commit 4fcb92ee43ab536003156c406ec907396cc65253
from: Omar Polo <op@omarpolo.com>
date: Sun Nov 07 18:26:12 2021 UTC

correctly highlight comments

Algol68 support three styles of comments:

    1) COMMENT ... COMMENT
    2) CO ... CO
    3) # ... #

These can't be nested, although you can have things like

	COMMENT CO ... CO COMMENT

as a whole comment because from `COMMENT' up to the next closer
`COMMENT' is a single comment (duh.)

commit - 6c5ab75422e36989043a11d63a59a4821e483d65
commit + 4fcb92ee43ab536003156c406ec907396cc65253
blob - 9ddd2e3f8a5952a2e0d88db7656611b8990ff404
blob + 496f4a59b5b124b2fc43fa6432dae6c7f274f170
--- a68-mode.el
+++ a68-mode.el
@@ -219,7 +219,23 @@
   (setq-local font-lock-defaults '(a68-font-lock-keywords))
   (setq-local indent-line-function #'a68-indent-line)
   (setq-local comment-start "#")
-  (setq-local comment-end "#"))
+  (setq-local comment-end "#")
+  (setq-local syntax-propertize-function
+              (syntax-propertize-rules ((rx (group bow "COMMENT" eow)
+                                            (group (*? anychar))
+                                            (group bow "COMMENT" eow))
+                                        (1 "<")
+                                        (3 ">"))
+                                       ((rx (group bow "CO" eow)
+                                            (group (*? anychar))
+                                            (group bow "CO" eow))
+                                        (1 "<")
+                                        (3 ">"))
+                                       ((rx (group "#")
+                                            (group (*? anychar))
+                                            (group "#"))
+                                        (1 "<")
+                                        (3 ">")))))
 
 ;;;###autoload
 (add-to-list 'auto-mode-alist '("\\.a68\\'" . a68-mode))