The Lispref says: Emacs supports two comment styles simultaneously in any one syntax table. This is for the sake of C++. [...] The two comment-start sequences must begin with the same character; only the second character may differ. but this isn't really enforced. A consequence of this is that you can make xemacs hit an abort() in font-lock.c. An example of this occurs in some recent version of a sql mode, which tries to support '/*' and '--' as comment starters (see recipe below for the crash). The abort() is triggered in find_context(). In Fparse_partial_sexp() we are not so aggressive and just parse '/-' and '-*' as comments -- this also happens in FSF emacs, which uses Fparse_partial_sexp in font-lock. Any suggestions? Gunnar crash recipe: ------------------------------ (setq sql-mode-syntax-table (let ((table (make-syntax-table))) ;; C-style comments /**/ (see elisp manual "Syntax Flags")) (modify-syntax-entry ?/ ". 14" table) (modify-syntax-entry ?* ". 23" table) ;; double-dash starts comment (modify-syntax-entry ?- ". 56" table) ; (modify-syntax-entry ?\n "> b" table) table) ) (defun sql-mode () "Major mode to edit SQL." (interactive) (kill-all-local-variables) (setq major-mode 'sql-mode) (setq mode-name "SQL") (set-syntax-table sql-mode-syntax-table) ) ------------------------------ - evaluate the above - make a new buffer and switch to sql-mode - type '-* ' (without the quotes) - M-: (syntactically-sectionize nil 3 3) BOOM -- Gunnar Evermann Speech, Vision & Robotics Group Engineering Department Cambridge University