public void Init()
{
_testTree = new ParseNode(ParseEnum.Start);
_testTree.AddChild(new ParseNode(ParseEnum.Expression));
_testTree.GetChildren()[0].AddChild(new ParseNode(ParseEnum.Term));
_testTree.GetChildren()[0].AddChild(new ParseNode(ParseEnum.ExpressionAccent));
ParseNode node = _testTree.GetChildren()[0].GetChildren()[0];
node.AddChild(new ParseNode(ParseEnum.Factor));
node.AddChild(new ParseNode(ParseEnum.TermAccent));
node.GetChildren()[0].AddChild(new ParseNode(ParseEnum.Number, "3"));
node.GetChildren()[1].AddChild(new ParseNode(ParseEnum.Empty));
node = _testTree.GetChildren()[0].GetChildren()[1];
node.AddChild(new ParseNode(ParseEnum.Operator, "+"));
node.AddChild(new ParseNode(ParseEnum.Term));
node.AddChild(new ParseNode(ParseEnum.ExpressionAccent));
ParseNode termNode = node.GetChildren()[1];
termNode.AddChild(new ParseNode(ParseEnum.Factor));
termNode.AddChild(new ParseNode(ParseEnum.TermAccent));
termNode.GetChildren()[0].AddChild(new ParseNode(ParseEnum.Number, "4"));
termNode.GetChildren()[1].AddChild(new ParseNode(ParseEnum.Empty));
node.GetChildren()[2].AddChild(new ParseNode(ParseEnum.Empty));
}
/// <summary>
/// Generates a abstract syntrax tree from the given ParseTree
/// </summary>
/// <param name="node">Start node</param>
/// <returns>Abstract syntax tree </returns>
public ASTNode GenerateAST(ParseNode node)
{
ASTNode root;
// Skip start node
if (node.GetEnum() == ParseEnum.Start)
{
node = node.GetChildren()[0];
}
List<ParseNode> bfQueue = GetBreadthFirstQueue(node).FindAll(x => x.GetEnum() == ParseEnum.Operator || x.GetEnum() == ParseEnum.Number
|| x.GetEnum() == ParseEnum.Variable || x.GetEnum() == ParseEnum.Equals);
// If there is only one interesting node no further processing needs to be done.
if (bfQueue.Count == 1)
{
root = ConvertPNtoASTNode(bfQueue[0]);
}
else
{
// Handle special condition
if (bfQueue.Count == 3 &&
(bfQueue.Find(x => x.GetEnum() == ParseEnum.Operator || x.GetEnum() == ParseEnum.Equals) != null))
{
ParseNode op =
bfQueue.Find(x => x.GetEnum() == ParseEnum.Operator || x.GetEnum() == ParseEnum.Equals);
bfQueue.Remove(op);
if (op.GetEnum() == ParseEnum.Equals)
{
root = new EqualSign(op.GetValue());
}
else
{
root = new Operator(op.GetValue());
}
root.LeftChild = ConvertPNtoASTNode(bfQueue[0]);
root.RightChild = ConvertPNtoASTNode(bfQueue[1]);
}
else
{
// Normal routine
// Handles the left and right tree recursivly
ParseNode subTree = node.GetChildren().Find(x => ContainsNode(x, bfQueue[0]));
root = ConvertPNtoASTNode(bfQueue[0]);
if (node.GetChildren()[0].Equals(subTree))
{
subTree.GetChildren().Remove(bfQueue[0]);
root.LeftChild = GenerateAST(subTree);
root.RightChild = GenerateAST(node.GetChildren()[1]);
}
else
{
subTree.GetChildren().Remove(bfQueue[0]);
root.RightChild = GenerateAST(subTree);
root.LeftChild = GenerateAST(node.GetChildren()[0]);
}
}
}
return root;
}
private bool ContainsNode(ParseNode startNode, ParseNode nodeToFind)
{
if (startNode.Equals(nodeToFind))
{
return true;
}
return startNode.GetChildren().Exists(x => ContainsNode(x, nodeToFind));
}