[bug #54909] Paragraph indention after heading; extra space between heading and list

[anonymous]

URL:
  <https://savannah.gnu.org/bugs/?54909>

                 Summary: Paragraph indention after heading; extra space
between heading and list
                 Project: GNU troff
            Submitted by: None
            Submitted on: Mon 29 Oct 2018 02:48:37 AM UTC
                Category: Macro - mm
                Severity: 3 - Normal
              Item Group: Incorrect behaviour
                  Status: None
                 Privacy: Public
             Assigned to: None
             Open/Closed: Open
         Discussion Lock: Any
         Planned Release: None

    _______________________________________________________

Details:


Computer: Core-i7 6700, 32 GB RAM
OS: Windows 10 Pro, version 1803, 64 bit
Environment: MKS Toolkit, version 10.0
groff version: 1.22.3, Windows binary distribution
              
(https://sourceforge.net/projects/ezwinports/files/groff-1.22.3-3-w32-bin.zip)


There seem to be a couple of bugs in the mm macro package (file m.tmac):

0 According to the documentation (and long-established behavior), when
register Pt=2, paragraphs are not supposed to be indented following a heading,
list, or display.  Although paragraphs are not indented following a heading,
they are indented following a list or display.

0  If a list or display follows a heading, there is considerable extra
vertical space between the heading and the list or display.

I just discovered these issues because for the last 20 years, I was using a
modified version of AT&T mm (which worked fine after I made sure that requests
were followed by whitespace; I may have had to make a few other changes, but
not many).

= Paragraph Indention =
For the paragraph indention, the problem seems to arise because, although the
register address@hidden is set to zero, the P macro only checks registers nl and
.k against registers hd*last-pos and hd*last-hsize to see if there has been
any intervening vertical or horizontal motion; the address@hidden is not
checked.

One possible fix is to have the LE, address@hidden, and address@hidden macros 
set the hd*...
registers when the set address@hidden to zero, e.g.,


      .  .  .
    .nr hd*last-pos \\n[nl]
    .nr hd*last-hsize \\n[.k]
    .nr address@hidden 0
      .  .  .


Perhaps the registers could be renamed to ‘hld*...’ to indicate their
broader use.  I don’t know whether they should be considered “external,”
but if so, perhaps they should be renamed to address@hidden

= Extra Vertical Space =
For the extra vertical space, the problem seems to result from the line


    \h'\\n[misc*.k]u'\c


near the end of the macro address@hidden, which is called at the end of macro 
H. 
This seems to generate something that is forced out when the br request is
given at the beginning of macro SP.

Offhand, I don’t have a fix.  To be honest, I don’t really understand what
is happening with the generation of HTML tags.  But—at least with mm—the
results I get from Thtml aren’t very good, so I’ve just commented out the
call to address@hidden  Although it solves my problem, it clearly isn’t a 
general
solution.

Jeff Conrad





    _______________________________________________________

Reply to this item at:

  <https://savannah.gnu.org/bugs/?54909>

_______________________________________________
  Message sent via Savannah
  https://savannah.gnu.org/