Backward compatibility support for `man' program.

* tmac/an-old.tmac (LL): Initialize it to respect prior LL register
assignment, prior `.ll' request and then package defaults, in this
specified order of decreasing priority.

* tmac/groff_man.man, doc/groff.texinfo: Document altered `LL'
register initialization priorities.

1 files changed, 20 insertions, 3 deletions

diff --git a/tmac/an-old.tmac b/tmac/an-old.tmac
index 6742fb77..b51f2e2f 100644
--- a/tmac/an-old.tmac
+++ b/tmac/an-old.tmac
@@ -1,6 +1,6 @@
 .\" an-old.tmac
 .\"
-.\" Copyright (C) 1989, 1990, 1991, 1992, 2001, 2002, 2003, 2004
+.\" Copyright (C) 1989, 1990, 1991, 1992, 2001, 2002, 2003, 2004, 2005
 .\"   Free Software Foundation, Inc.
 .\"      Written by James Clark (jjc@jclark.com)
 .\"
@@ -62,10 +62,27 @@
 .
 .nr need_eo_h 0
 .
+.\" set up the line length...
+.\" giving precedence to any prior assignment to the \n[LL] register.
 .if !r LL \{\
-.  ie n .nr LL 78n
-.  el   .nr LL 6.5i
+.
+.  \" but if that isn't predefined...
+.  \" then try to respect any prior `.ll' request.
+.  nr LL \n[.l]
+.
+.  \" For troff, this is sufficient to give us a default line length of
+.  \" 6.5i, but for nroff, we prefer a default of 78n to nroff's default
+.  \" 65n.  This has the unfortunate side effect that we will override a
+.  \" user's `.ll 65n' request, with our preferred 78n default; we can't
+.  \" possibly know that the 65n came from a `.ll' request, and MUST
+.  \" assume that it was set by nroff, as its built-in default!  If the
+.  \" user wants to force this setting, then he MUST use the `-rLL=65n'
+.  \" option, or an equivalent `.nr LL 65n' request.
+.  if n \
+.    if (\n[LL] = 65n) \
+.      nr LL 78n
 .\}
+.
 .if !r LT \
 .  nr LT \n[LL]
 .