static internal AstNode NewAstNode(String parsestring)
{
try {
return(XPathParser.ParseXPathExpresion(parsestring));
}
catch (XPathException e)
{
Debug.WriteLine(e.Message);
}
return(null);
}
public static AstNode ParseXPathPattern(string xpathPattern)
{
XPathScanner scanner = new XPathScanner(xpathPattern);
XPathParser parser = new XPathParser(scanner);
AstNode result = parser.ParsePattern(null);
if (scanner.Kind != XPathScanner.LexKind.Eof)
{
throw new XPathException(string.Format("'{0}' has an invalid token.", scanner.SourceText));
}
return(result);
}
public void Build(string xpath, ArrayList compiledXPath, int depth)
{
IQuery query;
//
// build the AST node first
//
AstNode root = XPathParser.ParseXPathExpresion(xpath);
Stack stack = new Stack();
query = ProcessNode(root, null);
while (query != null)
{
if (query is BaseAxisQuery)
{
stack.Push(query);
query = ((BaseAxisQuery)query).QueryInput;
}
else
{
// these queries are not supported
// for example, the primary exprission not in the predicate.
throw new XPathReaderException("XPath query is not supported!");
}
}
query = (IQuery)stack.Peek();
if (query is AbsoluteQuery) //AbsoluteQuery at root means nothing. Throw it away.
{
stack.Pop();
}
// reverse the query
// compute the query depth table
while (stack.Count > 0)
{
compiledXPath.Add(stack.Pop());
BaseAxisQuery currentQuery = (BaseAxisQuery)compiledXPath[compiledXPath.Count - 1];
FilterQuery filterQuery = null;
if (currentQuery is FilterQuery)
{
filterQuery = (FilterQuery)currentQuery;
currentQuery = ((FilterQuery)currentQuery).Axis;
}
if (currentQuery is ChildQuery || currentQuery is AttributeQuery || currentQuery is DescendantQuery)
{
++depth;
}
else if (currentQuery is AbsoluteQuery)
{
depth = 0;
}
currentQuery.Depth = depth;
if (filterQuery != null)
{
filterQuery.Depth = depth;
}
}
//
// matchIndex always point to the next query to match.
// We use the matchIndex to retriev the query depth info,
// without this added Null query, we need to check the
// condition all the time in the Expression Advance method.
//
compiledXPath.Add(new NullQuery());
}
