It is necessary to use C ++ to implement an XML parser.

A complete XML parser is generally composed of several parts:

Necessary components:

1. DOM interface definition and Dom model implementation.
2. An XML lexical analyzer used to convert an XML token stream into a token stream.
3. An XML Parser organizes the token stream into a DOM model.
4. A set of data structures andAlgorithm, Nodeiterator, treewalker.
5. a dtd lexical analyzer and DTD Parser.
6. An XPath expression language compiler that compiles an XPATH expression into an ast tree.
7. An XPath engine performs operations on the DOM tree based on XPath ast.
8. An XSLT engine is used to complete the XSLT transform.
9. If you need to support XHTML, CSS parser is also required.

Auxiliary components:

1. memory management mechanism.
2. File reader supporting various encoding and network environments.
3. com encapsulation.