+# this comment block implements the W3C spec
+# if t.type is TYPE_START_TAG and (t.name is 'rb' or t.name is 'rp' or t.name is 'rtc')
+# if is_in_scope 'ruby', NS_HTML
+# generate_implied_end_tags()
+# unless open_els[0].name is 'ruby' and open_els[0].namespace is NS_HTML
+# parse_error()
+# insert_html_element t
+# return
+# if t.type is TYPE_START_TAG and t.name is 'rt'
+# if is_in_scope 'ruby', NS_HTML
+# generate_implied_end_tags 'rtc' # arg is exception
+# unless (open_els[0].name is 'ruby' or open_els[0].name is 'rtc') and open_els[0].namespace is NS_HTML
+# parse_error()
+# insert_html_element t
+# return
+# below implements the WATWG spec https://html.spec.whatwg.org/multipage/syntax.html#parsing-main-inbody
+ if t.type is TYPE_START_TAG and (t.name is 'rb' or t.name is 'rtc')