//-------------------------------------------------------------------------
//
// findNodes() Locate all the nodes of the specified type, starting
// at the specified root.
//
//-------------------------------------------------------------------------
internal virtual void FindNodes(IList <RBBINode> dest, int kind)
{
if (fType == kind)
{
dest.Add(this);
}
if (fLeftChild != null)
{
fLeftChild.FindNodes(dest, kind);
}
if (fRightChild != null)
{
fRightChild.FindNodes(dest, kind);
}
}
//-----------------------------------------------------------------------------
//
// calcChainedFollowPos. Modify the previously calculated followPos sets
// to implement rule chaining. NOT described by Aho
//
//-----------------------------------------------------------------------------
internal virtual void CalcChainedFollowPos(RBBINode tree)
{
IList <RBBINode> endMarkerNodes = new JCG.List <RBBINode>();
IList <RBBINode> leafNodes = new JCG.List <RBBINode>();
// get a list of all endmarker nodes.
tree.FindNodes(endMarkerNodes, RBBINode.endMark);
// get a list all leaf nodes
tree.FindNodes(leafNodes, RBBINode.leafChar);
// Collect all leaf nodes that can start matches for rules
// with inbound chaining enabled, which is the union of the
// firstPosition sets from each of the rule root nodes.
IList <RBBINode> ruleRootNodes = new JCG.List <RBBINode>();
AddRuleRootNodes(ruleRootNodes, tree);
ISet <RBBINode> matchStartNodes = new JCG.HashSet <RBBINode>();
foreach (RBBINode node in ruleRootNodes)
{
if (node.fChainIn)
{
matchStartNodes.UnionWith(node.fFirstPosSet);
}
}
// Iterate over all leaf nodes,
//
foreach (RBBINode tNode in leafNodes)
{
RBBINode endNode = null;
// Identify leaf nodes that correspond to overall rule match positions.
// These include an endMarkerNode in their followPos sets.
foreach (RBBINode endMarkerNode in endMarkerNodes)
{
if (tNode.fFollowPos.Contains(endMarkerNode))
{
endNode = tNode;
break;
}
}
if (endNode == null)
{
// node wasn't an end node. Try again with the next.
continue;
}
// We've got a node that can end a match.
// Line Break Specific hack: If this node's val correspond to the $CM char class,
// don't chain from it.
// TODO: Add rule syntax for this behavior, get specifics out of here and
// into the rule file.
if (fRB.fLBCMNoChain)
{
int c = this.fRB.fSetBuilder.GetFirstChar(endNode.fVal);
if (c != -1)
{
// c == -1 occurs with sets containing only the {eof} marker string.
int cLBProp = UChar.GetIntPropertyValue(c, UProperty.Line_Break);
if (cLBProp == LineBreak.CombiningMark)
{
continue;
}
}
}
// Now iterate over the nodes that can start a match, looking for ones
// with the same char class as our ending node.
foreach (RBBINode startNode in matchStartNodes)
{
if (startNode.fType != RBBINode.leafChar)
{
continue;
}
if (endNode.fVal == startNode.fVal)
{
// The end val (character class) of one possible match is the
// same as the start of another.
// Add all nodes from the followPos of the start node to the
// followPos set of the end node, which will have the effect of
// letting matches transition from a match state at endNode
// to the second char of a match starting with startNode.
endNode.fFollowPos.UnionWith(startNode.fFollowPos);
}
}
}
}
