/// <summary>
/// When adding a production that uses an NCC, we use the build-or-share-ncc-nodes function.
/// Most of the work in this function is done by the helper function build-or-share-network-for-
/// conditions, which builds or shares the whole subnetwork for the subconditions of the NCC. The
/// rest of the build-or-share-ncc-nodes function then builds or shares the NCC and NCC partner
/// nodes.
/// </summary>
/// <param name="parent">The parent.</param>
/// <param name="c">The c.</param>
/// <param name="earlier_conds">The earlier_conds.</param>
/// <returns></returns>
private ReteNode build_or_share_ncc_nodes(JoinNode parent, Condition c, List<LeftHandSideCondition> earlier_conds)
{
ReteNode bottom_of_subnetwork = build_or_share_network_for_conditions(parent, c.SubConditions, earlier_conds);
foreach (ReteNode child in parent.Children)
{
if (child.Type == ReteNodeType.NCC && ((NCCNode) child).Partner.Parent == bottom_of_subnetwork)
{
return child;
}
}
NCCNode new_node = new NCCNode();
NCCPartnerNode new_partner = new NCCPartnerNode();
new_node.Type = ReteNodeType.NCC; // "NCC";
new_partner.Type = ReteNodeType.NCCPartner; // "NCC-partner";
parent.IsHeadOfSubNetwork = true;
new_node.Parent = parent;
parent.Children.Add(new_node);
new_partner.Parent = bottom_of_subnetwork;
bottom_of_subnetwork.Children.AddToFront(new_partner);
new_node.Partner = new_partner;
new_partner.NCCNode = new_node;
new_partner.NumberOfConjuncts = c.SubConditions.Count;
update_new_node_with_matches_from_above(new_node);
update_new_node_with_matches_from_above(new_partner);
return new_node;
}
/// <summary>
/// Ncc_partner_node_left_activations the specified partner.
/// </summary>
/// <remarks>
/// To handle an NCC partner node (left) activation, we take the new match from the subnetwork
/// and build a "result" token to store it. (The pseudocode for this is shown in Figure 2.8.) Next we
/// try to find the appropriate owner token in the NCC node's memory. (There might be one there,
/// if this is a new subconditions match for an old preceding-conditions match, or there might not
/// be one there, if this is an initial subconditions match for a new preceding-conditions match.)
/// If we find an appropriate owner token, then we add the new result token to its local memory;
/// if the number of results in the local memory changes from zero to one | indicating that the
/// NCC was previously true but is now false | then we call the delete-descendents-of-token helper
/// function to delete any tokens lower in the network that depend on this owner token. (This is
/// similar to the negative-node-right-activation procedure on page 43.) On the other hand, if there
/// isn't an appropriate owner token already in the NCC node's memory, then this new result token
/// is placed in the new-result-buffer. (The NCC node will soon be activated and collect any new
/// results from the buffer.)
/// </remarks>
/// <param name="partner">The partner.</param>
/// <param name="t">The t.</param>
/// <param name="w">The w.</param>
private void ncc_partner_node_left_activation(NCCPartnerNode partner, Token t, WME w)
{
NCCNode nccNode = partner.NCCNode;
Token new_result = make_token(partner, t, w);
Token owners_t = t;
WME owners_w = w;
for (int i = 0; i < partner.NumberOfConjuncts; i++)
{
owners_w = owners_t.WME;
owners_t = owners_t.Parent;
}
foreach (Token owner in nccNode.Items)
{
if (owner.Parent == owners_t && owner.WME == owners_w)
{
owner.NCCResults.Add(new_result);
new_result.Owner = owner;
delete_descendents_of_token(owner);
}
else
{
partner.NewResultBuffer.AddToFront(new_result);
}
}
}