private static string GetNodeLabel(ReteNode reteNode)
{
var labelParts = new List <object>();
labelParts.Add(reteNode.NodeType.ToString());
switch (reteNode.NodeType)
{
case NodeType.Type:
labelParts.Add(reteNode.OutputType.Name);
break;
case NodeType.Selection:
labelParts.AddRange(reteNode.Expressions.Select(x => $"{x.Value.Body}"));
break;
case NodeType.Join:
labelParts.AddRange(reteNode.Expressions.Select(x => $"{x.Value.Body}"));
break;
case NodeType.Aggregate:
labelParts.Add(reteNode.Properties.Single(x => x.Key == "Name").Value);
labelParts.AddRange(reteNode.Expressions.Select(x => $"{x.Key}={x.Value.Body}"));
break;
case NodeType.Binding:
labelParts.AddRange(reteNode.Expressions.Select(x => $"{x.Value.Body}"));
break;
case NodeType.Rule:
labelParts.Add(reteNode.Rules.Single().Name);
labelParts.AddRange(reteNode.Expressions.Select(x => $"{x.Key}={x.Value.Body}"));
break;
}
var label = string.Join("\n", labelParts);
return(label);
}
/// <summary>
/// To remove an existing production from the network, we start down at the bottom of the
/// beta network, at the p-node for that production. The basic idea is to start walking from there
/// up to the top of the net. At each node, we clean up any tokens it contains, and then get rid of
/// the node | i.e., remove it from the children or successors lists on its predecessors (its parent
/// and, for some nodes, its alpha memory as well), and deallocate it. We then move up to the
/// predecessors. If the alpha memory is not being shared by another production, we deallocate it
/// too. If the parent is not being shared by another production, then we apply the same procedure
/// to it | clean up its tokens, etc. | and repeat this until we reach either a node being shared by
/// some other production, or the top of the beta network.
/// </summary>
/// <param name="node">The node.</param>
private void delete_node_and_any_unused_ancestors(ReteNode node)
{
if (node.Type == ReteNodeType.NCC)
{
delete_node_and_any_unused_ancestors(node);
}
if (node.Type == ReteNodeType.BetaMemory)
{
while (((BetaMemory) node).Items.Count > 0)
{
delete_token_and_descendents(((BetaMemory) node).Items[0]);
}
}
if (node.Type == ReteNodeType.Negative)
{
while (((NegativeNode) node).Items.Count > 0)
{
delete_token_and_descendents(((NegativeNode) node).Items[0]);
}
}
if (node.Type == ReteNodeType.NCC)
{
while (((NCCNode) node).Items.Count > 0)
{
delete_token_and_descendents(((NCCNode) node).Items[0]);
}
}
if (node.Type == ReteNodeType.NCCPartner)
{
while (((NCCPartnerNode) node).NewResultBuffer.Count > 0)
{
delete_token_and_descendents(((NCCPartnerNode) node).NewResultBuffer[0]);
}
}
if (node.Type == ReteNodeType.Production)
{
ProductionNode pNode = (ProductionNode) node;
while (pNode.Items.Count > 0)
{
delete_token_and_descendents(pNode.Items[0]);
//pNode.items.RemoveFirst();
}
//_rules_that_fired.Remove(pNode);
}
if (node.Type == ReteNodeType.Join)
{
if (((JoinNode) node).IsRightUnlinked == false)
{
((JoinNode) node).AlphaMemory.Successors.Remove(node);
}
if (((JoinNode) node).IsLeftUnlinked == false)
{
node.Parent.Children.Remove(node);
}
--((JoinNode) node).AlphaMemory.ReferenceCount;
if (((JoinNode) node).AlphaMemory.ReferenceCount == 0)
{
delete_alpha_memory(((JoinNode) node).AlphaMemory);
}
}
if (node.Type == ReteNodeType.Negative)
{
if (((NegativeNode) node).IsRightUnlinked == false)
{
((NegativeNode) node).AlphaMemory.Successors.Remove(node);
}
--((NegativeNode) node).AlphaMemory.ReferenceCount;
if (((NegativeNode) node).AlphaMemory.ReferenceCount == 0)
{
delete_alpha_memory(((NegativeNode) node).AlphaMemory);
}
}
if (node.Type == ReteNodeType.Join)
{
JoinNode tmpNode = (JoinNode) node;
((BetaMemory) tmpNode.Parent).AllChildren.Remove(node);
if (((BetaMemory) tmpNode.Parent).AllChildren.Count == 0)
{
delete_node_and_any_unused_ancestors(((JoinNode) node).Parent);
}
}
else if (node.Parent.Children.Count == 0)
{
delete_node_and_any_unused_ancestors(node.Parent);
}
}
/// <summary>
/// The build-or-share-network-for-conditions helper function takes a list of conditions, builds
/// or shares a network structure for them underneath the given parent node, and returns the
/// lowermost node in the new-or-shared network. Note that the list of conditions can contain
/// negative conditions or NCC's, not just positive conditions.
/// </summary>
/// <param name="parent">The parent.</param>
/// <param name="conds">The conds.</param>
/// <param name="earlier_conds">The earlier_conds.</param>
/// <returns></returns>
private ReteNode build_or_share_network_for_conditions(ReteNode parent, IEnumerable<LeftHandSideCondition> conds, List<LeftHandSideCondition> earlier_conds)
{
List<LeftHandSideCondition> conds_higher_up;
ReteNode current_node = parent;
if (earlier_conds == null)
conds_higher_up = new List<LeftHandSideCondition>();
else
conds_higher_up = earlier_conds;
foreach (LeftHandSideCondition cond in conds)
{
if (cond.ConditionType == ConditionType.Positive)
{
current_node = build_or_share_beta_memory_node(current_node);
List<TestAtJoinNode> tests = get_join_tests_from_condition(cond, conds_higher_up);
AlphaMemory am = build_or_share_alpha_memory(cond);
current_node = build_or_share_join_node(current_node as BetaMemory, am, tests);
}
else if (cond.ConditionType == ConditionType.Negative)
{
List<TestAtJoinNode> tests = get_join_tests_from_condition(cond, conds_higher_up);
AlphaMemory am = build_or_share_alpha_memory(cond);
current_node = build_or_share_negative_node(current_node, am, tests);
}
else if (cond.ConditionType == ConditionType.NCC)
{
current_node = build_or_share_ncc_nodes(current_node as JoinNode, cond, conds_higher_up);
}
else if (cond.ConditionType == ConditionType.Function)
{
current_node = build_builtin_node(current_node, cond, conds_higher_up);
}
conds_higher_up.Add(cond);
}
return current_node;
}
/// <summary>
/// The function for creating new negative nodes is similar to the ones for creating beta memories
/// and join nodes. However, one additional consideration is important with negative conditions,
/// and also with conjunctive negations. Any time there is a variable <v> which is tested in a negative
/// condition and bound in one or more other (positive) conditions, at least one of these positive
/// conditions must come before the negative condition. Recall that when we add a production to
/// the network, the network-construction routines are given a list of its conditions in some order. If
/// all conditions are positive, any order will work. Negative conditions require the aforementioned
/// constraint on the order, though, because negative nodes need to be able to access the appropriate
/// variable bindings in tokens, and the tokens "seen" by negative nodes indicate only variable
/// bindings from earlier conditions, i.e., conditions higher up in the network.
/// </summary>
/// <param name="parent">The parent.</param>
/// <param name="am">The am.</param>
/// <param name="tests">The tests.</param>
/// <returns></returns>
private ReteNode build_or_share_negative_node(ReteNode parent, AlphaMemory am, ICollection<TestAtJoinNode> tests)
{
foreach (ReteNode child in parent.Children)
{
if (child.Type == ReteNodeType.Negative)
{
NegativeNode negativenodeChild = (NegativeNode) child;
if (negativenodeChild.AlphaMemory == am)
{
if (negativenodeChild.Tests.Count == 0 && tests.Count == 0)
{
return child;
}
else
{
//Need to compare tests...
throw new ApplicationException("Unhandled...");
}
}
}
}
NegativeNode new_node = new NegativeNode();
new_node.Type = ReteNodeType.Negative; // "negative";
new_node.Parent = parent;
parent.Children.AddToFront(new_node);
foreach (TestAtJoinNode test in tests)
{
new_node.Tests.Add(test);
}
new_node.AlphaMemory = am;
am.Successors.AddToFront(new_node);
++am.ReferenceCount;
new_node.NearestAncestorWithSameAmem = find_nearest_ancestor_with_same_amem(parent, am);
update_new_node_with_matches_from_above(new_node);
// *** Right Unlinking ***
if (new_node.Items.Count == 0)
{
am.Successors.Remove(new_node);
new_node.IsRightUnlinked = true;
}
// *** End Right Unlinking ***
return new_node;
}
/// <summary>
/// We will use several helper functions to make the main add-production procedure simpler.
/// The first one, build-or-share-beta-memory-node, looks for an existing beta memory node that is
/// a child of the given parent node. If there is one, it returns it so it can be shared by the new
/// production; otherwise the function builds a new one and returns it. This pseudocode assumes
/// that beta memories are not indexed; if indexing is used, the procedure would take an extra
/// argument specifying which field(s) the memory must be indexed on.
/// </summary>
/// <param name="parent">The parent.</param>
/// <returns></returns>
private ReteNode build_or_share_beta_memory_node(ReteNode parent)
{
if (parent is DummyTopNode)
{
return parent;
}
foreach (ReteNode child in parent.Children)
{
if (child.Type == ReteNodeType.BetaMemory)
{
return child;
}
}
BetaMemory new_rete = new BetaMemory();
new_rete.Type = ReteNodeType.BetaMemory;
new_rete.Parent = parent;
new_rete.Label = "B" + (++_next_beta_node);
parent.Children.AddToFront(new_rete);
update_new_node_with_matches_from_above(new_rete);
return new_rete;
}
/// <summary>
/// Build_builtin_nodes the specified parent.
/// </summary>
/// <param name="parent">The parent.</param>
/// <param name="c">The c.</param>
/// <param name="earlier_conds">The earlier_conds.</param>
/// <returns></returns>
private BuiltinMemory build_builtin_node(ReteNode parent, Condition c, IList<LeftHandSideCondition> earlier_conds)
{
BuiltinMemory new_node = new BuiltinMemory(c.ToString());
new_node.Type = ReteNodeType.Builtin;
new_node.Parent = parent;
parent.Children.AddToFront(new_node);
new_node.Builtin = ((FuncTerm) c.Attribute).Builtin;
int cntOfEarlierConditions = earlier_conds.Count - 1;
if (c.Id.TermType == TermType.Variable)
{
for (int i = cntOfEarlierConditions; i >= 0; i--)
{
Condition earlier_cond = earlier_conds[i];
if (earlier_cond.ConditionType == ConditionType.Positive)
{
for (int f2 = 0; f2 < 3; f2++)
{
Variable o = earlier_cond.Fields[f2] as Variable;
if (o != null && o.Equals(c.Id))
{
VariableSubstituter vs = new VariableSubstituter();
vs.FieldNumber = f2;
vs.NumberOfLevelsUp = (cntOfEarlierConditions - i);
vs.BindingPair.Variable = o;
new_node.LeftArgument = vs;
f2 = 3;
i = -1; //escape loop of cntOfEarlierConditions
}
}
}
}
}
else
{
new_node.LeftArgument = new ConstantSubstitutor(c.Id);
}
if (c.Value.TermType == TermType.Variable)
{
for (int i = cntOfEarlierConditions; i >= 0; i--)
{
Condition earlier_cond = earlier_conds[i];
if (earlier_cond.ConditionType == ConditionType.Positive)
{
for (int f2 = 0; f2 < 3; f2++)
{
Variable o = earlier_cond.Fields[f2] as Variable;
if (o != null && o.Equals(c.Value))
{
VariableSubstituter vs = new VariableSubstituter();
vs.FieldNumber = f2;
vs.NumberOfLevelsUp = (cntOfEarlierConditions - i);
vs.BindingPair.Variable = o;
new_node.RightArgument = vs;
f2 = 3;
i = -1; //escape loop of cntOfEarlierConditions
}
}
}
}
}
else
{
new_node.RightArgument = new ConstantSubstitutor(c.Value);
}
update_new_node_with_matches_from_above(new_node);
return new_node;
}
/// <summary>
/// Adds the production.
/// </summary>
/// <param name="new_production">The new_production.</param>
/// <param name="lhs">The LHS.</param>
private void AddProduction(ReteNode new_production, IEnumerable<LeftHandSideCondition> lhs)
{
ReteNode current_node = build_or_share_network_for_conditions(_dummy_top_node, lhs, null);
new_production.Parent = current_node;
current_node.Children.AddToFront(new_production);
update_new_node_with_matches_from_above(new_production);
}
/// <summary>
/// Called when [rete node] is visited.
/// </summary>
/// <param name="node">The node.</param>
public virtual void OnReteNode(ReteNode node)
{
}
/// <summary>
/// Controls the activation flow based on node type
/// </summary>
/// <param name="child">The child.</param>
/// <param name="w">The w.</param>
private void right_activation(ReteNode child, WME w)
{
switch (child.Type)
{
case ReteNodeType.Join:
join_node_right_activation(child as JoinNode, w);
break;
case ReteNodeType.Negative:
negative_node_right_activation(child as NegativeNode, w);
break;
default:
throw new ApplicationException("???");
}
}
/// <summary>
/// Similarly, whenever a new token tok = ht;wi is added to a beta memory, we add tok to
/// t.children and to w.tokens. We also fill in the new node field on the token. To simplify our
/// pseudocode, it is convenient to define a "helper" function make-token which builds a new token
/// and initializes its various fields as necessary for tree-based removal. Although we write this as
/// a separate function, it would normally be coded "inline" for efficiency.
/// </summary>
/// <param name="node">The node.</param>
/// <param name="parent">The parent.</param>
/// <param name="w">The w.</param>
/// <returns></returns>
private Token make_token(ReteNode node, Token parent, WME w)
{
Token tok = new Token();
tok.Parent = parent;
tok.WME = w;
tok.Node = node;
parent.Children.AddToFront(tok);
if (w != null)
{
w.Tokens.AddToFront(tok);
}
return tok;
}
/// <summary>
/// Left_activations the specified new_node.
/// </summary>
/// <param name="new_node">The new_node.</param>
/// <param name="tok">The tok.</param>
/// <param name="w">The w.</param>
private void left_activation(ReteNode new_node, Token tok, WME w)
{
switch (new_node.Type)
{
case ReteNodeType.BetaMemory:
beta_memory_left_activation(new_node as BetaMemory, tok, w);
break;
case ReteNodeType.Negative:
negative_node_left_activation(new_node as NegativeNode, tok, w);
break;
case ReteNodeType.Builtin:
builtin_node_left_activation(new_node as BuiltinMemory, tok, w);
break;
case ReteNodeType.NCCPartner:
ncc_partner_node_left_activation(new_node as NCCPartnerNode, tok, w);
break;
case ReteNodeType.NCC:
ncc_node_left_activation(new_node as NCCNode, tok, w);
break;
case ReteNodeType.Join:
join_node_left_activation(new_node as JoinNode, tok);
break;
case ReteNodeType.Production:
p_node_activation(new_node as ProductionNode, tok, w);
break;
case ReteNodeType.Mutex:
mutex_node_activation(new_node as MutexNode, tok, w);
break;
case ReteNodeType.Aggregator:
aggregator_node_activation(new_node as AggregatorNode, tok, w);
break;
default:
throw new ApplicationException("Unknown left_activation type: " + new_node.GetType().Name);
}
}
/// <summary>
/// For right unlinking, we need to initialize the nearest-ancestor-with-same-amem fields on
/// newly-created join and negative nodes. The find-nearest-ancestor-with-same-amem procedure
/// finds the appropriate value. It starts at a given node and walks up the beta network, returning
/// the first node it finds that uses a given alpha memory. Note that this node may be in the
/// subnetwork for a conjunctive negation.
/// </summary>
/// <param name="node">The node.</param>
/// <param name="am">The am.</param>
/// <returns></returns>
private ReteNode find_nearest_ancestor_with_same_amem(ReteNode node, AlphaMemory am)
{
if (node is DummyTopNode)
{
return null;
}
if (node.Type == ReteNodeType.Dummy)
{
return null;
}
if (node.Type == ReteNodeType.Join)
{
if (((JoinNode) node).AlphaMemory == am)
{
return node;
}
}
if (node.Type == ReteNodeType.Negative)
{
if (((NegativeNode) node).AlphaMemory == am)
{
return node;
}
}
if (node.Type == ReteNodeType.NCC)
{
return find_nearest_ancestor_with_same_amem(((NCCNode) node).Partner.Parent, am);
}
return find_nearest_ancestor_with_same_amem(node.Parent, am);
}
private string Id(ReteNode reteNode)
{
return($"{reteNode.Id}");
}
/// <summary>
/// Called when [rete node] is visited.
/// </summary>
/// <param name="node">The node.</param>
public override void OnReteNode(ReteNode node)
{
_sb.AppendLine(node.ToString());
}
/// <summary>
/// Called when [rete node] is visited.
/// </summary>
/// <param name="node">The node.</param>
public override void OnReteNode(ReteNode node)
{
_sb.AppendLine(node.ToString());
}
/// <summary>
/// The update-new-node-with-matches-from-above procedure initializes the memory node to store
/// tokens for any existing matches for the earlier conditions.
/// </summary>
/// <remarks>
/// Finally, we give the update-new-node-with-matches-from-above procedure. This is needed
/// to ensure that newly added productions are immediately matched against the current working
/// memory. The procedure's job is to ensure that the given new-node's left-activation procedure is
/// called with all the existing matches for the previous conditions, so that the new-node can take
/// any appropriate actions (e.g., a beta memory stores the matches as new tokens, and a p-node
/// signals new complete matches for the production). How update-new-node-with-matches-from-
/// above achieves this depends on what kind of node the new-node's parent is. If the parent is a
/// beta memory (or a node for a negated condition, as we will discuss later), this is straightforward,
/// since the parent has a list (items) of exactly the matches we want. But if the parent node is a
/// join node, we want to find these matches, we iterate over the WMEs and tokens in the join node's alpha
/// and beta memories and perform the join tests on each pair. The pseudocode below uses a trick to
/// do this: while temporarily pretending the new-node is the only child of the join node, it runs the
/// join node's right-activation procedure for all the WMEs in its alpha memory; any new matches
/// will automatically be propagated to the new-node. For a variation of this implementation, see
/// (Tambe et al., 1988); for a general discussion, see (Lee and Schor, 1992).
/// </remarks>
/// <param name="newNode">The new node.</param>
private void update_new_node_with_matches_from_above(ReteNode newNode)
{
ReteNode parent = newNode.Parent;
switch (parent.Type)
{
case ReteNodeType.BetaMemory:
BetaMemory tmpBetaMem = (BetaMemory) parent;
foreach (Token tok in tmpBetaMem.Items)
{
left_activation(newNode, tok, new WME());
}
break;
case ReteNodeType.Builtin:
BuiltinMemory tmpBiMem = (BuiltinMemory) parent;
foreach (Token tok in tmpBiMem.Items)
{
left_activation(newNode, tok, new WME());
}
break;
case ReteNodeType.Join:
BigList<ReteNode> saved_list_of_children = parent.Children.Clone();
parent.Children.Clear();
parent.Children.AddToFront(newNode);
JoinNode tmpJNode = (JoinNode) parent;
if (tmpJNode.AlphaMemory != null)
{
foreach (ItemInAlphaMemory item in tmpJNode.AlphaMemory.Items)
{
right_activation(parent, item.WME);
}
}
parent.Children.Clear();
parent.Children.AddRange(saved_list_of_children);
break;
case ReteNodeType.Negative:
NegativeNode tmpNNode = (NegativeNode) parent;
foreach (Token tok in tmpNNode.Items)
{
if (tok.JoinResults.Count == 0)
{
left_activation(newNode, tok, null);
}
}
break;
case ReteNodeType.NCC:
NCCNode tmpNCCNode = (NCCNode) parent;
foreach (Token tok in tmpNCCNode.Items)
{
if (tok.NCCResults.Count == 0)
{
left_activation(newNode, tok, null);
}
}
break;
}
}
/// <summary>
/// Called when [rete node] is visited.
/// </summary>
/// <param name="node">The node.</param>
public virtual void OnReteNode(ReteNode node)
{
}
internal ReteLink(ReteNode source, ReteNode target)
{
Source = source;
Target = target;
}
