Result tree doctypes

The result tree's structure is that of an XML document, and its objects correspond to elements with attributes

The result tree's structure and "tag set" can match that of any XML document or doctype. In particular, the result tree could be:

HTML/XHTML

result tree is easily written out as an HTML document

other XML doctype

result tree is easily written out as an XML document in this other doctype (for some further application-specific processing)

FO result tree

result tree's structure (and element and attribute names) matches the set of formatting objects and formatting properties defined by the (non-transformation) part of XSL

Serialization of the result tree is not necessary for further processing of the result tree.