public static object CreateInstance(this Type type, List<object> constructorArguments)
{
if (type == null) throw new ArgumentNullException("type");
if (constructorArguments == null) throw new ArgumentNullException("constructorArguments");
return type.CreateInstance(constructorArguments.ToArray());
}
/// <summary>
/// Creates a blank DB entry for the specified functor
/// </summary>
public PredicateInfo(Symbol functorName, int arity, KnowledgeBase kb)
{
Name = functorName;
Arity = arity;
Entries = new List<KnowledgeBaseEntry>();
KnowledgeBase = kb;
}
public ArrayVariable(string name, TermArray ta, ListTerm subscripts)
{
this.ta = ta;
this.name = ta.Name;
this.subscripts = subscripts.ArgumentsToArrayList ();
if (this.subscripts.Count != ta.Rank)
IO.Error ("Wrong number of subscripts for '{0}': expected {1}, got {2}",
name, ta.Rank, this.subscripts.Count);
}
/// <summary>
/// Creates a PrologContext that can for at most the specified number of steps.
/// </summary>
public PrologContext(KnowledgeBase kb, int stepLimit)
{
StepsRemaining = stepLimit;
goalStack = new List<GoalStackFrame>();
goalStackCurrentRules = new List<KnowledgeBaseEntry>();
GoalStackDepth = 0;
KnowledgeBase = kb;
traceVariables = new LogicVariable[256];
traceValues = new object[256];
tracePointer = 0;
IndexicalBindingStack = new List<KeyValuePair<Symbol, object>>();
}
private static AST.Program ConvertToAst(Runtime.ISolutionTreeNode unnamed_top_node)
{
var clause_nodes = ParsePossiblyEmptyList (unnamed_top_node ["run"] ["program"], "clause_list", "clause");
var dcgClauses = new List <AST.DcgClause> ();
var prologClauses = new List <AST.Clause> ();
foreach (var clause_node in clause_nodes)
{
var dgc_clause_node = clause_node ["dcg_clause"];
if (dgc_clause_node != null)
{
var head = GoalToAst (dgc_clause_node ["dcg_head"] ["goal"]);
var dcgClause = new AST.DcgClause
{
Head = new AST.Goal {
PredicateName = head.PredicateName,
Arguments = head.Arguments
},
Body = ParsePossiblyEmptyList (dgc_clause_node ["dcg_body"], "dcg_goal_list", "dcg_goal").Select (DcgGoalToAst).ToArray ()
};
dcgClauses.Add (dcgClause);
}
else
{
var prolog_clause_node = clause_node ["prolog_clause"];
if (prolog_clause_node != null)
{
var prologClause = new AST.Clause
{
Head = GoalToAst (prolog_clause_node ["head"] ["goal"]),
Body = ParsePossiblyEmptyList (prolog_clause_node ["body"], "goal_list", "goal").Select (GoalToAst).ToArray ()
};
prologClauses.Add (prologClause);
}
else
{
throw new Exception ("A 'clause' is expected to be either a 'dcg_clause' or a 'prolog_clause'.");
}
}
}
return new AST.Program {
Clauses = prologClauses.ToArray (),
DcgClauses = dcgClauses.ToArray ()
};
}
public WamChoicePoint(WamChoicePoint predecessor, WamEnvironment environment, int stackIndex, WamInstructionPointer returnInstructionPointer, IEnumerable<WamReferenceTarget> argumentRegisters, WamChoicePoint cutChoicePoint)
{
m_generation = s_nextGeneration++;
m_predecessor = predecessor;
m_environment = environment;
m_stackIndex = stackIndex;
m_returnInstructionPointer = returnInstructionPointer;
m_argumentRegisters = new WamReferenceTargetList(argumentRegisters);
m_cutChoicePoint = cutChoicePoint;
m_backtrackInstructionPointer = WamInstructionPointer.Undefined;
m_predicateEnumerator = null;
m_trail = new List<WamVariable>();
}
public WamChoicePoint(WamChoicePoint predecessor, WamEnvironment environment, int stackIndex, WamInstructionPointer returnInstructionPointer, IEnumerable<WamReferenceTarget> argumentRegisters, WamChoicePoint cutChoicePoint)
{
Generation = NextGeneration++;
Predecessor = predecessor;
Environment = environment;
StackIndex = stackIndex;
ReturnInstructionPointer = returnInstructionPointer;
ArgumentRegisters = new WamReferenceTargetList(argumentRegisters);
CutChoicePoint = cutChoicePoint;
BacktrackInstructionPointer = WamInstructionPointer.Undefined;
PredicateEnumerator = null;
Trail = new List<WamVariable>();
}
/// <summary>
/// Creates a KnowledgedBaseRule given a Term object for a :- expression.
/// </summary>
public static KnowledgeBaseRule FromTerm(Structure structure, bool checkSingletons, string source, int line)
{
if (structure == null) throw new ArgumentNullException("structure");
if (structure.IsFunctor(Symbol.Implication, 2))
{
var body = new List<Structure>();
UnwindCommaExpression(structure.Argument(1), body);
if (structure.Argument(0) == null)
throw new ArgumentException("head of rule is null");
Structure head = Term.Structurify(structure.Argument(0), "Head of :- must be a valid proposition or predicate.");
if (head == null)
throw new ArgumentException("Head of rule is not a term.");
return MakeRule(head, body, checkSingletons, source, line);
}
return MakeRule(structure, null, checkSingletons, source, line);
}
internal static void UnwindCommaExpression(object subgoal, List<Structure> body)
{
if (subgoal == null) throw new ArgumentNullException("subgoal", "Subgoal of rule is null");
Structure structure;
if (subgoal is LogicVariable)
structure = new Structure(Symbol.Call, subgoal);
else
structure = Term.Structurify(subgoal, "Not a valid subgoal.");
if (structure.IsFunctor(Symbol.Comma, 2))
{
UnwindCommaExpression(structure.Argument(0), body);
UnwindCommaExpression(structure.Argument(1), body);
}
else
body.Add(structure);
}
/// <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;
}
static KnowledgeBaseRule MakeRule(Structure head, List<Structure> body, bool checkSingletons, string source, int line)
{
if (body == null)
return new KnowledgeBaseRule0(head, new Structure[0], checkSingletons, source, line);
switch (body.Count)
{
case 0:
return new KnowledgeBaseRule0(head, body.ToArray(), checkSingletons, source, line);
case 1:
return new KnowledgeBaseRule1(head, body.ToArray(), checkSingletons, source, line);
case 2:
return new KnowledgeBaseRule2(head, body.ToArray(), checkSingletons, source, line);
case 3:
return new KnowledgeBaseRule3(head, body.ToArray(), checkSingletons, source, line);
case 4:
return new KnowledgeBaseRule4(head, body.ToArray(), checkSingletons, source, line);
case 5:
return new KnowledgeBaseRule5(head, body.ToArray(), checkSingletons, source, line);
case 6:
return new KnowledgeBaseRule6(head, body.ToArray(), checkSingletons, source, line);
case 7:
return new KnowledgeBaseRule7(head, body.ToArray(), checkSingletons, source, line);
case 8:
return new KnowledgeBaseRule8(head, body.ToArray(), checkSingletons, source, line);
default:
throw new ArgumentException(string.Format("Rules with {0} clauses are not supported.", body.Count));
}
}
private List<string> MakeRow(object row)
{
//Debug.Log("Making row "+ISOPrologWriter.WriteToString(row));
var rowData = new List<string>();
int column = 0;
foreach (var columnData in Prolog.PrologListItems(row))
{
//Debug.Log("Making column " + ISOPrologWriter.WriteToString(columnData));
var data = MakeColumn(columnData);
rowData.Add(data);
ReserveColumnWidth(column, data);
column++;
}
return rowData;
}
private static IEnumerable<CutState> DeclareHigherOrderImplementation(object[] args, PrologContext context)
{
if (args.Length != 1)
throw new ArgumentCountException("higher_order", args, "*predicate");
var predicate = Term.Deref(args[0]) as Structure;
if (predicate == null)
throw new ArgumentTypeException("higher_order", "predicate", args[0], typeof(Structure));
var higherOrderArguments = new List<int>();
for (int argumentIndex=0; argumentIndex<predicate.Arity; argumentIndex++)
{
int indicator = Convert.ToInt32(predicate.Argument(argumentIndex));
if (indicator > 0)
higherOrderArguments.Add(argumentIndex);
}
context.KnowledgeBase.DeclareHigherOrderArguments(predicate.PredicateIndicator, higherOrderArguments.ToArray());
yield return CutState.Continue;
}
private static List<object> SolutionList(PrologContext context, object template, object goal, int maxSolutions, bool deleteDuplicates)
{
var bag = new List<object>();
#pragma warning disable 414, 168, 219
// ReSharper disable UnusedVariable
foreach (var ignore in context.Prove(goal, "goal argument to findall must be a valid Prolog goal."))
// ReSharper restore UnusedVariable
#pragma warning restore 414, 168, 219
{
object instance = Term.CopyInstantiation(template);
bag.Add(instance);
if (--maxSolutions <= 0)
break;
}
if (deleteDuplicates)
Term.Sort(bag, true);
return bag;
}
/// <summary>
/// All we have to do here is check whether this is one of the variables we're looking for.
/// </summary>
public override object AlphaConvert(List<LogicVariable> oldVars, LogicVariable[] newVars, PrologContext context, bool evalIndexicals)
{
var index = oldVars.IndexOf(this);
if (index < 0)
return this;
return newVars[index] ?? (newVars[index] = new LogicVariable(this.Name));
}
public static object CreateInstanceWithInitializerKeywords(this Type type, List<object> constructorArguments)
{
if (type == null) throw new ArgumentNullException("type");
if (constructorArguments == null) throw new ArgumentNullException("constructorArguments");
var constructorArgs = new List<object>();
// Everything up to the first keyword is a constructor arg
int i;
for (i = 0; i < constructorArguments.Count; i++)
{
var s = constructorArguments[i] as Symbol;
if (s != null && s.IsKeyword)
break;
constructorArgs.Add(constructorArguments[i]);
}
if (((constructorArguments.Count - i) & 1) != 0)
throw new ArgumentException("Odd number of initializer arguments provided");
object o = type.CreateInstance(constructorArgs);
for (; i + 1 < constructorArguments.Count; i += 2)
{
var name = constructorArguments[i] as Symbol;
if (name == null)
throw new ArgumentException("Improper initializer name: " + constructorArguments[i]);
o.SetPropertyOrField(name.KeywordName, constructorArguments[i + 1]);
}
return o;
}
public static object CreateGenericInstance(this Type genericType, Type[] genericTypeParameters, List<object> constructorArguments)
{
if (genericType == null) throw new ArgumentNullException("genericType");
if (genericTypeParameters == null) throw new ArgumentNullException("genericTypeParameters");
if (constructorArguments == null) throw new ArgumentNullException("constructorArguments");
return genericType.CreateGenericInstance(genericTypeParameters, constructorArguments.ToArray());
}
/// <summary>
/// Substitutes occurances of newVars for all occurances of oldVars in argList.
/// Returns new array, if substitutions were made, the original array if not.
/// Original array is not modified
/// </summary>
internal static object[] AlphaConvertArglist(object[] argList, List<LogicVariable> oldVars, LogicVariable[] newVars, PrologContext context, bool evalIndexicals)
{
object[] newArgs = null;
for (int i = 0; i < argList.Length; i++)
{
var term = argList[i] as AlphaConvertibleTerm;
if (term != null)
{
object converted = term.AlphaConvert(oldVars, newVars, context, evalIndexicals);
if (converted != argList[i])
{
if (newArgs == null)
{
newArgs = new object[argList.Length];
argList.CopyTo(newArgs, 0);
}
newArgs[i] = converted;
}
}
}
// Return newArgs unless it turns out it was never actually allocated
// (in which case none of the args had renamed vars)
return newArgs ?? argList;
}
static void AddBinding(LogicVariable lv, object value, ref List<LogicVariable> vars, ref List<object> values)
{
if (vars == null)
{
vars = new List<LogicVariable> { lv };
values = new List<object> { value };
}
else
{
vars.Add(lv);
values.Add(value);
}
}
public List<object> ReadTerms()
{
List<object> terms = new List<object>();
object term;
while ((term = ReadTerm()) != Symbol.EndOfFile)
terms.Add(term);
return terms;
}
/// <summary>
/// Recopy the term to replace variables. If term contains no variables, no recopying is done.
/// </summary>
/// <param name="oldVars">Variables to be replaced</param>
/// <param name="newVars">The corresponding variables that are replacing the oldVars</param>
/// <param name="context">PrologContext to evaluating indexicals</param>
/// <param name="evalIndexicals">If true, any indexicals will be replaced with their values.</param>
/// <returns>Converted term or original term if not conversion necessary</returns>
public abstract object AlphaConvert(
List<LogicVariable> oldVars,
LogicVariable[] newVars,
PrologContext context,
bool evalIndexicals);
List<KnowledgeBaseEntry> GetEntriesListForUpdate()
{
List<KnowledgeBaseEntry> entries = Entries;
if (entriesListUsed)
{
entriesListUsed = false;
return Entries = new List<KnowledgeBaseEntry>(entries);
}
return this.Entries;
}
/// <summary>
/// Replace self with value if evalIndexicals is true, otherwise return self unchanged.
/// </summary>
public override object AlphaConvert(List<LogicVariable> oldVars, LogicVariable[] newVars, PrologContext context, bool evalIndexicals)
{
// Temporarily ignoring evalIndexicals to try out programming here rule bodies expand indexicals, not just rule heads.
//return evalIndexicals ? this.GetValue(context) : this;
return this.GetValue(context);
}
public override bool Unify (BaseTerm t, VarStack varStack)
{
if ((t = t.ChainEnd ()) is Variable) // t not unified
{
((Variable)t).Bind (this);
varStack.Push (t);
return true;
}
if (t is ListPatternTerm && arity == t.Arity) // two ListPatternTerms match if their rangeTerms match
{
for (int i = 0; i < arity; i++)
if (!args [i].Unify (t.Args [i], varStack)) return false;
return true;
}
if (t is ListTerm)
{
pattern = args; // pattern is searched ...
target = ((ListTerm)t).ToList (); // ... in target
int ip = 0;
int it = 0;
return UnifyTailEx (ip, it, varStack);
}
return false;
}
void FindVariables(object obj, List<LogicVariable> singletons)
{
if (obj == null)
return;
var v = obj as LogicVariable;
if (v != null)
{
bool inSingletons = singletons.Contains(v);
if (FreeVariables.Contains(v))
{
if (inSingletons)
singletons.Remove(v);
}
else
{
FreeVariables.Add(v);
if (!v.Name.Name.StartsWith("_"))
singletons.Add(v);
}
}
else
{
var t = obj as Structure;
if (t != null)
foreach (var a in t.Arguments)
FindVariables(a, singletons);
}
}
/// <summary>
/// Sorts arbitrary list of Prolog terms
/// </summary>
public static void KeySort(List<object> terms, bool deleteDuplicates)
{
if (terms.Count == 0)
return;
terms.Sort(CompareKeys);
if (deleteDuplicates)
{
for (int i = terms.Count - 2; i > 0; i--)
if (Compare(terms[i], terms[i + 1]) == 0)
terms.RemoveAt(i + 1);
if (terms.Count > 1 && Compare(terms[0], terms[1]) == 0)
terms.RemoveAt(1);
}
}
public static Object ReadAndGetFreeVariables(string exp, List<LogicVariable> variables)
{
ISOPrologReader r = new ISOPrologReader(exp);
var term = r.ReadTerm();
variables.Clear();
variables.AddRange(r.vars);
return term;
}
internal static bool Unifiable(object v1, object v2, ref List<LogicVariable> vars, ref List<object> values)
{
v1 = CanonicalizeWithExplicitBindingList(v1, vars, values);
v2 = CanonicalizeWithExplicitBindingList(v2, vars, values);
if (v1 == v2)
// Fast path
return true;
var l1 = v1 as LogicVariable;
if (l1 != null)
{
// v1 is an unbound variable; bind it.
AddBinding(l1, v2, ref vars, ref values);
return true;
}
var l2 = v2 as LogicVariable;
if (l2 != null)
{
// v2 is an unbound variable; bind it
AddBinding(l2, v1, ref vars, ref values);
return true;
}
// Neither is an unbound variable
var s1 = v1 as Structure;
var s2 = v2 as Structure;
if (s1 != null && s2 != null)
{
// They're both structures
if (s1.Functor != s2.Functor || s1.Arguments.Length != s2.Arguments.Length)
return false;
for (int i = 0; i < s1.Arguments.Length; i++)
if (!Unifiable(s1.Arguments[i], s2.Arguments[i], ref vars, ref values))
return false;
return true;
}
// None of the above
if (v1 == null)
return v2 == null;
return v1.Equals(v2);
}
string CaptureStack()
{
List<object> result = new List<object>();
if (this.TokenString != "")
result.Add(this.TokenString);
StackFrame s = pStack;
while (s != null)
{
object item;
switch(s.tokentype)
{
case EOFFILE:
item = "end_of_file";
break;
case OPEN_TOKEN:
case OPEN_CT_TOKEN:
item = '(';
break;
case CLOSE_TOKEN:
item = ')';
break;
case OPEN_LIST_TOKEN:
item = '[';
break;
case CLOSE_LIST_TOKEN:
item = ']';
break;
case OPEN_CURLY_TOKEN:
item = '{';
break;
case CLOSE_CURLY_TOKEN:
item = '}';
break;
case HEAD_TAIL_SEPARATOR_TOKEN:
item = '|';
break;
case COMMA_TOKEN:
item = ',';
break;
case END_TOKEN:
item = '.';
break;
default:
item = s.term;
break;
}
result.Insert(0, item); // okay, so this is technically quadratic, but the stack shouldn't be deep, and this only runs when syntax errors are thrown
s = s.down;
}
StringWriter sw = new StringWriter();
ISOPrologWriter w = new ISOPrologWriter(sw);
bool first = true;
foreach (var t in result)
{
if (first)
first = false;
else
w.WriteString(" ");
w.Write(t);
}
return sw.ToString();
}
static object CanonicalizeWithExplicitBindingList(object value, List<LogicVariable> vars, List<object> values)
{
value = Deref(value);
if (vars == null)
return value;
var lv = value as LogicVariable;
while (lv != null)
{
int bindingPosition;
if ((bindingPosition = vars.IndexOf(lv)) >= 0)
{
// it's aliased by the binding list
value = values[bindingPosition];
lv = value as LogicVariable;
}
else
// It's not in the binding list, so we're done.
return value;
}
return value;
}
