Changes

The extension uses a hardwritten simple XML parser implemented in pure LusLua. The parser is expat-style and the implementation is based on string.find() and string.sub(). The advantage of this approach is that it can handle bad XML input by throwing an appropriate (and understandable) error. Neither the Lpeg-based Lua parser from the 13th ConTeXt meeting nor the ConTeXt built-in parser allows allow for that, both . Both those parsers assume well-formed XML as input.

A tailored parser also allowed for easy extension for to deal with the CDATA issue mentioned below.

*While When a fresh set of ‘virgin’ XML files is created from <code>context-en.xml</code>, each separate file is parsed using a set of expat callback functions that create a lua table representing the ‘virginal’ parse tree of the XML file. This Lua table is dumped to disk and distributed along with the XML file.

*When a wiki user presses the ‘Save’ button in the page editor, their edited XML is parsed using a slightly different set of expat callback functions from the ones for viewing. These altered callbacks functions in this set skip all documentation content while building the parse tree. The two lua tables representing the parse trees are then compared. They should be identical. If not, an error is raised and the save action is aborted with a user-visible error message.