Background information: An important part of loading web pages is the process of turning HTML source into a DOM. We have parsers that do that in Servo already, but the ability to turn XHTML (based on XML) into a DOM is missing. We need a parser that can read XML and build a tree of DOM nodes out of it in the same manner that the current HTML parser does; using it as a model for the new parser is encouraged.

Initial step: Build Servo, create a new Parser trait inhubbub_html_parser.rs, create a new HTMLParser struct that contains ahubbub::Parser<'a> member, andimplement theParser trait forHTMLParser. Make sure it builds and pages still load correctly.

• Create a Parser trait has aparse_chunk method
• Create an HTMLParser struct that contains the hubbub-related data in parse_html (such as the TreeHandler), and have it impl the Parser trait
• MakeRustyXML adependency of the script crate. Learn more aboutCargo, the dependency manager and build system that we use.
• Create an XMLParser struct that contains the data necessary for using RustyXML and make it impl the Parser trait
• Rewrite parse_html to create the right Parser based on the HTTP Content-Type header (useapplication/xhtml+xml for the XML parser; see anexample
• Expand on the XML parser to use the events (https://github.com/Florob/RustyXML/blob/master/src/xml/lib.rs#L135) to perform the same actions as the HTML parser (see the callbacks inTreeHandler). Start with creating elements and setting attributes.
• Support executing scripts by checking the elements being added and using the same "discovery" mechanism the HTML parser does (seejs_script_listener)