#| comments |# auto-fill failure on Emacs 24.4.1

[mwand]

In emacs 24.4.1, with auto-fill turned on, the #| string is repeated at every filled line. Example:

#|
here issfjljsld fsfa dfsd fs fas fa fa fa fasd fa df asf as fa dfa fa
#|f ads fa sdf  fa f f fa  fsd f f gjldjg;g dfjgflgdfjg;df lgdklgjl;
#|gdfklgj ;g;glg ggjsdgljggj; ffg d 

[mwand]

racket-mode version is 20161029.1105

[greghendershott]

Interesting. It hadn't occurred to me auto-fill-mode ought to work; I manually M-q a.k.a. M-x fill-paragraph.

I can reproduce.

I see that auto-fill-mode works fine with

• scheme-mode and #| comments |#
• c-mode and /* comments */

[greghendershott]

Well, scheme-mode "works fine" in the sense that it doesn't start new lines with #|. But it prepends an extra newline, i.e. a blank line.

c-mode works the way I imagine you'd want racket-mode to work.

[greghendershott]

Also, for me on GNU Emacs 24.5.1 (x86_64-apple-darwin13.4.0, NS apple-appkit-1265.21) of 2015-04-10 on builder10-9.porkrind.org:

racket-mode with M-x auto-fill-mode is generating something different from what you report:

#| afd asdf as fa sdf asdf a dsf adsf a df asdf adf af asdf a dfa dsf  |#
#| asd fa sdf asd f asd fa sdf asd fa sd fa dsf asd f asd fa sd fas  |#
#| dfas df as df asdf as df as dfa sdf a dsf asd fa sd fas df as df  |#
#| asd f a |#

This is at least valid -- there are no mismatched comment starts and ends, as in what you saw.

However stylistically it's not as nice -- IMHO, and maybe yours? -- as e.g. what c-mode and auto-fill-mode does:

/* adf afd asdf af asf adsf asdf adf a dfa asdf asdf a sdfas df asdf
   as dfa sdf asdf ads fa sdf asd fasdf asdf ad fasdf adf as dfa sdf
   a sf dsf adf */

[greghendershott]

I'm still researching this -- there's quite a tangle of fill and comment Elisp I'm trying to understand, and step through using edebug.

However as at least a temporary work-around, what if you set comment-multiline to t?

comment-multi-line is a variable defined in `newcomment.el'.
Its value is t
Original value was nil

Documentation:
Non-nil means `comment-indent-new-line' continues comments.
That is, it inserts no new terminator or starter.
This affects `auto-fill-mode', which is the main reason to
customize this variable.

It also affects C-M-j.  However, if you want this
behavior for explicit filling, you might as well use M-x newline-and-indent.

You can customize this variable.

That seems to cause the desired behavior, for me. But I'm not sure it's the correct answer, or if it might have unintended consequences.

[mwand]

Nope, doesn't work for me. Again, with emacs 24.5.1 , in racket-mode with auto-fill turned on. Look at the last example

comment-multi-line = nil

;; sd fsdf sfsdfasf asdf sfa sf adsads fsd fasdf asdf sdf sdf asdf sf ;; ads fasd fasf ads f

comment-multi-line = t

;; a sfs fsfads fadsfa dsfdsaf sfa fdsf dsf sdfa sfs fads fsfa dsfa ;; sdf asf asdf sfa s fa sf df

| a sfs fsf asdfasd fsdf asfaf adsf dsf asf as fasd fasdf as fas dfsd

| fs dfa df ds f s fs dfa f fsdf

;; as dfs fasf sfa sdf sdf asdfa sf asf asdf s fasf asd fsdf asd fasdf

| asd fs fa sd fdsf

--Mitch

On Mon, Oct 31, 2016 at 8:27 PM, Greg Hendershott notifications@github.com wrote:

I'm still researching this -- there's quite a tangle of fill and comment Elisp I'm trying to understand, and step through using edebug.

However as at least a temporary work-around, what if you set comment-multiline to t?

comment-multi-line is a variable defined in `newcomment.el'. Its value is t Original value was nil

Documentation: Non-nil means comment-indent-new-line' continues comments. That is, it inserts no new terminator or starter. This affectsauto-fill-mode', which is the main reason to customize this variable.

It also affects C-M-j. However, if you want this behavior for explicit filling, you might as well use M-x newline-and-indent.

You can customize this variable.

That seems to cause the desired behavior, for me. But I'm not sure it's the correct answer, or if it might have unintended consequences.

— You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub https://github.com/greghendershott/racket-mode/issues/237#issuecomment-257460309, or mute the thread https://github.com/notifications/unsubscribe-auth/ACOxMIcBjiHavPpROPwHlwyPDs9bob1Fks5q5odwgaJpZM4KlZ2P .

[greghendershott]

Can you please try a quick experiment:

In a .rkt buffer, M-: (Alt+Shift+:) and at the Eval: prompt enter (setq-local comment-start-skip ";+ *").

Then do you still get the extra #|s?

[mwand]

I think this gives the right behavior for #| comments, but ;; comments get screwed up

#| jds;fljs sflksjf adslkfsj fasjfadsf adsjfadsjf;lsdjfa
dsjflsjf;lajdsf adsf;adsj;asjf ads;fjslfasjd;sjf;fjff;fldsjf
lasf;jfalf
sdffaf
|#

;; ajsdfjslkfjls fja;sdljf sdjflksjf akjsfa dsflkdsjf dsjfadsjf s jfa
;;sajf afa dskfsf akdsjfsldfj lasfdssfj

#|
aksjf;ads sd fds sf sd fas fs fsd fas fasf sd fsd fs dfs fsd fsd fa
fas f sff fa fds f f f ff
|#

Normal behavior would be to put a space after the ;; on succeeding lines of the comment, eg

;; ajsdfjslkfjls fja;sdljf sdjflksjf akjsfa dsflkdsjf dsjfadsjf s jfa
;; sajf afa dskfsf akdsjfsldfj lasfdssfj

[greghendershott]

;; ajsdfjslkfjls fja;sdljf sdjflksjf akjsfa dsflkdsjf dsjfadsjf s jfa
;;sajf afa dskfsf akdsjfsldfj lasfdssfj

I don't see that happen. I get the desired space.

Could you please M-x racket-bug-report and paste the contents here? That will a number of settings including active minor modes. Maybe one is responsible for this, and I can figure it out.

[greghendershott]

By the way, cc-mode seems to have ~1100 lines of code related to breaking and filling. Although I'm not sure how much of that racket-mode would need to borrow -- to be able to handle #| |# style comments as thoroughly as that mode handles /* */ style comments -- I think it's unlikely I'll take many steps down that road. :)

Although I admit it's "anecdata", I very rarely see #| |# style comments in Racket code.

Having said all that, f there are a few tactical fixes that make them work well-enough, I'll definitely try to improve it.

[mwand]

I don't see that happen. I get the desired space.

Works for me now, too. I may have omitted the space before the asterisk in (setq-local comment-start-skip ";+ *"). Sorry about that.

[mwand]

By the way, cc-mode seems to have ~1100 lines of code related to breaking and filling. Although I'm not sure how much of that racket-mode would need to borrow -- to be able to handle #| |# style comments as thoroughly as that mode handles /* */ style comments -- I think it's unlikely I'll take many steps down that road. :)

Although I admit it's "anecdata", I very rarely see #| |# style comments in Racket code.

I hear you. The simple workaround is to write the block-comment not as a comment, and then put the #| ... |# around it afterwards. That has the useful side-effect of allowing me to use the indenter while I'm writing my comment.

Thanks for the prompt responses.

I'm going to leave this open for now, but I won't be offended if you close it.

--Mitch

[greghendershott]

Well I should at least push a commit to make that be the default for comment-start-skip.

For me, with that it unfortunately still does the same weird thing as scheme-mode -- inserting extra blank lines when it wraps. To avoid that, I need to set comment-multi-line to t. However that var isn't not buffer-local, so I don't think racket-mode should do this automatically. (Also I discovered that only through reading, but not truly understanding, a lot of Emacs' fill and comment code.) So I might need to just document that as a tip -- then close this issue :smile: -- until/unless I learn more someday.

[greghendershott]

Actually I can set comment-multi-line to t locally for racket-mode buffers. About to push a commit.