Two primary tasks validating xml parser
Also, it allows one to access the parent and ancestor nodes.However, since the objects refer to volatile C-level objects, one cannot store these nodes for use in further computations within R.When an XML tag (element) is processed, we look for a function in this collection with the same name as the tag's name. All but the last should take the XMLnode as their first argument.In the future, other information may be passed via …, for example, the depth in the tree, etc.HTTP servers, XML-RPC, etc.) and still use this parser.logical indicating whether to use a validating parser or not, or in other words check the contents against the DTD specification.
We discard all other tags by returning NULL # from the start Element handler.This gives the function an opportunity to report all the errors and raise an exception rather than doing this when it sees th first one.This function can do what it likes with the information.It is invoked with the new node and its parent node.
This applies to regular nodes and also comments, processing instructions, CDATA nodes, etc.
They “disappear” after the processing the XML document is completed.