Inconsistent HTML anchor names

Inconsistent HTML anchor names

[Eldred Habert]

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Hello,

We at RGBDS[https://rgbds.gbdev.io] use Mandoc for our manual pages, as well as the online documentation. I happened to notice that the "At-files" anchor under "REVERSE MODE"[https://rgbds.gbdev.io/docs/master/rgbgfx.1#REVERSE_MODE] does not work, as it points to #At_files instead of #At-files.

While we do some post-processing[https://github.com/gbdev/rgbds-www/blob/master/maintainer/man_to_html.sh], none of it should affect this, as far as I'm aware, therefore I think it is a Mandoc bug. Sorry if I'm wrong on that.

Thank you for your continued efforts!
~ Eldred

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Re: Inconsistent HTML anchor names

[Ingo Schwarze]

Salut Eldred,

Eldred Habert wrote on Mon, Aug 08, 2022 at 02:24:35PM +0000:

> We at RGBDS[https://rgbds.gbdev.io] use Mandoc for our manual pages,
> as well as the online documentation.

Nice.  :-)

Thanks for telling me.  I took this as a reason to finally create
the sub-page

  https://mandoc.bsd.lv/css.html

and list RGBDS there.

I'm sure neither Debian nor Arch will run on the Game Boy, so RGBDS
now has a unique position on that page.  ;-)

It's also nice to see you using the mdoc(7) language for your manual
pages.  You might also consider using "mandoc -T lint" on your manual
pages, it produces a lot of output.  Even if you don't care about
STYLE messages, at least running "mandoc -T lint -W warning" would
make sense, for example:

   $ mandoc -T lint -W warning rgbgfx.1       
  mandoc: rgbgfx.1:168:2: WARNING: skipping empty macro: Sy
  mandoc: rgbgfx.1:573:2: WARNING: sections out of conventional
                                   order: Sh SEE ALSO
  mandoc: rgbgfx.1:575:2: WARNING: unusual Xr order: rgbasm(1) after rgbds(7)
  mandoc: rgbgfx.1:577:2: WARNING: unusual Xr order: rgbfix after rgblink

All four of these are legitimate warnings, and getting rid of them
would improve the manual page.

> I happened to notice that the "At-files" anchor under
> "REVERSE MODE"[https://rgbds.gbdev.io/docs/master/rgbgfx.1#REVERSE_MODE]
> does not work, as it points to #At_files instead of #At-files.

Heh, what a subtle bug.  The hyphen in the sentence

   .Do Sx At-files Dc may help with this .

   "At-files" may help with this.

is breakable (i.e. if the word "At-files" begins shortly before the
end of an output line, an output line break may be inserted between
"At-" and "files").

To distinguish breakable from non-breakable hyphens, the roff(7)
pre-parser (roff.c) replaces breakable hyphens with a dedicated C0
contol character, ASCII_HYPH = U+001E.  Of course, RFC 3986 does not
allow that in URI fragments, so it got wrongly turned into an
underscore.

The commit appended below (made both to OpenBSD and to the portable
mandoc at bsd.lv) fixes the bug.  Please check that it works for
you, too, and tell me in case you notice any regressions.

> While we do some post-processing
> [https://github.com/gbdev/rgbds-www/blob/master/maintainer/man_to_html.sh],

I'm not convinced i understood all of that, but here are some remarks
anyway:

 * The idea to link from flags in the SYNOPSIS to the descriptions
   of the flags is interesting.  I might consider doing that in
   mandoc.  :)  Not today, though.

 * Using ".Fl Fl foo" for GNU-style long options is discouraged because
   it is semantically wrong.  Using ".Fl \-foo" is better.
   https://mandoc.bsd.lv/mdoc/style/options.html

 * You may no longer need to shift headings; mandoc-current already
   translates .Sh to <h2> and .Ss <h3>.  That change was motivated
   by accessibility considerations very similar to your comment
   "level 1 is reserved for the page's title".

> none of it should affect this, as far as I'm aware, therefore I think
> it is a Mandoc bug. Sorry if I'm wrong on that.

You are correct.
Thank you for reporting the bug!

Yours,
  Ingo


Log Message:
-----------
prevent breakable hyphens in segment identifiers 
from being turned into underscores;
bug reported by <Eldred dot fr> Habert

Modified Files:
--------------
    mandoc:
        html.c

Revision Data
-------------
Index: html.c
===================================================================
RCS file: /home/cvs/mandoc/mandoc/html.c,v
retrieving revision 1.278
retrieving revision 1.279
diff -Lhtml.c -Lhtml.c -u -p -r1.278 -r1.279
--- html.c
+++ html.c
@@ -403,10 +403,13 @@ html_make_id(const struct roff_node *n, 
 	 * In addition, reserve '~' for ordinal suffixes.
 	 */
 
-	for (cp = buf; *cp != '\0'; cp++)
-		if (isalnum((unsigned char)*cp) == 0 &&
+	for (cp = buf; *cp != '\0'; cp++) {
+		if (*cp == ASCII_HYPH)
+			*cp = '-';
+		else if (isalnum((unsigned char)*cp) == 0 &&
 		    strchr("!$&'()*+,-./:;=?@_", *cp) == NULL)
 			*cp = '_';
+	}
 
 	if (unique == 0)
 		return buf;
--
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Re: Inconsistent HTML anchor names

[Eldred HABERT]

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On 8/9/22 2:36 PM, Ingo Schwarze wrote:
> Salut Eldred,
Well, I hope you will forgive my lack of response for a month and a 
half. I've been busy elsewhere, and this email got buried under many 
others. Apologies.
> It's also nice to see you using the mdoc(7) language for your manual
> pages.
Blame bentley for that. I think he originally wrote the man pages, and I 
think they provide good defaults that are more convenient than directly 
messing with groff formatting, so I use it for all my (admittedly few) 
man pages.
> You might also consider using "mandoc -T lint" on your manual
> pages, it produces a lot of output.  Even if you don't care about
> STYLE messages, at least running "mandoc -T lint -W warning" would
> make sense, for example:
It does make sense, and I do run this from time to time. The warnings 
haven't been fixed mainly because they seemed harmless/false positives, 
but this seems like a good occasion to discuss them, if you want.
>    mandoc: rgbgfx.1:168:2: WARNING: skipping empty macro: Sy
I'm not really sure what this is pointing out.
>    mandoc: rgbgfx.1:573:2: WARNING: sections out of conventional
>                                     order: Sh SEE ALSO
>    mandoc: rgbgfx.1:575:2: WARNING: unusual Xr order: rgbasm(1) after rgbds(7)
>    mandoc: rgbgfx.1:577:2: WARNING: unusual Xr order: rgbfix after rgblink

My understanding is that the Xr order is supposed to be by section, then 
alphabetical, right?
The rationale for our ordering is that it is the order in which we 
expect the users to read the manual pages; this made more sense back 
when we served the renders online directly; now that we have a separate 
navbar, it might be okay to reorder the footers.

> The commit appended below (made both to OpenBSD and to the portable
> mandoc at bsd.lv) fixes the bug.  Please check that it works for
> you, too, and tell me in case you notice any regressions.
I haven't found any thus far, but my testing isn't thorough. We haven't 
really set up any kind of anchor checker, sadly.
>> While we do some post-processing
>> [https://github.com/gbdev/rgbds-www/blob/master/maintainer/man_to_html.sh],
> I'm not convinced i understood all of that, but here are some remarks
> anyway:
>
>   * Using ".Fl Fl foo" for GNU-style long options is discouraged because
>     it is semantically wrong.  Using ".Fl \-foo" is better.
>     https://mandoc.bsd.lv/mdoc/style/options.html
Again, blame bentley. I didn't realise this page existed until I went 
through two fairly small links lost in the middle of others. Good 
resources, despite not being very easy to find. I'll fix this.
(I'm also noticing the '\-', and I /really/ hope we didn't mess up and 
use a breakable hyphen in places we shouldn't have...)
>   * You may no longer need to shift headings; mandoc-current already
>     translates .Sh to <h2> and .Ss <h3>.  That change was motivated
>     by accessibility considerations very similar to your comment
>     "level 1 is reserved for the page's title".
Great! That said, I'm reluctant to use a non-release version of Mandoc 
in our documentation generator, as I don't have much time to dedicate to 
maintaining it; so I think I'll patiently wait for the next release.

Late but yours nonetheless,
~ Eldred

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