In the previous article I have shown how to convert JSON to XML using XSLT 2.0 capabilities.
The problem w/ implementing parsers in XSLT, is conversion from flat structure to tree structure. XSLT was simply NOT created for such kind of conversions. For example, JSON to XML transformation is using XML Pipeline of mode1, mode2, mode3 to build a tree structure from a sequence of tokens generated by regexp in mode0.