* lisp/textmodes/mhtml-mode.el: Fix bug#38372

The `sgml-syntax-propertize-rules` rely on the `sgml--syntax-propertize-ppss`
setup by `sgml-syntax-propertize` so it is not correct/safe to use
them directly like html used to do.

Change `sgml-syntax-propertize` so it can be used by mhtml,
and then adjust mhtml-mode accordingly.

* lisp/textmodes/mhtml-mode.el: Remove redundant `eval-and-compile`.
Only require cl-lib at compile-time.
(mhtml--syntax-propertize): New const, extracted from mhtml-syntax-propertize.
(mhtml-syntax-propertize): Use `sgml-syntax-propertize`.

* lisp/textmodes/sgml-mode.el (sgml--syntax-propertize): New const,
extracted from sgml-syntax-propertize.
(sgml-syntax-propertize): Add optional `rules-function` arg.

1 files changed, 8 insertions, 5 deletions

diff --git a/lisp/textmodes/sgml-mode.el b/lisp/textmodes/sgml-mode.el
index f75ce905472..8d39958d749 100644
--- a/lisp/textmodes/sgml-mode.el
+++ b/lisp/textmodes/sgml-mode.el
@@ -395,16 +395,19 @@ Any terminating `>' or `/' is not matched.")
                         (car (sgml--syntax-propertize-ppss
                               (match-beginning 0)))))
                (string-to-syntax ".")))))
-     )))
+     )
+    "Syntax-propertize rules for sgml text.
+These have to be run via `sgml-syntax-propertize'"))
 
-(defun sgml-syntax-propertize (start end)
+(defconst sgml--syntax-propertize
+  (syntax-propertize-rules sgml-syntax-propertize-rules))
+
+(defun sgml-syntax-propertize (start end &optional rules-function)
   "Syntactic keywords for `sgml-mode'."
   (setq sgml--syntax-propertize-ppss (cons start (syntax-ppss start)))
   (cl-assert (>= (cadr sgml--syntax-propertize-ppss) 0))
   (sgml-syntax-propertize-inside end)
-  (funcall
-   (syntax-propertize-rules sgml-syntax-propertize-rules)
-   start end)
+  (funcall (or rules-function sgml--syntax-propertize) (point) end)
   ;; Catch any '>' after the last quote.
   (sgml--syntax-propertize-ppss end))