Re: groff now undoing .ad settings after .IP

[Russ Allbery]

Dave Kemper <saint.snit@gmail.com> writes:
> On Fri, Mar 15, 2024 at 8:34 AM G. Branden Robinson
> <g.branden.robinson@gmail.com> wrote:
>> At 2024-03-14T22:02:26-0700, Russ Allbery wrote:
>> > Now, any .TP directive restores full justification for all subsequent
>> > text.  This appears to be due to the addition of:
>> >
>> > .  ad \\*[AD]
>> >
>> > in an-write-paragraph-tag.  I'm not sure why this was added,
>>
>> Here's the commit message.
>>
>> https://git.savannah.gnu.org/cgit/groff.git/commit/?id=e7094b209f0f39fc16de687f116ea9a9c1ba0364

> It doesn't affect the larger point of this email, but the specific .ad
> call Russ cites (in an-write-paragraph-tag) appears to have been added
> in response to http://savannah.gnu.org/bugs/?62051 .

Right, the invocation in .TH was already handled because groff is not the
first an macro implementation to set the adjustment in the body of the .TH
macro, so pod2man puts the ".if n .ad l" line after the .TH invocation.
It was the change to the implementation of .TP/.IP that caused the
user-visible behavior change.

It's been enough years that I don't recall what other implementation set
adjustment in the .TH macro body, although I do remember originally
setting adjustment in the preamble and having to move it until after the
.TH invocation for it to be effective.  Given what systems I was doing
development on the time, it's possible it was Solaris of the 2.6 or 7
vintage.

-- 
Russ Allbery (eagle@eyrie.org)             <https://www.eyrie.org/~eagle/>