[groff] 30/40: [man]: Fix problem with `FT` register validation.

[G. Branden Robinson]

gbranden pushed a commit to branch master
in repository groff.

commit 380eccfed18271f0740ab0fb0bd5e7a3917cd697
Author: G. Branden Robinson <g.branden.robinson@gmail.com>
AuthorDate: Mon Dec 12 11:00:15 2022 -0600

    [man]: Fix problem with `FT` register validation.
    
    * tmac/an.tmac (initialization): Fix problem with `FT` register
      validation.  Small but valid values were being rejected due to
      inappropriate use of scaling operator.  Also throw user a bone by
      expressing what size '1v' is for the output device, in basic units.
---
 ChangeLog    |  8 ++++++++
 tmac/an.tmac | 12 ++++++++----
 2 files changed, 16 insertions(+), 4 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 422b81a52..13f812608 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,11 @@
+2022-12-12  G. Branden Robinson <g.branden.robinson@gmail.com>
+
+       * tmac/an.tmac (initialization): Fix problem with `FT` register
+       validation.  Small but valid values were being rejected due to
+       inappropriate use of scaling operator.  Also throw user a bone
+       by expressing what size '1v' is for the output device, in basic
+       units.
+
 2022-12-12  G. Branden Robinson <g.branden.robinson@gmail.com>
 
        [man, mdoc]: Fix Savannah #63500.  Support use of `P` (initial
diff --git a/tmac/an.tmac b/tmac/an.tmac
index 1ebe5bee4..2bc5ec9ef 100644
--- a/tmac/an.tmac
+++ b/tmac/an.tmac
@@ -1365,14 +1365,18 @@ contains unsupported escape sequence
 .  ie \n[cR] \
 .    ds an-msg footer distance when continuously rendering\"
 .  el \{\
+.    nr an*tmp 1v
+.    ds an*help " (1v=\n[an*tmp]u)\"
 .    ie (\n[FT] : (\n[FT] = 0)) \
-.      ds an-msg non-negative footer distance: \n[FT]u\"
+.      ds an-msg non-negative footer distance: \n[FT]u\*[an*help]\"
 .    el \{\
 .      ie (-(\n[FT]) > (\n[.p] / 2)) \
-.        ds an-msg implausibly large footer distance: \n[FT]u\"
+.        ds an-msg implausibly large footer distance: \n[FT]u\*[an*help]\"
 .      el \
-.        if ((v;\n[FT]) < 1v) \
-.          ds an-msg implausibly small footer distance: \n[FT]u\"
+.        if (-(\n[FT]) < 1v) \
+.          ds an-msg implausibly small footer distance: \n[FT]u\*[an*help]\"
+.    rm an*help
+.    rr an*tmp
 .    \}
 .  \}
 .  if d an-msg \{\