In particular, input character lookahead now knows how to stop at the
insertion point marker if needed.
This makes it possible to do amazing things like having document.write()
insert doctypes one character at a time.
If we reach the insertion point at the same time as we switch to another
tokenizer state, we have to bail immediately without proceeding with the
next code point. Otherwise we'd fetch the next token, get an EOF marker,
and then proceed as if we're at the end of the input stream, even though
more data may be coming (with more calls to document.write()..)
This fixes 4 issues:
- RECONSUME_IN_RETURN_STATE was functionally equivalent to
SWITCH_TO_RETURN_STATE, which caused us to lose characters.
For example, &test= would lose the =
- & characters by themselves would be lost. For example, 1 & 2
would become 1 2. This is because we forgot to flush
characters in the the ANYTHING_ELSE path in CharacterReference
- Named character references didn't work at all in attributes.
This is because there was a path that was checking the entity
code points instead of the entity itself. Plus, the path that
was checking the entity itself wasn't quite spec compliant.
- If we fail to match a named character reference, the first
character is lost. For example &test would become &est.
However, this relies on a little hack since I can't wrap my
head around on how to change the code to do as the spec says.
The hack is to reconsume in AmbigiousAmpersand instead of
just switching to it.
Fixes#3957
