public static bool TryQueryStructure(
Structure term,
PrologContext context,
out ELNode foundNode,
out ELNodeEnumerator enumerator)
{
//
// Dispatch based on the functor and arity.
//
// Handle root queries, i.e. /Key
if (term.IsFunctor(Symbol.Slash, 1))
return TryRootQuery(term, context, out foundNode, out enumerator);
if (!IsELTerm(term))
throw new Exception("Malformed EL query: " + ISOPrologWriter.WriteToString(term));
if (term.IsFunctor(SBindNodeOperator, 2))
{
var variableToBind = term.Argument(1) as LogicVariable;
if (variableToBind == null)
throw new ArgumentException("RHS of >> must be an uninstantiated variable: "+ ISOPrologWriter.WriteToString(term.Argument(1)));
foundNode = null;
return TryNodeBindingQuery(out enumerator, term.Argument(0), variableToBind, context);
}
return TryChildQuery(
out foundNode,
out enumerator,
term.Argument(0),
term.Argument(1),
term.Functor == Symbol.Colon,
context);
}
public static bool TryChildQuery(
out ELNode foundNode,
out ELNodeEnumerator enumerator,
object parentExpression,
object keyExpression,
bool isExclusive,
PrologContext context)
{
// Decode the parent expression
ELNode parentNode;
ELNodeEnumerator parentEnumerator;
if (!TryQuery(parentExpression, context, out parentNode, out parentEnumerator))
{
// Parent failed, so we fail
enumerator = null;
foundNode = null;
return false;
}
//
// Decode the key argument
//
var key = keyExpression;
var v = key as LogicVariable;
return isExclusive?TryExclusiveQuery(out foundNode, out enumerator, parentNode, parentEnumerator, key, v)
: TryNonExclusiveQuery(out foundNode, out enumerator, parentNode, key, v, parentEnumerator);
}
public static bool TryQuery(object term, PrologContext context, out ELNode foundNode, out ELNodeEnumerator enumerator)
{
// Dereference any top-level variables.
var t = Term.Deref(term);
// Dereference indexicals
var i = t as Indexical;
if (i != null)
t = i.GetValue(context);
// A game object means the gameobject's EL KB.
var g = t as GameObject;
if (g != null)
t = g.KnowledgeBase().ELRoot;
// If it's already an ELNode, use that.
var n = t as ELNode;
if (n != null)
{
foundNode = n;
enumerator = null;
return true;
}
// Otherwise, it's an expression, so evaluate it.
var s = t as Structure;
if (s != null)
return TryQueryStructure(s, context, out foundNode, out enumerator);
var v = t as LogicVariable;
if (v != null && !v.IsBound)
throw new Exception("EL query root is an unbound variable: " + v);
throw new Exception("Malformed EL query: " + ISOPrologWriter.WriteToString(term));
}
private static bool TryNonExclusiveQuery(out ELNode foundNode, out ELNodeEnumerator enumerator, ELNode parentNode, object key, LogicVariable v, ELNodeEnumerator parentEnumerator)
{
if (parentNode != null)
{
return TryNonExclusiveQueryDeterministicParent(out foundNode, out enumerator, parentNode, key, v);
}
return TryNonExclusiveQueryEnumeratedParent(out foundNode, out enumerator, key, v, parentEnumerator);
}
private static IEnumerable <CutState> DeleteSuccessive(ELNodeEnumerator enumerator)
{
while (enumerator.MoveNext())
{
enumerator.Current.DeleteSelf();
yield return(CutState.Continue);
}
}
public ELNodeEnumeratorBindEnumeratedNodesToVariable(ELNodeEnumerator nodeEnumerator, LogicVariable variableToBind)
{
this.nodeEnumerator = nodeEnumerator;
this.variableToBind = variableToBind;
if (nodeEnumerator.BindsVar(variableToBind))
{
throw new InvalidOperationException("Variable appears on both the LHS and RHS of >>: " + variableToBind.Name);
}
}
private static bool TryExclusiveQueryEnumeratedParent(
out ELNode foundNode,
out ELNodeEnumerator enumerator,
ELNodeEnumerator parentEnumerator,
object key,
LogicVariable v)
{
// Non-deterministic parent path
// NonUniqueParent:Something
foundNode = null;
enumerator = (v == null)
? new ELNodeEnumeratorEnumerateParentAndLookupExclusiveKey(parentEnumerator, key)
: (parentEnumerator.BindsVar(v)? (ELNodeEnumerator)new ELNodeEnumeratorPreboundVariable(parentEnumerator, v, true)
: new ELNodeEnumeratorEnumerateParentAndBindVariable(parentEnumerator, v));
return true;
}
private static bool TryExclusiveQuery(
out ELNode foundNode,
out ELNodeEnumerator enumerator,
ELNode parentNode,
ELNodeEnumerator parentEnumerator,
object key,
LogicVariable v)
{
//
// Expression is Parent:Something
//
if (parentNode != null)
{
return TryExclusiveQueryDeterministicParent(out foundNode, out enumerator, parentNode, key, v);
}
return TryExclusiveQueryEnumeratedParent(out foundNode, out enumerator, parentEnumerator, key, v);
}
public static bool TryNodeBindingQuery(
out ELNodeEnumerator enumerator,
object nodeExpression,
LogicVariable variableToBind,
PrologContext context)
{
// Decode the node expression
ELNode foundNode;
ELNodeEnumerator nodeEnumerator;
if (!TryQuery(nodeExpression, context, out foundNode, out nodeEnumerator))
{
// Parent failed, so we fail
enumerator = null;
return false;
}
enumerator = (foundNode != null)
? (ELNodeEnumerator)new ELNodeEnumeratorBindFixedNodeToVariable(foundNode, variableToBind)
: new ELNodeEnumeratorBindEnumeratedNodesToVariable(nodeEnumerator, variableToBind);
return true;
}
public static bool TryNodeBindingQuery(
out ELNodeEnumerator enumerator,
object nodeExpression,
LogicVariable variableToBind,
PrologContext context)
{
// Decode the node expression
ELNode foundNode;
ELNodeEnumerator nodeEnumerator;
if (!TryQuery(nodeExpression, context, out foundNode, out nodeEnumerator))
{
// Parent failed, so we fail
enumerator = null;
return false;
}
enumerator = (foundNode != null)
? (ELNodeEnumerator)new ELNodeEnumeratorBindFixedNodeToVariable(foundNode, variableToBind)
: new ELNodeEnumeratorBindEnumeratedNodesToVariable(nodeEnumerator, variableToBind);
return true;
}
public static bool TryQueryStructure(
Structure term,
PrologContext context,
out ELNode foundNode,
out ELNodeEnumerator enumerator)
{
//
// Dispatch based on the functor and arity.
//
// Handle root queries, i.e. /Key
if (term.IsFunctor(Symbol.Slash, 1))
{
return(TryRootQuery(term, context, out foundNode, out enumerator));
}
if (!IsELTerm(term))
{
throw new Exception("Malformed EL query: " + ISOPrologWriter.WriteToString(term));
}
if (term.IsFunctor(SBindNodeOperator, 2))
{
var variableToBind = term.Argument(1) as LogicVariable;
if (variableToBind == null)
{
throw new ArgumentException("RHS of >> must be an uninstantiated variable: " + ISOPrologWriter.WriteToString(term.Argument(1)));
}
foundNode = null;
return(TryNodeBindingQuery(out enumerator, term.Argument(0), variableToBind, context));
}
return(TryChildQuery(
out foundNode,
out enumerator,
term.Argument(0),
term.Argument(1),
term.Functor == Symbol.Colon,
context));
}
private static bool TryExclusiveQueryDeterministicParent(
out ELNode foundNode,
out ELNodeEnumerator enumerator,
ELNode parentNode,
object key,
LogicVariable v)
{
// Deterministic parent path
// UniqueParent:Something
if (parentNode.IsNonExclusive)
{
throw new ELNodeExclusionException("Exclusive query of an non-exclusive node", parentNode, key);
}
if (v == null)
{
// Deterministic child path
// UniqueParent:Key
enumerator = null;
return parentNode.TryLookup(key, out foundNode);
}
// Enumerated child path
// UniqueParent:Variable
if (parentNode.Children.Count > 0)
{
foundNode = null;
enumerator = new ELNodeEnumeratorBindAndUnbindVariable(parentNode.Children[0], v);
return true;
}
// parentNode is exclusive, but is childless, so we can't match.
foundNode = null;
enumerator = null;
return false;
}
private static bool TryRootQuery(Structure term, PrologContext context, out ELNode foundNode, out ELNodeEnumerator enumerator)
{
// Expression is /Key.
var arg0 = term.Argument(0);
// This is a "/constant" expression, i.e. a top-level lookup.
if (arg0 is LogicVariable)
{
throw new NotImplementedException("Lookups of the form /Variable are not supported.");
}
enumerator = null;
return context.KnowledgeBase.ELRoot.TryLookup(arg0, out foundNode);
}
private static bool TryNonExclusiveQueryEnumeratedParent(
out ELNode foundNode,
out ELNodeEnumerator enumerator,
object key,
LogicVariable v,
ELNodeEnumerator parentEnumerator)
{
// Enumerated parent path
// NonUniqueParent/Something
foundNode = null;
if (v == null)
{
// NonUniqueParent/Key
// Enumerate parent, then do deterministic lookup for child.
enumerator = new ELNodeEnumeratorFixedChildFromParentEnumerator(parentEnumerator, key);
return true;
}
if (parentEnumerator.BindsVar(v))
{
// We're doing a search for a variable that's aready bound.
enumerator = new ELNodeEnumeratorPreboundVariable(parentEnumerator, v, false);
return true;
}
// NonUniqueParent/Variable
// Enumerate both parent and child.
enumerator = new ELNodeEnumeratorLogicVariableFromParentEnumerator(parentEnumerator, v);
return true;
}
public static bool TryQuery(object term, PrologContext context, out ELNode foundNode, out ELNodeEnumerator enumerator)
{
// Dereference any top-level variables.
var t = Term.Deref(term);
// Dereference indexicals
var i = t as Indexical;
if (i != null)
t = i.GetValue(context);
// A game object means the gameobject's EL KB.
var g = t as GameObject;
if (g != null)
t = g.KnowledgeBase().ELRoot;
// If it's already an ELNode, use that.
var n = t as ELNode;
if (n != null)
{
foundNode = n;
enumerator = null;
return true;
}
// Otherwise, it's an expression, so evaluate it.
var s = t as Structure;
if (s != null)
return TryQueryStructure(s, context, out foundNode, out enumerator);
var v = t as LogicVariable;
if (v != null && !v.IsBound)
throw new Exception("EL query root is an unbound variable: " + v);
throw new Exception("Malformed EL query: " + ISOPrologWriter.WriteToString(term));
}
public ELNodeEnumeratorEnumerateParentAndLookupExclusiveKey(ELNodeEnumerator parentEnumerator, object key)
{
this.parentEnumerator = parentEnumerator;
this.key = key;
}
public ELNodeEnumeratorPreboundVariable(ELNodeEnumerator parentEnumerator, LogicVariable variable, bool exclusive)
{
this.parentEnumerator = parentEnumerator;
this.variable = variable;
this.exclusive = exclusive;
}
public ELNodeEnumeratorFixedChildFromParentEnumerator(ELNodeEnumerator parentEnumerator, object childKey)
{
this.parentEnumerator = parentEnumerator;
this.childKey = childKey;
}
public ELNodeEnumeratorEnumerateParentAndLookupExclusiveKey(ELNodeEnumerator parentEnumerator, object key)
{
this.parentEnumerator = parentEnumerator;
this.key = key;
}
private static bool TryExclusiveQuery(
out ELNode foundNode,
out ELNodeEnumerator enumerator,
ELNode parentNode,
ELNodeEnumerator parentEnumerator,
object key,
LogicVariable v)
{
//
// Expression is Parent:Something
//
if (parentNode != null)
{
return TryExclusiveQueryDeterministicParent(out foundNode, out enumerator, parentNode, key, v);
}
return TryExclusiveQueryEnumeratedParent(out foundNode, out enumerator, parentEnumerator, key, v);
}
private static System.Collections.Generic.IEnumerable<CutState> DeleteSuccessive(ELNodeEnumerator enumerator)
{
while (enumerator.MoveNext())
{
enumerator.Current.DeleteSelf();
yield return CutState.Continue;
}
}
private static bool TryRootQuery(Structure term, PrologContext context, out ELNode foundNode, out ELNodeEnumerator enumerator)
{
// Expression is /Key.
var arg0 = term.Argument(0);
// This is a "/constant" expression, i.e. a top-level lookup.
if (arg0 is LogicVariable)
{
throw new NotImplementedException("Lookups of the form /Variable are not supported.");
}
enumerator = null;
return context.KnowledgeBase.ELRoot.TryLookup(arg0, out foundNode);
}
public ELNodeEnumeratorPreboundVariable(ELNodeEnumerator parentEnumerator, LogicVariable variable, bool exclusive)
{
this.parentEnumerator = parentEnumerator;
this.variable = variable;
this.exclusive = exclusive;
}
private static System.Collections.Generic.IEnumerable<CutState> DeleteSuccessive(ELNodeEnumerator enumerator)
{
while (enumerator.MoveNext())
{
enumerator.Current.DeleteSelf();
yield return CutState.Continue;
}
}
public ELNodeEnumeratorFixedChildFromParentEnumerator(ELNodeEnumerator parentEnumerator, object childKey)
{
this.parentEnumerator = parentEnumerator;
this.childKey = childKey;
}
public ELNodeEnumeratorEnumerateParentAndBindVariable(ELNodeEnumerator parentEnumerator, LogicVariable variable)
{
this.parentEnumerator = parentEnumerator;
this.variable = variable;
}
public ELNodeEnumeratorBindEnumeratedNodesToVariable(ELNodeEnumerator nodeEnumerator, LogicVariable variableToBind)
{
this.nodeEnumerator = nodeEnumerator;
this.variableToBind = variableToBind;
if (nodeEnumerator.BindsVar(variableToBind))
throw new InvalidOperationException("Variable appears on both the LHS and RHS of >>: "+ variableToBind.Name);
}
public ELNodeEnumeratorEnumerateParentAndBindVariable(ELNodeEnumerator parentEnumerator, LogicVariable variable)
{
this.parentEnumerator = parentEnumerator;
this.variable = variable;
}
private static bool TryExclusiveQueryDeterministicParent(
out ELNode foundNode,
out ELNodeEnumerator enumerator,
ELNode parentNode,
object key,
LogicVariable v)
{
// Deterministic parent path
// UniqueParent:Something
if (parentNode.IsNonExclusive)
{
throw new ELNodeExclusionException("Exclusive query of an non-exclusive node", parentNode, key);
}
if (v == null)
{
// Deterministic child path
// UniqueParent:Key
enumerator = null;
return parentNode.TryLookup(key, out foundNode);
}
// Enumerated child path
// UniqueParent:Variable
if (parentNode.Children.Count > 0)
{
foundNode = null;
enumerator = new ELNodeEnumeratorBindAndUnbindVariable(parentNode.Children[0], v);
return true;
}
// parentNode is exclusive, but is childless, so we can't match.
foundNode = null;
enumerator = null;
return false;
}
private static bool TryExclusiveQueryEnumeratedParent(
out ELNode foundNode,
out ELNodeEnumerator enumerator,
ELNodeEnumerator parentEnumerator,
object key,
LogicVariable v)
{
// Non-deterministic parent path
// NonUniqueParent:Something
foundNode = null;
enumerator = (v == null)
? new ELNodeEnumeratorEnumerateParentAndLookupExclusiveKey(parentEnumerator, key)
: (parentEnumerator.BindsVar(v)? (ELNodeEnumerator)new ELNodeEnumeratorPreboundVariable(parentEnumerator, v, true)
: new ELNodeEnumeratorEnumerateParentAndBindVariable(parentEnumerator, v));
return true;
}
private static bool TryNonExclusiveQuery(out ELNode foundNode, out ELNodeEnumerator enumerator, ELNode parentNode, object key, LogicVariable v, ELNodeEnumerator parentEnumerator)
{
if (parentNode != null)
{
return TryNonExclusiveQueryDeterministicParent(out foundNode, out enumerator, parentNode, key, v);
}
return TryNonExclusiveQueryEnumeratedParent(out foundNode, out enumerator, key, v, parentEnumerator);
}
public ELNodeEnumeratorLogicVariableFromParentEnumerator(ELNodeEnumerator parentEnumerator, LogicVariable v)
{
this.parentEnumerator = parentEnumerator;
this.variable = v;
childIndex = -1;
}
private static bool TryNonExclusiveQueryDeterministicParent(
out ELNode foundNode,
out ELNodeEnumerator enumerator,
ELNode parentNode,
object key,
LogicVariable v)
{
// Deterministic parent path
// The expression is UniqueParent/Something
if (parentNode.IsExclusive)
{
throw new ELNodeExclusionException("Non-exclusive query of an exclusive node", parentNode, key);
}
if (v == null)
{
// fully deterministic path
// UniqueParent/Key corresponds to at most one ELNode.
enumerator = null;
return parentNode.TryLookup(key, out foundNode);
}
// UniqueParent/Variable, so do a singly-nested iteration.
foundNode = null;
enumerator = new ELNodeEnumeratorLogicVariableFromNode(parentNode, v);
return true;
}
private static IEnumerable<CutState> EnumerateAndBindNode(ELNodeEnumerator enumerator, object varToBindTo)
{
while (enumerator.MoveNext())
#pragma warning disable 414, 168, 219
// ReSharper disable once UnusedVariable
foreach (var ignore in Term.Unify(varToBindTo, enumerator.Current))
#pragma warning restore 414, 168, 219
yield return CutState.Continue;
}
public ELNodeEnumeratorLogicVariableFromParentEnumerator(ELNodeEnumerator parentEnumerator, LogicVariable v)
{
this.parentEnumerator = parentEnumerator;
this.variable = v;
childIndex = -1;
}