New Vocabularies Solution

tokeniser:

move the insertion mode flag to before the tokeniser ✓‬
tokeniser changes so that when insertion mode is "in namespace", support CDATA blocks. ✓‬
- add a paragraph to the "Markup declaration open state" saying that if the next seven characters match "[CDATA[", and the insertion mode is "in namespace", and the current node is not html nor either <mi>, <mo>, <mn>, <ms>, <mtext> in mathml, nor <foreignObject>, <desc>, <title> in svg, then you switch to a state that emits character tokens until it hits "]]>". ✓‬
tokeniser keeps track of /> endings.
- add a new tokeniser state which you go to when hitting a / instead of going to the "before attribute name state". This new state has just two exits -- one for ">", which sets a flag saying that the tag is self-closing, and one for anything else, which has a parse error and reconsumes in the "before attribute name state". ✓‬
- make it a parse error for end tags to have this slash ✓
- change the definition of "permitted slash" paragraph to instead say "if a start tag is emitted with the self-closing flag set, and the token is processed by the tree construction stage without that flag being acknowledged, then there is a parse error". ✓
- change the handling of the void elements "in body" and "in head" (anywhere else?) to acknowledge the self-closing flag. ✓‬
we add all the MathML entities to the entity list.

resetting appropriately:

"in body":

"math" element:
1. insert math element in mathml namespace✓‬
2. switch to "in namespace", with secondary mode set to whatever insertion mode used to be✓‬
3. if the tag had a closing slash, imply a closing tag with the same tag name✓‬
"svg" element
1. insert svg element in svg namespace✓‬
2. switch to "in namespace", with secondary mode set to whatever insertion mode used to be✓‬
3. if the tag had a closing slash, imply a closing tag with the same tag name✓‬

"in namespace":

start tag if current node is <mi>, <mo>, <mn>, <ms>, <mtext> in mathml
start tag if current node is <foreignObject>, <desc>, <title> in svg
start tag if current node is in the html namespace
start tag with tag name "svg" if current node is <annotation-xml> in mathml
end tag
1. treat as in the secondary mode
2. if the insertion mode is still "in namespace", but there is no namespaced element in scope, switch to the secondary mode

start tag for one of: (html elements)
1. parse error
2. pop nodes until the current node is in the html namespace
3. switch to the secondary mode
4. reprocess token

other start tag
1. if namespace is svg, apply case fixups
2. insert element for token, in same namespace as current node
3. if the tag had a closing slash, imply a closing tag with the same tag name and acknowledge the self-closing flag

syntax:

add a kind of element for those elements not in the HTML namespace ✓‬
add a definition for how tags work for those elements to the Tags paragraph, including mentioning that start tags can be marked as self-closing, in which case there must not be a matching end tag ✓‬
define what these elements can contain in the subsequent paragraphs, including cdata; nothing if the start tag is marked self-closing ✓‬
add the definition of the /> syntax to the start tag bit, "self-closing" start tag ✓‬
define cdata blocks ✓‬

content models:

MathML error handling in text/html

Require the following behaviour, since MathML requires the host language to define error handling:

An element with the wrong number or type of children must render as an error indicator. (list cases)
a sequence of one or more text nodes containing non-inter-element-whitespace must be treated as <mtext>

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