Ambiguous ampersands (detailed review of Writing HTML documents)

(This is part of my detailed review of the Writing HTML documents section.)

At the tokenization level, a stray ampersand is allowed if the character  
following it is one of U+0009, U+000A, U+000B, U+000C, U+0020, U+003C,  
U+0026, or EOF.

    http://www.whatwg.org/specs/web-apps/current-work/#consume

The syntax section says:

    An ambiguous ampersand is a U+0026 AMPERSAND (&) character that is not
    the last character in the file, that is not followed by a space
    character, that is not followed by a start tag that has not been
    omitted, and that is not followed by another U+0026 AMPERSAND (&)
    character.

    http://www.whatwg.org/specs/web-apps/current-work/#ambiguous

This doesn't catch all cases. "<" characters can also be the start of an  
end tag, a comment, an escaping text span start (in the RCDATA case), or  
the actual character (in the RCDATA or attribute value cases). "&"  
characters can also be the start of a character entity reference.

-- 
Simon Pieters
Opera Software