There is such a rule: the definition of lua-syntax-propertize begins by
calling lua-syntax-propertize-string-or-comment-end which:
and then in lua-syntax-propertize-string-or-comment I'd use syntax-ppss
to check the parser state (i.e. determine if I'm in a type-b comment or
delimited-string corresponding to a long-bracket construct as opposed to
some type-a comment or standard string, or plain old code), and if I'm
in one of those long-bracket-constructs, use (nth 8 ppss) to find the
beginning, count the number of = used there, then search for the
matching ]==] pattern and place the matching "> b" or "|" syntax on the
second closing bracket.
so while the second call is for "end1+1 ... end2", your code will go
back to the beginning of the long bracket to figure out its end and then
look for that end again (which might show up before end2 this time, tho
maybe not).
Oh, my bad. Thanks a lot for your help!