bug#25685: fill-paragraph vs. \n vs. Chinese / English boundaries

[Katsumi Yamaoka]

On Sat, 11 Feb 2017 08:22:19 +0800, 積丹尼 Dan Jacobson wrote:
> We proceeded to dig up 些 some Canna edulis Ker 食用美人蕉
> when surprise surprise...

> and do  M-h  then  M-q
> It becomes

> We proceeded to dig up 些 some Canna edulis Ker 食用美人蕉when
> surprise surprise...

> I.e., the "食用美人蕉when" are now stuck together, making our text
> look very unprofessional.

Fixing such things one by one manually is my routine, too.  But
I first tried:

* lisp/textmodes/fill.el (fill-delete-newlines):
Don't delete leading and trailing space from CJK word.

I'm not sure if it is the right solution for every case, though.

--- fill.el~    2017-01-04 22:17:04.000000000 +0000
+++ fill.el     2017-02-12 23:57:42.946118200 +0000
@@ -494,8 +494,8 @@
            (replace-match (get-text-property (match-beginning 0) 'fill-space))
          (let ((prev (char-before (match-beginning 0)))
                (next (following-char)))
-           (if (and (or (aref (char-category-set next) ?|)
-                        (aref (char-category-set prev) ?|))
+           (if (and (aref (char-category-set next) ?|)
+                    (aref (char-category-set prev) ?|)
                     (or (aref fill-nospace-between-words-table next)
                         (aref fill-nospace-between-words-table prev)))
                (delete-char -1))))))