At 2024-03-15T10:57:03-0700, Russ Allbery wrote: > Dave Kemper <saint.s...@gmail.com> writes: > > 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.
Ahh, hmm. Yes, Dave's got a point. I may have been so bowled over at
my command of *roff history not being what I thought it was that I
mis-scoped the problem you reported and, potentially, its solution.
The fix for Savannah #62051 was a two-liner:
diff --git a/tmac/an.tmac b/tmac/an.tmac
index 59a7156b1..a568d69cd 100644
--- a/tmac/an.tmac
+++ b/tmac/an.tmac
@@ -554,6 +554,7 @@ .de1 an-footer
.de an-write-paragraph-tag
. br
. di
+. ad \\*[AD]
. nr an-is-in-diversion 0
. ll
. \" We must emit the diversion in a separate environment to ensure
@@ -707,6 +708,7 @@ .de1 TP
. if !\\n[an-is-in-diversion] \{\
. ll -\\n[an-margin]u
. di an-div
+. na
. \}
. nr an-is-in-diversion 1
..
Can you name me a misbehaving perlpod(1)-generated page? I'll check it
out. Perhaps what I really needed here was:
--- a/tmac/an.tmac
+++ b/tmac/an.tmac
@@ -554,6 +554,7 @@ .de1 an-footer
.de an-write-paragraph-tag
. br
. di
+. ad \\n[an*saved-adjustment-mode]
+. rr an*saved-adjustment-mode
. nr an-is-in-diversion 0
. ll
. \" We must emit the diversion in a separate environment to ensure
@@ -707,6 +708,7 @@ .de1 TP
. if !\\n[an-is-in-diversion] \{\
. ll -\\n[an-margin]u
. di an-div
+. nr an*saved-adjustment-mode \\n[.j]
+. na
. \}
. nr an-is-in-diversion 1
..
I want to do some testing because we have another scenario coming up in
groff 1.24.
.\" The TP macro _requires_ a one-line input trap.
.de1 an*TP-trap
. br
. di
. ad \\*[AD]
. ll
. if \\n[an*have-paragraph-tag] .an-write-paragraph-tag
..
I see additional regression tests in my future. We're closing in on 200
automated test scripts.
> 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.
A long time for sure. In Solaris _10_ troff's tmac.an, which has a
GitHub repo,[1] `TH` has a relict ".if n .na"--that is, it's commented
out. But for how long it had been commented out, I have no idea. And
sure enough, SSHing to a Solaris 10 box and "man ls" tells me that
adjustment to both margins is on.
[Continues poking around, in non-publicly available sources...]
Ah. Same commented out request in the same tmac.an macro in...
Drum roll, please...
SunOS 4 (1988).
Same thing in SunOS 3.5, SunOS 3.2, and SunOS 2.0 (1982!).
So as with many decisions James Clark made with groff, he was aiming at
straight-down-the-line Sun compatibility. Mystery solved.
Regards,
Branden
[1] https://github.com/n-t-roff/Solaris10-ditroff
signature.asc
Description: PGP signature
