예제 #1
0
        public void Accept(IAstNodeReplacement visitor)
        {
            visitor.VisitEnter(this);

            foreach (AstNode node in Children)
            {
                node.Accept(visitor);
            }

            visitor.VisitLeave(this);
        }
        public override void VisitLeave(CapturingGroup expression)
        {
            String           name = expression.Name;
            Boolean          reduceBySingleChildNode = expression.DoReplaceBySingleChildNode;
            IsMatchPredicate local = _matchStack.Pop();

            _matchStack.Push(
                delegate(IInputIterator iterator)
            {
                if (expression.DoCreateCustomAstNode && _astNodeFactory == null)
                {
                    throw new ArgumentNullException("Second constructor overload is required during instantiation.  astNodeFactory requires to be set with this parser implementation.");
                }


                Int32 savePosition = iterator.Index;
                _sandbox.Peek().Push(new AstNode());

                if (local(iterator))
                {
                    // predicates being processed should not append ast
                    if (_disableCapturingGroup.Count > 0)
                    {
                        _sandbox.Peek().Pop();
                        iterator.Index = savePosition;
                        return(true);
                    }

                    if (savePosition >= iterator.Index)
                    {
                        // Warn terminal does not consume and ast should not be created for it, yet it should return that it was successful match.
                        _sandbox.Peek().Pop();
                        iterator.Index = savePosition;
                        return(true);
                    }


                    Byte[] matchedBytes = iterator.Text(savePosition, iterator.Index - 1);
                    if (_xmlBackReferenceLookup.ContainsKey(name))
                    {
                        _xmlBackReferenceLookup[name].Push(matchedBytes);
                    }
                    else
                    {
                        _xmlBackReferenceLookup.Add(name, new Stack <Byte[]>());
                        _xmlBackReferenceLookup[name].Push(matchedBytes);
                    }


                    AstNode node = _sandbox.Peek().Pop();
                    node.Token   = new TokenMatch(name, savePosition, iterator.Index - 1);


                    if (expression.DoCreateCustomAstNode)
                    {
                        // create a custom astnode
                        IAstNodeReplacement nodevisitor = _astNodeFactory.Create(node);
                        nodevisitor.Token    = node.Token;
                        nodevisitor.Parent   = node.Parent;
                        nodevisitor.Children = node.Children;
                        foreach (AstNode updateparent in nodevisitor.Children)
                        {
                            updateparent.Parent = nodevisitor;
                        }

                        // since the whole tree has not finished completing this.Parent will be null on this run.
                        // logic inside astnodereplacement is to create properties, business names, that internally check Children collection to mine data.
                        // you still will need a top level visitor to process tree after it completely available.
                        node.Accept(nodevisitor);
                        node = nodevisitor;
                    }


                    if (reduceBySingleChildNode)
                    {
                        if (node.Children.Count == 1)
                        {
                            node = node.Children[0];
                        }
                    }


                    if (_sandbox.Peek().Count > 0)
                    {
                        node.Parent = _sandbox.Peek().Peek();
                        _sandbox.Peek().Peek().Children.Add(node);
                    }
                    else
                    {
                        _sandbox.Peek().Push(node);
                        // don't loose the root node
                        // each successful sandbox will have 1 item left in the stack
                    }

                    return(true);
                }
                _sandbox.Peek().Pop();
                iterator.Index = savePosition;
                return(false);
            });
        }