused)
{
throw new ArgumentException("Invalid value.", "targetRegister");
}
_opCode = opCode;
_sourceRegister = WamInstructionRegister.Unused;
_functor = null;
_index = -1;
_targetRegister = targetRegister;
_referenceTarget = null;
}
public WamInstruction(WamInstructionOpCodes opCode, WamReferenceTarget referenceTarget)
{
if (referenceTarget == null)
{
throw new ArgumentNullException("referenceTarget");
}
_opCode = opCode;
_sourceRegister = WamInstructionRegister.Unused;
_functor = null;
_index = -1;
_targetRegister = WamInstructionRegister.Unused;
_referenceTarget = referenceTarget;
}
public WamInstruction(WamInstructionOpCodes opCode, Functor functor)
{
if (functor == null)
{
throw new ArgumentNullException("functor");
}
_opCode = opCode;
_sourceRegister = WamInstructionRegister.Unused;
_functor = functor;
_index = -1;
_targetRegister = WamInstructionRegister.Unused;
_referenceTarget = null;
}
void SetRegister(WamInstructionRegister register, WamReferenceTarget value)
{
switch (register.Type)
{
case WamInstructionRegisterTypes.Argument: ArgumentRegisters[register.Id] = value; break;
case WamInstructionRegisterTypes.Permanent: Environment.PermanentRegisters[register.Id] = value; break;
case WamInstructionRegisterTypes.Temporary: TemporaryRegisters[register.Id] = value; break;
default:
throw new InvalidOperationException(string.Format("Unknown register type {0}.", register.Type));
}
}
static bool IsPartialList(WamReferenceTarget wamReferenceTarget)
{
var wamCompoundTerm = wamReferenceTarget as WamCompoundTerm;
if (wamCompoundTerm != null)
{
if (wamCompoundTerm.Functor == Functor.ListFunctor)
{
var tail = wamCompoundTerm.Children[1].Dereference();
return(tail is WamVariable || IsPartialList(tail));
}
}
return(false);
}
public static bool Compound(WamMachine machine, WamReferenceTarget[] arguments)
{
Debug.Assert(arguments.Length == 1);
WamReferenceTarget wamReferenceTarget = arguments[0].Dereference();
WamCompoundTerm wamCompoundTerm = wamReferenceTarget as WamCompoundTerm;
if (wamCompoundTerm != null)
{
return(wamCompoundTerm.Functor.Arity > 0);
}
return(false);
}
public static bool SetSeed(WamMachine machine, WamReferenceTarget[] arguments)
{
Debug.Assert(arguments.Length == 1);
WamValueInteger operand = arguments[0].Dereference() as WamValueInteger;
if (operand == null)
{
return false;
}
s_seed = operand.Value;
s_random = new Random(s_seed);
return true;
}
private PrologVariableList GetPermanentVariables(int stackIndex, bool getCodeTerm)
{
PrologVariableList result = new PrologVariableList();
WamEnvironment environment = WamMachine.GetEnvironment(stackIndex);
if (environment != null)
{
// Retrieve register name assignments from instruction stream.
//
Dictionary <int, string> variableNames;
WamInstructionStream wamInstructionStream = WamMachine.GetInstructionPointer(stackIndex).InstructionStream;
if (wamInstructionStream != null)
{
variableNames = wamInstructionStream.GetPermanentVariableAssignments();
}
else
{
variableNames = new Dictionary <int, string>();
}
for (int index = 0; index < environment.PermanentRegisters.Count; ++index)
{
PrologVariable variable = result.Add(string.Format("Y{0}", index));
string name;
if (variableNames.TryGetValue(index, out name))
{
variable.Name = name;
}
WamReferenceTarget referenceTarget = environment.PermanentRegisters[index];
if (referenceTarget != null)
{
if (getCodeTerm)
{
variable.CodeTerm = referenceTarget.GetCodeTerm();
}
else
{
variable.Text = referenceTarget.ToString();
}
}
}
}
return(result);
}
public static bool Atomic(WamMachine machine, WamReferenceTarget[] arguments)
{
Debug.Assert(arguments.Length == 1);
WamReferenceTarget wamReferenceTarget = arguments[0].Dereference();
WamCompoundTerm wamCompoundTerm = wamReferenceTarget as WamCompoundTerm;
if (wamCompoundTerm != null)
{
return(wamCompoundTerm.Functor.Arity == 0);
}
return(wamReferenceTarget is WamValueInteger ||
wamReferenceTarget is WamValueDouble);
}
public WamInstruction(WamInstructionOpCodes opCode, WamInstructionRegister sourceRegister, WamReferenceTarget referenceTarget)
{
if (referenceTarget == null)
{
throw new ArgumentNullException("referenceTarget");
}
if (sourceRegister.IsUnused)
{
throw new ArgumentException("Invalid value.", "sourceRegister");
}
_opCode = opCode;
_sourceRegister = sourceRegister;
_functor = null;
_index = -1;
_targetRegister = WamInstructionRegister.Unused;
_referenceTarget = referenceTarget;
}
public static bool Assert(WamMachine machine, WamReferenceTarget[] arguments)
{
Debug.Assert(arguments.Length == 1);
var expression = machine.Evaluate(arguments[0]);
var codeTerm = expression.GetCodeTerm();
if (codeTerm != null)
{
var codeValue = codeTerm as CodeValue;
if (codeValue != null)
{
return Convert.ToBoolean(codeValue.Object);
}
}
return false;
}
static bool IsList(WamReferenceTarget wamReferenceTarget)
{
var wamCompoundTerm = wamReferenceTarget as WamCompoundTerm;
if (wamCompoundTerm != null)
{
if (wamCompoundTerm.Functor == Functor.NilFunctor)
{
return(true);
}
if (wamCompoundTerm.Functor == Functor.ListFunctor)
{
var tail = wamCompoundTerm.Children[1].Dereference();
return(IsList(tail));
}
}
return(false);
}
private PrologVariableList GetArgumentVariables()
{
PrologVariableList result = new PrologVariableList();
for (int index = 0; index < WamMachine.ArgumentRegisters.Count; ++index)
{
string value = "*";
WamReferenceTarget referenceTarget = WamMachine.ArgumentRegisters[index];
if (referenceTarget != null)
{
value = referenceTarget.ToString();
}
result.Add(string.Format("A{0}", index)).Text = value;
}
return(result);
}
public WamInstruction(WamInstructionOpCodes opCode, WamInstructionRegister sourceRegister, WamReferenceTarget referenceTarget)
{
if (referenceTarget == null)
{
throw new ArgumentNullException("referenceTarget");
}
if (sourceRegister.IsUnused)
{
throw new ArgumentException("Invalid value.", "sourceRegister");
}
m_opCode = opCode;
m_sourceRegister = sourceRegister;
m_functor = null;
m_index = -1;
m_targetRegister = WamInstructionRegister.Unused;
m_referenceTarget = referenceTarget;
}
public WamInstruction(WamInstructionOpCodes opCode, Functor functor, WamInstructionRegister targetRegister)
{
if (functor == null)
{
throw new ArgumentNullException("functor");
}
if (targetRegister.IsUnused)
{
throw new ArgumentException("Invalid value.", "targetRegister");
}
m_opCode = opCode;
m_sourceRegister = WamInstructionRegister.Unused;
m_functor = functor;
m_index = -1;
m_targetRegister = targetRegister;
m_referenceTarget = null;
}
public WamInstruction(WamInstructionOpCodes opCode, Functor functor, int index)
{
if (functor == null)
{
throw new ArgumentNullException("functor");
}
if (index < 0)
{
throw new ArgumentException("Invalid index.", "index");
}
m_opCode = opCode;
m_sourceRegister = WamInstructionRegister.Unused;
m_functor = functor;
m_index = index;
m_targetRegister = WamInstructionRegister.Unused;
m_referenceTarget = null;
}
public static bool Assert(WamMachine machine, WamReferenceTarget[] arguments)
{
Debug.Assert(arguments.Length == 1);
WamReferenceTarget expression = machine.Evaluate(arguments[0]);
CodeTerm codeTerm = expression.GetCodeTerm();
if (codeTerm != null)
{
CodeValue codeValue = codeTerm as CodeValue;
if (codeValue != null)
{
return(Convert.ToBoolean(codeValue.Object));
}
}
return(false);
}
public static bool Next(WamMachine machine, WamReferenceTarget[] arguments)
{
Debug.Assert(arguments.Length == 3);
var minValue = arguments[0].Dereference() as WamValueInteger;
if (minValue == null)
{
return false;
}
var maxValue = arguments[1].Dereference() as WamValueInteger;
if (maxValue == null)
{
return false;
}
var operand = arguments[2];
var value = WamValueInteger.Create(s_random.Next(minValue.Value, maxValue.Value));
return machine.Unify(operand, value);
}
private static bool IsListOrPartialList(WamReferenceTarget wamReferenceTarget)
{
WamCompoundTerm wamCompoundTerm = wamReferenceTarget as WamCompoundTerm;
if (wamCompoundTerm != null)
{
if (wamCompoundTerm.Functor == Functor.NilFunctor)
{
return(true);
}
if (wamCompoundTerm.Functor == Functor.ListFunctor)
{
WamReferenceTarget tail = wamCompoundTerm.Children[1].Dereference();
return(tail is WamVariable ||
IsListOrPartialList(tail));
}
}
return(false);
}
public static bool CannotUnify(WamMachine machine, WamReferenceTarget[] arguments)
{
Debug.Assert(arguments.Length == 2);
return machine.CannotUnify(arguments[0], arguments[1]);
}
private void Bind(WamVariable variable, WamReferenceTarget target)
{
variable.Bind(target);
Trail(variable);
}
public static bool Fail(WamMachine machine, WamReferenceTarget[] arguments)
{
Debug.Assert(arguments.Length == 0);
return false;
}
internal WamReferenceTarget Evaluate(WamReferenceTarget wamReferenceTarget)
{
if (wamReferenceTarget == null)
{
throw new ArgumentNullException("wamReferenceTarget");
}
WamCompoundTerm wamCompoundTerm = wamReferenceTarget.Dereference() as WamCompoundTerm;
if (wamCompoundTerm == null)
{
return wamReferenceTarget;
}
if (!Program.Libraries.Contains(wamCompoundTerm.Functor))
{
return wamReferenceTarget;
}
LibraryMethod method = Program.Libraries[wamCompoundTerm.Functor];
if (method == null
|| method.CanEvaluate == false)
{
return wamReferenceTarget;
}
WamReferenceTarget[] arguments = new WamReferenceTarget[method.Functor.Arity];
for (int index = 0; index < method.Functor.Arity; ++index)
{
arguments[index] = Evaluate(wamCompoundTerm.Children[index]);
}
Function function = method as Function;
if (function != null)
{
CodeTerm[] codeTerms = new CodeTerm[method.Functor.Arity];
for (int index = 0; index < method.Functor.Arity; ++index)
{
codeTerms[index] = arguments[index].GetCodeTerm();
}
CodeTerm result;
try
{
result = function.FunctionDelegate(codeTerms);
if (result == null)
{
result = new CodeValueObject(null);
}
}
catch (Exception ex)
{
result = new CodeValueException(ex);
}
return WamValue.Create(result);
}
Predicate predicate = method as Predicate;
if (predicate != null)
{
bool result;
try
{
result = predicate.PredicateDelegate(this, arguments);
}
catch
{
result = false;
}
return WamValueBoolean.Create(result);
}
return wamReferenceTarget;
}
internal bool Unify(WamReferenceTarget lhs, WamReferenceTarget rhs)
{
return Unify(lhs, rhs, false);
}
private void SetRegister(WamInstructionRegister register, WamReferenceTarget value)
{
switch (register.Type)
{
case WamInstructionRegisterTypes.Argument: ArgumentRegisters[register.Id] = value; break;
case WamInstructionRegisterTypes.Permanent: Environment.PermanentRegisters[register.Id] = value; break;
case WamInstructionRegisterTypes.Temporary: TemporaryRegisters[register.Id] = value; break;
default:
throw new InvalidOperationException(string.Format("Unknown register type {0}.", register.Type));
}
}
public WamInstruction(WamInstructionOpCodes opCode, WamInstructionRegister sourceRegister, WamInstructionRegister targetRegister)
{
if (sourceRegister.IsUnused)
{
throw new ArgumentException("Invalid value.", "sourceRegister");
}
if (targetRegister.IsUnused)
{
throw new ArgumentException("Invalid value.", "targetRegister");
}
m_opCode = opCode;
m_sourceRegister = sourceRegister;
m_functor = null;
m_index = -1;
m_targetRegister = targetRegister;
m_referenceTarget = null;
}
public WamInstruction(WamInstructionOpCodes opCode, Functor functor)
{
if (functor == null)
{
throw new ArgumentNullException("functor");
}
m_opCode = opCode;
m_sourceRegister = WamInstructionRegister.Unused;
m_functor = functor;
m_index = -1;
m_targetRegister = WamInstructionRegister.Unused;
m_referenceTarget = null;
}
internal bool CannotUnify(WamReferenceTarget lhs, WamReferenceTarget rhs)
{
return !Unify(lhs, rhs, true);
}
private bool Unify(WamReferenceTarget lhs, WamReferenceTarget rhs, bool testOnly)
{
if (lhs == null)
{
throw new ArgumentNullException("lhs");
}
if (rhs == null)
{
throw new ArgumentNullException("rhs");
}
lhs = lhs.Dereference();
rhs = rhs.Dereference();
WamVariable lhsVariable = lhs as WamVariable;
WamVariable rhsVariable = rhs as WamVariable;
WamCompoundTerm lhsCompoundTerm = lhs as WamCompoundTerm;
WamCompoundTerm rhsCompoundTerm = rhs as WamCompoundTerm;
WamValue lhsValue = lhs as WamValue;
WamValue rhsValue = rhs as WamValue;
// Ensure that each term is either a compound term or variable.
//
Debug.Assert(lhsVariable != null || lhsCompoundTerm != null || lhsValue != null);
Debug.Assert(rhsVariable != null || rhsCompoundTerm != null || rhsValue != null);
// Ensure if that we've dereferenced to a variable that it is unbound.
//
Debug.Assert(lhsVariable == null || lhsVariable.Target == null);
Debug.Assert(rhsVariable == null || rhsVariable.Target == null);
if (lhsVariable != null)
{
if (rhsVariable != null)
{
if (lhsVariable.Generation < rhsVariable.Generation)
{
if (!testOnly) Bind(rhsVariable, lhs);
}
else
{
if (!testOnly) Bind(lhsVariable, rhs);
}
}
else
{
if (!testOnly) Bind(lhsVariable, rhs);
}
}
else
{
if (rhsVariable != null)
{
if (!testOnly) Bind(rhsVariable, lhs);
}
else
{
if (lhsCompoundTerm != null && rhsCompoundTerm != null)
{
if (lhsCompoundTerm.Functor != rhsCompoundTerm.Functor)
{
return false;
}
for (int index = 0; index < lhsCompoundTerm.Functor.Arity; ++index)
{
if (!Unify(lhsCompoundTerm.Children[index], rhsCompoundTerm.Children[index], testOnly))
{
return false;
}
}
}
else if (lhsValue != null && rhsValue != null)
{
if (!lhsValue.Object.Equals(rhsValue.Object))
{
return false;
}
}
else
{
return false;
}
}
}
return true;
}
public WamInstruction(WamInstructionOpCodes opCode, WamReferenceTarget referenceTarget)
{
if (referenceTarget == null)
{
throw new ArgumentNullException("referenceTarget");
}
m_opCode = opCode;
m_sourceRegister = WamInstructionRegister.Unused;
m_functor = null;
m_index = -1;
m_targetRegister = WamInstructionRegister.Unused;
m_referenceTarget = referenceTarget;
}