'use subset of XHTML. It must be valid XML, so parsing is just one call to the XML library which is available on every language.' HTML5 defined a concrete, fin

'use subset of XHTML. It must be valid XML, so parsing is just one call to the XML library which is available on every language.' HTML5 defined a concrete, final mechanism for parsing tag soup and presenting it as a standardized tree. While the library itself isn't simple, using it is, and being standardized, most non-fringe languages ought to have a library for it by now. It should probably use that, for all the same reasons trying to use XHTML didn't work the first time. XHTML raises the bar on writing correct HTML too far.