 quirks-mode?
 fostering-parent?
 tree
-tree-insert-mode
+tree-insertion-mode
+original-insertion-mode
+last
+node
+context
 doctype
 tag
 end-tag

: <document> ( -- document )
    document new
        V{ } clone >>tree
        initial-mode >>tree-insert-mode
        <doctype> >>doctype
        SBUF" " clone >>attribute-name
        SBUF" " clone >>attribute-value

: push-doctype-system-identifier ( ch document -- )
    doctype>> system-identifier>> push ;

GENERIC: tree-insert* ( document obj tree-insertion-mode -- document )
M: initial-mode tree-insert*
    drop {
        { CHAR: \t [ ] }
