Help with GNU Emacs syntax.el and XEmacs buffer-syntactic-context et al?

[Stephen J. Turnbull]

Stephen J. Turnbull writes:

 > But the syntax stuff and anything related to parse-partial-sexp is
 > hairy.  That code is not based on a real parser; it requires ugly
 > heuristics like "defuns start with an open-paren-syntax character
 > in column 0".

N.B. Alan Mackenzie over on emacs-devel is right now experiencing
Excedrin headache #31459 over performance problems in CC Mode related
to exactly that heuristic.